US3455401A - Orienting tool for slant hole drilling - Google Patents

Description

July 15, 1969 Filed May 6, 1968 R. G. TAYLOR, JR

ORIENTING TOOL FOR SLANT HOLE DRILLING m7 m5 lO we w 3 Sheets- Sheet 1 IN V EN'TOR. 5/1 VMO/VQ 6- mywz, J2

BY gj i" A TTOEA/EV July 15, 1969 R. G. TAYLOR, JR 3,455,401

ORIENTING TOOL FOR SLANT HOLE DRILLING v Filed May a, 1968 s Sheets-Sheet 2 I NVENTOR. t ,64 VMOA/0 6. m we, Je

756" Q iwf A TTOEA/EV July 15, 1969 T JR 3,455,401

ORIENTING TOOL FOR SLANT HOLE DRILLING Filed May 6, 1968 3 Sheets-Sheet 5 INVENTOR. BMW/v0 6- m we, J6

United States Patent ORIENTING TOOL FOR SLANT HOLE DRILLING Raymond G. Taylor, Jr., Santa Monica, Calif., assignor to Byron Jackson Inc., Long Beach, Calif., a corporation of Delaware Filed May 6, 1968, Ser. No. 726,870 Int. Cl. E21b 47/02 U.S. Cl. 175-45 22 Claims ABSTRACT OF THE DISCLOSURE A signaling orientation indicator instrument of the type employing drilling fluid operated means for producing a number of pressure pulses in the stream of drilling fluid as an indication of the angular orientation of the instrument within a well bore about its longitudinal axis and, in which, movement of a flow restricting member is limited to an extent related to the angular orientation of the instrument by a gravity responsive weight, movement of which is initially arrested in response to a reduction in the rate of drilling fluid flow in advance of cessation of such drilling fluid flow, the pressure pulses in the drilling fluid being produced upon resumption of the circulation of drilling fluid.

Background of the invention In the drilling of certain oil and other wells or boreholes at an angle to vertical, it sometimes becomes necessary to change the angle at which the drill stem is progressing. This is to say, if the well drilling program requires that the well proceed at an angle of 15 from vertical in a given direction for a given distance in order to arrive at a given depth and ofiset position relative to the surface equipment, then it sometimes is necessary to correct for deviation from the prescribed angle. As is well known, this correction may be made by use of selected jet bit orifices or by whipstocking, for example.

In the case of jet bit drilling, it is possible to increase or decrease the angle of the hole being drilled by the use of a bit having a jet orifice on one side larger than the other jet orifices. For example, if a conventional tri-cone bit is provided with a jet orifice at one side of diameter and two jet orifices at the other sides of /8" diameter, a cavity will be made in line with the larger jet orifice when the drill string remains stationary during circulation of drilling fluid through the bit orfices. When rotaton of the drill string is resumed the bit will tend to move into the cavity thereby tending to change the angle at which the hole will progress. If such jetting of a cavity be accomplished on the low side of the hole, the result will be shifting of the direction of drilling toward vertical; and, conversely, if jetting of a cavity be accomplished at the high side of a hole, the result will be shifting of the direction of drilling further away from vertical. Intermediate corrections may also be accomplished.

In whipstocking the drill stem, a wedge-like device or shoe is located in the hole so that upon resumption of drilling the bit is caused to be deflected by the wedge to change the angle at which the drill progresses. Here again, if the wedge is disposed at the low side of the hole, the angle of the hole will be increased; and, conversely, if the wedge is disposed at the high side of the hole, the angle of the hole relative to vertical will be decreased. Other corrections may be made, as is well known, whereby to alter the direction in which the well bore is progressing.

Still another mode of deflecting or changing the angle or maintaining the desired angle of progression of well drilling operations involves the use of a deflector shoe made up as a part of the drill string and either hydraulically or spring biased laterally of the drill string which will Patented July 15, 1969 alter the angle. If the shoe acts on the low side of the hole the angle of progression will either be increased or decreased, depending upon the nature of the particular deflection tool being employed; and similarly corrections can be made by causing the shoe to act on the high side of the hole.

In all of the above types of drilling operations it is notable that it is necessary to be able to locate the drill str ng in respect of the relative angular disposition or orientation about the axis of the drill of a reference point on the drill string, namely, the relationship in the hole of either the large jet orifice in jet drilling, the face of the wedge in whipstocking, or the deflection shoe in the case of a deflection tool. In this connection, it is common practice to provide in a drill string at a stabilized location above the bit a magnetic reference point which can be detected by a so-called single-shot surveying tool adapted to make a record showing the compass orientation and inclination of the hole. Such single shot tools are either dropped into or run into the drill string on a cable before the drill string is pulled from the well to enable changing bits or at other selected times so that the driller can more or less apply weight on the bit and vary rotational speed as may be necessary to maintain or modify the progression of the hole.

After determining that correction of the progression of the hole is desirable, it is necessary to run the drill string back into the hole if bit change has occurred and/ or relatively orient the drill string to effect orientation of the larger jet orifice, whipstock, or deflection shoe as desired relative to the high or low side of the hole. The low side is exemplary and is employed to generically indicate either high or low side.

Some of the problems associated with directional drilling as referred to above, and more particularly, the problems encountered when it is desired that the well be drilled on a large are extending downwardly and horizontally at a substantial angle from the point of entrance of the well into the earths surface, have been solved by the use of motor operated drills which are driven by positive displacement hydraulic motors or by mud turbines, the usual circulation of drilling fluid providing a convenient source of power for such motors. In the use of such devices the drill pipe string and the motor housing remain stationary, and the mud motor rotor, either the turbines or the positive displacement rotor effect rotation of the drill bit. Thus, angular subs or elbows may be employed for connecting the mud motor housing to the lower end of the drill string so as to establish the desired angular relationship between the motor housing and the drill string, whereby as the drilling progresses the well bore will be formed on a wide are extending progressively downwardly and horizontally into the earth.

