US2326219A - Well depth recording - Google Patents

Description

1943- J. :r. HAYWARI": 2,326,219

WELL DEPTH RECORDING Filed Dec. 30, 1939 3 Sheets-Sheet 1 v INVENTOR. 12 -J. YTHAYWARD if? 30 ATTORNEYS.

Aug. 10, 1943. J. T. HAYWARD WELL DEPTH RECORDING Filed Dec. 30, 1939 3 Sheets-Sheet 2 D 4 m mm 40. MW n 9 1 m 1 7 H w E vnm J w E w j m 1 A TTORNEYS.

Patented Aug. 10, 1943 UNITE-D STATES PATENT. OFFICE WELL DEPTH RECORDING John T. Hayward, Tulsa, Okla. Application December 30, 1939, Serial No. 311,805

16 Claims. -('o1. 33-134) This invention relates to a chart drive and particularly to a driv mechanism for driving a depth recording chart from the movements of drilling tools in a well.

In the development of modern well drilling methods, particularly rotary drilling, wherein a drilling fluid, such as mud fluid, is circulated of the traversed strata may be readily determined directly from the mud stream during drilling and'the various strata logged at their respe'c tive depths. In these'methods, as well as in connection with other; operations about 'a drilling well, it is highly important that the progress of the drill and depth ofthe well be known at all times within very narrow limits of accuracy. In

logging particularly, it is important that those this system a continuous accurate record of the depth of the well can be made on which curves characteristic of the traversed strata can be traced in proper relationship to the depth.

The system of this invention employs a novel iorm or drive mechanism whereby only those movements of the drilling tools which represent progressively increasing depth oi the well are employed to drive a strip chart carrying footage indications thereon. It will be obvious to those skilled in the art that in the ordinary methods of rotary drilling, the drilling tools make numerous movements in and out of a well which are not directly representative of increasing depth of the well. For example, the drilling string must be frequently withdrawn from and inserted into the well when changing bits, when adding new joints of drill pipe, when removing defective sections of the drill pipe, when reaming dowm. to a previously attained depth, and for various other operations. It is a principal object, therefore, of this invention toprovide an apparatus whereby only those movements of the drilling tools which are representative of progressively increasing depth are selectively employed to drive a chart bearing the depth record.

Another object is to provide a novel form of selective transmission for the'aforesaid movements from the drilling tools to the depth recording chart.

Still another object is to provide a novel form of transmissionemploying co ting devices for selecting those movements of the drilling tools which are transmitted to a depth reading chart.

A further object is to provide in conjunction with the transmission, apparatus of this invention, additional mechanism for mechanically in-' troducing therein correction factors to compensate for-wearing of the parts and for changes in length of portions of the drilling tools.

An additional object is to provide a novel form of connection between the drilling tools and the transmission mechanism proper of this invention.

()ther objects include the provision of electrically operated controls, actuated by the transmission mechanism for selecting the desired movements to be transmitted to the chart; for

providing either audible or visible signals, or both,

at certain stages in the operation of the device; to controlthe operation of the pens which draw the various curves on the chart; and for numerous other operations which are directly related to the progress of the"drill in the well.

Variousother objects. and advantages of my new invention will become apparent to those skilledin the art from the following detailed description when read in conjunction with the accompanying drawings which illustrate a pre-' ferred form of this invention and several useful embodiments thereof. In the drawings: I Fig. 1 is a general assembly showing a drilling rig and the chart drive mechanism .connected thereto.

Fig. 2 is a sectional detail taken along line 2-2 of Fig. l to better illustrate a novel form ofconnection between the drill rig and th chart drive mechanism.

Fig. 3 is a detail in perspective of the connection between the mechanism. Fig. 4 is an enlarged assembly of the chart drive mechanism proper.

drill tools and the chart drive Fig. 4. ;-Fig. 7 is a modified" form of one. of the parts of the chart drive mechanism.

Fig. 8 is an assembly similar to Fig. 4 but including electrical circuits and connections emloyed'in othermodifications of this invention.

Figs. 9 and 11 are details of the apparatus illustrated in Fig.8. Fig/10 is a sectional view taken along line lii'i0 of Fi 9, and

Fig. 12 is a simplified and more or less symbolicrepresentation of a form of selective transmission included in this invention. j Referring to the drawings and to Fig. 1 in particular; a conventional derrick it i shown mounted over a well 12. The derrick is equipped with the usual crown block pulley it from which is suspended a conventional traveling block it by means of cables i8. The drilling string 20, of conventional oonstructiomis suspended from the hook 22 carried by the traveling block. The

drilling string includes the usual water swivel Figs. and s are details of the apparatus or and the traveling block iii are known, although only a single loop is shown, then by simple calculation, the relationship of the vertical movement in feet, of the traveling block l6 and, therefore, of the drilling string to the rotations of the pulley I4 can be easily determined. By properly proportioning measuring wheel II in relationship to the diameter of pulley i4, one turn of wheel H can be made to measure any 24, to which is attached the ordinary Kelly joint 26 which is in turn connected to, the usual Jointed hollow drill pipe 28 carrying a drill bit 30 at its lowerend. The drilling string extends through the usual rotary-table 32 which rotates the drilling string by turning the Kelly joint in'the usual way.

Since all vertical movements of the drilling string20 in well i2 necessarily reslllt'in corresponding vertical movements of traveling block it, and these in turn result in corresponding rotary movement of crown block pulley it through the movements of cables i8 about the pulley, the latter provides a convenient take-off connection for transmitting the vertical movements of the,

traveling block and drilling string to suitable recording apparatus to be later described. A convenient form of take-ofi connection to pulley it is shown in enlarged detail in Figs. 2 and 3 particularly. This connection consists of a measuringwheel ii mounted .on an axle it which is suitably Journalled in the forks of ayoke i5 which is in turntcarried by one end of an arm I! which has its other end rotatively mounted on shaft i9 I which is fixedly attached to the beams 2i forming apart of derrick crown structure. The meas-' uring wheel H is arranged to run inside the groove 23 of crown block pulley i4 and the side desired length of vertical movement of the drilling string. A convenient proportion is one wherein each turn of measuring wheel Ii represents one foot of vertical movement of the drilling tools.

