CA1061411A - Method of transmitting signals from a drill bit to the surface - Google Patents
Method of transmitting signals from a drill bit to the surfaceInfo
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- CA1061411A CA1061411A CA262,281A CA262281A CA1061411A CA 1061411 A CA1061411 A CA 1061411A CA 262281 A CA262281 A CA 262281A CA 1061411 A CA1061411 A CA 1061411A
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- location
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Abstract
ABSTRACT
A system for performing wellbore telemetry operations wherein a communication link between a subsurface location in a well and the location substantially at the surface is established and maintained through electromagnetic coupling between two in-sulated electric conductors. The first conductor is electrically coupled to a transmitter, normally located at the subsurface location, and extends upwardly in the well. The second conductor is electrically coupled to a receiver, normally at the surface location, and extends down into the well. Normally, the two con-ductors will overlap along a substantial portion of the lengths thereof. As the well is drilled deeper and the drill string is lengthened, the transmitter and the first conductor follow the progression of the wellbore into the earth, thereby reducing the overlap between the first and second conductors. When the two conductors cease to overlap, the second conductor may be leng-thened to re-establish the overlap.
A system for performing wellbore telemetry operations wherein a communication link between a subsurface location in a well and the location substantially at the surface is established and maintained through electromagnetic coupling between two in-sulated electric conductors. The first conductor is electrically coupled to a transmitter, normally located at the subsurface location, and extends upwardly in the well. The second conductor is electrically coupled to a receiver, normally at the surface location, and extends down into the well. Normally, the two con-ductors will overlap along a substantial portion of the lengths thereof. As the well is drilled deeper and the drill string is lengthened, the transmitter and the first conductor follow the progression of the wellbore into the earth, thereby reducing the overlap between the first and second conductors. When the two conductors cease to overlap, the second conductor may be leng-thened to re-establish the overlap.
Description
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2 1. Field of the Invention
3 This invention relates to an improved method and apparatus for
4 performing wellbore telemetry operations. In one aspect, it relates to a method for establishing and maintaining a communication link between a 6 subsurfac~ location in a rotary drill string and a surface location.
7 2. Description of the Prior Art 8 In the drilling of oil wells, gas wells, and similar boreholes, it 9 frequently is desirable to transmit data between subsurface and surface locations. One application where data transmission has received considerable 11 attention in recent years is in wellbore telemetry systems designed to 12 sense, transmit, and receive information indicative of a subsurface condi-13 tion. This operation has become known in the art as "logging while dril-14 ling."
A major problem associated with wellbore telemetry systems has been 16 that of providing reliable means for transmitting signals between the sub-17 surface and surface locations. This problem can best be appreciated by 18 considering the manner in which rotary drilling operations are normally 19 performed. In conventional rotary drilling, a borehole is advanced by rotating a drill string provided with a drill bit at its lower end. Lengths 21 of drill pipe, usually about 30 feet long, are added to the drill string, 22 one-at-a-time, as the borehole is advanced in increments. In adapting a 23 telemetry system to rotary drilling equipment, the means for transmitting the 24 electric signal through the drill string must permit the connection of additional pipe lengths to the drill string as the borehole is advanced.
26 An early approach to the problem involved the use of continuous 27 electric cable which was adapted to be lowered inside the drill string and to 28 make contact with a subsurface terminal. This technique, however, required 29 withdrawing the cable from the drill string each time a pipe length was added to the drill string. A more recent approach involves the use of special 106~4~.
1 drill pipe. Each pipe section of the special pipe is provided with an 2 electric conductor having connectors at its opposite ends. Electric con-3 tinuity is maintained across the junction of two pipe sections by connectors 4 of one section contacting a connector on the adjacent pipe section (see U.S.
Patent Nos. 3,518,608 and 3,518,609). Disadvantages of this system include 6 the high cost of the special pipe sections, the need for a large number of 7 electric connections (one at each joint), and the difficulty of maintaining 8 insulation of the electric connectors at each joint.
9 Still another approach involves the use of cable sections mounted in each pipe section (see U.S. Patent No. 2,748,358). The cable sections are 11 connected together as pipe sections are added to the drill string. Each 12 cable section is normally made slightly longer than its associated pipe 13 section, with the result that a small amount of slack is present in the 14 conductor string at all times.
A more recent approach involves the use of a cable maintained in 16 a looped configuration within the drill string. The looped arrangement 17 stores cable in the drill string and permits the cable to be extended as 18 the drill string is lengthened. This technique normally requires the use 19 of sheaves and other apparatus within the drill string to maintain the cable in the looped configuration. However, this arrangement presents flow res-21 trictions within the relatively narrow opening. Moreover, care must be 22 exercised to prevent cable entanglement, particularly for long cable loops.
24 The purpose of the present invention is to provide a communication link between a subsurface location in a well and the surface.
26 Briefly the invention, in one embodiment, involves transmitting 27 data from the subsurface location via an insulated conductor extending 28 upwardly from the subsurface location and functioning as an antenna. A
29 second insulated conductor extends downwardly from the surface and, normally, will substantially overlap the first conductor. The transmitted signal is 41~
1 picked up by this second conductor through electromagnetic coupling. The 2 second conductor functions as a receiving antenna and is coupled to a 3 receiver at the surface.