In such drilling operations, however, as in other conventional whipstocking or drill string deflecting drilling techniques, it is necessary to ascertain the direction in which the drilling fluid motor housing is projecting in order to effect the proper progression of the Well bore on the desired course. Moreover, it is periodically desirable that the current disposition of the motor housing be ascertainable so as to assure that the well is progressing as desired, without necessitating the running of the usual wireline-type instruments for detecting the compass orientation of the well bore. Inasmuch as the drilling fluid motors include a drilling fluid driven impeller within a stationary housing, there is imposed on the motor housing a reaction force tending to effect opposite rotation of the housing in relation to the rotor and the bit. Thus, when the motor housing is connected to the drill pipe string thereabove by an angular sub, there is a tendency for the reaction force applied to the motor housing to cause the bit to swing off in an undesired direction relative to the desired course of the well, the motor housing essentially swinging about a pivot defined by the angular sub so as to commence the drilling of a spirally extended well bore. When the pumping of drilling fluid through the fluid motor is arrested so as to enable the running of a wireline instrument to survey the direction in which the well is progressing, the reaction force previously applied to the housing is interrupted and the housing may move back to What appears to be the correct course, but, upon resumption of the pumping of drilling fluid, the reaction force applied to the housing may cause it to swing back to an erratic course as compared with the desired course of progression of the well.

Summary The present invention provides signalling apparatus adapted to produce pressure pulses in the stream of drilling fluid which are indicative of the angular orientation of the drill string adjacent the drill bit or hydraulic motor in relation to a gravity responsive member which tends to assume an orientation related to the low side of the hole or to a vertical line.

More specifically, the invention provides such an instrument in which the production of drilling fluid pressure pulses is produced by apparatus, the function of which is pre-conditioned by a modification of the rate of drilling fluid flow preliminary to the cessation of drilling fluid flow, so that, in the case of a hydraulic motor, the housing of which is improperly directed as a result of the reaction force applied thereto, the mud pressure pulses will be indicative of the actual disposition of the mud motor while it is working to drive the drill.

In accomplishing the foregoing, the invention contemplates the provision of a stop member having a plurality of angularly extended stop elements spaced axially of the instrument housing in a known angular relationship and adapted to be engaged by a gravity responsive member which normally assumes a position at the low side of the instrument so as to selectively engage one of the stop elements, and wherein the instrument includes means for fixing the angular position of the gravity responsive member while the drilling fluid circulation continues and the hydraulic motor housing employed to drive the bit is subjected to the reaction torque of the motor, so that when the circulation of drilling fluid is interrupted and the gravity responsive member engages one of the stop elements the signals produced upon resumption of drilling fluid flow will be indicative of the working position of the hydraulic motor, which may be different from the nonworking position of the hydraulic motor.

An object of the invention is to provide a signalling instrument adapted to be incorporated in a drill collar installed in a well drilling pipe string and which is relatively insensitive to the shocks to which it is subjected during the drilling operations, and which, for an instrument of its relative complexity, is certain and reliable in its operation.

Other objects and advantages of the invention will be described hereinafter or will become apparent to those skilled in the art, and the novel features of the invention will be defined in the appended claims.

Brief description of the drawings FIG. 1 is a view diagrammatically illustrating an instrument in accordance with the invention installed in a well drilling string, including a hydraulic motor and an angular sub for drilling a well in a progressive arc;

FIG. 2 is a view partly in longitudinal section and partly in elevation illustrating the signalling instrument of FIG. 1;

FIG. 3a is an enlarged fragmentary detail view in longitudinal section showing the upper end of the instrument of FIG. 1, minus the pulse ring assembly;

FIG. 3b is a downward extension of FIG. 3a;

FIG. 4 is a further enlarged fragmentary detail view in longitudinal section more particularly illustrating the stop assembly and gravity responsive member of the instrument;

FIG. 5 is a transverse sectional view, as taken on the line 55 of FIG. 4;

FIG. 6 is a detail view in perspective illustrating a stop member employed in the instrument;

FIG. 7 is a graphic representation of the angular relationship of the stop elements of the stop member of FIG. 6; and

FIG. 8 is a graphic representation of a modified arrangement of stop elements on a stop member, such as that illustrated in FIG. 6.

Description of the preferred embodiment Referring first to FIG. 1, there is generally illustrated a drilling string S, to the lower end of which is connected in the usual manner a drill collar sub D adapted to contain an instrument, as will be hereinafter described, for producing pressure pulses in the stream of drilling fluid which, in the conventional manner, is caused to circulate downwardly through the drilling string S and through the drill collar sub D, through a hydraulic motor M for the purpose of effecting rotation of a drill bit B, the drilling fluid then returning to the earths surface through the well bore W outside of the drill pipe string S. The motor M is connected to the drill string S and, more specifically in the illustrative embodiment, to the lower end of the drill collar sub D by means of an angular sub A. This angular sub A establishes a predetermined angle between the drill string S and the motor M, so that as the drilling of the well bore W progresses it will form progressively a wide are, extending progressively further horizontally from a vertical reference line indicated at V in the showing of FIG. 1. The motor M may be of any known type capable of effecting rotation of the bit B responsive to the flow of drilling fluid through the motor housing H, the flow of fluid through the housing H effecting rotation of a motor rotor R. Typically, rotation of the rotor R and the bit B by the pressure of fluid flowing through the motor housing will be in a say right-hand direction, resulting inherently in the application of reaction torque to the motor housing H tending to cause the latter to rotate in a left-hand direction. Inasmuch as the progression of the well bore W in its desired direction essentially depends upon the motor housing H remaining in the proper direction relative to the drill string S, the reaction torque applied to the housing H tending to cause it to rotate in the opposite direction relative to the bit B results in a tendency of the housing H to swing off in an erratic direction about the apex A of the angular sub A, the housing H tending to swing about the point A, thereby twisting the drill string S and resulting in progression of the drilling operation in an improper direction relative to a desired direction. The instrument hereinafter to be described within the drill collar sub D is adapted to produce signals in a number representative of the relationship of the point A to the low side of the well bore W. Otherwise stated, the instrument will be productive of pressure signals in the well drilling fluid which are indicative of the angular orientation of the drill collar D about its longitudinal axis in relation to a gravity responsive member which will normally be in a position pointing towards the low side of the drill collar D. Thus the signals produced by the instrument will be indicative of whether the motor M and the bit B are progressing in the desired relationship to the intended course of the well bore W.

