US3037295A - Process and means for determining hole direction in drilling - Google Patents

Description

June 5, 1962 Filed April 21, 1958 Fig./

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PROCESS AND MEANS O DETER NING HOLE DIRECTION DRILL Filed April 21, 1958 8 Sheets-Sheet 2 95 Fig. 2/

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PROCESS AND MEANS FOR DETERMINING HOLE DIRECTION IN DRILLING Filed April 21, 1958 i 8 Sheets-Sheet 5 Fig.4 Fig.5 "W w N ""Y Bob J. Roberson INVENTOR.

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PROCESS AND MEANS FOR DETERMINING HOLE DIRECTION IN DRILLING Filed April 21, 1958 8 Sheets-Sheet 5 Fig. /0

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Bob J. Roberson 1 N VEN TOR.

BY WW 5m June 5, 1962 B J. ROBERSON 3,037,295

PROCESS AND MEANS FOR DETERMINING HOLE DIRECTION IN DRILLING 1 Filed April 21, 1958 8 Sheets-Sheet 6 I3 FI'g./2

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PROCESS AND MEANS FOR DETERMINING HOLE DIRECTION IN DRILLING Filed April 21, 1958 a Sheets-Sheet a Fig/8 Bob J. Roberson 236 INVENTOR.

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United States Patent 3 037 295 PRoeEss AND MEANs Eda DETERMINING HOLE DIRECTIGN 1N DRILLING Bob J. Roberson, Levelland, Tex., assignor of ten percent to Alvin R. Allison, Levelland, Tex. Filed Apr. 21, 1958, Ser. No. 729,618 13 Claims. (Cl. 33-205) This invention relates to equipment for determining the direction of a hole during or after drilling. In well drilling the urgency in having the hole vertical is very well known. This invention contemplates various apparatus which function slightly dilferent from each other but whose general purpose is to achieve a vertical hole during drilling. This is accomplished either directly or indirectly. Some embodiments of this invention contemplate .automatic means responsive to instantaneous deflection (inclination) in the hole while it is being drilled for altering the drilling rig controls, as the brake, drilling mud, bentonite, throttle, etc. Other embodiments of this invention contemplate in addition to the automatic control functioning, a recording graph which mimics the deflection of the drill stem. A further variation entails the production of a graph without automatic control of the drilling rig.

In some installations not only is the deflection important but also information is desired concerning azimuth deviations. A further object of the invention is to provide apparatus for more reliably and simply sensing deviation in azimuth during drilling operations and/or transmitting this information to a surface recorder and/ or means to operate the controls of the drilling rig so as to automatically provide corrective measures. Therefore, this invention entails not only the combination of the deflection sensing equipment but it also contemplates azimuth deflection sensing equipment, either of which are useful separately or in combination. Moreover, any of the three alternatives can have a recording producing attachments applied thereto or can be used to directly operate the controls of the drill rig or can be used in both ways.

After drilling, regardless of the time lapse, e.g. existing shafts or holes, the deflection and/or azimuth deviation from vertical canbe determined by the apparatus of this invention. The deflection is generally of more importance. To achieve these determinations the invention is practiced by a collar that is lowered into the hole and which contains a transmitter or transmitters whose signals are accepted by one or more receivers. I have a unique collar-case combination where the case is rotated in the collar to sense deflection and/or azimuth deviation in a full 360 plane of operation. While the collar is being lowered in the hole the case is rotated. Should a record producing device be operatively connected to the signal receiver or receivers, a record of the path of travel of the collar and particularly, the deviations from a vertical path of travel, is produced and can be inspected while being made and studied thereafter.

In practicing the invention a Selsyn or synchro-tie motor system is used including a transmitter motor having its rotor at right angles to the nominally vertical rotating axis of the collar, is attached in the collar. A weighted arm is secured to the rotor shaft and therefore, and deflection or instantaneous inclination of the rotating axis from the gravitational vertical will be instantaneously sensed by the Selsyn transmitter in that there will be a corresponding angular deflection of the rotor with respect to the stator. A Selsyn motor or receiver is located remote from the transmitter and by electrical conductors or a radial length, the Selsyn motor is caused to operate in a mimic fashion. Each angular deflection of the rotor with respect to the stator of the transmitter produces a corresponding angular deflection of the receiver rotor with respect to its stator.

Therefore the deflection of the receiver can be used for either producing a graph and/or operating the controls of a drill rig.

