EP2715031B1

EP2715031B1 - Mud motor assembly

Info

Publication number: EP2715031B1
Application number: EP12789232.1A
Authority: EP
Inventors: William Banning Vail, Iii
Original assignee: Smart Drilling and Completion Inc
Current assignee: Smart Drilling and Completion Inc
Priority date: 2011-05-23
Filing date: 2012-05-23
Publication date: 2016-12-28
Anticipated expiration: 2032-05-23
Also published as: CA2837082C; EP2715031A4; CA2837082A1; WO2012162408A1; EP2715031A1

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The general field of the invention relates to the drilling and completion of wellbores in geological formations, primarily in the oil and gas industries.
Commercially available progressing cavity mud motors are used in many drilling applications. The particular field of the invention relates to a new type of long-lasting mud motor that is not based upon the typical progressing cavity design, but may be used in many similar or analogous applications.

2. Description of the Related Art

Typical rotary drilling systems may be used to drill oil and gas wells. Here, a surface rig rotates the drill pipe attached to the rotary drill bit at depth. Mud pressure down the drill pipe circulates through the bit and carries chips to the surface via annular mud flow.
Alternatively, a mud motor may be placed at the end of a drill pipe, which uses the power from the mud flowing downhole to rotate a drill bit. Mud pressure still carries chips to the surface, often via annular mud flow.
Typical mud motors as presently used by the oil and gas industry are based upon the a progressing cavity design, typically having a rubber type stator and a steel rotor. These are positive displacement devices that are hydraulically efficient at converting the power available from the mud flow into rotational energy of the drill bit. These devices convert that energy by having an intrinsically asymmetric rotor within the stator cavity - so that following pressurization with mud, a torque develops making the rotor spin. These devices also generally have tight tolerance requirements.
In practice, mud motors tend to wear out relatively rapidly, requiring replacement that involves tripping the drill string to replace the mud motor. Tripping to replace a mud motor is a very expensive process. In addition, there are problems using these mud motors at higher temperatures. It is probably fair to say, that if the existing mud motors were much more long-lasting, that these would be used much more frequently in the industry. This is so in part because the rotary steering type directional drilling controls function well with mud motors, providing relatively short radii of curvature as compared to standard rotary drilling with drill pipes. Mud motors also work well with industry-standard LWD/MWD data acquisition systems.
As an alternative to using mud motors, there are turbine drilling systems available today. These are not positive displacement type motors. They work at relatively high RPM to achieve hydraulic efficiency, often require a gear box to reduce the rotational speed of any attached rotary drill bit, are expensive to manufacture, and are relatively fragile devices having multiple turbine blades within their interiors.
So, until now, there are two widely used basic alternatives - rotary drilling and the use of mud motors. The mud motors "almost work well enough" to satisfy many industry requirements. However, looking at the progressing cavity design a little more closely also reveals that the rotor must be asymmetric in its stator to develop torque. In general, positive displacement motors suffer from this disadvantage - they are generally not cylindrically symmetric about a rotational axis. This in turn results in requiring that the output of a shaft of the mud motor couple to a "wiggle rod" to decouple the unwanted motion from the rotary drill bit. Such eccentric motion results in unwanted vibrations in adjacent equipment - such as in directional drilling systems.
US 2009/0139769 discloses a downhole motor to drill a wellbore including a pumping apparatus having a first chamber configured to receive a first fluid (e.g. a mud fluid) and a second fluid (e.g. a hydraulic fluid), and a first flexible diaphragm disposed with the first chamber to separate the first and second fluids, wherein the first flexible diaphragm is configured to transfer hydraulic energy between the first fluid and the second fluid.

SUMMARY OF THE INVENTION

An object of the invention is to provide a long-lasting mud motor assembly that may be used in applications where progressing cavity mud motors are presently used.
Another object of the invention is to provide a long-lasting mud motor assembly that continues to function even when its internal parts undergo significant wear.
Another object of the invention is to provide a long-lasting mud motor assembly that is primarily made from all-metal parts.
Another object of the invention is to provide a long-lasting mud motor assembly having internal parts that have relatively loose tolerances that are therefore relatively inexpensive to manufacture.
Another object of the invention is to provide a long-lasting mud motor assembly that is primarily made from all-metal, relatively loosely fitting parts that operates at temperatures much higher than the operational temperatures of typical progressing cavity type mud motors.
Another object of the invention is to provide a long-lasting mud motor assembly having loosely fitting internal parts that allows relatively small amounts of pressurized mud to leak through these loosely fitting internal parts.
Another object of the invention is to provide a long-lasting mud motor assembly having at least one loosely fitting internal piston within a cylindrical housing that forms a leaky seal that allows a predetermined mud flow through the leaky seal during operation.
Another object of the invention is to provide a long-lasting mud motor assembly that produces more power per unit length than standard progressing cavity mud motors.
Yet another object of the invention is to provide a mud motor assembly having a drive shaft that rotates concentrically about an axis of rotation.
Another object of the invention is to provide a mud motor assembly that does not require a wiggle rod to compensate for eccentric motion of internal parts.
According to one aspect of the invention, a mud motor apparatus (12) is provided possessing one single drive shaft (20) that turns a rotary drill bit (70), which apparatus is attached to a drill pipe (486) that is a source of high pressure mud (14) to said apparatus, wherein said drive shaft (20) receives at least a first portion (494) of its rotational torque from any high pressure mud (492) flowing through a first hydraulic chamber (84) within said apparatus, and said drive shaft (20) receives at least a second portion (498) of its rotational torque from any high pressure mud (496) flowing through a second hydraulic chamber (98) within said apparatus.
According to a second aspect of the invention, a method is provided to provide torque and power to a rotary drill bit (70) rotating clockwise attached to a drive shaft (20) of a mud motor assembly (12) comprising at least the following steps:

a. providing relatively high pressure mud (14) from a drill pipe (486) attached to an uphole end of said mud motor assembly (484);
b. passing at least a first portion (492) of said relatively high pressure mud through a first hydraulic chamber (84) having a first piston (24) that rotates a first crankshaft (22) clockwise about its own rotation axis from its first relative starting position at 0 degrees through a first angle of at least 210 degrees, but less than 360 degrees during its first power stroke (Figures 9, 9A, 9B,9C, 9D, 9E, 9F,and 9G);
c. mechanically coupling said first crankshaft (22) by a first ratchet means (30) to a first portion (44) of said drive shaft (20) to provide clockwise rotational power to said drive shaft during said first power stroke (Figures 9, 9A, 9B,9C, 9D, 9E, 9F,and 9G);
d. passing at least a second portion (496) of said relatively high pressure mud through a second hydraulic chamber (98) having a second piston (28) that rotates a second crankshaft (26) clockwise about its own rotation axis from its first relative starting position of 0 degrees through a second angle of at least 210 degrees, but less than 360 degrees during its second power stroke (502);
e. mechanically coupling said second crankshaft (26) by a second ratchet means (48) to a second portion (62) of said drive shaft (20) to provide clockwise rotational power to said drive shaft during said second power stroke 502; and
f. providing first control means (46) of said first ratchet means (30), and providing second control means (64) of said second ratchet means (48), to control the relative timing of rotations of said first crankshaft and said second crankshaft (Figures 20, 21A, and 21B) so that at the particular time that said first crankshaft (22) has rotated from its first relative starting position through 180 degrees nearing the end of its first power stroke at 210 degrees, said second crankshaft begins its rotational motion from its relative starting position of 0 degrees were it begins its second power stroke 502.