It will be understood that numerouseother measuring devices may be used in place of that described. Another form which may be used is describedin detail in my U. S Patent No. 2,166,212, dated July 18,1939.

Axle I3 of the measuring wheel I i is connected by a flexible shaft 29, of conventional construction, to the armature of the drive motor SI of a I self-synchronous transmission system, the function of which is well known in the electrical art and is commonly. referred toss a "Selsyn system. -Thus each turn of wheel ll pro gluces one rotation of the armature of driver motor 3| which in turn synchronously transmits this rotation electrically through leads 33 to the armature of the driven motor 35 of the Selsyn system, which correspondingly rotates the armature shaft 86 on which is mounted a conical smooth surfaced drive pulley 38. 15y the aforedescribed arrangement of apparatus, it will be seen that means edges of wheel ii are held inclose frictional contact with the adjacent sides of groove 23 by pressure applied through .a coil spring 25 which has oneend attached to'an intermediate portion of arm l1 and the other to one of the beams 2| at a point beneath arm." (see Fig. 3). The peripheral surface .ofmeasuring wheel il has a groove 2-I.-to permit the wheel to clear cable i8 w ch is threaded in. pulley 14. By mounting me suring wheel II to run inside the groove 28 of pulley ll, a very efiicient drive connection is provided from pulley I4 to measuring wheel Ii,

since the sides of groove 23 are ordinarily mak shined surfaces and are k t smooth by the rubbing action of the steel cable l8. By accurately machining the side edges of wheel ii a very positive frictional contact can thus be maintained between the pulley and the wheel. Spring 2! provides ajyieldable hold-down which'permits some relative movement between the contacting members'while' maintaining positive contact be- ,tween'them. a

has been provided whereby all the vertical move- ,7

ments, in either direction, of traveling block l8, and of the drilling string 20 when suspended therefrom, are translated into rotation in the corresponding direction of Shaft 36 and pulley 38, each rotation of which will represent one foot of vertical-movement of the traveling block or of the drilling string where measuring wheel II has been so proportioned that each turn of this wheel corresponds to one foot of vertical movement of the drilling string. Also, the rotations of shaft 36 and pulley 38 are now available for connection to a strip recorder chart 40, of more or less conventional form, by mean of a novel form of selective transmission apparatus which .forms one of the important features of this in-.

vention. v The selective transmission mechanism of this invention includes a main drive shaft 42 which shaft is connected by a sprocket and chain drive 52 to a first countershaft 54 which is-connected to a revolution counter 56 of more or less conventional construction. Driven shaft 50 is connected by a sprocket and chain drive 58 to a second countershaft 60 which is connected to a tension forminga stub shaft 64,1, which-is consecond revolution counter 82. Countershaft 60 extends through the case of counter 82. the ex- I nected by gear connections; designated generally by the numeral 6 6, ton suitable drive forchart l0. Countershaft 60 is provided with a'fr'iction brake, designated generally 88, the functionloi which will be explained'in greater detail herein- Since the diameter of pulley I4 is fixed and the number of ables'threaded between the pulle after The end of main drive shaft 42 anterior to auxiliary differential carries a smooth cone shaped drive pulley 10, which is positioned adiacent to drive pulley 38 but slopes in the opposite direction to the latter. conventional construction, is positioned between the adjacent faces of drive pulleys 38 and I and is'adapted to be adjustably moved between the faces of these pulleys by means of screw shalt I4 which is suitably journalled and rotatable by means of a handle I6. Variable gear '12, as noted, is of conventional construction and is provided to vary the speed ratios between the drive pulanism to chart 40 is in turn ordinarily designed to carry the rotations from drive pulley 38in a oneto-one ratio to countershafts 54 and B0 and thence to chart 40 whereby the chart will be caused to move a distance representing one foot of depth of the well for each rotation of countershaft60. By use of variable gear 12 any errors occurring in the. drive connection mechanism due to wearing of the parts can be corrected and compensated for in transmitting the rotations of'shaft 36 and pulley 38 to the transmission mechanism, and the chance for error in the chart drive is thereby eliminated.

As noted previously, the crown block pulley I4 engages in numerous rotations during drilling which are responsive to movements of the drilling string other than those which represent increasing depth of the well. For example, when the drilling string is drilling ahead, drilling ordinarily continues for an interval of depth which 'is substantially equivalent to the length of the Kelly joint 28, which may be as much as thirty or forty feet or more. This movement of the drilling string, since it represents progressive A variable'gear 12, of I supplied by means of counter 56 which will be designated as the off-bottom counter. The details of the apparatus and the manner in which it functions will be described hereinafter,

Since the essential element of the present in; vention comprises a novel formof selective transmission mechanism which is of somewhat complex character in the modification illustrated deepening of the well, it is desired to transmit.

to the recording chart. When, however, this I drilling interval is completed, a new sectionof drill pipe must be added, or it may be desired to remove the entire drilling string from the well, as for example, to changethe bit. The resulting reverse movements of the drilling string from the well are, of course, transmitted to the crown block pulley l4 and itsrotations are then transmitted to the transmission mechanism connected e held at a position corresponding to the attained depth, of the well, while the non-significant movements of the drilling string occur, and then to permit the chart to move ahead again only when the drill bit begins to move downwardly in the well from the previously attained maximum depth. This maximum depth measurement is supplied by means of counter '62 which will be designated as the maximum. counter, while the *measurementsof the off-bottom movements of I traveling block I8 or of. the drilling string are particularly in Figs. 4, 5 and 6, reference will be first had to the more or less simplified design 11- lustrated in Fig. 12 for the purpose of explaining the functioning of such a transmission.