For deviations measured in azimuth, there is .a Selsyn transmitter attached vertically and means, for example a magnetic or non-magnetic compass or a gyroscope, for holding the rotor of this Selsyn transmitter in a fixed angular position. As the collar is rotated there will be a relatively rotation of the rotor and stator of the Selsyn transmitter. An electrical signal is produced in this way and transmitted to a Selsyn receiver remote from the Selsyn transmitter. The receiver is then, actuated to mimic the relative movement between the Selsyn rotor and stator of the transmitter. When both vertical and horizontal Selsyn motors are in operation any vertical deviation is recorded in its correct azimuth direction.

Such movement is exceedingly useful in applying corrective controls to the'drilling rig for producing a graph or other recording by which the direction of the hole is indicated. A further and general object of the invention is to provide an apparatus for detecting deviations in deflection and/or azimuth of a hole while it is being drilled or an existing hole, and to transmit this detected information by a Selsyn system to a position remote from the transmitter or transmitters of the system. Individual or composite recordings can be made from this information and when converted to electrical signals, this information can be used to control the drilling rig where one is involved.

Other objects and features of importance will become apparent in following the description of the illustrated forms of the invention.

FIGURE 1 is an elevational view of a drill stem in a hole, the stem having detection apparatus therein and adapted to connect with a recording system located exteriorly of the hole.

FIGURE 2 is an enlarged transverse sectional view taken on the line 2-2 of FIGURE 1 and showing principally the azimuth deviation detecting Selsyn motor and its power equipment.

FIGURE 3 is a transverse sectional view on an enlarged scale and taken on the line 3-3 of FIGURE 1, showing principally the deflection detecting Selsyn transmitter.

FIGURE 4 is a sectional view taken on the line 4-4 of FIGURE 2.

FIGURE 5 is a sectional view taken on the line 5-5 of FIGURE 3.

FIGURE 6 is a top view of the recording instrument in FIGURE 1 which is not only useful in connection with the apparatus in the drill stem collar of FIGURE 1 but which is also useful in connection with the apparatus of FIGURE 13.

FIGURE 7 is an elevational side view of the recording instrument of FIGURE 6.

FIGURE 8 is a fragmentary sectional view taken on the line 8-8 of FIGURE 6.

FIGURE 9 is a fragmentary sectional view showing the scriber of the recording instrument and taken on the line 99 of FIGURE 6.

FIGURE 10 is a schematic view showing principally the wiring for the Selsyn motor receivers as they would appear when a radio link transmits the signals from the Selsyn transmitters to the remotely located Selsyn receivers.

FIGURE 11 is a schematic view showing the wiring for the Selsyn transmitter operated radio transmitters that provide signals for radio receivers of FIGURE 10.

FIGURE 12 is a transverse sectional view of a modification that has principal application in exploring and transmitting information concerning the deflection of an existing hole.

FIGURE 13 is a sectional view taken on the line 13-13 of FIGURE 12.

FIGURE 14 is a fragmentary sectional view of a slip ring assembly in FIGURE 13 and a schematic wiring diagram of the Selsyn transmitters for both deflection and azimuth together with the motor which sets the case within the collar into rotation during hole exploration.

FIGURE 15 is a top view of a modified recording instrument whose principal purpose is to record deflections in a hole either while drilling or in an existing hole.

FIGURE 16 is an elevational view of the instrument in FIGURE 15.

FIGURE 17 is an end view of the instrument in FIG- URE 15.

FIGURE 18 is a top view of a further modification showing Selsyn receiver together with schematically represented means for operating the controls of a drilling rig.

FIGURE 19 is an elevational view of the modification of FIGURE 18.

FIGURE 20 is a top view of a further modification illustrating a Selsyn receiver for generating control signals that vary in accordance with azimuth and deflection variations, the signals adapted to operate the controls of a drilling rig.

This modification is designed to provide controls for directional drilling other than vertical e.g. intentional angular drilling.

FIGURE 21 is a longitudinal sectional view of another drill sub-assembly.

FIGURE 22 is a cross-section taken on the line 22-22 of FIGURE 21.

In the accompanying drawings (FIGURE 1) hole 10 is illustrated. This has the drill stem 12 disposed in it, and the drill stem has a drill bit 14 at its lower extremity. Drilling rig (unshown) is used in the ordinary manner for actuating the drill stem. Recording instru ment 16 located near the top of the hole 10 functions to provide a visual representation of events that are transpiring during the drilling of hole 10. More particularly, recording instrument 16 is capable of producing a graph which shows deflection changes (inclinations) and deviation in azimuth as the drill stem moves in its well forming path of travel.