Referring now to FIG. 2, the drill collar sub D is adapted to contain the instrument generally denoted I, drilling fluid being free to flow between the instrument and the inside wall of the sub D. At the upper end of the instrument I is a pulse ring sleeve generally denoted at P, and at the lower end of the instrument I is a bottom support P whereby the instrument I is supported top and bottom in the sub D and such flow of drilling fluid is permitted.

The pulse ring sleeve P has an enlarged end flange 2 which shoulders and is sealed in a seat 3. At its lower end the sleeve P is provided with a cylindrical member 4 connected to the sleeve by arms 5 providing windows or flow passages 6 so that fluid may pass through the sleeve P, the member 4 mounting the sleeve P on the housing I. This mounting is preferably like that more specifically described in the pending application for United States Letters Patent, Ser. No. 561,637, filed June 29, 1966. Within the sleeve P it is provided with a series of axially spaced pulse rings 7, only two of a larger number being shown but each of which is adapted to cause a pressure pulse in the fluid stream passing therethrough, as will hereinafter appear. This pulse ring construction may be like that more specifically described in the pending application for United States Letters Patent, Ser. No. 552,150, filed May 23, 1966.

Bottom support P has an outer rim 9 and a hub 10 on which the rim 9 is supported by webs 11 forming therebetween flow passages at the lower end of housing I. A port 12 is provided in the hub 10 so that fluid finds access to the housing I at its lower end. The instrument I is maintained in a known orientation within the sub D by suitable means such as a keyway 9a in skirt 9 and a set screw 9b in sub D which is suitably sealed and extends into the keyway.

The housing at its upper end has reciprocably mounted therein and extensible therefrom a shaft 13 having at its outer extremity a head or knob 14. Within housing I is spring means 15 which normally bias shaft 13 upwardly out of the housing I, thereby causing the head 14 to be moved upwardly through the pulse rings 7. However, the flow of drilling fluid downwardly through the pulse ring sleeve P will cause the head 14 to move downwardly into engagement with the upper end of housing I. Thus, during circulation of drilling fluid the shaft 13 and knob 14 will remain as shown in FIG. 1, but when such circulation is halted, the shaft will be forced outward and the head will move upward through the rings 7. Such circulation of drilling fluid is automatically ceased each time an additional length of drill pipe is to be added at the earths surface, and otherwise as desired. When circulation is resumed, a pressure pulse is caused as the knob 14 passes through the rings 7 due to the restriction in flow area, and such pulses are detectable at the earths surface by a typical pressure gauge or pressure recorder.

In order that the upward movement of the shaft 13 will be limited in accordance with the angular disposition of the drill string about its axis, i.e., the orientation of the drill string relative to the low side of the hole being drilled, gravity responsive means, in this embodiment including an eccentrically weighted member generally denoted at 16, is adapted to selectively engage stop means generally denoted at 17 as the member 16 moves upwardly. In order to retard downward movement of the shaft 13 so that the resultant pressure pulses will be distinct and adequately spaced, means generally indicated at 18 are provided for retarding fluid displacement through a transverse barrier 19. At the lower end of the housing I is a divider 20 shiftable to balance internal fluid pressure and external drilling fluid pressure, and so as to enable the transfer of fluid through the retarding means 18 as the shaft 13 displaces fluid downwardly, and the upward transfer of fluid through a check valve 22 as the shaft 13 is urged upwardly.

Referring to FIGS. 3a and 3b it will be seenthat the instrument housing I includes an upper tubular section having an upper shaft guide 31 threadedly mounted therein. Shaft guide 31 has a seal and wiper means 32 and 33, respectively, engageable with the shaft. At the outer extremity of the shaft, the knob 14 is supported by means of a knob bushing 34, a pin 35 connecting the bushing to the shaft and a snap ring 36 retaining the knob on the bushing. As seen in FIG. 2, the upperhousing'section 30 is threaded to a lower housing section 37, to the lower end of which is connected the hub 10 of bottom support P.

Supported by barrier 19 is an orifice disc assembly having a stack of orifice discs 48 retained in place by a ported plug 49. At one side of barrier 19 is the upwardly opening ball check valve 22 and at another location in the barrier 19 is a downwardly opening spring loaded relief valve 50. Thus, the barrier 19, the valve 22 and the orifice discs 48 constitute the means 18 for retarding downward flow of housing fluid through the barrier 19, while enabling comparatively free upward flow of housing fluid as the shaft is extended from the housing and forced back into the housing during operation of the instrument. The valve 50 serves to relieve pressure in the event that such relief may be necessary.