Numeral I00 represents a main drive shaft which is'rotative first in one direction and then in the other for varying numbers of rotations. Main shaft I00 is drivingly connected through a differential I02 toa first driven shaft I04, which is connected by a gear I06 to the ring gear I08 of the differential, and to a seconddriven shaft I I0 which is connected to one of the mitre gears I I2 of the differential and extends through an axial'opening in the ring gear I08. The gear ratios are preferably such that each of the shafts I04 and IIO make one rotation for each rotation of main shaft I00. The shafts I04 and H0 are threaded and their ends are journalledin a supporting frame II4. A threaded nut II B carrying a pointer I I1 is mounted on second shaft I I0 and held against rotation by a guide bar II8 extending between the end members of frame II4. Thus rotation of shaft .I I0 causes nut I I6 to move back and forth along shaft IIO depending upon the direction of rotation of the latter: A stop member I20 is positioned on the right hand end of guide bar I I8 to positively limit the movement of nut H0 in the right hand direction. 'A second nut I 22 carrying a pointer I24 is mounted on shaft I04 and held against rotation by a second guide bar I26, so that it is also adapted to move along shaft I04 when it is rotated. For purposes of explanation, each of the threads will be taken to represent one foot of lineal movement corresponding to one rotation of main shaft I00 and also of the driven shafts I 04 and H0. A scale I28 bearing indicia representing rotations of shaft I00, or feet, as the case may be, is positioned parallel to shaft I 04 and in indicating re lationship to pointer I24. Shaft I04 is provided with an outboard extension I30 which is in frictional engagement with a symbolically illustrated friction applying member I32. A second scale I34 bearing indicia similar to'scale I28 but reading in the reverse direction-is positioned parallel to shaft H0 and in indicating relationship to pointer I11.

This described transmission mechanism will function to selectively accumulate only certain of',the rotations in one direction only of main shaft I00, and .these selected rotations will be accumulated in shaft I 04 and their cumulative total indicated on scale I28 by pointer I24. The operation is as follows: Sufficient friction is ap plied to shaft I04 by means of member I32 to make shaft I04 more difficult to rotate than shaft H0. Nut I22 is initially positioned at the left hand end o'fshaft I04 at the zero position on scale I28, while nut H6 -is at its maximum right hand position against the stop member I20, corresponding to the zero position on scale I34. Assume main shaft I00 is rotated 'in the forward (clockwise) direction for fifty revolutions, nut I22 will move along shaft I04 in the right hand direction to the position 50 on scale I28. At the same t nge, since nut II6 is already at its maximum right hand position, shaft I'I0 is locked and cannot turn, and although friction has been applied to shaft I04, it will, nevertheless, be selectively rotated by main shaft I through the differential I02, Now assume main shaft I00 is rotated in the reverse directipn for twenty rotations. Both shafts. I04 and III! will .tend to rotate in the reverse direction, but be- Thus the indicia on the respective scales will now show that shaft I04 has turned fifty revolutions, or feet, in the forward direction while shaft I I0 has moved twenty revolutions or feet in the reverse direction. If these indications are considered to represent well operations,

scale I28 will correspond to a showing that the maximum depth of the well is fifty feet while scale I34 will show thatthe bit is at a position twenty feet on-bottom. o it is. desired to again rotate main shaft I00 in the forward direction, but is desired that no additions be made to the reading on scale I28 until nut I I6 has returned to its zero position, that is, using the well drilling analogy, no increases in depth should appear until the drilling string is again on-bottom, irrespective of any intermediate. movements of the drilling string. Since nut H6 is now at the position, when main shaft I00 is rotated in the forward direction, both driven shafts would ordinarily tend to rotate in the same direction. However, because of the friction applied to shaft I04, shaft IIO will be preferentially rotated by main shaft I00 .acting through differential I02 until nut III;

has moved forward twenty threads and comes up against stop member I20. Immediately that nut IIB comes against stop member I20, the rotations of shaft I00 will immediately be transferred by normal differential action to shaft I04 which will again begin moving nut I22 in the right. hand direction from the 50 position as many threads as shaft I00 has turned, less the twenty turns necessary to bring nut H6 back to its zero position. Translating again to well drilling operationsfonly after the drilling string is again on-bottom"'is the maximum depth recorder. released to record subsequent increases in depth.

It will also be apparent from the foregoing description, that so long as nut II6 remains away from stop I20, shaft 0 may be turned in either direction by shaft I00, and as many times as desired, without affecting the maximum attained position of nut I22. Only when the number of turns of shaft H0 in the for-f ward direction brings nut IIG against stop I20,

will shaft I04 be released to move nut I22further in the right hand direction; Translating,

again to well drilling operations: So long as the drilling string.remains off-bottom the string may engage in any number of vertical movements of any length without afiecting the recording of the'maximum well depth. At the I same time every. change in position of the string relative to the bottom of the well will be continuously recorded on the off-bottom register.