4 Normally, the transmitting antenna is lowered to the desired sub-surface location when it is desired to begin telemetering operations and 6 the receiving antenna is also inserted into the well at this time. Because 7 the overlapping length of the two antennas is not critical, both antennas 8 may initially extend substantially the entire length of the wellbore. The 9 well can then be drilled to approximately twice its original depth before the wires cease to overlap and the communication link is lost. At that 11 time, the length of the receiving antenna may be increased to reestablish 12 the overlap to resume telemetering operations.
13 A principal advantage of this invention is that the well depth 14 can be substantially increased and the communication link maintained with-out increasing the length of either conductor.
16 Another advantage is that the interior of the drill pipe is rela-17 tively unobstructed.
1~ BRIEF DESCRIPTION OF TH DRAWINGS
19 FIGURE 1 is a schematic view of well drilling equipment with two electric conductors arranged within the drill string in a preferred con-21 figuration.
22 FIGURE 2 is an enlarged fragmentary view, shown partially in 23 longitudinal section, of apparatus useful in the invention for supporting 24 the lower conductor within the drill string.
FIGURE 3 is a top plan view of the apparatus illustrated in 26 FIGURE 2.
27 FIGURES 4-6 are schematic views illustrating a preferred sequence 28 of steps for adding a length of drill pipe into the drill string.
~06~41~
1 DESCRIPTION OF _HE PREFERRED EMBODIMENT
2 Conventional rotary drilling equipment, as illustrated schemat-3 ically in FIGURE 1, includes swivel 10, kelly 11, tubular drill string 12 and4 a bit 13. These components, connected in the manner illustrated, are sus-pended from the drilling derrick 14 by means of rig hoisting equipment. The 6 kelly 11 passes through rotary table 16 and connects to the upper end of the 7 drill string 12. The term "drill string" as used herein refers to the column8 of tubular pipe between the bit 13 and kelly 11. The major portion of the 9 drill string 12 normally is composed of drill pipe with a lower portion beingcomposed of drill collars. The drill string 12 consists of individual pipe 11 sections, either drill pipe or drill collars connected together in end-to-end 12 relation. In the lower three sections of FIGURE 1, the diameters of the 13 borehole and the drill string 12 have been expanded in relation to the upper14 section to reveal further details.
The borehole 17 is advanced by rotating the drill string 12 and 16 bit 13. Drilling fluid is pumped down through the drill string 12 and up the 17 borehole annulus. The drilling fluid is delivered to swivel 10 through a 18 hose (not shown) attached to hose connection 18 and is returned to the sur-19 face fluid system from the borehole annulus through pipe 19. A kelly bush-ing 20 couples the rotary table 16 to the kelly 11 and provides means for 21 transmitting power from the rotary table 16 to the drill string 12 and bit 13.
22 The present invention may also be used in systems which employ a power swivel 23 in lieu of a kelly and rotary table; for purposes of illustration, however, 24 the invention will be described in connection with the kelly and rotary table arrangement.
26 As mentioned previously, it frequently is desirable to monitor a 27 subsurface drilling condition during drilling operations. This requires 28 measuring a physical condition at the subsurface location, transmitting the 29 data signal to the surface, and reducing the signal to useful form. Typicalsituations where telemetry is applicable in drilling operations include 106~4~1 1 drilling through abnormal pressure zones, drilling through zones where hole 2 deviation is likely to be a problem, directional drilling, exploratory dril-3 ling and the like.
4 An instrument 21 capable of measuring a subsurface condition and generating an electrical signal indicative of or representative of that 6 condition is provided within the drill string 12. A variety of devices 7 capable of sensing a physical condition are available. These include trans-8 ducers for measuring pressure, temperature, strain, and the like; surveying g instruments for measuring hole deviation; and logging instruments for mea-suring resistivity or other properties of subsurface formations. The instru-11 ment 21 may normally be powered by batteries. Alternatively, a subsurface 12 generator driven by fluid flowing through the drill string 12 may be used to 13 power instrument 21.
14 The communication link between the instrument 21, located within the well, and the surface is established by transmitting the data from instru-16 ment 21 to the surface via an electromagnetic link. Normally, the data will 17 be transmitted by encoding a train of electrical pulses and using these 18 encoded pulses to modulate a carrier. Phase modulation may preferably be 19 employed in the transmission link since phase modulation is relatively insen-sitive to noise. More than one transducer or other device may be employed in 21 the instrument 21 if desired, in which case a multiplexer may be used for 22 sending the various signals over a single transmission link.
23 Instrument 21 includes a conventional transmitter. Conductor 40 is 24 coupled to the transmitter within instrument 21 so as to function as an antenna. This conductor wire must be electrically insulated throughout its 26 entire length to prevent shorting out the electrical signal. Conductor 40 may 27 be of sufficient stiffness to be self-standing within the well. Alternatively, 28 support member 42 may be employed to support a more flexible wire.
29 As shown in FIGURES 2 and 3, support member 42 is basically a ring-shaped device, made from stainless steel or other strong material, adapted to 106~4~
1 fit in an annular notched shoulder 50 formed in the box end of a pipe sec-2 tion 12B. Shoulder 50 may be provided by milling the box end of the pipe 3 section in which support member 48 rests or, alternatively, may be provided 4 by a special sub. On one side of support member 42 (see FIGURE 3) there is an extended section 46 having a slot 48. Support bracket 51 is mounted by 6 welding or other means, colinearly with slot 48. The upper end of wire 40 7 fits into the slot 48 and support bracket 51 and is restrained from lateral 8 movement by means of a bolt 52 that is mounted in holes in support bracket 519 as shown. Wire 40 has an expansion 54 at its upper end having q diameter wider than bracket 51 to prevent townward movement of the wire and maintain 11 the wire in tension.