The shaft 13 is connected to the gravity responsive member 16 by coding means which allow upward movement of the shaft a distance inversely related to the upward travel of the gravity responsive member 16. The coding means includes, as seen in FIGS. 3a and 3b, a longitudinally extended coding rod generally indicated at which is reciprocally disposed in a tubular guide and stop ball support 61. The guide 61 is connected to and essentially constitutes a portion of the upper housing section 30 and is supported at its lower end in a tubular part 62 which is formed as an upward extension of a block 63 which in turn is secured within the instrument at the lower end of the upper housing section 30 by means of a suitable number of fasteners 64 (see FIG. 2). More specifically, as seen in FIG. 3b, the guide 61 seats at its lower end on a washer 65 which shoulders at 66 in the upper end of the tube 62; and in upwardly spaced relation to the washer 65 is a second washer 67 fastened in the tube 62 by lock ring 68, the lower end of the guide 61 extending through washer 67 and having a lock ring 69 which engages beneath the washer 67. Thus it is apparent that while the guide 61 is assembled with the tube 62 prior to connection of the block 63 to the lower end of housing section 30, means are provided so that the ultimate assembling of these components results in the guide 61 being rigidly and concentrically supported within the upper housing section 30.

The coding rod 60 previously referred to is composed of an upper end section 70 slidably disposed within the guide 61. Beneath the upper end 70 is an axially spaced series of reduced stern sections 71 and thimbles 72a, 72b, 72c, 72d, 72e and 72 Beneath the lowermost thimble 72] is a connector 73 which connects the upper coding rod section 70 to a lower connecting rod section 74, the latter extending downwardly through the guide 61 and the guide supporting washers 6-5 and 67 into the tube 62. At its upper end, coding rod section 70 has a centralizing guide 70a secured thereto and slidably engaged in the shaft 13, this guide being perforated to permit bypass of fluid within the instrument. Above the guide 70a is a coil spring 70b freely disposed in shaft 13 so as to engage and bias the coding rod downward when the shaft is in its downward position, as shown in FIG. 3a. As shown in FIG. 3b, there is another coil spring 60a which surrounds the lower coding rod section 74 within rod guide 61 and engages at its upper end with connector 73 and which, at its lower end, engages the support washer 65 for tube 61. This spring 60a is adapted to normally bias the coding rod 60 upward when the shaft 13 moves upwardly.

It is the purpose of the thimbles 72a72f depending upon the extent of upward movement of the coding rod, as will be more fully explained hereinafter, to selectively hold in an outwardly projected position a set of stop projections which more specifically are composed of sets of balls. In the illustrative embodiment, there are 6 sets of such balls respectively designated from top to bottom, as viewed in FIG. 3a, 75a, 75b, 75c, 75d, 75c and 75 adapted to be moved outward by thimbles 72a-72f, respectively. The balls are disposed in openings 76 in the rod guide 61 so that the latter also constitutes a ball support. The sets of balls are cammed outward upon engagement by the respective thimbles 7211-721 into annular space 13a defined by the guide 61 and the shaft 13. Within the shaft 13 (see FIG. 3b) is a stop 77 which defines the bottom of the just-mentioned annular space 13a and essentially this stop forms a portion of the shaft 13 which will limit upward movement of the latter, under the influence of spring 15, upon engagement of the stop 77 with one of the sets of stop balls 7511-75), or upon engagement of the stop 77 with a stop ring 75 carried by tube 61 in spaced relation above stop balls 75a, thus selectively limiting upward movement of the knob 14 with respect to the pulse ring section P.

Essentially the stop shoulder 77 is a portion of the shaft 13, but in the specifically shown structure the shaft 13 incorporates means for allowing freedom of upward movement of the shaft independently of the stop shoulder 77 in order to relieve the stop shoulder and stop balls from excessive loading, in the event of backflow of drilling fluid through the drill collar D, as well as during running of the drill string into the well bore following the changing of drill bits. Accordingly, as shown in FIG. 3b, the shaft 13 is reduced in diameter at the point of its connection with a downwardly extended shaft extension 80. concentrically disposed about the downward shaft extension 80 is a spring coupling sleeve 81 having an upper outwardly projecting flange 82 engaged by the upper end of the shaft biasing spring means 15, the lower end of the latter abutting, as shown in FIG. 1, with the block 63. The just-mentioned flange 82 also abuts with the larger diameter upper shaft section so that the shaft 13 is biased upwardly. At its lower end the spring coupling sleeve 81, as seen in FIG. 3b, is connected between a pair of snap rings 84 with an internal sleeve 85 which is disposed within the downward shaft extension 80. Thus it will be seen that the shaft extension 80 is free to move upwardly relative to the spring coupling sleeve 81 and the connected internal sleeve 85, but the spring means acts to bias the shaft 13 upwardly through the intermediary of the spring coupling sleeve 81 and internal sleeve 85, the latter having at its upward extremity the abovementioned stop shoulder 77 (see FIG. 3b). Therefore, the extent of upward movement of the shaft 13 and the knob 14 under the influence of the spring means 15 is limited by the stop 77, even though the shaft may be free to move further upwardly in response to the influence of fluid flow upwardly through the drill collar D.

Thus it will be apparent that if the balls 75 be cammed into the path of stop 77, the shaft 13 will be limited in its upward travel under the influence of spring 15 to a position at which the knob 14 is disposed between the lowermost and the next above pulse ring 7. As the shaft 13 is allowed further increments of upward movement then the knob 14 will correspondingly be allowed further upward movement a distance equal to another pulse ring per increment of shaft movement. Thus if the stop 77 is allowed to pass all the sets of stop balls 75f through 75a but engages stop ring 75, the knob 14 will be allowed to travel a distance equal to the spaces between seven pulse rings as a result of which downward movement of the knob caused by drilling fluid flow will cause the production of seven pressure pulses or signals which will travel through the column of drilling fluid to the earths surface for detection or recordation as an indication of the orientation of the housing within the well bore in relation to the low side of the hole W. As previously described, the gravity responsive member 16 and the cooperative stop means 17, hereinafter to be described, Serve to limit upward movement of the coding rod so as to cause the projection of the appropriate set of stop balls a through 75f to limit upward movement of shaft 13.