It will be apparent also that by the applica- 1 tion of friction to shaft I04 and the'described arrangement of the 'parts of the transmission apparatus, shaft I04 will be constrained to rotate in one direction only, the forward direc- Now, however,

tion, while shaft IIO will have limited rotation in the corresponding direction and relatively unlimited rotation in the opposite direction. Stated briefly, the novel form of selective.

transmission above described comprises a main shaft which is intermittently rotative in opposite directions for varying numbers of rotations, and means for accumulating selected rotations in one direction only of the main shaft. The

accumulative means comprise first and second driven shaft, means constraining the first shaft to rotate in one direction only with the main shaft, a member limiting the rotation of said second driven shaft in said one direction while 1 permitting relatively unlimited rotation thereof in the opposite direction, and means, such as a differential member, cooperating between the driven shafts whereby the first driven shaft is released for rotation with the'main shaft, only be described hereinafter, by means of shaft 42a to the selecting differential 46 which corresponds in function to differential I02 of the above described transmission. Shaff/ 42a carries a pinion 43 which is drivingly connected to ring gear 45 of the difierential 40 which transmits the rotations of the main shaft through the corresponding initre gears 41 and 49 to differential shafts 50 and 40, respectively. Shaft 50 is driv ingly connected by chain drive 58 to countershaft 00 corresponding to driven shaft I04 above.

Shaft 60 drives maximum counter 62 and stub shaft 64., A pinion 5| mounted on stub shaft 64 turns a gear 50 which in turn drives a shaft carrying a worm 51 which engages a gear 58 which is mounted on a shaft SI for turning the driving roll 63 for stri chart' 40, andfor un-.

winding it from ,feed roll .65. I-he gear ratios carried through the transmission apparatus to the chart are preferably such that the chartis moved in the direction of the adjacent arrow through intervals corresponding to one'rotation of main shaft 42 which in turn represents one foot of vertical movement of the drilling string,

as above explained The chart 40 is preferably marked with lines spaced at intervals of onefiftieth of an inch. That is, one inch of movement,of the chart represents 50 feet of depth of the well, and each rotation of main shaft 42 will move the chart one-fiftieth of an inch. Nu-' meral 61 designates a representation of a conventional form of marking pen which traces on chart 40 the record of any test made by any 1 suitable instrument, not'shown, of the character of 'the formation or the drilling conditions in the well at the articular depths shown at the left hand sideof the chart.

Shaft carries a brake drum 69 against which. is pressed a brake block II constructed of any suitable friction material. These elements cerrespond to the friction applying member I32, above described. The details of the brake mechanism are shown in detail in Fig. 5 and consist of a curved arm 13 which is pivotally attached by one end at 15 to some convenient portion of the transmission frame, not shown. Brake block 'H surrounds the intermediate portion of arm 13 and is held in engagement with the'surface of drum. 69 by connecting the free end of arm 13 to a coil spring 11 which is in turn connected to a convenient portion of the transmission frame,

not shown. The tension of spring 11 isadjusted so that the proper amount of friction can be applied through drum 69 to shaft 60. I Counter 62 may be any one of the conventional types of rev- Returning now to differential shaft 48. This shaft is, connected by a sprocket and chain drive 52 tocountershaft 54 which drives counter 56, referred to as the off-bottom counter, equivalent to scale I34 and pointer H1, above. This counter is similar in construction to counter 62 except that it is provided with stop mechanism which, while permitting rotation of the indicia wheels in either direction when the number of revolutions recorded thereon is greater than zero,

- prevents any rotation of the indicia wheels from the zero position in the opposite direction toward the 9--9-9 position. That is, the indicia wheels are free to move forwardly from the zero position to any position up to that representing the maximum recording capacity of the counter shown,

namely, 999, and in the reverse direction between this maximum and the zero position, but cannot move in the opposite direction from the zero position. This stop mechanism corresponds to stop member 120, of the above described simplified transmission, and consists of 8. lug 19 which is aflixed to the zero marking on the left hand indicia wheel 83 and extends radially therefrom. Lug l9 cooperates with a second lug 6i mounted inside the counter case and extending toward indicia wheel83 and under lug [9 (Fig.6). Thus while indicia wheel 83 is free to rotate counterclockwise from lug 8i, that is in the forward direction to the maximum counting capacity of the counter, namely 999 revolutions, and in the opposite direction to any position corresponding to any number of rotations greater than zero, it can never move past the counters zero position, and the rotation of shaft 54 is thus locked against rotation beyond this position.

The manner in which the selective transmission just described functions to drive the chart 4U from the movements of the drilling string will now be described.

For purposes of this illustrative description, reference being had particularly to Figs. 1, 4, 5 and 6, we will assume that drilling operations are about to begin, bit being at the top'of the ground. In accordance with conventional practhis counter is designed to turn in the opposite direction to counter 62 'in'measuring distances off-bottom. Drilling is now begun. As the drilling string 20 moves downwardly in the well,

off-bottomtraveling block l6 moves correspondingly downward, rotating crown block pulley l4 in a direction corresponding to such movement, and drives measuring wheel H which in turntransmits its rotations, representing the footage of downward movement, to main shaft 42 of the selective.

mechanism. The corresponding forward rotation of main shaft 42 is transmitted through differentials 44 and 46 to maximum counter 62, which registers the progressively increasing depth of the well, and at the same time drives chart 40 which has also been started from its zero position when drilling began. The depth reading on chart 40 will correspond to the depth reading appearing on counter 62, the chart moving an interval corresponding to one foot of depth for each rotation of shaft 60 and for each increase of one digit in the reading on counter 62. These movements continue until the drilling has proceeded for an interval-substantiallyequal to the length of the kelly 26, say 40 feet. However, since I measurement is normally begun when the lower end of the drill bit begins to descend below the level of the top of the rotary table, the total measurement recorded after the full length of the kelly ha been drilled will be 40 feet, the length of the kelly, plus the length of the bit stem and collar, which. is, say, 20 feet, or a total length of 60 feet will be recorded. Counter 62 and chart 40 will each record 60 feet as the maximum depth of the well. Counter 56 will, of course, continue to show a zero reading since it is locked in this position as above described. It now becomes necessary to add another joint of drill pipe, say 40 feet in length, in order to continue deepening the well. To perform this operation, the drilling string must be drawn upwardly out of the well until the lower end of the kelly is above the rotarytable 32. off the bottom a distance somewhat greater than the length of the kelly so that the upper end of drill collar and bit may be grasped by the usual slips and held so that the kelly may be unscrewed. Assume that this,reverse movement is 50 feet. Traveling block IE will of course move upward a similar distance and produces corresponding reverse rotations of crown block pulley I 4, which will be immediately transmitted to the selective transmission in the form of reverse rotations of main shaft 42 which are in turn transmitted to countershafts 54 and 69. However, since friction has been applied to shaft 60 through the medium of brake 68, and since shaft 54 is free to rotate in the reverse direction, differential 46 will become operative through the friction in shaft 60 to selectively rotate shaft 54 in the reverse direction while shaft 60 remains stationary. Shaft 54 will, therefore, rotate the wheels of counter 56 in accordance with the reverse rotations of main shaft 42 until the counter wheels register 50 feet, A