In one embodiment, said first ratchet means (30) is comprised of a first pawl (40) that is flexibly attached by a first torsion rod spring (350) and second torsion rod spring (352) to said first crankshaft (22), and first pawl latch (44) that is an integral portion of the drive shaft (20).
In another embodiment, said second ratchet means (48) is comprised of a second pawl (58) that is flexibly attached by third torsion rod spring (504) and fourth torsion rod spring (506) to said second crankshaft (26), and second pawl latch (62) that is an integral portion of the drive shaft (20).
In yet another embodiment, said first control means is comprised of a first pawl lifter means (46) that is an integral portion of the drive shaft (20) that lifts said first pawl (40) in a first fixed relation to said drive shaft (20).
In still another embodiment, said second control means is comprised of a second pawl lifter (64) means that is an integral portion of the drive shaft (20) that lifts said second pawl (58) in a second fixed relation to said drive shaft.
In still another embodiment, following the clockwise rotation of the said first crankshaft (22) about its rotational axis through an angle of at least 210 degrees during its first power stroke(Figures 9, 9A, 9B,9C, 9D, 9E, 9F,and 9G), said first pawl lifter means (46) disengages said first pawl (40) from said first pawl latch (44), so that first torsion spring (78) returns first crankshaft (22) in a counter-clockwise rotation to its initial starting position completing a first power stroke and first return cycle for said first crankshaft (22) while said drive shaft (20) continues to rotate clockwise unimpeded by the return motion of said first crankshaft (Figure 9J and Figure 16B).
In still another embodiment, following the clockwise rotation of the said second crankshaft (26) about its rotational axis through an angle of at least 210 degrees during its second power stroke (502), said second pawl lifter means (64) disengages said second pawl (58) from said second pawl latch (62), so that second torsion spring (92) returns second crankshaft (26) in a counter-clockwise rotation to its initial starting position completing a second power stroke and second return cycle for the second crankshaft (26) while said drive shaft (20) continues to rotate clockwise unimpeded by the return motion of said second crankshaft (508 and 510).
In still another embodiment, the first torsional energy stored in said first torsion return spring (78) at the end of said first power stroke is obtained by said first crankshaft (22) twisting said first torsion return spring (78) during said first power stroke (Figures 9, 9A, 9B,9C, 9D, 9E, 9F,and 9G).
In still another embodiment, the second torsional energy stored in said second torsion return spring (92) at the end of said second power stroke is obtained by said second crankshaft 26 twisting said second torsion return spring (92) during said second power stroke (502).
In still another embodiment, said first power stroke and said second power stroke are repetitiously repeated so that torque and power is provided to said clockwise rotating drive shaft (20) attached to said drill bit (70), whereby said clockwise rotation is that rotation observed looking downhole toward the top of the rotary drill bit.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a side view of the Mud Motor Assembly 12.
Figure 2 shows regions within the Mud Motor Assembly having Relatively High Pressure Mud Flow (RHPMF) 14. Special shadings are used in Figures 2 and 2A as discussed in the specification.
Figure 2A shows regions within the Mud Motor Assembly having Relatively Low Pressure Mud Flow (RLPMF) 16
Figure 3 shows the Housing 18 of the Mud Motor Assembly. Special shadings are used for the series of Figure 3, 4 and 5 drawings as discussed in the specification.
Figure 3A shows the Drive Shaft 20 of the Mud Motor Assembly.
Figure 3B shows Crankshaft A 22 of the Mud Motor Assembly.
Figure 3C shows Piston A 24 of the Mud Motor Assembly.
Figure 3D shows Crankshaft B 26 of the Mud Motor Assembly.
Figure 3E shows Piston B 28 of the Mud Motor Assembly
Figure 3F shows Ratchet Assembly A 30 of the Mud Motor Assembly.
Figure 3G shows Return Assembly A 32 of the Mud Motor Assembly.
Figure 3H shows Flywheel A 34 of the Mud Motor Assembly.
Figure 3J shows the Raised Guide for Pawl A Capture Pin 36 of the Mud Motor Assembly.
Figure 3K shows the Pawl A Capture Pin 38 of the Mud Motor Assembly.
Figure 3L shows Pawl A 40 of the Mud Motor Assembly.
Figure 3M shows Drive Pin A 42 of the Mud Motor Assembly.
Figure 3N schematically shows the Pawl A Latch Lobe 44 of the Mud Motor Assembly.
Figure 3P schematically shows the Pawl A Lifter Lobe 46 of the Mud Motor Assembly.
Figure 4 shows Ratchet Assembly B 48 of the Mud Motor Assembly.
Figure 4A shows Return Assembly B 50 of the Mud Motor Assembly.
Figure 4B shows Flyweel B 52 of the Mud Motor Assembly.
Figure 4C shows the Raised Guide for Pawl B Capture Pin 54 of the Mud Motor Assembly.
Figure 4D shows the Pawl B Capture Pin 56 of the Mud Motor Assembly.
Figure 4E shows Pawl B 58 of the Mud Motor Assembly.
Figure 4F shows Drive Pin B 60 of the Mud Motor Assembly.
Figure 4G schematically shows the Pawl B Latch Lobe 62 of the Mud Motor Assembly.
Figure 4H schematically shows the Pawl B Lifter Lobe 64 of the Mud Motor Assembly.
Figure 4J shows the Drill Bit Coupler 66 of the Mud Motor Assembly.
Figure 4K shows the Drill Pipe 68 of the Mud Motor Assembly.
Figure 4L shows the Rotary Drill Bit 70 of the Mud Motor Assembly.
Figure 4M shows the Upper, Middle and Lower Main Bearings (respectively numerals 72, 74, and 76 from left-to-right) of the Mud Motor Assembly.
Figure 4N shows Return Spring A 78 of the Mud Motor Assembly.
Figure 4P shows Intake Valve A 80 of the Mud Motor Assembly.
Figure 5 shows the First External Crankshaft A Bearing 82 of the Mud Motor Assembly.
Figure 5A schematically shows Chamber A 84 of the Mud Motor Assembly.
Figure 5B shows the Internal Crankshaft A Bearing 86 of the Mud Motor Assembly.
Figure 5C shows Second External Crankshaft A Bearing 88 of the Mud Motor Assembly.
Figure 5D shows Exhaust Valve A 90 of the Mud Motor Assembly.
Figure 5E shows Return Spring B 92 of the Mud Motor Assembly.
Figure 5F shows Intake Valve B 94 of the Mud Motor Assembly.
Figure 5G shows the First External Crankshaft B Bearing 96 of the Mud Motor Assembly.
Figure 5H schematically shows Chamber B 98 of the Mud Motor Assembly.
Figure 5J shows the Internal Crankshaft B Bearing 100 of the Mud Motor Assembly.
Figure 5K shows the Second External Crankshaft B Bearing 102 of the Mud Motor Assembly.
Figure 5L shows the Exhaust Valve B 104 of the Mud Motor Assembly.
Figure 5M shows the Coupler Bearing 106 of the Mud Motor Assembly.
Figure 6 side view of the Mud Motor Assembly 108 which is longitudinally divided into portions shown in Figures 6A, 6B, 6C, 6D, 6E, 6F and 6G.
Figure 6A shows an enlarged first longitudinal portion 110 of the Mud Motor Assembly as noted on Figure 6.
Figure 6B shows an enlarged second longitudinal portion 112 of the Mud Motor Assembly.
Figure 6C shows an enlarged third longitudinal portion 114 of the Mud Motor Assembly.
Figure 6D shows an enlarged fourth longitudinal portion 116 of the Mud Motor Assembly.
Figure 6E shows an enlarged fifth longitudinal portion 118 of the Mud Motor Assembly.
Figure 6F shows an enlarged sixth longitudinal portion 120 of the Mud Motor Assembly.
Figure 6G shows an enlarged seventh longitudinal portion 122 of the Mud Motor Assembly.
Figure 7 shows an Isometric View of Hydraulic Chamber S 124 that is a schematic portion of one embodiment of one embodiment of a Mud Motor Assembly.
Figure 7A shows an Isometric View of Hydraulic Chamber T 182 that is a schematic portion of one embodiment of one embodiment of a Mud Motor Assembly.
Figures 7B shows a end view 238 of Chamber S looking uphole which is Shown Isometically in Figure 7.
Figure 7C shows an End View 240 of Chamber T looking uphole which is shown isometrically in Figure 7A.
Figure 8 shows the Right-Hand Rule 268 appropriate for the Mud Motor Assembly.
Figure 9 shows a cross-section view FF of the Mud Motor Assembly in Figure 6C with Piston A at angle theta of 0 Degrees in the Mud Motor Assembly.
Figure 9A shows Piston A in Position at 30 Degrees in the Mud Motor Assembly during its Power Stroke.
Figure 9B shows Piston A in Position at 60 Degrees in the Mud Motor Assembly during its Power Stroke.
Figure 9C shows Piston A in Position at 90 Degrees in the Mud Motor Assembly during its Power Stroke.
Figure 9D shows Piston A in Position at 120 Degrees in the Mud Motor Assembly during its Power Stroke.
Figure 9E shows Piston A in Position at 150 Degrees in the Mud Motor Assembly during its Power Stroke.
Figure 9F shows Piston A in Position at 180 Degrees in the Mud Motor Assembly during its Power Stroke.
Figure 9G shows Piston A in Position at 210 Degrees in the Mud Motor Assembly at the end of its 100% full strength Power Stroke.
Figure 9H shows the various compnents within cross section FF in Figure 6C.
Figure 9J shows Piston A during a portion of its Reset Stroke, or its Return Stroke.
Figure 9K shows Piston A during a portion of its Power Stroke.
Figure 9L shows new positions for previous elements 278 and 280.
Figure 10 shows a Cross-Section View of the Housing 18 in the Mud Motor Assembly. Special shadings are used for the series of Figure 10 drawings as discussed in the specification.
Figure 10A shows a Cross-Section View of Crankshaft A 22 in the Mud Motor Assembly.
Figure 10B shows a Cross-Section View of the Internal Crankshaft A Bearing 86 in the Mud Motor Assembly.
Figure 10C shows a Cross-Section View of the Drive Shaft 20 in the Mud Motor Assembly.
Figure 10D shows a Cross-Section of Piston A 24 in the Mud Motor Assembly.
Figure 10E shows a Cross-Section of Backstop A 272 in the Mud Motor Assembly.
Figure 10F shows a Cross-Section of Bypass Tube A-1 274 in the Mud Motor Assembly.
Figure 10G shows a Cross-Section of Bypass Tube A-2 276 in the Mud Motor Assembly.
Figure 10H shows a Cross-Section of the Drive Port of Chamber A ("DPCHA") 278 in the Mud Motor Assembly.
Figure 10J shows a Cross-Section of the Exhaust Port of Chamber A ("EPCHA") 280 in the Mud Motor Assembly.
Figure 10K shows a Cross-Section of the Backstop Port of Chamber A ("BPCHA") 282 in the Mud Motor Assembly.
Figure 10L shows a Cross-Section of the Backstop to Housing Weld 284 in the Mud Motor Assembly.
Figure 10M shows a Cross-Section of Piston A to Crankshaft A Weld 286 in the Mud Motor Assembly.
Figure 11 shows the Basic Component Dimensions for a preferred embodiment of the Mud Motor Assembly having an OD of 6 1/4 Inches.
Figure 12 shows an Uphole View of the Upper Main Bearing 72 in the Mud Motor Assembly.
Figure 12A shows a Section View of the Upper Main Bearing 72 in the Mud Motor Assembly.
Figure 12B shows an Uphole View of the Middle Main Bearing 74 in the Mud Motor Assembly having passageways.
Figure 12C shows a Section View of the Middle Main Bearing 74 in the Mud Motor Assembly.
Figure 13 shows a Section View of Installed Return Spring A 78 Which is a Portion of Ratchet Assembly A 30 in the Mud Motor Assembly.
Figure 13A shows a Perspective View of Return Spring A 78 in the Mud Motor Assembly.
Figure 14 shows a Cross Section View CC of Ratchet Assembly A in the Mud Motor Assembly.
Figure 14A shows a cross section portion 354 of Drive Pin A for a Preferred Embodiment of the Mud Motor Assembly Having an OD of 6 1/4 Inches.
Figure 14B shows a Cross Section View DD of one embodiment of Ratchet Assembly A in the Mud Motor Assembly.
Figure 14C shows a Cross Section View EE of one embodiment of Ratchet Assembly A in the Mud Motor Assembly.
Figure 14D shows How to Utilize a Larger Drive Pin 364 than that shown in Figure 14C.
Figure 14E shows an Optional Larger and Different Shaped Drive Pin 370 than in Figure 14C.
Figure 14F shows a Cross Section View AA of Ratchet Assembly A in the Mud Motor Assembly.
Figure 14G shows an Uphole View of Flywheel A and Raised Guide for Pawl A Capture Pin in Section BB of Ratchet Assembly A Showing Sequential Movement of Pawl A Capture Pin in the Mud Motor Assembly.
Figure 15 shows one embodiment of the Pawl A Latch Lobe 44 Fully Engaged With Pawl A 40 at mating position 376 in the Mud Motor Assembly.
Figure 15A shows one embodiment of the Pawl A Latch Lobe 44 Completely Disengaged From Pawl A 40 in the Mud Motor Assembly.
Figure 15B shows an Optional Slot 378 Cut in Pawl A 40 to Make Torsion Cushion at mating position 376 During Impact of Pawl A Latch Lobe in the Mud Motor Assembly.
Figure 16 shows the Pawl A Lifter Lobe at theta of 0 Degrees in the Mud Motor Assembly.
Figure 16A shows the Pawl A Lifter Lobe at 210 Degrees in the Mud Motor Assembly.
Figure 16B shows the Pawl A Lifter Lobe 46 at -90 Degrees and the Partial Return of Pawl A 40 in the Mud Motor Assembly.
Figure 17 shows Intake Port A 402 in Intake Valve A 80 Passing theta of 0 Degrees allowing relatively high pressure mud to flow through the Intake Port A 402 and then through the Drive Port of Chamber A ("DPCHA") 278 and thereafter into Chamber A, thus beginning the Power Stroke of Piston A in the Mud Motor Assembly.
Figure 17A shows the Intake Port A 402 in Intake Valve A 80 Passing theta of 90 degrees during the Power Stroke of Piston A in the Mud Motor Assembly.
Figure 17B shows the Intake Port A 402 in Intake Valve A 80 Passing theta of 180 degrees during the Power Stroke of Piston A in the Mud Motor Assembly.
Figure 17C shows the Intake Port A 402 in Intake Valve A 80 Passing theta of 210 degrees during the very end of the Power Stroke of Piston A in the Mud Motor Assembly.
Figure 17D shows Intake Port A 402 in Intake Valve A 80 Passing theta of 240 degrees after the Power Stroke of Piston A has ended.
Figure 17E shows Intake Port A 402 in Intake Valve A 80 at theta of - 30 Degrees in the Mud Motor Assembly During the Return Stroke of Piston A.
Figure 17F shows Intake Port A 402 in Intake Valve A again passing theta of 0 degrees that begins the Power Stroke of Piston A in the Mud Motor Assembly.
Figure 18 shows the upper portion of the Bottom Hole Assembly 408 that includes the Mud Motor Assembly 12.
Figure 19 shows the downhole portion of the Bottom Hole Assembly 422.
Figure 20 shows the Relatively High Pressure Mud Flow ("RHPMF") through various ports, valves, and channels within the Mud Motor Apparatus.
Figure 20A shows the Relatively Low Pressure Mud Flow ("RLPMF") through various ports, valves, and channels within the Mud Motor Apparatus.
Figure 21 compares the pressure applied to the Drive Port of Chamber B ("DPCHB") to the pressure applied to Drive Port of Chamber A ("DPCHA").
Figure 21A shows that a low pressure PL is applied to the Exhaust Port of Chamber A ("EPCHA") and to the Exhaust Port of Chamber B ("EPCHB") during the appropriate Return Strokes.
Figure 21B shows the relationship between the maximum lift of the tip of the Pawl A Lifter Lobe 394 and the pressure applied to the Drive Port of Chamber A ("DPCHA").