12 Other structures serving the same function as support member 42 13 will suggest themselves to those skilled in the art. It is desirable that 14 the drill string not be substantially obstructed.
A receiving antenna 43 extends downwardly from the top of the well 16 so that its length substantially overlaps transmitting antenna 40. It is not 17 necessary to use special antenna wire for either the receiving or trans-18 mitting antennas. Conducting wire such as teflon coated #18 copper clad 19 steel can be employed. This conductor must also be electrically insulated throughout its entire length.
21 The installation of the apparatus and performance of the method of22 the present invention is as follows. After drilling has progressed to the 23 point where it is desired to commence wellbore telemetry operations, drilling 24 operations are interrupted and package 21 is lowered into the drill string using conventional techniques with antenna 40 connected to the transmitter 26 antenna terminal thereon. For this operation, a sheave disposed above the 27 derrick floor is normally employed to guide the antenna wire 40 into the 28 wellbore as it is unreeled from a drum. When the instrument 21 is properly 29 seated in the lower end of the drill string 12, preferably in a locking sub immediately above bit 13, the support member 42, if used, is inserted into ~061~1 1 the annular notched shoulder in the box end of the pipe section as shown in 2 FIGURE 2, and the top of antenna 40 is attached to the support member in the 3 manner described above. Receiving antenna 43 is also run into the well to 4 the desired length, which may preferably be nearly the entire length of the well. A weight may preferably be attached to the lower end of antenna 43 6 to maintain the wire in tension. The two wires, 40 and 43, may be initially 7 lowered into the well simultaneously. Alternatively, instrument package 21 8 may be positioned within the drill string when drilling commences, or some 9 tlme later, and conducting wire 40 lowered with a conventional stabbing connector 14 at the lower end thereof for connecting to instrument package 21 11 when it is desired to begin telemetering operations.
12 In order to facilitate the addition of pipe sections to the drill 13 string 12 it is preferred that a conductor 43A, comprising the upper portion14 of the receiving antenna, extend through the interior of kelly 11 as illus-trated in FIGURE 1 and connect to the upper end of conductor 43.
16 If telemetry operations are to be performed while the kelly 11 and17 drilling string 12 are rotating, the upper end of conductor 43A terminates 18 at a device 26 near the upper end of the kelly, capable of conducting the 19 received signal from the rotating member to a stationary member. Device 26 may be a slip ring and brush assembly. Device 26 and electric conductor 27 21 provide means for transferring signals from the receiving antenna within the22 drill string and kelly to receiver 28. If telemetry operations are to be 23 performed only at times when the drill string 12 and kelly 11 are stationary, 24 device 26 will not be needed and the conductor 27 may be connected directly to conductor 43A through a suitable connector. In this situation, conductor 27 26 will be disconnected from conductor 43A when the kelly 11 and drill string 12 27 are rotated. Other possibilities include connecting a receiving unit to 28 conductor 43A and positioning the receiver on a rotating member; e.g., the 29 kelly 11.
Normally, the wellbore is advanced in increments substantially 31 equal to one length of drill string. The procedure for lengthening the drill 10614:1~
1 string will be described with reference to FIGURES 4 through 6. A length of 2 drill pipe 31, to be added to the drill string 12 is shown disposed in a 3 shallow hole 32 ("mouse hole") below the derrick floor.
4 In order to insert the new pipe section, the drill string is initially eleva~ed and suspended on the rotary table 16 and the kelly 11 6 disconnected from the drill string as shown in FIGURE 4. Conductor 43 will 7 normally be connected to conductor 43A by means of connectors 36 and 35 at 8 a distance below the top of the drill string slightly greater than one 9 drill pipe section. The wire must be retracted so that the mated connec-tors 36 and 35 are above the upper end of drill string 12. A support 11 plate 38 or spider is inserted between the upper end of the drill string 12 and connector 36 and serves to support conductor 43 within the drill string.13 Connectors 36 and 35 are then separated. FIGURE 4 illustrates the position 14 of the equipment at this juncture in the procedure. As shown in FIGURE 5, the kelly 11 is then swung over into alignment with pipe length 31 and the 16 length of conductor suspended beneath the kelly is inserted through the new 17 length of drill pipe 31. The kelly 11 is then screwed into the pipe sec-18 tion 31. This assembly is then elevated above the drill string 12 and 19 exposed connector 35 is reconnected with connector 36. After the support plate 38 is removed, the lower end of pipe length 31 is screwed into the 21 drill string 12 and becomes a part thereof. The equipment is then returned 22 to the drilling position and drilling operations resumed.
23 As drilling operations proceed, pipe sections are added which 24 lengthen the pipe string. As the well is drilled deeper, the transmitting antenna, which retains its original length, will follow the drilling bit 26 down into the well. This means that as the well is drilled deeper, the 27 length of overlap of the transmitting and receiving antennas will diminish.
28 When they cease to overlap the communication link may be broken, and to 29 retain the communication link, it will be necessary to lengthen the receiv-ing antenna to reestablish the overlap. This can be accomplished by retract-31 ing the entire receiving antenna 43 and inserting a new longer wire; or _g_ 4~1 1 more preferably, at a time when a new drill pipe section is being added, a 2 new section of wire having a connector that mates with connector 36 will be 3 connected to the existing receiving antenna and the old section of antenna 4 wire, with the new section attached, lowered into the well to reestablish the desired overlap between the transmitting and receiving antenna.