the distance through which the traveling block and the drilling string have moved upwardly in the well. The reading on counter 56 of 50 feet is the present off-bottom position of the bit,

traveling block are, of course, transmitted to the crown block pulley I4 and thence to the transmission mechanism whereby they produce corre- This requires that the bit he lifted drilling string and in order to do this, the travel-- ing above the door of the derrick, traveling block IE will necessarily have, returned to thesame position it had previously attained when it lifted the drilling string and kelly out of the well, name'- ly 50 feet off-bottom, and counter 56 will accordingly again carry a reading of 50 feet. Now it is necessary to replace the kelly at the top .of the ing block must lower the drilling string, now in-. cluding the new joint of pipe, into the well until only the upper end protrudes above the rotary table. Assume this downward movement to be 40 feet. The reading of counter 56 will there-' upon be reduced by the corresponding downward movement of the traveling block and will now read 10' feet, the present distance ofl-bottomof the bit. Traveling block it is now disconnected from the upper end of the drill pipe and echnected to the kelly which is swung into place and screwed to the upper end of the drilling string. When this operation has been completed, traveling block IE will have come to rest again,'at an upward position in the derrick above the upper end of the added. joint of drill pipe equal to the length of the kelly, namely 40 feet, and this additional upward movement will have been recorded on counter 56, which will riow register an oil bottom measurement of 50- feet, although, as noted, the actual position of the bit will have remained unchanged at 10 feet off-bottom. Now, as the entire drilling string is lowered in the well to bring the bit on-bottom, traveling block it will move downwardly only 10 feet to attain the on-bottom position, and the correspondingrecording on counter 56 will bring its reading down from feet to 40 feet. If now, drilling would be permitted to proceed, no additional footage, rep-.- resenting the deepening of the well, would be recorded on maximum counter 82, since counter 58 had not yet reached its zero position so as to release countershaft 60 to turn counter 62. It is necessary, therefore, to provide some means for returning the reading of counter 58 tozero when the bit has actually touched bottom, so that shaft 89 may be released and immediately 'begin recording on counter 62 the further downward movement of the bit from the previously attained maximum depth. In performing thisoperatlon of returning counter 56 to its zero reading, what is actually done, is to subtract from the reading of counter 56 the footage representing the length 0 of tlr e'new joint of drill pipe which has been added to the drilling string. This operation is performed by means of auxiliary differential 44 which has been previously adverted to,and itsconstruction and function will now be described 65. indetail. f As illustrated particularly in Fig. 4, auxiliary differential 44 is of more or less conventional construction and is arranged between main drive shaft 42 and selecting differential 48 so that shaft 4: drives directly throughthe mitre gears 81 of dlflerential 44 to differential 48 without variation inthe movements imparted to differential 46 except possibly to reverse the direction, of rotation of shaft 42a which connec'tsthe two diflefen- .78

tials. This reversal 'of rotation is, 'of'course, again correctedby the various gearand drive connections in differential so that the rota-- tions of the driven shafts 48 and"!!! correspond in the desired manner to the vertical movements of the drilling string. The spider 89 of the differ- 1 '62 which represent vertical movements. of the drilling string, ring'gear 9| remains stationary.

- When, however, it is desired to subtract the additional footage represented by the added joint of drill pipe, the handle 91 is turned, rotating ring gear 9| which in tum' rotates countershaft 5 4, as this shaft is still free to turn toward the zero position, since its reading is 40'feet, although the bit is actually on bottom. As many rotations are thus made as are necessary to equal the footage of the added section of drill pipe. Since, as noted, this added section was 40 feet long, when the number ofturns of auxiliary differential 44 equivalent to this footage hasbeen made, 40 feet will have been subtracted from the reading of counter 56 and its reading will become zerowhich isthe true reading, since the bit is on bottom. Now when drilling is, again begun,

causing corresponding downward movement of the traveling block l6, this movement will be transferred through diflerehtial 46 to shaft 60 because counter 56 has now become locked at its zero position and counter 62 and chart 40 will accordingly begin' registering the increasing depth. I X

Y The aforedescribed operations, including-the corrective rotations of auxiliary differential 44 are repeated for each! addition of sections to the drilling string, and it tei shaft 60 will accumulate only those downward movements of traveling block l6 which represent progressively downward movements of the bit. These accumulated movements will be registered on maximum counter 62 and on chart 48. which will be moved in exact accordance thereand friction brake 68 toselectively transmit to counter 82 and chart 40 only those movements of main shaft 42 which correspond to, progressive- I ly downward movements of the drill bit.