This concludes the Brief Description of the Drawings. In all, there are 119 Figures, but with two Figures on one page in the case of Figures 7B and 7C, there are 118 Sheets of Drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1 shows a side view of the Mud Motor Assembly 12.

High and Low Pressure Mud Flow

Figure 2 shows regions within the Mud Motor Assembly having Relatively High Pressure Mud Flow (RHPMF) 14 designated by the unique shading used only for this purpose defined on the face of Figure 2.
Figure 2A shows regions within the Mud Motor Assembly having Relatively Low Pressure Mud Flow (RLPMF) 16 designated by the unique shading used only for this purpose defined on the face of Figure 2A.

Cross-Hatch Shading of Individual Components of Mud Motor Assembly (forty three figures)

Note: There are not a sufficient number of unique shadings for drawing components which can be used to identify individual components of the Mud Motor Assembly and which satisfy drawing rules. Consequently, in this series of figures, the same identical double cross-hatching is used in each figure to identify a specific component on any one figure, but the same looking double cross-hatching shading is used in all the different figures in this series of figures for component labeling purposes. On any one figure, there is only one component identified with double cross-hatching, but the meaning of that double cross-hatching is unique and applies solely and only to that one figure. In general, the meaning of the double cross-hatching is defined by a relevant box on the face of the figure having an appropriate legend.
Figure 3 shows the Housing 18 of the Mud Motor Assembly.
Figure 3A shows the Drive Shaft 20 of the Mud Motor Assembly.
Figure 3B shows Crankshaft A 22 of the Mud Motor Assembly.
Figure 3C shows Piston A 24 of the Mud Motor Assembly.
Figure 3D shows Crankshaft B 26 of the Mud Motor Assembly.
Figure 3E shows Piston B 28 of the Mud Motor Assembly
Figure 3F shows Ratchet Assembly A 30 of the Mud Motor Assembly.
Figure 3G shows Return Assembly A 32 of the Mud Motor Assembly.
Figure 3H shows Flywheel A 34 of the Mud Motor Assembly.
Figure 3J shows the Raised Guide for Pawl A Capture Pin 36 of the Mud Motor Assembly.
Figure 3K shows the Pawl A Capture Pin 38 of the Mud Motor Assembly.
Figure 3L shows Pawl A 40 of the Mud Motor Assembly.
Figure 3M shows Drive Pin A 42 of the Mud Motor Assembly.
Figure 3N schematically shows the Pawl A Latch Lobe 44 of the Mud Motor Assembly.
Figure 3P schematically shows the Pawl A Lifter Lobe 46 of the Mud Motor Assembly.
Figure 4 shows Ratchet Assembly B 48 of the Mud Motor Assembly.
Figure 4A shows Return Assembly B 50 of the Mud Motor Assembly.
Figure 4B shows Flyweel B 52 of the Mud Motor Assembly.
Figure 4C shows the Raised Guide for Pawl B Capture Pin 54 of the Mud Motor Assembly.
Figure 4D shows the Pawl B Capture Pin 56 of the Mud Motor Assembly.
Figure 4E shows Pawl B 58 of the Mud Motor Assembly.
Figure 4F shows Drive Pin B 60 of the Mud Motor Assembly.
Figure 4G schematically shows the Pawl B Latch Lobe 62 of the Mud Motor Assembly.
Figure 4H schematically shows the Pawl B Lifter Lobe 64 of the Mud Motor Assembly.
Figure 4J shows the Drill Bit Coupler 66 of the Mud Motor Assembly.
Figure 4K shows the Drill Pipe 68 of the Mud Motor Assembly.
Figure 4L shows the Rotary Drill Bit 70 of the Mud Motor Assembly.
Figure 4M shows the Upper, Middle and Lower Main Bearings (respectively numerals 72, 74, and 76 from left-to-right) of the Mud Motor Assembly.
Figure 4N shows Return Spring A 78 of the Mud Motor Assembly.
Figure 4P shows Intake Valve A 80 of the Mud Motor Assembly.
Figure 5 shows the First External Crankshaft A Bearing 82 of the Mud Motor Assembly.
Figure 5A schematically shows Chamber A 84 of the Mud Motor Assembly.
Figure 5B shows the Internal Crankshaft A Bearing 86 of the Mud Motor Assembly.
Figure 5C shows Second External Crankshaft A Bearing 88 of the Mud Motor Assembly.
Figure 5D shows Exhaust Valve A 90 of the Mud Motor Assembly.
Figure 5E shows Return Spring B 92 of the Mud Motor Assembly.
Figure 5F shows Intake Valve B 94 of the Mud Motor Assembly.
Figure 5G shows the First External Crankshaft B Bearing 96 of the Mud Motor Assembly.
Figure 5H schematically shows Chamber B 98 of the Mud Motor Assembly.
Figure 5J shows the Internal Crankshaft B Bearing 100 of the Mud Motor Assembly.
Figure 5K shows the Second External Crankshaft B Bearing 102 of the Mud Motor Assembly.
Figure 5L shows the Exhaust Valve B 104 of the Mud Motor Assembly.
Figure 5M shows the Coupler Bearing 106 of the Mud Motor Assembly.

Enlarged Portions of Mud Motor Assembly (eight figures)

Figure 6 shows a particular side view of the Mud Motor Assembly 108 which is longitudinally divided into seven portions respectively identified by double-ended arrows meant to designate the particular longitudinal portions appearing in Figures 6A, 6B, 6C, 6D, 6E, 6F and 6G.
Figure 6A shows an enlarged first longitudinal portion 110 of the Mud Motor Assembly as noted on Figure 6. Cross-sections AA, BB, CC, DD and EE are defined in Figure 6A.
Figure 6B shows an enlarged second longitudinal portion 112 of the Mud Motor Assembly as noted on Figure 6. Cross-sections AA, BB, CC, DD and EE are defined in Figure 6B.
Figure 6C shows an enlarged third longitudinal portion 114 of the Mud Motor Assembly as noted on Figure 6. Cross-section CC is defined in Figure 6C.
Figure 6D shows an enlarged fourth longitudinal portion 116 of the Mud Motor Assembly as noted on Figure 6.
Figure 6E shows an enlarged fifth longitudinal portion 118 of the Mud Motor Assembly as noted on Figure 6.
Figure 6F shows an enlarged sixth longitudinal portion 120 of the Mud Motor Assembly as noted on Figure 6.
Figure 6G shows an enlarged seventh longitudinal portion 122 of the Mud Motor Assembly as noted on Figure 6.