It will be noted that the spacing of axial stop balls 75a75f relative to the thimbles 7211-72 as shown in FIG. 3a, is such that none of the stop balls will be projected outwardly into the path of shaft stop 77 when the coding rod has traveled upwardly the minimum extent, but the latch balls 75 will be projected outwardly into the path of stop 77 when the coding rod has traveled upwardly to the maximum extent. As a result the shaft will be allowed to move upwardly a minimum extent when balls 75 are projected outwardly and a maximum extent when none of the balls are projected outwardly. This inverse relationship as just described results in a direct relationship between extent of angular displace ment of a reference point on the drill stem relative to the low side of the hole when the upward motion of the gravity responsive member is arrested and the extent of upward travel of shaft 13. More particularly, there is a resultant direct relationship between the number of pulse rings through which the knob 14 will pass upwardly and the number of pressure signals when the knob is forced downwardly by the flow of drilling fluid and the orientation of the housing I relative to the low side of the hole. Therefore, in respect of each increment of angular displacement as determined by the structure of the stop means 17, there will be produced one pressure signal.

Referring now to FIGS 2 and 4, the stop means 17 will be seen to comprise an annular body adapted to fit within a bore 101 within a supporting sleeve 102 within the lower section 37 of the instrument housing I, the member 100 having an upper inwardly extended flange 103 adapted to be suitably secured as by fasteners 103a beneath a shoulder 104 provided by the supporting sleeve 102. This supporting sleeve is connected to the above-described block 63 by means of a number of upstanding fingers 105 which extend into slots 106 angu larly spaced with respect to the fasteners 64 which connect the block 63 to the housing 30. Fingers 105 have outwardly extended terminals 107 adapted to abut with a lock ring 108 which extends about block 63 in a groove therein for interlocking the fingers with the block.

In the illustrative embodiment the stop member 100 is provided with seven angularly spaced stop elements respectively designated 200, 2000, 200b, 2000, 200d, 200a and 200 these stop elements being in the nature of steps and being progressively axially spaced one above the other, as well as angularly spaced relative to one another. Thus, if upward movement of the gravity responsive member 16, as will hereinafter be described, is arrested during operation of the instrument by stop shoulder 200a the balls 75e of the coding means will be caused to project into the path of the stop shoulder 77 on the shaft 13. The same relationship exists between each of the stop shoulders 200 through 2000 and the stop ring 75 and stop balls 75a through 75d, so that while the permitted upward travel of the gravity responsive member 15 will be inversely related to the extent of angular displacement of the instrument housing about its axis relative to the low side of the hole, the permitted upward travel of the coding rod 60 and the shaft 13 will be directly related to the angular disposition of the housing about its axis relative to the low side of the hole, and a single pressure pulse will be produced in the drilling fluid for each detectable increment of such angular displacement.

The gravity responsive member 16 is revolvably supported on suitable anti-friction bearing means 109 upon a lower stem section 110 of a support member 111 which is reciprocably disposed within the supporting sleeve 102 previously referred to. At its upper end the member 111 slidably fits within a bore 112 in the support sleeve 102, and means such as an elongated slot 113 in the member 111 and a screw or other key means 114 are employed to retain the member 111 in the sleeve 102 against rotation, while allowing vertical movement of the member 111 along with the gravity responsive member 16 which is journalled thereon.

Such vertical movement of the member 111 is effected in response to upward movement of the connecting rod 74 previously referred to which, as seen in FIG. 4, is connected by a washer 115 confined between a pair of lock rings 116 to the upper end of a sleeve 117 which extends downwardly through a bore 118 in the block 63. If desired, a bushing 119 may be provided for centralizing the sleeve 117. Internally of the sleeve 117 is a head 120 of an actuator pin 121 which extends downwardly through an opening 122 in the lower end of the sleeve 117 and downwardly through a central opening 123 in the member 111. A spring 124 is disposed within the sleeve 117 and engages at one end with the head 120 of the pin 121 and at its other end with a spring seat 125 which abuts with one of the lock rings 116.

At its lower end the pin 121 is provided with a crosskey 126 which extends through. axially elongated radial slots 127 in the stem section 110 of the member 111 so as to permit lost-motion between the pin 121 and the member 111 when the coding rod 60 and the connecting rod 74 are pulled upwardly pulling the sleeve 117 and the pin 121 therewith. The purpose of this lost-motion connection is to provide for the operation of means which normally allow freedom of rotation of the gravity responsive member 16 on the anti-friction bearing means 109 about the stem section 110 of the member 111, such means being illustrated herein as a positive clutch means generally denoted at 130. This clutch means comprises a clutch sleeve 131 slidably disposed upon the stern 110 of the member 111 and connected to the pin 121 by the cross-key 126. The spring 124 normally holds the clutch sleeve 131 in a downward position with the cross-key 126 engageable at the low ends of the slots 127. At its upper end the clutch sleeve 131 is provided with diametrically extended projections 132 which are cooperatively engageable with circumferentially spaced downwardly extended teeth 133 provided beneath. the gravity responsive member 16. It will be apparent from FIG. 4 that upward movement of the clutch sleeve 131 will effect engagement of the projections 132 with the teeth 133 of the gravity responsive member 16, thereby effec tively preventing angular movement of the gravity responsive member 16 relative to the stop means 17. The angular position of the gravity responsive member 16 within the instrument I when the member 16 is free to rotate will at all times be determined by the eflect of gravity on an eccentrically weighted radially offset portion 134 which will hold the gravity responsive member 16 in a position with the eccentric weight 134 disposed at the low side of the instrument. Medially of the eccentric weight portion 134 of the gravity responsive member 16 is a further outwardly extended lug or abutment portion 135, the upper surface of which is preferably rounded. This projection 135 is adapted to abut with one of the stop elements 200-200f upon upward movement of the pin 12-1, the gravity responsive member 16 and the supporting member 111. A particular stop element 200-2001 engaged by the stop projection 135 will be determined by the relative orientation of the instrument housing and the eccentric weighted portion 134 of the gravity responsive member 16 when the gravity responsive member 16 moves upwardly. Thus, as previously described, the permitted upward movement of the shaft 13 and the knob 14 thereon will be determined by the relative orientation of the instrument housing and the gravity responsive member 16 when the latter moves upwardly to effect engagement of one of the stop elements 200-2001.