It will be understood that auxiliary'diflerential 44 may be employed either for adding or subtracting corrective rotations to the shafts i4 and 60, depending upon whether sections of drill pipe 'are being added to, or removed from, the drilling string, or to correct for errors in the length of the drilling string. By the form of'its construction and its arrangement auxiliary diflerential can be employed to introduce rotations into the transmission mechanism while main shaft 421s rotating or stationary, and the rotations thus introduced will correspondingly alter the reading i of counters 58 and 82 independently of manure-"- ber of rotations already made by main shaft 42;

Fig. 7 illustrates a modified form of off-bottom counter 58 which, by its construction, combines-in asingle piece of equipment, the functions of the off-bottom counter and of the auxiliary differential 44. 'In' this modified form, the ends of shaft 54 which extend beyond each end of the case I09 of the counter, which will be designated 98, are Journalled in bearings 9.9 and which-is attached a handle will beapparent that coun-' llll which are shaft II carries ahandle H9. Counter 98 func- I tions normally in exactly the same manner as counter 56 in the earlier described modification.' However, when corrections in the reading of counter 98 are to be made to account for the adding-in of sections of drill pipe to the drilling string, by turning handle H9 in the proper direction, the case I09 of the counter will be retated and will change the reading of the counter in accordance with the number of turns made.

The turning of the case will effect the same subtraction in the counter as is effected by the operation of auxiliary differential 44, as previously described. It will be understood that various other forms of apparatus may be similarly designed for use with the transmission mechanism of this invention to introduce the corrections occasioned by the additions to the length of the drilling string. I

The aforedescribed chart drive system maybe employed as described to effect a selection from all of the movements of traveling block I6 of only those particular movements which are to be em-' ployed to drive the chart, or particular movements of the drilling toolswhich are coupled to the chart drive may be pre-selected, as by means of the apparatusshown in my former Patent No. 2,166.212, or in my co-pending applicat on Serial .No. 279,422. filed June 16, 1939, now U. S. Patout No. 2,221,767, Nov. 19, 1940, or by any other ployed to drive such other mechanism in accordance with the downward movement of the drill. This) auxiliary drive is particularly useful for driving mechanism such as drilling rate indicators, generally illustrated at I54 in Fig. 8, which is illustrated as driving marking pen 61 to trace the record of drilling rate against depth on chart 40.

the switching arrangement will be described hereinafter in connection with the detailed de scription of this new modification.

Referring to Figs. 8 to 11, a normally open switch consisting of a detentarm I34 and a fixed arm I36 are mounted inside the case of counter 56 and detent arm I34 is arranged so as to be depressed into contact with fixed arm I36 by pres- .sure from lug 19 when indicia wheel 83 attempts to move past its zero position toward the 9--99 position of the counters. Wire leads I33 and I35 connect arms I34 and I36, respectively, in circuit with a group of relays I31, I38 and I39, and with a suitable current source such as a battery I40. The relays control switche I4I, I42 and I43, re-

spectively. Relay switch MI is connected by leads I44 and I45 in circuit with a battery 'I46 and- I with a solenoid I41 which controls the operation with a pawl I49 which is hingedly attached to the case of counter 62. The pawl I49 cooperates with ratchet wheel I48 so as to positively prevent reverse rotation of shaft 60. That is, shaft 60 can nowmove only in the forward direction representing progressive downward movement of the Figs. 8, 9, 10 and 11 illu'strate a modified form of the chart drive of this invention. In this modified form, the stop member in counter 56, which normally functions as a. control for the movements of shaft and counter 62, includes an electrical switching arrangement which is em ployed to automatically control and perform a number of useful operations. Primarily it is employed to automatically control the movements of shaft 60, by actuating an electric control for brake 68, which automatic'ally releases brake 68 and allows shaft 30 to rotate forwardly when the indicia wheels of counter 56 attempt to movebeyond the zero position. and automatically sets brake 63 when the reading of. counter 56 is .greater than zero, irrespective of the direction of rotation of shaft 54. Other useful functions of drill. The free end of brake arm 13 is pivotally attached to the end of the armature I50 of solenoid I41, and an extension of armature I50 is connected to an end of coil spring 11 which is now arranged to normally hold arm 13 and brake block 1| out of engagement with brake drum 69.

The electric control of brake-.63 operates as follows: When the drill bit is on bottom, counter 56 will register zero on all its wheels, as previously described. At the instant further drilling begins, countershaft 54 will tend to rotate beyond the zero position and the initial rotary movement will cause lug 19 to depress arm I34 and close the counter switch which will in turn immediately open relay switch I4I cutting off the flow of current in the windings of solenoid I41. Armature I50 will thereupon be released anclwill be pulled upwardlyby the tension of spring 11 and will draw brake block 1I out of braking engagement with brakedrum 69, and releases shaft 60 for rotation. As long as the drill continues to move downwardly in the well. shaft 60 will remain free to rotate the wheels of counter 62 and the drive to chart 40 in accordance with the downward movement of the bit. When, however, the bit is lifted off-bottom the corresponding reverse movement of the wheels of counter 56 will relieve the pressure of lug 19 ondetent arm I34 and break its contact witharm I36. This action will in turn cause relay switch I M to close'actuating solenoid I 41 to draw armature I 50 down and thereby pull brake'block 1I into braking engagement with drum 69 thus eifectivelystopping anyrev'erse movement of countershaft 60. However, since the initial reverse movement of.

- the bit would normally tend to cause correspond ing reverse movement of shaft '50, as well as of shaft 54, since the brake on shaft 60 is not yet engaged, then, in order to preventanysuch' re versal of shaft 60, and to permit preferential reversal of shaft-54 so as to cause the switch in counter 56 to actuate and set. the brake on shaft 60, ratchet I48 and pawl I49 are provided to cooperate to prevent any reverse movementof shaft 60, and thus enforce the desired preferential rotation of shaft 54 which results in setting of the brake 6 8. when the brake has thus become set, no movements of the traveling block I6 occurring while the bit is off-bottom can affect counter 82 until-such movements occur as will bring counter 56 back to the zero position so'as to again close the circuit to relay I31 and release brake 88.