Schematic Views of Hydraulic Chambers S and T (four figures) Figure 7

Figure 7 shows an Isometric View of Hydraulic Chamber S 124 that is a schematic portion of one embodiment of one embodiment of a Mud Motor Assembly. This view is looking uphole. It posses cylindrical housing 126 and integral interior backstop 128 that may be welded to the interior of the housing 126. Piston S 130 is welded to rotating shaft 132 that rotates in the clockwise direction (see the legend CW) looking downhole.
Lower plate 134 and upper plate 135 (not shown) form a hydraulic cavity. Relatively high pressure mud 136 is forced into input port 138, and relatively low pressure mud 140 flows out of the hydraulic chamber through exhaust port 142. The distance of separation 146 between the downhole edge 148 of the cylindrical housing and the uphole face 150 of lower plate 134 results in a gap between these components that generally results in mud flowing in direction 152 during the Power Stroke of Piston S 130. The distance of separation and other relevant geometric details defines of the leaky seal 154. Different distances of separation may be chosen. For example, various embodiments of the invention may choose this distance to be .010, .020, .030 or .040 inches. A close tolerance in one embodiment might be chosen to be .001 inches. A loose tolerance in another embodiment might be chosen to be .100 inches. How much mud per unit time F154 flows out of this leaky seal 154 at a given pressure P136 of mud flowing into input port 138 is one parameter of significant interest. Rotating shaft 132 is constrained to rotate concentrically within the interior of cylindrical housing 126 by typical bearing assemblies 156 (not shown for brevity) that are suitably affixed to a splined shaft (158 not shown), a portion of which slips into splined shaft interior 160 through hole 161 in lower plate 134.
In Figure 7, pressure P136 is applied to input port 138 that causes mud to flow into that input port 138 at the rate of F136. Typical units of pressure P136 are in psi (pounds per square inch) and typical units of mud flow rates F136 into that input port 138 are in gpm (gallons per minute). In Figure 7, mud 140 flows out of the exhaust port 142 at the rate of F140 and at pressure P140. In a hypothetical example, there might be only one leaky seal 154 in Hydraulic Chamber S, and then mud flows out of leaky seal 154 at the rate of F154. In the further hypothetical example that leaky seal 154 might be a tight seal and impervious to leakage, then the flow rate F136 into the Hydraulic Chamber S would then equal the flow rate F140 out of the Hydraulic Chamber S. The horsepower HP136 delivered to the mud 136 flowing into the input port 138 is given by the following: $HP 136 + P 136 \times F 136$
The horsepower HP140 delivered to the mud 140 flowing out the exhaust port 142 is given by the following: $HP 140 = P 140 \times F 140$
The difference in the two horsepower's is used to provide rotational power to the rotating shaft 132 (HP132) and to overcome mechanical and fluid frictional effects (HPF). So, in this case of a tight seal 154: $HP 132 = HP 136 - HP 140 - HPFS$
(In general, HPFS = HPMS + HPFS, where HPMS provide the combined mechanical frictional losses and HPF are combined fluid frictional losses in Hydraulic Chamber S, and each of these components, can be further subdivided into individual subcomponents.)
This rotational power can be used to do work - including providing the rotational power to rotate a drill bit during a portion of the "Power Stroke" of Piston S 130. The rotational speed of the Piston S 130 is given by the volume swept out by the piston as it rotates about the axis of rotating shaft 132. That rotational speed is in RPM, and is defined by RPM132. If the volume swept out by Piston S due to a hypothetical 360 degree rotation is VPS360, then one estimate of the RPM is given by the following: $RPM = VPS 360 / F 136$
However, if there is fluid flow F154 through leaky seal 154, then part of the power is delivered to mud flowing out of the leaky seal that is HP154. In this case, the power delivered to the rotating shaft is then given by: $HP 132 = HP 136 - HP 140 - HPFS - HP 154$
In general, hydraulic cavities are relatively expensive to manufacture. And, close tolerances typically lead to relatively earlier failures - especially in the case of using Hydraulic Chamber S to provide rotational energy from mud flowing down a drill string. The looser the tolerances on the leaky seal, the less expensive, and more prone to long service lives. So, there is a trade-off between loss of horsepower delivered to mud flowing through leaky seal 154 in this one example, and expense and longevity of the related Hydraulic Chamber S. The Hydraulic Chamber S shown in Figure 7 may have many leaky seals. Leaky seal 154 has been described. However, there may be another leaky seal 158 between the analogous seal between the upper edge 162 of housing 126 and the downhole face 164 (not shown) of upper plate 135 (not shown). Yet another leaky seal 168 exists between the outer radial portion of the rotating shaft 170 (not shown) and the inner edge of the backstop 172 (not shown). Yet another leaky seal 174 exists between
the outer radial edge of Piston S 176 (not shown) and the inside surface
of the housing 178 (not shown).
The mud flow rates associated with these leaky seals 154, 158, 168 and 174 are respectively F154, F158, F168, and F174. The horsepower's consumed by these leaking seals are respectively HP154, HP158, HP168 and HP174. In this case, the power delivered to the rotating shaft during the Powered Stroke of Piston is then given by: $HP 132 = HP 136 - HP 140 - HPFS - HP 154 - HP 158 - HP 168 - HP 174$
The Power Stroke of Piston S 130 is defined as when Piston S is rotating CW as shown in Figure 7. Of course, as shown there, Piston S 130 will eventually rotate through an angle approaching 360 degrees, and will hit the backstop 128. Therefore, to extract further power, Piston S 130 must be "reset" by rotation CCW back to its original starting position. This is called the Reset Stroke of Piston S 130. To provide continuous rotation to a rotating drill bit then requires other features to be described in the following.

Figure 7A

Figure 7A shows an Isometric View of Hydraulic Chamber T 182 that is a schematic portion of one embodiment of one embodiment of a Mud Motor Assembly. This view is looking uphole. It posses cylindrical housing 184 and integral interior backstop 186 that may be welded to the interior of the housing 184. Piston T 188 is welded to rotating shaft 190 that rotates in the clockwise direction (see the legend CW) looking downhole. Lower plate 192 and upper plate 193 (not shown) form a hydraulic cavity. Relatively high pressure mud 194 is forced into input port 196, and relatively low pressure mud 198 flows out of the hydraulic chamber through exhaust port 200. The distance of separation 204 between the downhole edge 206 of the cylindrical housing and the uphole face 208 of lower plate 192 results in a gap between these components that generally results in mud flowing in direction 210 during the Power Stroke of Piston T 188. The distance of separation and other relevant geometric details defines of the leaky seal 212. Different distances of separation may be chosen. For example, various embodiments of the invention may choose this distance to be .010, .020, .030 or .040 inches. A close tolerance in one embodiment might be chosen to be .001 inches. A loose tolerance in another embodiment might be chosen to be .100 inches. How much mud per unit time F212 flows out of this leaky seal 212 at a given pressure P194 of mud flowing into input port 196 is one parameter of significant interest.
Rotating shaft 190 is constrained to rotate concentrically within the interior of cylindrical housing 184 by typical bearing assemblies 214 (not shown for brevity) that are suitably affixed to a splined shaft (216 not shown), a portion of which slips into splined shaft interior 218 through hole 219 in lower plate 192.
In Figure 7A, pressure P 194 is applied to input port 196 that causes mud to flow into that input port 196 at the rate of F194. Typical units of pressure P194 are in psi (pounds per square inch) and typical units of mud flow rates F194 into that input port 196 are in gpm (gallons per minute). In Figure 7A, mud 198 flows out of the exhaust port 200 at the rate of F198 and at pressure P198. In a hypothetical example, there might be only one leaky seal 212 in Hydraulic Chamber T, and then mud flows out of leaky seal 212 in a direction 210 at the rate of F212. In the further hypothetical example that leaky seal 212 might be a tight seal and impervious to leakage, then the flow rate F 194 into the Hydraulic Chamber T would then equal the flow rate F198 out of the Hydraulic Chamber T. The horsepower HP194 delivered to the mud 194 flowing into the input port 196 is given by the following: $HP 194 = P 194 \times F 194$
The horsepower HP198 delivered to the mud 198 flowing out the exhaust port 200 is given by the following: $HP 198 = P 198 \times F 198$
The difference in the two horsepower's is used to provide rotational power to the rotating shaft 190 (HP190) and to overcome mechanical and fluid frictional effects in chamber T (HPFT). So, in this case of a tight seal 212: $HP 212 = HP 194 - HP 198 - HPFT$
(In general, HPFT = HPMT + HPFT, where HPMT provide the combined mechanical frictional losses HPMT and HPFT are combined fluid frictional losses in Chamber T, and each of these components, can be further subdivided into individual subcomponents.) This rotational power can be used to do work - including providing the rotational power to rotate a drill bit during a portion of the "Power Stroke" of Piston T 188. The rotational speed of the Piston T 188 is given by the volume swept out by the piston as it rotates about the axis of rotating shaft 190. That rotational speed is in RPM, and is defined by RPM190. If the volume swept out by Piston T due to a hypothetical 360 degree rotation is VPT360, then one estimate of the RPM is given by the following: $RPM = VPT 360 / F 136$
However, if there is fluid flow F212 through leaky seal 212, then part of the power is delivered to mud flowing out of the leaky seal that is HP212. In this case, the power delivered to the rotating shaft is then given by: $HP 190 = HP 194 - HP 198 - PHFT - HP 212$
In general, hydraulic cavities are relatively expensive to manufacture. And, close tolerances typically lead to relatively earlier failures - especially in the case of using Hydraulic Chamber T to provide rotational energy from mud flowing down a drill string. The looser the tolerances on the leaky seal, the less expensive, and more prone to long service lives. So, there is a trade-off between loss of horsepower delivered to mud flowing through leaky seal 212 in this one example, and expense and longevity of the related Hydraulic Chamber T.
The Hydraulic Chamber T shown in Figure 7A may have many leaky seals. Leaky seal 212 has been described. However, there may be another leaky seal 216 between the analogous seal between the upper edge 220 of housing 184 and the downhole face 222 (not shown) of upper plate 193 (not shown). Yet another leaky seal 226 exists between the outer radial portion of the rotating shaft 228 (not shown) and the inner edge of the backstop 230 (not shown). Yet another leaky seal 232 exists between the outer radial edge of Piston T 234 (not shown) and the inside surface of the housing 236 (not shown).
The mud flow rates associated with these leaky seals 212, 216, 226 and 232 are respectively F212, F216, F226, and 232. The horsepower's consumed by these leaking seals are respectively HP212, HP216, HP226 and HP232. In this case, the power delivered to the rotating shaft during the Powered Stroke of Piston T is then given by: $HP 190 = HP 194 - HP 198 - HPFT - HP 212 - HP 216 - HP 226 - HP 232$
The Power Stroke of Piston T 188 is defined as when Piston T is rotating CW as shown in Figure 7A. Of course, as shown there, Piston T 188 will eventually rotate through an angle approaching 360 degrees, and will hit the backstop 186. Therefore, to extract further power, Piston T 188 must be "reset" by rotation CCW back to its original starting position. This is called the Reset Stroke of Piston T 188. To provide continuous rotation to a rotating drill bit then requires other features to be described in the following.

Figures 7B and 7C

Figures 7B shows a end view 238 of Chamber S looking uphole which is Shown Isometically in Figure 7. The other numerals have been previously defined above.
Figure 7C shows an End View 240 of Chamber T looking uphole which is shown isometrically in Figure 7A. The other numerals have been previously defined above.

Two Hydraulic Chambers

Various possibilities were examined that provided a mud motor assembly having two hydraulic chambers, each having its own power stroke and return stroke, acting together, and providing continuous power to a rotary drill bit.
With regards to Figure 7, it states above: "Rotating shaft 132 is constrained to rotate concentrically within the interior of cylindrical housing 126 by typical bearing assemblies 156 (not shown for brevity) that are suitably affixed to a splined shaft (158 not shown), a portion of which slips into splined shaft interior 160 through hole 161 in lower plate 134."
With regards to Figure 7A, it states above: "Rotating shaft 190 is constrained to rotate concentrically within the interior of cylindrical housing 184 by typical bearing assemblies 214 (not shown for brevity) that are suitably affixed to a splined shaft (216 not shown), a portion of which slips into splined shaft interior 218 through hole 219 in lower plate 192."
In a series of preferred embodiments of the invention, methods and apparatus are disclosed that allow two separate Power Chambers, each having its own Power Stoke, and Return Stroke, to provide continuous rotation to a rotary drill bit. In terms of the simple diagrams in Figures 7 and 7A, 7B, and 7C, different methods and apparatus are disclosed that allow Hydraulic Chamber S and Hydraulic Chamber T to provide continuous rotation to a rotary drill drill bit. The applicant has investigated several different approaches to this problem including several that are briefly listed below.