Means are provided whereby at least limited upward movement of the shaft 13 and the connecting rod 74 will be permitted while the drilling operation is progress ing in the case that the instrument is employed with a hydraulic motor M, as previously described, so that the disposition of the instrument within the well bore will be that assumed while the motor is working and subjected to the reaction torque. Accordingly, as seen in FIG. 2, a reduced diameter region 140 is provided in the pulse ring assembly P which provides a restricted flow path 141 past the knob 14 when it is in its lowermost position, namely, the position at which the clutch means 130 would be disengaged. This restricted flow path 141 is selected so that a predetermined drilling fluid flow will provide a pressure on the knob 14 to keep the same seated at normal drilling fluid flow rates, say, for example, 350 gallons per minute. However, when the rate of drilling fluid flow is reduced it is desired that the knob 14 be permitted to rise slightly so as to allow sufficient upward movement of the connecting rod 74 to effect engagement of the clutch means 130; for example, the reduction in drilling fluid flow may be on the order of 50 gallons per minute, so that the motor M will be operating under the conditions of 300 gallons per minute of drilling fluid flow instead of the original 350 gallons per minute. Thus the clutch means will be engaged while the motor housing H is subjected to the reaction torque which causes the opposite hand torque to be imposed on the drill string, as compared with the direction of rotation of the drill bit B. Following engagement of the clutch and cessation of the pumping of drilling fluid through the motor M the knob 14 will rise to a position between the pulse rings 7, determined by the engagement of the stop projection on the gravity responsive member 16 on one of the stop elements 200-200 1.

Inasmuch as extension and retraction of the shaft 13 effects a change in the internal fluid volume within the instrument I, as permitted by the diaphragm 20 previously described or other suitable floating piston, the gravity responsive means and the stop means structures are such as to permit the flow of instrument fluid therethrough. Accordingly, the support member 111 may be provided with suitable passages 145 extending longitudinally therethrough and, at the lower end of the stem section 110 of the member 111, it may be provided with a guide ring 146 having suitable passages 147. This guide ring in the illustrative embodiment is slidably disposed in a bore 148 of a cylindrical member 149 which is secured against axial displacement in the supporting sleeve 102 by means of a perforated washer 150 locked in place by a lock ring 151. Preferably, means are provided for damping the rotation of the gravity responsive member 16 about the stem 110 of its support 111. Accordingly, the member 16 is provided with an upwardly extended annular flange 152 and the supporting member 111 is provided with a downwardly extended annular flange 153 which is concentrically disposed with respect to the flange 152 and in close proximity thereto so as to provide fluid film frictional resistance to rotation of the gravity responsive member 16. These flanges 152 and 153 also serve to impede the flow of instrument fluid through the anti-friction bearing means 109 during the transfer of fluid within the instrument housing, thereby reducing the possibility of solid particles in the instrument fluid, such as parts of metal or the like, interfering with the rotation of the gravity responsive member 16 about its support.

Referring now to FIG. 7, the operation of the signalling apparatus will be described employing a stop member 100 in the form illustrated in FIG. 6. Assuming that the drilling of a slant hole, as illustrated in FIG. 1, is progressing in a desired direction as determined by the use of the usual wireline surveying equipment, the motor M will be operated by the pumping of drilling mud downwardly through the drill string S, the drilling fluid returning to the surface through the well bore W. When it is desired to determine that the drilling is progressing in the desired direction by determining that the motor M and the bit driven thereby are still working in the proper direction, the rate of drilling fluid flow is reduced slightly, say 50 gallons per minute as previously indicated, thereby reducing the pressure acting to hold the knob 14 in the lowermost position. Such reduction in pressure will permit the clutch means 130 to be engaged to fix the angular position of the gravity responsive member 16 within the instrument housing as the motor is operating under the remaining fluid flow and the reaction torque is being applied to the motor housing I-I. Thereupon, the flow of drilling fluid will be interrupted allowing the knob 14 to rise an extent determined by upward movement of the gravity responsive member 16, engagement of the stop projection 135 with one of the stop elements 200400 and engagement of the stop 77 with one of the stop balls 75a-75f or with the stop ring 75. Since the angular disposition of the instrument I within the drill collar D is known, having been established by the screw member 9b engaged in the bottom support P, and since the angular disposition of the stop member 17 in the instrument housing is known, the number of signals or pressure pulses produced in the drilling fluid stream by the knob 14 as it passes through the pulse rings 7 upon the resumption of drilling fluid circulation will be indicative of the angular relationship or orientation of the drill collar D and the gravity responsive member 16 when the clutch means 130 was engaged and the motor M was operating. If the stop projection 135 abuts with the stop element 20011 which has a narrow angular extent of 20, five pressure signals will be produced. On the other hand, if the stop projection 135 engages any of the other stop elements then a different number of signals will be produced, as indicated by the numerals in the margin of the graphic illustration of FIG. 7. It will also be noted that the angular extent of all of the other stop elements is greater than the angular extent of the stop element 200]), so that if five signals are received the indication is that the drilling is progressing within plus or minus 20 of the desired direction. If only one signal is received, as an example, it would be indicative of the fact that the motor and drill are drifting otf of the desired direction as a result of the left-hand reaction torque of the motor. This drift from the desired direction may be corrected, for example, by applying more righthand torque to the drill string S to offset the reaction torque of the motor M; and a reading of signals may be taken to establish that sufficient right-hand torque has been applied to the drill string to hold the instrument in a relative angular position to the gravity responsive member 16 so that five signals are produced.