6 This invention has been successfully tested in a test well. Good 7 coupling between the two antennas was observed, with a gradual reduction in 8 coupling as the overlap decreased. The tests were conducted with two 9 teflon-insulated, 18-gauge wires inside a drill pipe filled with water, with no attempt to hold the wires together or apart.
7 2. Description of the Prior Art 8 In the drilling of oil wells, gas wells, and similar boreholes, it 9 frequently is desirable to transmit data between subsurface and surface locations. One application where data transmission has received considerable 11 attention in recent years is in wellbore telemetry systems designed to 12 sense, transmit, and receive information indicative of a subsurface condi-13 tion. This operation has become known in the art as "logging while dril-14 ling."
A major problem associated with wellbore telemetry systems has been 16 that of providing reliable means for transmitting signals between the sub-17 surface and surface locations. This problem can best be appreciated by 18 considering the manner in which rotary drilling operations are normally 19 performed. In conventional rotary drilling, a borehole is advanced by rotating a drill string provided with a drill bit at its lower end. Lengths 21 of drill pipe, usually about 30 feet long, are added to the drill string, 22 one-at-a-time, as the borehole is advanced in increments. In adapting a 23 telemetry system to rotary drilling equipment, the means for transmitting the 24 electric signal through the drill string must permit the connection of additional pipe lengths to the drill string as the borehole is advanced.
26 An early approach to the problem involved the use of continuous 27 electric cable which was adapted to be lowered inside the drill string and to 28 make contact with a subsurface terminal. This technique, however, required 29 withdrawing the cable from the drill string each time a pipe length was added to the drill string. A more recent approach involves the use of special 106~4~.
1 drill pipe. Each pipe section of the special pipe is provided with an 2 electric conductor having connectors at its opposite ends. Electric con-3 tinuity is maintained across the junction of two pipe sections by connectors 4 of one section contacting a connector on the adjacent pipe section (see U.S.
Patent Nos. 3,518,608 and 3,518,609). Disadvantages of this system include 6 the high cost of the special pipe sections, the need for a large number of 7 electric connections (one at each joint), and the difficulty of maintaining 8 insulation of the electric connectors at each joint.
9 Still another approach involves the use of cable sections mounted in each pipe section (see U.S. Patent No. 2,748,358). The cable sections are 11 connected together as pipe sections are added to the drill string. Each 12 cable section is normally made slightly longer than its associated pipe 13 section, with the result that a small amount of slack is present in the 14 conductor string at all times.
A more recent approach involves the use of a cable maintained in 16 a looped configuration within the drill string. The looped arrangement 17 stores cable in the drill string and permits the cable to be extended as 18 the drill string is lengthened. This technique normally requires the use 19 of sheaves and other apparatus within the drill string to maintain the cable in the looped configuration. However, this arrangement presents flow res-21 trictions within the relatively narrow opening. Moreover, care must be 22 exercised to prevent cable entanglement, particularly for long cable loops.
24 The purpose of the present invention is to provide a communication link between a subsurface location in a well and the surface.
26 Briefly the invention, in one embodiment, involves transmitting 27 data from the subsurface location via an insulated conductor extending 28 upwardly from the subsurface location and functioning as an antenna. A
29 second insulated conductor extends downwardly from the surface and, normally, will substantially overlap the first conductor. The transmitted signal is 41~
1 picked up by this second conductor through electromagnetic coupling. The 2 second conductor functions as a receiving antenna and is coupled to a 3 receiver at the surface.
4 Normally, the transmitting antenna is lowered to the desired sub-surface location when it is desired to begin telemetering operations and 6 the receiving antenna is also inserted into the well at this time. Because 7 the overlapping length of the two antennas is not critical, both antennas 8 may initially extend substantially the entire length of the wellbore. The 9 well can then be drilled to approximately twice its original depth before the wires cease to overlap and the communication link is lost. At that 11 time, the length of the receiving antenna may be increased to reestablish 12 the overlap to resume telemetering operations.
13 A principal advantage of this invention is that the well depth 14 can be substantially increased and the communication link maintained with-out increasing the length of either conductor.
16 Another advantage is that the interior of the drill pipe is rela-17 tively unobstructed.
1~ BRIEF DESCRIPTION OF TH DRAWINGS
19 FIGURE 1 is a schematic view of well drilling equipment with two electric conductors arranged within the drill string in a preferred con-21 figuration.
22 FIGURE 2 is an enlarged fragmentary view, shown partially in 23 longitudinal section, of apparatus useful in the invention for supporting 24 the lower conductor within the drill string.
FIGURE 3 is a top plan view of the apparatus illustrated in 26 FIGURE 2.
27 FIGURES 4-6 are schematic views illustrating a preferred sequence 28 of steps for adding a length of drill pipe into the drill string.
~06~41~
1 DESCRIPTION OF _HE PREFERRED EMBODIMENT
2 Conventional rotary drilling equipment, as illustrated schemat-3 ically in FIGURE 1, includes swivel 10, kelly 11, tubular drill string 12 and4 a bit 13. These components, connected in the manner illustrated, are sus-pended from the drilling derrick 14 by means of rig hoisting equipment. The 6 kelly 11 passes through rotary table 16 and connects to the upper end of the 7 drill string 12. The term "drill string" as used herein refers to the column8 of tubular pipe between the bit 13 and kelly 11. The major portion of the 9 drill string 12 normally is composed of drill pipe with a lower portion beingcomposed of drill collars. The drill string 12 consists of individual pipe 11 sections, either drill pipe or drill collars connected together in end-to-end 12 relation. In the lower three sections of FIGURE 1, the diameters of the 13 borehole and the drill string 12 have been expanded in relation to the upper14 section to reveal further details.