A First Embodiment of the Invention

Using a Shuttling Splined Shaft

In a first preferred embodiment of the invention, a special splined shaft 242 (not shown) with a first splined head 244 (not shown) and a second splined head 246 (not shown) is used to accomplish this goal. This invention is disclosed in detail in Serial No. 61/573,631 This embodiment of the device generally works as follows:

a. During the Power Stroke of Hydraulic Chamber S, first splined head 244 is engaged splined shaft interior 160.
b. During the Return Stoke of Hydraulic Chamber S, first splined head 244 is disengaged from splined shaft interior 160.
c. During the Power Stroke of Hydraulic Chamber T, second splined head 246 is engaged within splined shaft interior 218.
d. During the Return Stoke of Hydraulic Chamber T, second splined head 246 is disengaged within splined shaft interior 218.

Basically, the single splined shaft having two splined heads shuttles back and forth during the appropriate power strokes to provide continuous rotation of the drive shaft that is suitably coupled to the rotating drill bit. Different methods and apparatus are used to suitably control the motion of the two splined heads. Many methods and apparatus here use hydraulic power for the Return Strokes of the Pistons within the Hydraulic Chambers. This approach, while very workable, requires additional hydraulic passageways within the Hydraulic Chambers to make the hydraulic Return Stokes work.

A Second Embodiment of the Invention

Using a Shuttling Backstop

Another embodiment of the invention is disclosed in Serial No. 61/629,000 . Here, a different version of the backstop 128 is slid through a new slot plate 134 in and out of the hydraulic cavity so that Piston S 130 can continuously rotate - which is attached to the rotating shaft 132. However, this sliding backstop method requires relatively large motions of the sliding backstop that is a disadvantage of this approach.

A Third Embodiment of the Invention

Using Hydraulic Return Mechanisms

Another embodiment of the invention is described in Serial No. 61/629,000 . Here, a Return Springs are used for the Return Stokes, but there is a Distributor section to establish proper timing. A Distributor for the purposes herein directs the incoming high pressure mud to various tubes connected to hydraulic chambers, etc. The Distributor here sets the timing - much like an ignition distributor on an old V-8. This approach may not "free run" without the Distributor section. By "Free Run", means when the mud flow starts, the mud motor begins to rotate and requires no separate devices to synchronize its internal functioning.

A Fourth Embodiment of the Invention -

The "Mark IV Mud Motor"

The preferred embodiment of the invention described herein has advantages over the first, second and third approaches. With the exception of Figures 7, 7A, 7B, and 7C, the figures in this application are directed at this fourth approach. In Serial No. 61/629,000 , in Serial No. 61/633,776 and in Serial No. 61/687,394 this fourth approach is called "The Mark IV Mud Motor (TM)". The Mark IV is drives from the 4th fundamental approach to provide continuous rotation of the rotary drill bit by two separate Hydraulic Chambers each having its own Power Stroke and Return Stroke - and which "Free Runs".

General Comments About

Quasi-Positive Displacement Mud Motors

Typical rotary drilling systems may be used to drill oil and gas wells. Here, a surface rig rotates the drill pipe attached to the rotary drill bit at depth. Mud pressure carries chips to the surface via annular mud flow.
Alternatively, a mud motor may be placed at the end of a drill pipe 482 (not shown), which uses the power from the mud flowoing downhole to rotate a drill bit. Mud pressure still carries chips to the surface, often via annular mud flow.
Typical mud motors as used by the oil and gas industry are based upon the a progressing cavity design, typically having a rubber stator and a steel rotor. These are positive displacement devices that are hydraulically efficient at turning the power available from the mud flow into rotational energy of the drill bit. These devices convert that energy by having intrinsically asymmetric rotors within the stator cavity - so that following pressurization with mud, a torque develops making the rotor spin. These devices also generally have tight tolerance requirements. However, in practice, mud motors tend to wear out relatively rapidly, requiring replacement that involves tripping the drill string to replace the mud motor. Tripping to replace a mud motor is a very expensive process. In addition, there are problems using these mud motors at higher temperatures. It is probably fair to say, that if the existing mud motors were much more long-lasting, that these would be used much more frequently in the industry. This is so in part because the rotary steering type directional drilling controls work well with mud motors, providing relatively short radaii of curvature as compared to standard rotary drilling with drill pipes. Mud motors also work well with industry-standard LWD/MWD data acquisition systems.
An alternative to using mud motors, there are the turbine drilling systems available today. These are not positive displacement type motors. They work at relatively high RPM to achieve hydraulic efficiency, often require a gear box to reduce the rotational speed of any attached rotary drill bit, are expensive to manufacture, and are relatively fragile devices having multiple turbine blades within their interiors.
So, until now, there are two basic alternatives. The mud motors "almost work well enough" to satisfy many industry requirements. However, looking at the progressing cavity design a little more closely also reveals that the stator must be asymmetric in its stator to develop torque. In general, positive displacement motors suffer from this disadvantage - they are generally not cylindrically symmetric about a rotational axis. This in turn results in requiring that the output of a shaft of the mud motor couple to a "wiggle rod" to decouple the unwanted motion from the rotary drill bit.
The applicant began investigating motor designs having parts that run concentrically about an axis. If all the parts are truly concentric about a rotational axis, then in principle, there is no difference between right and left, and no torque can develop. However, the applicant decided to investigate if it was possible to make motors that are "almost" positive displacement motors that can be described as "quasi-positive displacement motors" which do develop such torque. The Mark IV Mud Motor is one such design. It runs about a concentric axis. However, the existence of leaky seals within its interior means that it is not a true positive displacement mud motor. If the leaky seals leak about 10% of the fluid from within a hydraulic chamber to the mud flow continuing downhole without imparting the energy from the leaked fluids to the piston, nevertheless, the piston would still obtain 90% of its power from the mud flow. In this case, a relatively minor fraction of the horsepower, such as 15% would be "lost". These leaky seal devices can then be classified as "quasi-positive displacement motors". For example, such motors may have relatively loose fitting components that reduce manufacturing costs. But more importantly, as the interior parts of these motors wear, the motor keeps operating. Therefore, these "quasi-postive displacement motors" have the intrinsic internal design to guarantee long lasting operation under adverse environmental conditions. Further, many of the embodiments, the "quasi-positive displacement motors" are made of relatively loose fitting metal components, so that high temperature operation is possible. The materials are selected so that there is no galling during operation, or jamming due to thermal expansion.

Right-Hand Rule for Mud Motor Assembly

Figure 8 shows the Right-Hand Rule 268 appropriate for the Mud Motor Assembly. In Figure 8, the uphole view is looking to the left-hand side, and the downhole view is looking to the right-hand side.
As an example, the Drive Shaft in Figure 8 can be chosen to be Drive Shaft 20 in Figure 3A. And, for example, the flywheel can be chosen to be Flywheel A 34 in Figure 3H. It is conceivable to make another assembly drawing appropriate for only this situation that could be labeled with numeral 270 (not shown), but in the interests of brevity, this approach will not be used any further.

Position of Piston A During

Its Power Stroke and Return Stroke

(twelve figures)

Figure 9 shows a cross-section view FF of the Mud Motor Assembly in Figure 6C with Piston A at angle theta of 0 Degrees in the Mud Motor Assembly. This view is looking uphole. The position of theta equal 0 degrees is defined as that position of Piston A when mud pressure inside Chamber A reaches a sufficient pressure where Piston A just begins initial movement during the Power Stroke of Piston A.
Figure 9A shows Piston A in Position at 30 Degrees in the Mud Motor Assembly during its Power Stroke.
Figure 9B shows Piston A in Position at 60 Degrees in the Mud Motor Assembly during its Power Stroke.
Figure 9C shows Piston A in Position at 90 Degrees in the Mud Motor Assembly during its Power Stroke.
Figure 9D shows Piston A in Position at 120 Degrees in the Mud Motor Assembly during its Power Stroke.
Figure 9E shows Piston A in Position at 150 Degrees in the Mud Motor Assembly during its Power Stroke.
Figure 9F shows Piston A in Position at 180 Degrees in the Mud Motor Assembly during its Power Stroke.
Figure 9G shows Piston A in Position at 210 Degrees in the Mud Motor Assembly at the end of its 100% full strength Power Stroke.
Figure 9H shows the various compnents within cross section FF in Figure 6C. Numerals 18, 20, 22, 24 and 86 had been previously defined. Numerals 272, 274, 276, 278, 280, 282, 284, and 286 are defined in Figures 10, 10A,...., 10L, 10M which follow. Element 288 in this direction looking uphole shows the direction of the Power Stroke for Piston A.
Figure 9J shows Piston A during a portion of its Reset Stroke, or its Return Stroke, where Piston A rotates clockwise looking uphole (counter-clockwise looking downhole), until it reaches at "Stop" at theta equals 0 degrees. As will be described later, the "Stop" it may be mechanical in nature, or may be hydraulic in nature. Element 290 is this direction looking uphole shows the direction of the Reset Stroke, or Return Stroke, of Piston A.
Figure 9K shows Piston A during a portion of its Power Stroke. During the Power Stroke of Piston A, leaky seal 292 may produce mud flowing in a direction past the seal shown as element 294 in Figure 9K. F292 is the flow rate in gpm through leaky seal 292. HP292 is the horsepower dissipated by the mud flow F292 through leaky seal 292. F292 and HP 292 are expected, of course, to be dependent upon the average pressure acting on Piston A during its Power Stroke. Here, the term "average pressure" includes a spatial or volumetric average, but that average may be at just one instant in time. The "average pressure" may be time dependent. Similar comments apply below to the usage "average pressure".
During the Power Stroke of Piston A, leaky seal 296 may produce mud flowing in a direction past the seal shown as element 298 in Figure 9K. F296 is the flow rate in gpm through leaky seal 296. HP296 is the horsepower dissipated by the mud flow F296 through leaky seal 296. F296 and HP296 are expected, of course, to be dependent upon the average pressure acting on Piston A during its Power Stroke.
Element 300 in Figure 9K defines the region called the Power Chamber. Pressurized mud in the Power Chamber 300 acts upon Piston A to cause it to move during its Power Stroke. The average pressure acting upon Piston A during its Power Stroke is defined to be P300. The pressure within the Power Chamber 300 may vary with position, and that knowledge is a minor variation of this invention.
Element 302 in Figure 9K defines the region called the Backstop Chamber. The mud within the Backstop Chamber 302 may will have an average pressure acting upon the "back side" Piston A. The average pressure acting upon the back side of Piston A during its Power Stroke is defined to be P302. The pressure within the Backstop Chamber may vary with position, and that knowledge is a minor variation of this invention.
The portion of Piston A facing the Power Chamber 300 is designated by numeral 304, and has average pressure P304 acting on that portion 304.
The portion of Piston A facing the Backstop Chamber 302 is designated by numeral 306, and has average pressure P306 acting on that portion 306.
The portion of the Backstop facing the Power Chamber 300 is designated by numeral 308, and has average pressure P308 acting on that portion 308. The portion of the Backstop facing the Backstop Chamber 302 is designated by numeral 310, and has average pressure P310 on that portion of 310.
Figure 9L shows new positions for previous elements 278 and 280. Element 312 corresponds to original 278 ("DPCHA"). Element 314 corresponds to original element 280 ("EPCHA"). As shown in Figure 9L, centers of elements 312 and 314 are now at different radii in this embodiment which may assist in the design of the proper operation of intake and exhaust valuing. Either of these new elements can be put at different radial positions than the radial position of the center of 282 ("EPCHA"). See Figures 10H, 10J, and 10K.