In FIG. 8 the graph illustrates a modified form of stop means in which the same number of stop elements are employed and are designated by the same reference numerals 20040012, but the angular extent of the stop elements is different. In this illustration four signals are selected as the number indicative of the progression of the drilling operation in the desired direction, and the stop element 2000 has an angular extent of only 10. Thus, if in the use of a stop member constructed in accordance with the chart of FIG. 8 four signals are received, it is indicated that the drilling is progressing within plus or minus from the desired direction. If five signals are received, it is indicated that the drill string need be rotated to the right in order to force the motor housing against the effect of reaction torque in a right-hand direction.

While the operation of the invention has been described in relation to the drilling of a slant hole employing an angular sub A, it will be appreciated that features of the invention are also applicable to the drilling of directional well bores employing the big eye bit method described at the commencement hereof, and that the gravity responsive means and the stop means are so constructed as to enable the production of the range of signals Within close tolerances and by the use of a simple structural arrangement in which the stop projection 135, being relatively narrow and arched on its upper surface, may engage a relatively narrow angular stop shoulder but will not tend to lodge at the edge of a stop shoulder whereby to permit the production of signals indicative of the progression of drilling in the desired direction when, in fact, the drilling is progressing at the maximum error within the range of stop element.

While the specific details of the invention have been herein shown and described, changes and alterations may be resorted to without departing from the spirit of the invention as defined in the appended claims.

What is claimed is:

1. Apparatus for drilling a well bore on an are extending progressively downwardly and horizontally into the earth formation, comprising: an elongated fluid operated motor including a housing and drilling fluid responsive rotor means in said housing, a rotary drill bit at one end of said housing and connected to said rotor means, an angular sub connected to the other end of said housing, a drill collar sub connected to said angular sub and adapted to be connected to a string of well drilling pipe, and signalling means in said drill collar sub for producing in the stream of drilling fluid a number of pressure pulses indicative of the angular orientation of said drill collar sub in the well bore relative to the low side of the well bore when said fluid motor is operating to drive said drill bit.

2. Apparatus as defined in claim 1, wherein said signalling means includes a signal member movable in one direction upon interruption of the flow of drilling fluid and movable in the other direction upon resumption of the flow of drilling fluid, means cooperative with said signal member for producing said pressure pulses in a number depending upon the extent of movement of said signal member, gravity responsive means operable to assume a position related to the low side of said drill collar sub and movable in one direction responsive to movement of said signal member in said one direction and movable in the other direction responsive to movement of said signal member in the other direction, and a plurality of stop elements spaced longitudinally of said drill collar sub and engageable by said gravity responsive means to limit movement of said gravity responsive means and said signal member in said one direction depending upon the angular relation of said gravity responsive means and said drill collar sub about the longitudinal axis of said drill collar sub.

3. Apparatus as defined in claim 2, including means supporting said gravity responsive means for angular movement about said axis of said drill collar sub, and means for fixing the angular position of said gravity responsive means relative to said stop elements while said motor is being operated and holding said gravity responsive means in said angular position upon interruption of the flow of drilling fluid.

4. Apparatus as defined in claim 2, including means supporting said gravity responsive means for angular movement about said axis of said drill collar sub, and means including a clutch engageable upon initial movement of said member in said one direction for fixing the angular position of said gravity responsive means relative to said stop elements while said motor is being operated and holding said gravity responsive means in said angular position upon interruption of the flow of drilling fluid.

5. Apparatus as defined in claim 2, including a support for said gravity responsive means, means connecting said support to said signal member for movement therewith, said gravity responsive means including an eccentrically weighted member rotatably mounted on said support, means on said eccentrically weighted member and on said support operable upon initial movement of said support for fixing said eccentrically weighted member on said support, and means for efiecting movement of said signal member in said on direction upon reduction in the flow of drilling fluid before interruption of the flow of drilling fluid.

6. Apparatus as defined in claim 5, wherein said means for fixing said eccentrically weighted member on said support includes a clutch sleeve on said support, and cooperative clutch means on said eccentrically weighted member.

7. Apparatus as defined in claim 5, wherein said means for fixing said eccentrically weighted member on said support'includes a clutch sleeve on said support, cooperative clutch means on said eccentrically weighted member, and said means connecting said support to said signal member. including means for normally holding said clutch sleeve spaced from said gravity responsive member.

8. Apparatus as defined in claim 5, including a housing for saidgravity responsive means and said stop elements, said signal member including a shaft projecting from said housing, said housing being filled with clean fluid and having means for equalizing the pressure in said housing upon movement of said signal member in opposite directions, and including concentric closely spaced surfaces on said eccentrically weighted member and said support in said clean fluid for damping movement of said eccentrically weighted member on said support.

9. Apparatus as defined in claim 5, wherein said means for eflecting movement of said signal member in said one direction upon reduction in the flow of drilling fluid includes means defining a restricted flow path past said signal member when it is at the end of its movement in the other direction, and spring means acting on said signal member to urge the same in said one direction.

10. Apparatus as defined in claim 2, including a support for said gravity responsive means, means connecting said support to said signal member for movement therewith, said grravity responsive means including an eccentrically weighted member rotatably mounted on said support, means on said eccentrically weighted member and on said support operable upon initial movement of said support for fixing said eccentrically weighted member on said support, means for effecting movement of said signal member in said one direction upon reduction in the flow of drilling fluid before interruption of the flow of drilling fluid, and said stop elements comprising a number of angularly spaced steps selectively engageable by said eccentrically weighted member.