The borehole 17 is advanced by rotating the drill string 12 and 16 bit 13. Drilling fluid is pumped down through the drill string 12 and up the 17 borehole annulus. The drilling fluid is delivered to swivel 10 through a 18 hose (not shown) attached to hose connection 18 and is returned to the sur-19 face fluid system from the borehole annulus through pipe 19. A kelly bush-ing 20 couples the rotary table 16 to the kelly 11 and provides means for 21 transmitting power from the rotary table 16 to the drill string 12 and bit 13.
22 The present invention may also be used in systems which employ a power swivel 23 in lieu of a kelly and rotary table; for purposes of illustration, however, 24 the invention will be described in connection with the kelly and rotary table arrangement.
26 As mentioned previously, it frequently is desirable to monitor a 27 subsurface drilling condition during drilling operations. This requires 28 measuring a physical condition at the subsurface location, transmitting the 29 data signal to the surface, and reducing the signal to useful form. Typicalsituations where telemetry is applicable in drilling operations include 106~4~1 1 drilling through abnormal pressure zones, drilling through zones where hole 2 deviation is likely to be a problem, directional drilling, exploratory dril-3 ling and the like.
4 An instrument 21 capable of measuring a subsurface condition and generating an electrical signal indicative of or representative of that 6 condition is provided within the drill string 12. A variety of devices 7 capable of sensing a physical condition are available. These include trans-8 ducers for measuring pressure, temperature, strain, and the like; surveying g instruments for measuring hole deviation; and logging instruments for mea-suring resistivity or other properties of subsurface formations. The instru-11 ment 21 may normally be powered by batteries. Alternatively, a subsurface 12 generator driven by fluid flowing through the drill string 12 may be used to 13 power instrument 21.
14 The communication link between the instrument 21, located within the well, and the surface is established by transmitting the data from instru-16 ment 21 to the surface via an electromagnetic link. Normally, the data will 17 be transmitted by encoding a train of electrical pulses and using these 18 encoded pulses to modulate a carrier. Phase modulation may preferably be 19 employed in the transmission link since phase modulation is relatively insen-sitive to noise. More than one transducer or other device may be employed in 21 the instrument 21 if desired, in which case a multiplexer may be used for 22 sending the various signals over a single transmission link.
23 Instrument 21 includes a conventional transmitter. Conductor 40 is 24 coupled to the transmitter within instrument 21 so as to function as an antenna. This conductor wire must be electrically insulated throughout its 26 entire length to prevent shorting out the electrical signal. Conductor 40 may 27 be of sufficient stiffness to be self-standing within the well. Alternatively, 28 support member 42 may be employed to support a more flexible wire.
29 As shown in FIGURES 2 and 3, support member 42 is basically a ring-shaped device, made from stainless steel or other strong material, adapted to 106~4~
1 fit in an annular notched shoulder 50 formed in the box end of a pipe sec-2 tion 12B. Shoulder 50 may be provided by milling the box end of the pipe 3 section in which support member 48 rests or, alternatively, may be provided 4 by a special sub. On one side of support member 42 (see FIGURE 3) there is an extended section 46 having a slot 48. Support bracket 51 is mounted by 6 welding or other means, colinearly with slot 48. The upper end of wire 40 7 fits into the slot 48 and support bracket 51 and is restrained from lateral 8 movement by means of a bolt 52 that is mounted in holes in support bracket 519 as shown. Wire 40 has an expansion 54 at its upper end having q diameter wider than bracket 51 to prevent townward movement of the wire and maintain 11 the wire in tension.
12 Other structures serving the same function as support member 42 13 will suggest themselves to those skilled in the art. It is desirable that 14 the drill string not be substantially obstructed.
A receiving antenna 43 extends downwardly from the top of the well 16 so that its length substantially overlaps transmitting antenna 40. It is not 17 necessary to use special antenna wire for either the receiving or trans-18 mitting antennas. Conducting wire such as teflon coated #18 copper clad 19 steel can be employed. This conductor must also be electrically insulated throughout its entire length.
21 The installation of the apparatus and performance of the method of22 the present invention is as follows. After drilling has progressed to the 23 point where it is desired to commence wellbore telemetry operations, drilling 24 operations are interrupted and package 21 is lowered into the drill string using conventional techniques with antenna 40 connected to the transmitter 26 antenna terminal thereon. For this operation, a sheave disposed above the 27 derrick floor is normally employed to guide the antenna wire 40 into the 28 wellbore as it is unreeled from a drum. When the instrument 21 is properly 29 seated in the lower end of the drill string 12, preferably in a locking sub immediately above bit 13, the support member 42, if used, is inserted into ~061~1 1 the annular notched shoulder in the box end of the pipe section as shown in 2 FIGURE 2, and the top of antenna 40 is attached to the support member in the 3 manner described above. Receiving antenna 43 is also run into the well to 4 the desired length, which may preferably be nearly the entire length of the well. A weight may preferably be attached to the lower end of antenna 43 6 to maintain the wire in tension. The two wires, 40 and 43, may be initially 7 lowered into the well simultaneously. Alternatively, instrument package 21 8 may be positioned within the drill string when drilling commences, or some 9 tlme later, and conducting wire 40 lowered with a conventional stabbing connector 14 at the lower end thereof for connecting to instrument package 21 11 when it is desired to begin telemetering operations.