Cross Section Views of the Mud Motor Assembly

(thirteen figures)

Note: There are not a sufficient number of unique shadings for drawing components which can be used to identify all of the individual components of the Mud Motor Assembly and which satisfy the drawing rules at the USPTO. Consequently, in this series of figures, the same identical double cross-hatching is used in each figure to identify a specific component on any one figure, but the same looking double cross-hatching shading is used in all the different figures in this series of figures for component labeling purposes. On any one figure, there is only one component identified with double cross-hatching, but the meaning of that double cross-hatching is unique and applies solely and only to that one figure. In general, the meaning of the double cross-hatching is defined by a relevant box on the face of the figure having an appropriate legend. These comments pertain to Figures 10, 10A, ... 10L, and 10M. The below Cross-Sections pertain to Cross Section FF in Figure 6C.
Figure 10 shows a Cross-Section View of the Housing 18 in the Mud Motor Assembly.
Figure 10A shows a Cross-Section View of Crankshaft A 22 in the Mud Motor Assembly.
Figure 10B shows a Cross-Section View of the Internal Crankshaft A Bearing 86 in the Mud Motor Assembly.
Figure 10C shows a Cross-Section View of the Drive Shaft 20 in the Mud Motor Assembly.
Figure 10D shows a Cross-Section of Piston A 24 in the Mud Motor Assembly.
Figure 10E shows a Cross-Section of Backstop A 272 in the Mud Motor Assembly.
Figure 10F shows a Cross-Section of Bypass Tube A-1 274 in the Mud Motor Assembly.
Figure 10G shows a Cross-Section of Bypass Tube A-2 276 in the Mud Motor Assembly.
Figure 10H shows a Cross-Section of the Drive Port of Chamber A ("DPCHA") 278 in the Mud Motor Assembly.
Figure 10J shows a Cross-Section of the Exhaust Port of Chamber A ("EPCHA") 280 in the Mud Motor Assembly.
Figure 10K shows a Cross-Section of the Backstop Port of Chamber A ("BPCHA") 282 in the Mud Motor Assembly.
Figure 10L shows a Cross-Section of the Backstop to Housing Weld 284 in the Mud Motor Assembly.
Figure 10M shows a Cross-Section of Piston A to Crankshaft A Weld 286 in the Mud Motor Assembly.

6 1/4 Inch OD Mud Motor

Figure 11 shows the Basic Component Dimensions for a preferred embodiment of the Mud Motor Assembly having an OD of 6 1/4 Inches. The original source drawing used to generate Figure 1 herein was a scale drawing that showed on a 1:1 scale the parts that would be used to make a 6 1/4 inch OD Mud Motor Assembly. Many of those details appear in Serial No. 61/687,394 which contains many drawings (which is 601 pages long).
There is a legend on Figure 11 that is quoted as follows: 3/8" STRIP. It is applicant's understanding that for a typical 6 1/2 inch OD mud motor now presently manufactured having a progressing cavity design, that the torque and horsepower output is often calculated based upon having an average 3/8 inch wide strip of effective differential piston area that is subject to the mud pressure that generates the torque on the rotor within the stator. The total area causing the torque in such a presently designed and manufactured mud motor is then given by 3/8 inch x the length of the rotor.
By contrast, the present design for a 6 1/4 inch OD Mud Motor Assembly shows that the effective piston width (the legend "PISTON W" in Figure 11), is 0.9625 inches wide. So, the width available to produce torque inside the new design is a factor of 2.6 greater. This is the reason why the new Mud Motor Assembly should be at least twice as powerful per unit length as a presently manufactured progressing cavity type mud motor. Furthermore, no "wiggle shaft" is needed with the new design, thereby again, making the present invention much more powerful per unit length (other factors being equal.)

Bearings

Figure 12 shows an Uphole View of the Upper Main Bearing 72 in the Mud Motor Assembly. It is a "split bearing" having an upper bearing part 316 and a lower bearing part 318. The bearing joining line is shown as element 320. It has a hole 322 that is designed to have the proper clearance around the drive shaft during operation. The split bearing is assembled over the proper portion of the drive shaft, and then Allen head cap screws 324 and 326 are tightened in place. When first placed on the drive shaft, and after the caps screws are tightened, bearing 72 will rotate about the center line of the drive shaft. The entire interior portion of the mud motor assembly is designed to slip into the housing. Then, external Allen head cap screws such as those designed by numeral 328 in Figure 20 are used to hold the bearing in place within the housing by screwing into threaded hole 330. To get threaded hole 330 lined up, a narrow tool can be inserted into the hole in the housing used to accept the cap screw, and that tool can be used to rotate the bearing into proper orientation. Small holes on the radial exterior of the bearing called "indexing holes" 332 (not shown) can be used to conveniently line up the bearing before the cap screw is put into place through the housing to engage threaded hole 330. Typical assembly methods and apparatus known to those having ordinary skill in the art are employed to design and install such split bearings. Bearing materials are chosen so as not to gall against the drive shaft.
Figure 12A shows a Section View of the Upper Main Bearing 72 in the Mud Motor Assembly.
Figure 12B shows an Uphole View of the Middle Main Bearing 74 in the Mud Motor Assembly. Hole passageways 334 and 336 are shown in Figure 12B. These are typical of the various types of passageways through a bearing for the pass-through of tubing above and below a bearing as may be typically required.
Figure 12C shows a Section View of the Middle Main Bearing 74 in the Mud Motor Assembly. Tubing 335 is shown passing through the hole 334 shown in Figure 12B. Tubing 337 is shown passing through the hole 336 shown in Figure 12B. During assembly, such tubing is first passed through the bearing, and then the entire assembly is pushed into the Housing for further assembly as previously described.

Return Spring A

Figure 13 shows a Section View of Installed Return Spring A 78 Which is a Portion of Ratchet Assembly A 30 in the Mud Motor Assembly. In this embodiment, one end 338 of the Return Spring A is positively anchored into a portion of Crankshaft A 22. The other end 340 of the Return Spring A is positively anchored into a split-bearing-like structure 344 held in place to the housing 18 by Allen cap screw 346 as is typical with such parts in the Mud Motor Assembly. Return Spring A 78 is a type of torsion spring. Typical design and testing procedures are used that are well known to individuals having ordinary skill in the art. Adequate space is to be made available to allow the Return Spring A to suitably change its radial dimensions during operation.
Figure 13A shows a Perspective View of Return Spring A 78 in the Mud Motor Assembly.

Cross Sections of Ratchet Assembly A (eight figures)

Figure 14 shows a Cross Section View CC of Ratchet Assembly A in the Mud Motor Assembly. Housing 18, drive shaft 20, and Crankshaft A 22 have already been defined. This Cross Section CC is marked on Figure 6B. This figure derives from a 1:1 scale drawing for a 6 1/4 inch OD Mud Motor Assembly. The detailed dimensions can be found in Serial No. 61/687,394. In one embodiment, the rounded base portion 348 of the Drive Pin A 42 may be chosen to be a robust 3/4 inches OD. First torsion rod return spring 350 and second torsion rod return spring 352 are shown. The first and second torsion rod return springs provide the spring forces to drive the Pawl A 40 onto the Pawl A Latch Lobe 44 during the final portion of the Return Stroke of Piston A. The symbol EQ stands for equal angles, and convenient choices may be made. There are many different choices for other dimensions including the radii identified by the legends R2, R4, R5 and R6. One particular choice radial dimensions for one embodiment invention may be found in Serial No. 61/687,394 that are appropriate for a 6 1/4 inch OD Mud Motor Assembly.
Figure 14A shows a cross section portion 354 of Drive Pin A 42 for a Preferred Embodiment of the Mud Motor Assembly Having an OD of 6 1/4 Inches.
Figure 14B shows a Cross Section View DD of one embodiment of Ratchet Assembly A in the Mud Motor Assembly. This Cross Section DD is marked on Figure 6B. Portion 356 of Drive Pin A 42 is shown. First and second torsion rods 350 and 352 are also shown. Various dimensions are shown that are appropriate for a 6 1/4 inch OD Mud Motor Assembly. There are many different choices for other dimensions including the radius R4 and a distance of separation X15. One particular choice of these dimensions for one embodiment invention may be found in Serial No. 61/687,394 that are appropriate for a 6 1/4 inch OD Mud Motor Assembly.
Figure 14C shows a Cross Section View EE of one embodiment of Ratchet Assembly A in the Mud Motor Assembly. This Cross Section EE is marked on Figure 6B. Portion 358 of Drive Pin A 42 is shown. First and second torsion rods 350 and 352 are also shown. A portion 360 of Pawl A 40 is shown. Drive Pin A Slot 362 is also shown. Various dimensions are shown that are appropriate for a 6 1/4 inch OD Mud Motor Assembly. There are many different choices for other dimensions including the radii identified by the legends R2 and R4, and the distances identified by the legends X6 and X7. One particular choice of these dimensions for one embodiment invention may be found in Serial No. 61/687,394 that are appropriate for a 6 1/4 inch OD Mud Motor Assembly.
Figure 14D shows How to Utilize a Larger Drive Pin 364 than that shown in Figure 14C. Arrows 366 and 368 show the directions of the enlargement of the Drive Pin A Slot 362. The dimensions shown are appropriate for a 6 1/4 inch OD Mud Motor Assembly. The remainder of the legends have been previously defined.
Figure 14E shows an Optional Larger and Different Shaped Drive Pin 370 than in Figure 14C. The dimensions shown are appropriate for a 6 1/4 inch OD Mud Motor Assembly. The remainder of the legends have been previously defined.
Figure 14F shows a Cross Section View AA of Ratchet Assembly A in the Mud Motor Assembly. This Cross Section AA is marked on Figure 6B. Pawl A Capture Pin 38 is shown in its "down position" 372 seated against the OD of Drive Shaft 20. This drawing was derived from a 1:1 scale drawing for a Mud Motor Assembly having an OD of 6 1/4 inches. There are many different choices for other dimensions including the radii identified by the legends R1, R2, and R3, and the distances identified by the legends X7, X8, and X9. One particular choice of these dimensions for one embodiment invention may be found in Serial No. 61/687,394 that are appropriate for a 6 1/4 inch OD Mud Motor Assembly.
Figure 14G shows an Uphole View of Flywheel A and Raised Guide for Pawl A Capture Pin in Section BB of Ratchet Assembly A Showing Sequential Movement of Pawl A Capture Pin in the Mud Motor Assembly.
A portion 374 of Flywheel 40 is shown. Raised Guide for Pawl A Capture Pin 36 is also shown. Sequential positions a, b, and c of the Pawl A Capture Pin 38 shows how that pin is captured so that the Pawl A 40 is returned to its proper seated position at the end of the Reset Stroke of Piston A. In position "a", the Pawl A Capture Pin is shown in its maximum radial distance R2 away from the center of rotation of the Drive Shaft 20, which is it's maximum "up position" and which can be identified herein as R2(a). In position "c", the Pawl A Capture Pin is in its closest radial distance R2 away from the center of rotation of the Drive Shaft 20, which is it's "down position" and which can be identified herein as R2(c). Position "b" shows an intermediate position of the Pawl A Capture Pin. In one preferred embodiment of the invention, the mathematical difference R2(a) - R2(c) = 3/8 inch plus 1/32 inch. It that embodiment, the Pawl A Seat Width ("PASW") is chosen to be 3/8" (see element 377 in Figure 15A), so that the clearance distance 379 is 1/32" between the Tip of Pawl A lifter Lobe 381 and the ID 383 of the Pawl A 40 in Figure 15A.
There are many choices for Flywheel A. In one preferred embodiment, the energy stored in Flywheel A and in Flywheel B is sufficient to keep the rotary drill bit turning through 360 degrees even if the mud pressure through the drill string drops significantly.