Relay I38 is employed to operate a lamp II.

and bell I52 which are arranged in parallel in;

ranged to close this circuit when the switch formed byarms I34-and I38 is closed. That is,- when the bit is on bottom. Closing of switch I42 .lights up lamp HI and rings bell I52, thus giving the drill operator both a visible and an audi ble signal when the bit is on bottom. The lamp IN is ordinarily allowed to remain lighted as circuit with switch I42. Relay switch I42 is ar-' -l0 with themain shaft in' one direction only cdrresponding to downward progress of said drilling string in the well and to render said second driven shaft normally preferentially rotatable by said main shaft, and means cooperating with said second driven shaft to limit its rotation with then main shaft in said one directionwhile permitting relatively unlimited rotation thereof in the opposite direction. '1 Y 2. In combination with a drilling string and a -welldepth exhibiting means adapted to exhibit the depth of the well in accordance with the downward progress of said drilling string in the well, a drive for said exhibiting means comprislong as, the bit is on bottom or drilling ahead.

Bell I52 may be cut-off by means of aswitch IE3 after it has given warning that the bit has touched bottom.

Switch I43 is also arranged to close when the switch in counter 56 closes, and is connected in circuit with an instrument such as a conventional drilling rate indicator I54 which is shown as operating pen 61. The circuit connects relay switch I43 with a conventional pen control when reverse movements of the drilling tools occur, opens relay switch I43 and stops pen 6'! at exactly the point it occupied at the instant chart 40 has likewise stopped.

It willbe seen, therefore, that the switch in counter 58, in addition to aiding in the automatic selection of the movements of the drilling tools to be transmitted to chart drive 40, may be employed for numerous other functions related to the position of the drill in the well. In addition to those specifically enumerated above, the

' switch may be employed, through the use of additional relays, in other capacities and for other uses which willbeapparent to those-skilled in the art to which this invention appertains.

It will be apparent that numerous modifications and alterations may be made in the details of construction and in the form of arrangement of the parts of this invention without departing from the scope of the appended claims,

What I claim and desire to secure by Letters Patent is: t

1. In combination with a drilling string and a well depth exhibiting means adapted to exhibit ing, a main drive shaft driven from said drilling string and reversibly rotative in synchronism with corresponding measured-vertical movementsof said drilling string, a first driven shaft drivingly'connecting said main drive shaft to said exhibiting means, a second driven'shaft driven by said main drive shaft, a differential member connecting said main. drive shaft to said first and second driven shafts, means operative upon said-first driven shaft to constrain its rotation with the main shaft in one direction only corresponding to downward progress of said drilling string in the well and to render said second driven shaft normally preferentially rotatable by said main shaft, and a revolution counter reversibly driven by said second driven shaft and including means for preventing rotation of said second driven shaft insaid one direction when said counterattains its zero reading in that direction.

3. In combination with a drilling string and a well depth exhibiting means adapted to exhibit the depth of the well in accordance with the downward progress of said drilling string in the well, a drive for said exhibiting means comprising, a main drive shaft driven from said drillin string and reversibly rotative in synchronism with corresponding measured vertical'movements' of said drilling string, a first driven shaft drivingly connecting said main drive shaft to said exhibiting means, a second driven shaft driven by said main shaft,-and means cooperating between said first and second driven shafts and said main drive shaft whereby said first driven shaft is constrainedto drive said exhibiting means in one direction only corresponding to progressive deepening movements of said drilling tools in the well, and auxiliary means for rotating said' driven shafts independently of said main drive shaft. V

the depth of the well in accordance with the downward progress of said drilling stringin the well, a drive for said exhibiting means, comprising, a main drive shaft driven from sale? drilling string and reversibly rotative in synchronism with corresponding measured vertical .movements ofv said drilling string. a first driven shaft drivingly connecting said main drive shaft to said exhibiting means, a' second driven shaft driven by said main drive shaft, a differential member connecting saidmain shaft to said first and second driven shafts, means operative upon said first driven shaft to constrain its rotation 4. In combination with a drilling string and a well depth exhibiting means adapted to exhibit .the depth of the well in accordance with the downwardprogress of said drilling string in the well, a drive for said exhibiting means comprismg, a main drive shaft driven from said drillin string and reversibly rotative in synchronism with-corresponding measured vertical movements of said drilling string, a first driven shaftdrivingly connecting said main, drive shaft to said exhibiting means, a second driven shaft driven by said main shaft; and shaft selecting me'ans' cooperating betweensaid first and second driven shafts and said main drive shaft whereby said first driven-shaft is selectively constrained to drive said exhibiting means in the direction .only corresponding to progressive depending movements of said drilling tools in the well and auxiliary means for altering the accumulated rotations of said driven shafts independently of said main drive shaft.

with corresponding measured vertical movements of said drilling string, a first driven shaft drivingly connecting said main drive shaft to said.

exhibiting means, a second driven shaft driven by said main drive shaft, a differential member connecting said main shaft to said first and second driven shafts, means operative upon said first driven shaft to constrain its rotation with the main shaft in one direction only corresponding to downward progress of said drilling string in the well and to render said second driven shaft normally preferentially rotatable by said main shaft, and means cooperating with said second driven shaft, to limit its rotation with the main shaft in said one direction while permitting relatively unlimited rotation thereof in the opposite direction, and an auxiliary differential member cooperating with said first'and second driven shafts for altering the accumulated rotations thereof independently of said main drive shaft.

6. In combination with a drilling string and a well depth recording chart adapted to record the depth of the well in accordance with the downward progress of said drilling string in the well, a drive for said chart comprising, a main drive shaft driven from said drilling string and reversibly rotative in synchronism with corresponding measured vertical movements of said drilling string, a first driven shaft drivingly connecting said main drive shaft to said chart, said first driven shaft being releasably constrained to rotate with said main shaft in one direction only corresponding to said downward movements of said drilling string, a second driven shaft reversibly driven by said main shaft, means limiting the rotation of said second driven shaft in said one direction while permitting relatively unlimited rotation thereof in the opposite direction,

tion, and means associated with said stop means and operative upon the limitation of rotation of said second driven shaft thereby to release said brake.