12 In order to facilitate the addition of pipe sections to the drill 13 string 12 it is preferred that a conductor 43A, comprising the upper portion14 of the receiving antenna, extend through the interior of kelly 11 as illus-trated in FIGURE 1 and connect to the upper end of conductor 43.
16 If telemetry operations are to be performed while the kelly 11 and17 drilling string 12 are rotating, the upper end of conductor 43A terminates 18 at a device 26 near the upper end of the kelly, capable of conducting the 19 received signal from the rotating member to a stationary member. Device 26 may be a slip ring and brush assembly. Device 26 and electric conductor 27 21 provide means for transferring signals from the receiving antenna within the22 drill string and kelly to receiver 28. If telemetry operations are to be 23 performed only at times when the drill string 12 and kelly 11 are stationary, 24 device 26 will not be needed and the conductor 27 may be connected directly to conductor 43A through a suitable connector. In this situation, conductor 27 26 will be disconnected from conductor 43A when the kelly 11 and drill string 12 27 are rotated. Other possibilities include connecting a receiving unit to 28 conductor 43A and positioning the receiver on a rotating member; e.g., the 29 kelly 11.
Normally, the wellbore is advanced in increments substantially 31 equal to one length of drill string. The procedure for lengthening the drill 10614:1~
1 string will be described with reference to FIGURES 4 through 6. A length of 2 drill pipe 31, to be added to the drill string 12 is shown disposed in a 3 shallow hole 32 ("mouse hole") below the derrick floor.
4 In order to insert the new pipe section, the drill string is initially eleva~ed and suspended on the rotary table 16 and the kelly 11 6 disconnected from the drill string as shown in FIGURE 4. Conductor 43 will 7 normally be connected to conductor 43A by means of connectors 36 and 35 at 8 a distance below the top of the drill string slightly greater than one 9 drill pipe section. The wire must be retracted so that the mated connec-tors 36 and 35 are above the upper end of drill string 12. A support 11 plate 38 or spider is inserted between the upper end of the drill string 12 and connector 36 and serves to support conductor 43 within the drill string.13 Connectors 36 and 35 are then separated. FIGURE 4 illustrates the position 14 of the equipment at this juncture in the procedure. As shown in FIGURE 5, the kelly 11 is then swung over into alignment with pipe length 31 and the 16 length of conductor suspended beneath the kelly is inserted through the new 17 length of drill pipe 31. The kelly 11 is then screwed into the pipe sec-18 tion 31. This assembly is then elevated above the drill string 12 and 19 exposed connector 35 is reconnected with connector 36. After the support plate 38 is removed, the lower end of pipe length 31 is screwed into the 21 drill string 12 and becomes a part thereof. The equipment is then returned 22 to the drilling position and drilling operations resumed.
23 As drilling operations proceed, pipe sections are added which 24 lengthen the pipe string. As the well is drilled deeper, the transmitting antenna, which retains its original length, will follow the drilling bit 26 down into the well. This means that as the well is drilled deeper, the 27 length of overlap of the transmitting and receiving antennas will diminish.
28 When they cease to overlap the communication link may be broken, and to 29 retain the communication link, it will be necessary to lengthen the receiv-ing antenna to reestablish the overlap. This can be accomplished by retract-31 ing the entire receiving antenna 43 and inserting a new longer wire; or _g_ 4~1 1 more preferably, at a time when a new drill pipe section is being added, a 2 new section of wire having a connector that mates with connector 36 will be 3 connected to the existing receiving antenna and the old section of antenna 4 wire, with the new section attached, lowered into the well to reestablish the desired overlap between the transmitting and receiving antenna.
6 This invention has been successfully tested in a test well. Good 7 coupling between the two antennas was observed, with a gradual reduction in 8 coupling as the overlap decreased. The tests were conducted with two 9 teflon-insulated, 18-gauge wires inside a drill pipe filled with water, with no attempt to hold the wires together or apart.
Claims (20)
1. In a method of drilling a well wherein an electrical signal is transmitted between a subsurface location within said well and a loca-tion substantially at the surface, the improvement comprising:
transmitting said electrical signal by means comprising a first insulated conductor, electrically connected to transmitting means at one of said locations and extending through said well a substantial distance toward the other location;
receiving said electrical signal by means comprising a second insulated conductor extending from said other location through said well a sufficient distance so as to at least par-tially overlap the first said conductor; and lowering the insulated conductor which extends through said well from said subsurface location further into said well, thereby reducing the overlap between said conductors, while continuing to transmit and receive said electrical signal.
transmitting said electrical signal by means comprising a first insulated conductor, electrically connected to transmitting means at one of said locations and extending through said well a substantial distance toward the other location;
receiving said electrical signal by means comprising a second insulated conductor extending from said other location through said well a sufficient distance so as to at least par-tially overlap the first said conductor; and lowering the insulated conductor which extends through said well from said subsurface location further into said well, thereby reducing the overlap between said conductors, while continuing to transmit and receive said electrical signal.