Pawl A and Pawl A Latch Lobe

Figure 15 shows one embodiment of the Pawl A Latch Lobe 44 Fully Engaged With Pawl A 40 at mating position 376 in the Mud Motor Assembly. As shown, the Pawl A Capture Pin 38 is opposite theta of 0 degrees ready for the beginning of the Power Stroke of Piston A.
Figure 15A shows one embodiment of the Pawl A Latch Lobe 44 Completely Disengaged From Pawl A 40 in the Mud Motor Assembly. Here the Pawl A Capture Pin is opposite an angle theta slightly in excess of 230 degrees. Pawl A 40 has been lifted into this position by the Pawl A Lifter Lobe 46 of the Mud Motor Assembly, and is ready to begin its return with the Return Stoke of Piston A. Numeral 377 is to designate the Pawl A Seat Width ("PASW"). In several preferred embodiments of the 6 1/4 inch OD Mud Motor Assembly, PASW is chosen to be 3/8". Figure 15A shows the clearance distance 379 between the Tip of Pawl A Lifter Lobe 381 and the ID 383 of the Pawl A 40. As explained in relation to Figure 14G, the clearance distance 379 is chosen to be 1/32 inch in one preferred embodiment.
Figure 15B shows a Optional Slot 378 Cut in Pawl A 40 to Make Torsion Cushion at mating position 376 During Impact of Pawl A Latch Lobe in the Mud Motor Assembly.

Pawl A Lifter Lobe and Pawl A

Figure 16 shows the Pawl A Lifter Lobe at theta of 0 Degrees in the Mud Motor Assembly. One embodiment of the Pawl A Lifter Lobe 46 in shown in Figure 16. Pawl A 40 is also shown. The Pawl A Lifter Lobe 46 has Lifter Lobe Profile 380 that rides within Pawl A Lifter Recession 382. At theta equals 0 degrees, the Pawl A Lobe Lifter 46 does NOT contact any portion of the Pawl A Lifter Recession 382. There is a clearance 384 between the Pawl A Lobe Lifter 46 and any portion of the Pawl A. Pawl A Stop 386 is shown that is welded in place with weld 388 to the Housing 18 at location 390.
Figure 16A shows the Pawl A Lifter Lobe at 210 Degrees in the Mud Motor Assembly. Here, the leading edge 392 of Pawl A has made contact with the Pawl A Stop 386, and when that happens, the Pawl A Lifter Lobe makes contact with the Pawl A Lift Recession 382, and drives the Pawl A radially away from the center line of the Mud Motor Assembly. Eventually, the tip of the Pawl A Lifter Lobe 394 rides on the interior portion of the maximum excursion 396 of the Pawl A Lifter Recession 382. As time moves forward from the event shown in Figure 16A, the Pawl A Lifter Lobe that is a part of the Drive Shaft 20 continues its clockwise rotation looking downhole. Meanwhile, Pawl A will begin its return ruing the Return Stroke of Piston A.
Figure 16B shows the Pawl A Lifter Lobe 46 at -90 Degrees and the Partial Return of Pawl A 40 in the Mud Motor Assembly. The Pawl A Lifter Lobe 46 is rotating clockwise 398 looking downhole. The Pawl A in Figure 16 is rotating counter-clockwise 400 looking downhole.

Intake Valve A (seven figures)

Figure 17 shows Intake Port A 402 in Intake Valve A 80 Passing theta of 0 Degrees allowing relatively high pressure mud to flow through the Intake Port A 402 and then through the Drive Port of Chamber A ("DPCHA") 278 and thereafter into Chamber A, thus beginning the Power Stroke of Piston A in the Mud Motor Assembly. This portion of mud flowing through this route is designated as numeral 492 (not shown). The Intake Port A 402 in Intake Valve A 80 is shown as a dotted line; the Drive Port of Chamber A ("DPCHA") 278 is shown as a solid circle; and these conventions will be the same in the following through Figure 17F. These views are looking uphole. The distance of separation between Intake Port A 402 in Valve 80 and the Drive Port of Chamber A ("DPCHA") 278 is discussed in relation to Figures 20A and 20B.
Figure 17A shows the Intake Port A 402 in Intake Valve A 80 Passing theta of 90 degrees during the Power Stroke of Piston A in the Mud Motor Assembly. When the input power to the Mud Motor Assembly matches the output power delivered, then under ideal circumstances, the Drive Port of Chamber A ("DPCHA") 278 synchronously tracks Intake Port A 402 in Intake Valve A 80. By "synchronously tracks" means that the two travel at the same angular velocity and they overlap.
Figure 17B shows the Intake Port A 402 in Intake Valve A 80 Passing theta of 180 degrees during the Power Stroke of Piston A in the Mud Motor Assembly. The Drive Port of Chamber A ("DPCHA") 278 is shown still synchronously tracking the Intake Port 402 while rotating in the clockwise direction 404.
Figure 17C shows the Intake Port A 402 in Intake Valve A 80 Passing theta of 210 degrees during the very end of the Power Stroke of Piston A in the Mud Motor Assembly. The Drive Port of Chamber A ("DPCHA") 278 is shown still synchronously tracking the Intake Port A 402.
Figure 17D shows Intake Port A 402 in Intake Valve A 80 Passing theta of 240 degrees after the Power Stroke of Piston A has ended. The Port A 402 in Intake Valve A 80 is an integral part of the Drive Shaft 20, and continues to rotate in the clockwise direction 404 looking downhole. The Drive Port of Chamber A ("DPCHA") 278 is shown during its counter-clockwise motion during the Return Stroke of Piston A that is rotating in the counter-clockwise direction 406 looking downhole.
Figure 17E shows Intake Port A 402 in Intake Valve A 80 at theta of - 30 Degrees in the Mud Motor Assembly During the Return Stroke of Piston A. The Drive Port of Chamber A ("DPCHA") 278 is shown at the end of the Return Stroke of Piston A.
Figure 17F shows Intake Port A 402 in Intake Valve A again passing theta of 0 degrees that begins the Power Stroke of Piston A in the Mud Motor Assembly. That Power Stroke of Piston A begins when relatively high pressure mud flows through Intake Port A 402 in Intake Valve A and then through the Drive Port of Chamber A ("DPCHA") 278 and then into Chamber A that in turns puts a torque on Piston A.

Directional Drilling, MWD & LWD

Figure 18 shows the upper portion of the Bottom Hole Assembly 408 that includes the Mud Motor Assembly 12. The upper threaded portion 410 of the housing 18 accepts the lower threaded portion 412 of the Instrumentation and Control System 414. The upper threaded portion 484 of the Instrumentation and Control System 414 is attached to the drill pipe 486 (not shown) that receives mud from the mud pumps 488 (not shown) located on the surface near the hoist 490 (not shown). The Instrumentation and Control System may include directional drilling systems, rotary steerable systems, Measurement-While-Drilling ("MWD") Systems, Logging-While-Drilling Systems ("LWD"), data links, communications links, systems to generate and determine bid weight, and all the other typical components used in the oil and gas industries to drill wellbores, particularly those that are used in conjunction with currently used progressing cavity mud motors. The uphole portion of the Bottom Hole Assembly 408 is connected to the drill string 416 (not shown) that is in turn connected to suitable surface hoist equipment typically used by the oil and gas industries 418 (not shown). For handling convenience, housing 18 may be optionally separated into shorter threaded sections by the use of suitable threaded joints such the one that is identified as element 420. The threads 420 may also be conveniently used when assembling Piston A and related parts into Chamber A. Similar threads are used in the Housing near Chamber B that is element 512 (not shown). Other threads 514 (not shown) are also in the Housing. Element 328 is representative of the Allen head caps screws used to hold bearings and other components in place that is further referenced in relation to Figure 12.

Downhole Portion of BHA

The downhole portion of the Bottom Hole Assembly 422 is shown in Figure 19. The entire Bottom Hole Assembly 424 (not shown) is comprised of elements 408 and 422 and is being used to drill borehole 426. Downward flowing mud 428 is used to cool the bit and to carry rock chips with the mud flowing uphole 430 in annulus 432 that is located in geological formation 434. The legend RLPMF stands for Relatively Low Pressure Mud Flow (RLPMF) 16 designated by the unique shading used only for this purpose in this application (see Figure 2A).

Mud Flow Paths Identified

Figure 20 shows the Relatively High Pressure Mud Flow ("RHPMF") through the Mud Motor Apparatus. See Figure 2. The paths for mud flow through the apparatus is described. Whether or not fluid actually flows is, of course, dependent upon whether or not certain valves are open, and in turn, that depends upon the "Timing State" of the apparatus.
The Mud Motor Apparatus 12 receives its input of mud flow 436 from the drill pipe 484 (not shown) and through the Instrument and Control System 414. The RHPMF then flows through upper apparatus A flow channels 438 and proceeds to two different places (dictated by the timing of the apparatus):

(a) through Intake Port A 402 in Intake Valve A 80 and then through the Drive Port of Chamber A ("DPCHA") 278 and thereafter into Chamber A 84, thus providing the RHPMF for the Power Stroke of Piston A 24 in the Mud Motor Assembly, and the portion of mud flowing through this route is designated as numeral 492 (not shown) that produces a first portion of rotational torque 494 (not shown) on drive shaft 20 ; and (b) through Bypass Tube A-1 274 and Bypass Tube A-2 276 through upper apparatus B flow channels 440 to Intake Port B 442 in Intake Valve B 94 and then through the Drive Port of Chamber B ("DPCHB") 444 and thereafter into Chamber B 98 thus providing the RHPMF for the Power Stroke of Piston B 28 in the Mud Motor Assembly, and the portion of mud flowing through this route is designated as numeral 496 (not shown) that produces a second portion of torque 498 (not shown) on drive shaft 20.