11. Apparatus as defined in claim 10, wherein said eccentrically weighted member includes a stop projection thereon engageable with said steps, said stop projection having an arcuate face for engagement with said steps.

12. In a signalling apparatus adapted to be installed in a well drilling string for producing pressure pulse signals in a stream of drilling fluid indicative of the disposition of the drilling string, said apparatus comprising: a tubular body adapted to be installed in the drilling string, signalling means in said body for producing pressure pulses following interruption of the flow of drilling fluid and responsiv to the resumption of the flow of drilling fluid,

said signalling means including a member movable in one direction upon interruption of the flow of drilling fluid and movable in the other direction upon resumption of the flow of drilling fluid, means cooperative with said member for producing said pressure pulses in a number depending upon the extent of movement of said member, and gravity responsive means operable to determine the extent of movement of said member in response to the disposition of the drilling string when the flow of drilling fluid is interrupted, the improvement wherein said gravity responsive means includes a gravity responsive element and a plurality of axially spaced stops selectively engageable by said gravity responsive element for controlling said signalling means to produce pressur pulses in a number indicative of the orientation of said drill string with respect to the well, means supporting said gravity responsive element for angular movement relative to said body, and holding means responsive to the commencement of upward movement of said member to hold said gravity responsive element against angular movement.

13. Signalling apparatus as defined in claim 12, wherein said holding means comprises normally disengaged clutch means and means for engaging said clutch means responsive to the commencement of upward movement of said member.

14. Signalling apparatus as defined in claim 12, wherein said clutch means includes a non-rotatable member, means on said gravity responsive element engageable by said non-rotatable member, and means normally biasing said non-rotatable member away from said non-rotatable member.

15. Signalling apparatus as defined in claim 12, wherein said angularly spaced stops comprise stepped elements spaced axially of said body and extending angularly therein, and said gravity responsive element comprises an eccentrically weighted member having a stop projection thereon engageable with one of said step elements.

16. Signalling apparatus as defined in claim 12, wherein said angularly spaced stops comprise stepped elements spaced axially of said body and extending angularly therein, and said gravity responsive element comprises an eccentrically weighted member having a stop projection thereon having an arched face engageable with one of said step elements.

17. Signalling apparatus as defined in claim 12, wherein said gravity responsive means includes a support axially movable in said body, anti-friction means mounting said gravity responsive element on said support for rotation thereon and movement axially therewith toward said stops, and clutch means for preventing rotation of said gravity responsive element on said support following initial axial movement of said support.

18. Signalling apparatus as defined in claim 17, wherein said clutch means includes a shiftable clutch member, and means connecting said clutch member to said member of said signalling means for movement with the latter.

19. Signalling apparatus as defined in claim 17, wherein said clutch means includes a shiftable clutch member, means connecting said clutch member to said member of said signalling means for movement with the latter including a tube, a pin projecting from said tube and connected to said clutch member, and a spring in said tube acting on said pin to normally hold said clutch disengaged.

20. Signalling apparatus as defined in claim 17, wherein said clutch means includes a shiftable clutch member, said gravity responsive element having cooperative clutch means engageable by said clutch member, said support having an opening therein, an actuator pin disposed in said opening, .said support having an elongated slot, a member extending through said slot and connecting said pin to said clutch member, and means connecting said pin to said member of said signalling means for movement therewith.

21. Signalling apparatus as defined in claim 17, wherein said clutch means includes a shiftable clutch member, said gravity responsive element having cooperative clutch means engageable by said clutch member, said support having an opening therein, an actuator pin disposed in said opening, said support having an elongated slot, 3. member extending through said slot and connecting said pin to said clutch member, means connecting said pin to said member of said signalling means for movement therewith, and spring means engaged with said pin to normally hold said clutch member out of engagement with said cooperative clutch means on said gravity responsive element.

22. Signalling apparatus as defined in claim 17, including a housing, said shiftable member of said signalling means projecting from said housing, said gravity responsive means being in said housing, said housing 'being filled with liquid and having means for balancing the pressure in said housing with the pressure outside said housing, and said gravity responsive element and said 15 16 support having means for damping rotation of said ele- 3,077,233 2/1963 Armstrong 175-45 ment on said support. 3,229,375 1/1966 Crake 17545 X 3,316,651 5/1967 Godbey 17545 X References Cited 3,349,856 10/1967 Richardson 175-40 UNITED STATES PATENTS 5 1,770,43 7 1930 Lachamp 175 97 NILE C. BYERS, JR., Primary Examiner 2,694,549 11/1954 James l7582 @3 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, L55, LOl Dated July 15, 1969 Inventor) Raymond G. Taylor, Jr.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the drawings, Sheet 1, Fig. 2, the top and bottom portions 0 spring 15, which abuts flange 82 and block 63, should be connected by broken lines; reference numeral 19 should be applied to the body portion of fluid displacement retarder 18. Sheet 3 Fig. t reference numeral 10 i should be applied to annular shoulder of sleeve 102, in abutment with flange 103; reference numeral 1 W should be applied to longitudinal passages through guide ring 1M6. Column 5 line 37, "1" should be 2 Column '7, line ()6, "30" should be I Column 8, line MO, "100" should be l7 Column 10, line 63, "100" should be l7 Column 11, line 35, "20" should be 10 --5 line 50, "200e" should be 200f Column 14, line 10-11 (lines 5-6 of claim 14) "non-rotatable member" (Second Occurrence) should be gravity responsive element SIGNED m0 swan (SEAL) Altest:

Edma mum: E. sammma, JR. Attesting Officer Commissioner of Patents

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