2. In a method of drilling a well wherein an electrical signal is transmitted from subsurface locations to a location substantially at the surface, the improvement comprising:
transmitting said electrical signal by means comprising an insulated electrical conductor functioning as a transmitting antenna, said conductor extending upwardly in said well from a first subsurface location;
detecting said electrical signal by means comprising a second insulated electrical conductor functioning as a receiving antenna, extending from said location substantially at the surface downwardly into said well so as to at least partially overlap said conductor functioning as a transmitting antenna;
lowering said insulated conductor functioning as a trans-mitting antenna within said well to a second subsurface location;
and transmitting an electrical signal from said second sub-surface location.
transmitting said electrical signal by means comprising an insulated electrical conductor functioning as a transmitting antenna, said conductor extending upwardly in said well from a first subsurface location;
detecting said electrical signal by means comprising a second insulated electrical conductor functioning as a receiving antenna, extending from said location substantially at the surface downwardly into said well so as to at least partially overlap said conductor functioning as a transmitting antenna;
lowering said insulated conductor functioning as a trans-mitting antenna within said well to a second subsurface location;
and transmitting an electrical signal from said second sub-surface location.
3. The method of claim 2 wherein said conductor functioning as a transmitting antenna is self standing in said well.
4. The method of claim 2 wherein said conductor functioning as a transmitting antenna extends upwardly within a drill string used for drilling said well and is suspended at its upper end from a support member fixedly positioned within said drill string.
5. A method for establishing and maintaining a communication link between a subsurface location within a drill string and a location substantially at the surface which comprises:
placing a transmitting device at said subsurface location;
extending a transmitting antenna upwardly from said device;
suspending a receiving antenna from said location substan-tially at the surface downwardly within said drill string, said receiving antenna overlapping a substantial portion of said transmitting antenna; and lengthening said drill string while maintaining the lengths of the transmitting and receiving antennas substantially con-stant.
placing a transmitting device at said subsurface location;
extending a transmitting antenna upwardly from said device;
suspending a receiving antenna from said location substan-tially at the surface downwardly within said drill string, said receiving antenna overlapping a substantial portion of said transmitting antenna; and lengthening said drill string while maintaining the lengths of the transmitting and receiving antennas substantially con-stant.
6. A method of establishing and maintaining a communication link within a well between a first terminal at a subsurface location within said well and a second terminal at a location substantially at the surface which comprises:
lowering a first insulated electrical conductor within said well to said subsurface location;
connecting said first electrical conductor at its lower end to said first terminal;
lowering a second insulated electrical conductor into said well so as to couple electromagnetically with said first elec-trical conductor;
connecting said second electrical conductor to said second terminal; and lowering said first terminal to a deeper subsurface location while maintaining the lengths of both said insulated electrical conductors substantially constant.
lowering a first insulated electrical conductor within said well to said subsurface location;
connecting said first electrical conductor at its lower end to said first terminal;
lowering a second insulated electrical conductor into said well so as to couple electromagnetically with said first elec-trical conductor;
connecting said second electrical conductor to said second terminal; and lowering said first terminal to a deeper subsurface location while maintaining the lengths of both said insulated electrical conductors substantially constant.
7. A method of establishing and maintaining a communication link within a drill string between a subsurface location within said drill string and a location substantially at the surface which comprises:
lowering a first insulated electrical conductor within said drill string to said subsurface location;
electrically connecting said first electrical conductor at its lower end to a transmitter so that said conductor functions as a transmitting antenna;
lowering a second insulated electrical conductor into said drill string so as to at least partially overlap said first electrical conductor;
electrically coupling said second electrical conductor to a receiver at said location substantially at the surface so that said second conductor functions as a receiving antenna; and lengthening said drill string while maintaining the lengths of said first and second insulated electrical conductors sub-stantially constant.
lowering a first insulated electrical conductor within said drill string to said subsurface location;
electrically connecting said first electrical conductor at its lower end to a transmitter so that said conductor functions as a transmitting antenna;
lowering a second insulated electrical conductor into said drill string so as to at least partially overlap said first electrical conductor;
electrically coupling said second electrical conductor to a receiver at said location substantially at the surface so that said second conductor functions as a receiving antenna; and lengthening said drill string while maintaining the lengths of said first and second insulated electrical conductors sub-stantially constant.
8. The method of claim 7 wherein said electrical conductors ro-tate with said drill string and said second electrical conductor is elec-trically coupled to said receiver by means comprising a slip ring and brush assembly.
9. The method of claim 7 further including the steps of ad-vancing said well sufficiently to require the addition of a length of drill pipe, retracting a portion of said second conductor from said drill string the length of at least one section of drill pipe, inserting said retracted portion of said second electrical conductor through said addi-tional length of drill pipe, and adding said new section of pipe to said drill string.
10. The method of claim 9 further including biasing said second conductor downwardly with a weight attached to the lower end thereof.
11. A method of drilling a well wherein an electrical signal is transmitted from the vicinity of a drill bit connected to the lower end of a drill string used for drilling said well and a location sub-stantially at the surface, the method comprising:
transmitting said electrical signal by means of a trans-mitter positioned in the vicinity of said drill bit and a first insulated electrical conductor connected to said trans-mitter and extending upwardly within said drill string so as to function as a transmitting antenna;
receiving said electrical signal by means of a second in-sulated electrical conductor electrically coupled to a receiver at said location substantially at the surface and extending downwardly within said drill string so as to at least partially overlap said first conductor; and drilling said well deeper while maintaining the lengths of said first and second insulated electrical conductors sub-stantially constant.
transmitting said electrical signal by means of a trans-mitter positioned in the vicinity of said drill bit and a first insulated electrical conductor connected to said trans-mitter and extending upwardly within said drill string so as to function as a transmitting antenna;
receiving said electrical signal by means of a second in-sulated electrical conductor electrically coupled to a receiver at said location substantially at the surface and extending downwardly within said drill string so as to at least partially overlap said first conductor; and drilling said well deeper while maintaining the lengths of said first and second insulated electrical conductors sub-stantially constant.