8. Apparatus according to claim 7 including, an electrically controlled release means for said brake, and an electrical switch means in circuit therewith and actuable by said stop means to release'said brake.

9. Apparatus for recording well depths during drilling comprising, a drilling string movable vertically in a well, a; traveling block for suspending the drilling string and movable vertically tical movements, a measuring wheel driven by and means cooperating between said first and said one direction only upon the attainment by said second driven shaft of the limit of its rotation in said one direction.

7. In combination with a drilling string and a well depth exhibiting means adapted to exhibit .the well depth in accordance with the downward progress of said drilling string in the well, a drive for said exhibiting 'means comprising, a main drive shaft driven from said drilling string and reversibly rotative in synchronism with corresponding measured vertical movements of said drilling string, a first driven shaft drivingly connecting said main drive shaft to said exhibiting means, a second driven shaft driven by said main drive shaft, a differential member connecting said main shaft to said first and second driven shafts, means constraining said first driven shaft to rotate with said main drive shaft in one direction only corresponding to downward progress of said drilling string in the well, releasable brake means ingly connect said mechanism to said said pulley for measuring the vertical movements of the traveling block, a selective transmissiondriven by said measuring wheel in synchronism, with the measured vertical movements of said traveling block, a depth recording chart releasably driven by said selective transmission, said selective transmission including selecting means arranged to be operative ony by those measured vertical movements of the traveling block corresponding to progressive deepening of the well to drivingly connect said mechanism to said chart, well logging apparatus for placing well logging data on said chart, and control means operative by said selecting means in said transmission mechanism for causing said logging apparatus to place its record on said chart only when said chart is being driven by said mechanism.

10. In combination with a drilling string movable vertically in a well, a strip recorder chart bearing footage indicia representative of the depth of said well and adapted to be driven in synchronism with the downward progress of said drilling string in the well, apparatus for placing continuous records of drilling operations on said chart, and a chart drive, comprising, a selective transmission mechanism releasably connecting said drilling string to said chart, said transmission mechanism including selecting means arranged to be operative only by those downward movements of the drilling string which constitute progressive deepening of the we?! to driv- Lhart, and control means operative by said selecting means to thereby cause said records to be placed on said chart by the recording apparatus only when said chart is being driven by said mechanism.

11. In combination with a drilling string and a well depth register adapted to register the depth of a well in accordance with the downward progress of the drilling string therein, a drive for said register comprising, a main drive shaft driven from the drilling string, a differe' .1 connected to said main drive shaft, first and second revolution counters driven by said main drive shaft through said differential, means constraining said first counter to cumulatively count revolutions of the main drive shaft in one direction only corresponding to downward progress of said drilling string, retarding means operative upon said first counter whereby said second counter is reversibly driven by the main shaft normally preferentially relative to said first counter, and means to lock said second counter against rotation in said one direction upon attainment of its zero reading in that direction to thereby cause further rotations of said main shaft in that direction to preferentially drive said first counter.

12. In combination with a drilling string adapted to 'move vertically in a well and a well depth recording chart adapted to be driven in accordance with the downward progress of the drilling string in th well, a drive for said chart comprising, a main drive shaft driven from the drilling string, a differential driven from said shaft and having one branch drivingly connected to said chart, means constraining the-chart to move in one direction only corresponding to downward progress of said drilling string, a revolution counter connected to said main shaft through a second branch of said differential and reversibly driven thereby normally preferentially relative to said chart, and means to lock said revolution counter against rotation in said one direction upon attainment of its zero reading in that'direction to thereby cause further rotations of said first branch in that direction to preferen tially drive said chart.

13. In combination with a drilling string and a well depth exhibiting means adapted to exhibit the depth of the well in accordance with the downward progress of the drilling string in deepening the well, a drive for said exhibiting means, comprising, a main drive shaft driven from said drilling string and reversibly rotative in synchronism with corresponding measured vertical movements of said drilling string, a first driven shaft drivingly connecting said main drive shaft to saidexhibiting means and constrained to rotate in one direction only corresponding to downward movements of said drilling string, a second driven shaft reversibly driven by said main shaft normally preferentially relative to said first drivon shaft, and means actuable by pro-determined limitation of the rotation of said second shaft in said one direction to produce preferential r0- tation of said first driven shaft in said direction.

14. Apparatus for recording well depths during drilling, comprising, a drilling string adapted to move vertically in a well, a well depth recorder, a drive for said recorder, said drive comprising, a main drive shaft driven from the vertical movements of said drilling string, a differential driven from said shaft and having a first branch drivingly connected to said recorder, means constraining said recorder to move in one direction only corresponding to downward progress of said drilling string, a second branch of said differential reversibly driven by said main shaft normally preferentially relative to said recorder, and

means to lock said second branch against rotation in said one direction upon attainment of a pre-determined limit of rotation in that direction to thereby cause further rotations of said first branch in that direction to preferentially drive said recorder.

15. In combination with a drilling string and a well depth register adapted to register the depth of a well in accordance with the downward progress of the drilling string therein, a drive for said register, comprising, a main drive shaft driven from the vertical movements of said drilling string, a differential member connected to drilling comprising in combination with a drill-' ing string movable vertically in a well, a well depth recording means, a transmission mechanism operative only by thosedownward movements of the drilling string which correspond to. progressive deepening of the well to drivingly connect said drilling string to said recording means, and an auxiliary adjusting mechanism foraltering the position of said transmission mechanism to compensate for changes in length of said drilling string;

JOHN T. HAYWARD.

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