Figure 20A shows the Relatively Low Pressure Mud Flow ("RLPMF") through the Mud Motor Apparatus. See Figure 2A. The paths for mud flow through the apparatus is described. Whether or not fluid actually flows is, of course, dependent upon whether or not certain valves are open, and in turn, that depends upon the "Timing State" of the apparatus. Mud flows to the drill bit as follows:

(c) during the Return Stroke of Piston A 24 in the Mud Motor Apparatus, RLPMF exhausts through the Exhaust Port of Chamber A ("EPCHA") 280, and then through Exhaust Port A 446 of Exhaust Valve A 90, and then into lower apparatus A flow channels 448, and then through Bypass Tube B-1 450 and Bypass Tube B-2 452, and then into RLPMF co-mingle chamber 454, and thereafter as a portion of co-mingled mud flow 428 through drill pipe 68 to the drill bit 70; and (d) during the Return Stoke of Piston B 28 in the Mud Motor apparatus, RLPMF exhaust through the Exhaust Port of Chamber B ("EPCHB") 456 and then through Exhaust Port B 458 of Exhaust Valve B 104, and then into RLPMF co-mingle chamber 454, and thereafter as a portion of co-mingled mud flow 428 through drill pipe 68 to the drill bit 70.

It should be noted that there are many ways to assemble the Intake Valve A 80 into its mating position with Crankshaft A 22. The Intake Valve A 80 can be a split member itself, and welded or bolted in place before the entire assembly is slipped into the Housing 10. Similar comments apply to the other intake and exhaust valves.
There are many mating parts where one or both move. The distance of separation between any of the parts shown in Figure 20 can chosen depending upon the application. In some preferred embodiments, such distances are chosen to be 1/32 of an inch for many mating parts. In other embodiments, distances of separation of .010 inches may be chosen. There are many alternatives.
In several preferred embodiments, the customer chooses the desired mud flow rate, the RPM, and the required HP (horsepower). If a pressure drop across the Mud Motor Assembly is then chosen to be a specific number, such as 750 psi for example, then the internal geometry of the Chambers and Pistons can thereafter be determined using techniques known to anyone having ordinary skill in the art.

Timing Diagrams for the Mud Motor Assembly

Figure 21 compares the pressure applied to the Drive Port of Chamber B ("DPCHB") to the pressure applied to Drive Port of Chamber A ("DPCHA"). The pressure applied to the DPCHB lags that applied to DPCHA by 180 degrees. Here, PH stands for higher pressure, and PL stands for lower pressure.
Figure 21A shows that a low pressure PL is applied to the Exhaust Port of Chamber A ("EPCHA") and to the Exhaust Port of Chamber B ("EPCHB") during the appropriate Return Strokes.
Figure 21B shows the relationship between the maximum lift of the tip of the Paw A Lifter Lobe 394 and the pressure applied to the Drive Port of Chamber A ("DPCHA").

Analogous Figures for Chamber B and Piston B

Figures 9, 9A, 9B,9C, 9D, 9E, 9F, and 9G show a Power Stroke for Chamber A. Analogous figures can be made for the Power Stroke for Chamber B. Those for "B" strongly resemble those for "A". If relative angles are used, then they would look very similar. If absolute angles are used, then the starting position for the Power Stroke for Piston B in Chamber B would start at 180 degrees on Figure 9 and proceed clockwise (180 degrees plus 210 degrees). This analogous second set of Figures for the Power Stoke for Chamber B is called numeral 502 herein for reference purposes, but it is not shown on any figures.
In the above disclosure, much effort has been directed at disclosing how Chamber A, Piston A, and related portions of the Mud Motor Assembly work. In the interests of brevity, many of those drawings were not repeated for Chamber B, Piston B, and related portions of the Mud Motor Assembly. Chamber B and Piston B work analogously to that of Chamber A and Piston A. Anybody with ordinary skill in the art can take the first description to get to second one. For example, the first torsion rod spring 350 and second torsion rod spring 352 apply to Crankshaft A and Chamber A. But analogous structures exist in relation to Crankshaft B and Chamber B. Anyone with ordinary skill in the art would know that these structures are present from the figures presented so far even if they were not numbered. These elements could be hypothetically numbered b350 and b352 - meaning they are analogous for Chamber B. Accordingly, all numerals herein defined are also defined for any numeral adding a "b" in front as stated. In the interests of brevity, applicant has decided not to do that explicitly herein. Instead, for example:

The third torsion rod return spring for Crankshaft B is 504 (also b350).

The fourth torsion rod return spring for Crankshaft B is 506 (also b352)
Figure 9J pertains to Chamber A. The analogous figure pertaining to Chamber B is numeral 508 (not shown).
Figure 16B pertains to Chamber A. The analogous figure pertaining to Chamber B is 510 (not shown).

Other Comments

The Mud Motor Assembly 12 is also called equivalently the Mud Motor Apparatus 12.
Theta describes the angle shown on many of the Figures including
Figure 9. The word "theta" describes in the text the symbol shown opposite Piston A in Figure 9.
Figure 3F shows Ratchet Assembly A 30 of the Mud Motor Assembly. However, Ratchet Assembly A 30 is an example of a ratchet means. Similar comments apply to other parts in the Mud Motor Assembly. Any such part can be an example of a "means".
Elements 520, 521, .... are reserved in the event that these are necessary to replace legends on the various figures.
While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as exemplification of preferred embodiments thereto. As have been briefly described, there are many possible variations. Accordingly, the scope of the invention should be determined by the appended claims.

Claims

A mud motor apparatus (12) possessing one single drive shaft (20) that turns a rotary drill bit (70), which apparatus is attached to a drill pipe (486) that is a source of high pressure mud (14) to said apparatus, wherein said drive shaft (20) receives at least a first portion (494) of its rotational torque from any high pressure mud (492) flowing through a first hydraulic chamber (84) within said apparatus, and said drive shaft (20) receives at least a second portion (498) of its rotational torque from any high pressure mud (496) flowing through a second hydraulic chamber (98) within said apparatus.
A method to provide torque and power to a rotary drill bit (70) rotating clockwise attached to a drive shaft (20) of a mud motor assembly (12) comprising at least the following steps:
a. providing relatively high pressure mud (14) from a drill pipe (486) attached to an uphole end of said mud motor assembly (484);

b. passing at least a first portion (492) of said relatively high pressure mud through a first hydraulic chamber (84) having a first piston (24) that rotates a first crankshaft (22) clockwise about its own rotation axis from its first relative starting position at 0 degrees through a first angle of at least 210 degrees, but less than 360 degrees during its first power stroke;

c. mechanically coupling said first crankshaft (22) by a first ratchet means (30) to a first portion (44) of said drive shaft (20) to provide clockwise rotational power to said drive shaft during said first power stroke;

d. passing at least a second portion (496) of said relatively high pressure mud through a second hydraulic chamber (98) having a second piston (28) that rotates a second crankshaft (26) clockwise about its own rotation axis from its first relative starting position of 0 degrees through a second angle of at least 210 degrees, but less than 360 degrees during its second power stroke (502);

e. mechanically coupling said second crankshaft (26) by a second ratchet means (48) to a second portion (62) of said drive shaft (20) to provide clockwise rotational power to said drive shaft during said second power stroke 502; and,

f. providing first control means (46) of said first ratchet means (30), and providing second control means (64) of said second ratchet means (48), to control the relative timing of rotations of said first crankshaft and said second crankshaft so that at the particular time that said first crankshaft (22) has rotated from its first relative starting position through 180 degrees nearing the end of its first power stroke at 210 degrees, said second crankshaft begins its rotational motion from its relative starting position of 0 degrees were it begins its second power stroke 502.
The method in Claim 2 wherein said first ratchet means (30) is comprised of a first pawl (40) that is flexibly attached by a first torsion rod spring (350) and second torsion rod spring (352) to said first crankshaft (22), and first pawl latch (44) that is an integral portion of the drive shaft (20).
The method in Claim 2 wherein said second ratchet means (48) is comprised of a second pawl (58) that is flexibly attached by third torsion rod spring (504) and fourth torsion rod spring (506) to said second crankshaft (26), and second pawl latch (62) that is an integral portion of the drive shaft (20).
The method in Claim 3 wherein said first control means is comprised of a first pawl lifter means (46) that is an integral portion of the drive shaft (20) that lifts said first pawl (40) in a first fixed relation to said drive shaft (20).
The method in Claim 4 wherein said second control means is comprised of a second pawl lifter (64) means that is an integral portion of the drive shaft (20) that lifts said second pawl (58) in a second fixed relation to said drive shaft.
The method in Claim 5 wherein following the clockwise rotation of the said first crankshaft (22) about its rotational axis through an angle of at least 210 degrees during its first power stroke, said first pawl lifter means (46) disengages said first pawl (40) from said first pawl latch (44), so that first torsion spring (78) returns first crankshaft (22) in a counter-clockwise rotation to its initial starting position completing a first power stroke and first return cycle for said first crankshaft (22) while said drive shaft (20) continues to rotate clockwise unimpeded by the return motion of said first crankshaft.
The method in Claim 6 wherein following the clockwise rotation of the said second crankshaft (26) about its rotational axis through an angle of at least 210 degrees during its second power stroke (502), said second pawl lifter means (64) disengages said second pawl (58) from said second pawl latch (62), so that second torsion spring (92) returns second crankshaft (26) in a counter-clockwise rotation to its initial starting position completing a second power stroke and second return cycle for the second crankshaft (26) while said drive shaft (20) continues to rotate clockwise unimpeded by the return motion of said second crankshaft (508 and 510).
The method in Claim 7 wherein the first torsional energy stored in said first torsion return spring (78) at the end of said first power stroke is obtained by said first crankshaft (22) twisting said first torsion return spring (78) during said first power stroke.
The method in Claim 8 wherein the second torsional energy stored in said second torsion return spring (92) at the end of said second power stroke is obtained by said second crankshaft 26 twisting said second torsion return spring (92) during said second power stroke (502).
The method in Claims 9 and 10 wherein said first power stroke and said second power stroke are repetitiously repeated so that torque and power is provided to said clockwise rotating drive shaft (20) attached to said drill bit (70), whereby said clockwise rotation is that rotation observed looking downhole toward the top of the rotary drill bit.