12. The method of claim 11 further including adding an addi-tional length of conductor to said second conductor, thereby lengthening said second conductor; and lowering said lengthened second conductor further into said well so as to increase the overlap of said first and second conductors.
13. The method of claim 11 wherein said transmitter is con-tained within an instrument package that is lowered into position within said drill string with said first conductor connected to said transmitter.
14. The method of claim 13 wherein said instrument package containing said transmitter is positioned within said drill string sub-stantially at the time that drilling operations commence and said first conductor is lowered into position subsequently.
15. The method of claim 11 further including the steps of ad-vancing said well sufficiently to require the addition of a section of drill pipe; disconnecting said drill string at a location substantially at the surface; retracting said second conductor an amount not less than the length of one drill pipe section; inserting the retracted portion of said second conductor wire within a new section of pipe; and, connecting the new pipe section to the drill string.
16. The method of claim 11 further including supporting the first conductor within said well by means of a support member connected within the drill string at the upper end of said first conductor.
17. The method of claim 16 wherein said support member is fixed-ly positioned within a tool joint of said drill string and said support member is a ring-shaped device that does not substantially obstruct the drill string.
18. A method of transmitting electrical signals in a well be-tween the surface of the earth and subsurface locations which comprises:
lowering a first insulated electrical conductor in said well to a position extending upward from a first subsurface location;
lowering a second insulated electrical conductor in said well to a position extending downward from the surface of the earth and overlapping said first insulated electrical conductor in an electromagnetically coupled relation;
transmitting an electrical signal between said surface lo-cation and said first subsurface location through said first and second electrical conductors;
lowering said first insulated electrical conductor in said well to a position extending upward from a second subsurface location to reduce the overlap between said conductors; and transmitting an electrical signal between said surface lo-cation and said second subsurface location through said first and second insulated electrical conductors.
lowering a first insulated electrical conductor in said well to a position extending upward from a first subsurface location;
lowering a second insulated electrical conductor in said well to a position extending downward from the surface of the earth and overlapping said first insulated electrical conductor in an electromagnetically coupled relation;
transmitting an electrical signal between said surface lo-cation and said first subsurface location through said first and second electrical conductors;
lowering said first insulated electrical conductor in said well to a position extending upward from a second subsurface location to reduce the overlap between said conductors; and transmitting an electrical signal between said surface lo-cation and said second subsurface location through said first and second insulated electrical conductors.
19. A method of drilling a well wherein an electrical signal is transmitted between a subsurface location within a drill string having a drill bit connected to the lower end thereof for drilling said well and a location substantially at the surface, the method comprising:
positioning an instrument package containing a transmitter within said drill string substantially at the time drilling operations commence;
lowering a first insulated electrical conductor into said well subsequent to commencing drilling operations;
connecting the lower end of said first conductor to said transmitter so that said first conductor functions as a transmit-ting antenna;
transmitting said electrical signal from said subsurface location by means of said transmitter and said first conductor connected thereto; and receiving said electrical signal by means of a second in-sulated electrical conductor electrically coupled to a receiver at said location substantially at the surface and extending downwardly into said well so as to at least partially overlap said first conductor.
positioning an instrument package containing a transmitter within said drill string substantially at the time drilling operations commence;
lowering a first insulated electrical conductor into said well subsequent to commencing drilling operations;
connecting the lower end of said first conductor to said transmitter so that said first conductor functions as a transmit-ting antenna;
transmitting said electrical signal from said subsurface location by means of said transmitter and said first conductor connected thereto; and receiving said electrical signal by means of a second in-sulated electrical conductor electrically coupled to a receiver at said location substantially at the surface and extending downwardly into said well so as to at least partially overlap said first conductor.
20. Apparatus for maintaining a communication link within a well between a transmitter mounted in the vicinity of a drill bit used for drilling said well and the surface as said drill bit drills the well deeper comprising:
a fixed length transmitting antenna extending upwardly within said well and coupled at its lower end to said transmitter so as to travel with said transmitter as said well is drilled deeper; and a receiving antenna suspended from the surface downward in-to said well to overlap at least a portion of the transmitting antenna, said receiving antenna having a fixed length during at least a portion of the time that said well is drilled deeper.
a fixed length transmitting antenna extending upwardly within said well and coupled at its lower end to said transmitter so as to travel with said transmitter as said well is drilled deeper; and a receiving antenna suspended from the surface downward in-to said well to overlap at least a portion of the transmitting antenna, said receiving antenna having a fixed length during at least a portion of the time that said well is drilled deeper.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA262,281A CA1061411A (en) | 1976-09-29 | 1976-09-29 | Method of transmitting signals from a drill bit to the surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA262,281A CA1061411A (en) | 1976-09-29 | 1976-09-29 | Method of transmitting signals from a drill bit to the surface |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1061411A true CA1061411A (en) | 1979-08-28 |
Family
ID=4106960
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA262,281A Expired CA1061411A (en) | 1976-09-29 | 1976-09-29 | Method of transmitting signals from a drill bit to the surface |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1061411A (en) |
-
1976
- 1976-09-29 CA CA262,281A patent/CA1061411A/en not_active Expired
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