Insofar as the embodiment of FIGURE 1 is concerned, there are two units that combine to yield the desired information as to the progress that is being made in sinking the well. One unit is instrument 16 and the other is a detecting unit sub-assembly 18 in the drill string and preferably located close to the drill bit 14. Sub-assembly 18 as more particularly shown in FIGS. 4 and 5 consists of a support having a collar 20 with means, as threads 22 and 24, at its ends to connect to the drill bit and to the adjacent part of stem 12. Bore 26 of collar 20 is divided into a passageway 28 through which 4 drilling mud and other substances may pass, and a liquid tight chamber 30. Wall 32 disposed longitudinally within collar 20 separates the bore 26 into passageway 28 and chamber 30.

In certain drilling operations the balance of the drill head is critical and in such case a specially constructed drill sub 380 (FIGURES 21 and 22) is employed to maintain that balance. The operative components (unshown) are in a collar 301 having a cylindrical compartment 302 located with its vertical axis coincident with the vertical axis of the drill stem. Passages 304 and 306 for the drill fluid or mud are provided by two bores located equidistant from the vertical axis of the sub and on the same diameter line. Two plug caps 308 and 310 close this special sub and provide attachment to the drill stem 314 and drill bit 316.

The detecting unit 18 has two Selsyn motor transmitters 34 and 36 respectively fixed in its chamber 30. Transmitter 34 is secured, for example, by mounting bracket 38, in chamber 30 with its rotor at right angles to the nominal axis of rotation (vertical) of collar 20. Rotor shaft 40 has a weight arm 42 secured to it swinging in the vertical plane containing the axis of rotation of 20. Weight 44 carried by weight arm 42 is attracted by the pull of gravity and this holds the rotor 40 in a position which is fixed with respect to the assumed vertical pull of gravity. Any deflection of collar 20 from the assumed vertical axis thereof will cause relative movement between the rotor and collar 20 to provide a signal for the transmitter motor 34. In accordance with the Selsyn system, the signal is electrically impressed on Selsyn receiver motor 46 in instrument 16 (FIG. 7).

Selsyn motor transmitter 36 has its rotor parallel to the assumed nominal (vertical) axis of sub 18. Rotor shaft 48 of transmitter 36 is held in a fixed angular position by the symbolically illustrated magnetic compass 50 the axis of which is located in the assumed nominal axis of sub 18. This magnetic compass device 50 incorporating conventional follow-up means as disclosed for example in Patent No. 2,611,191, will thereby be substituted for by a non-magnetic compass or a magnetometer. Gear train 52 operatively connects the compass 50 to rotor shaft 48. Accordingly, any motion in azimuth causes a relative movement between the rotor and stator of transmitter 36. This relative movement generates an electrical signal that is impressed on Selsyn receiver 56 in instrument 16 (FIGURE 7) to cause a mimic motion of the receiver rotor. Thus as the drill stem rotates so does the graph plate 70 (FIGURE 7). Although transmitters 34 and 36 can be adjustably mounted in collar 20, original installation on properly located brackets 38 and 39 can be accurate thereby necessitating no adjustrnent even after long use.

Recording instrument 16 consists of a stand 60 that has a plurality of legs and a platform 62 at the upper ends of the legs. Frame 64 is mounted above platform 62 and held in selected adjusted positions by a group of levelling screws 66 carried by platform 62 and engaged in threaded holes in frame 64. The screws 66 are in quadrature so that frame 64 can be tilted about both X and Y axes. Table 68 is secured to the top of frame 64 and has a turntable 70 provided with a graph slate mounted above its top surface. The turntable is secured to spindle 72 (FIGURE 8) that is driven by enmeshed gears 73 and 74. Gear 73 is fixed to spindle 72 while gear 74 is fixed to the rotor shaft 75 of Selsyn receiver 56. Anti-friction bearing assembly 76 supports spindle 72 in the table 68 and enables the turntable 70 to be rotated quite freely. Levels 79 and 81) are secured to table 68 and a compass 81 completes the complement of instrumentation on table 68. These are to assure that the table with its turntable 70 are absolutely level and oriented correctly as to azimuth.

the deflecting of arm 42 from the true vertical.

Selsyn receiver 46 is carried by mounting bracket 82 rising from table 68. Scriber 84 is fixed to pinion 85 (FIGURE 9) and the pinion is secured to a shaft 86. The shaft 86 is supported in bearings 87 that are at the upper part of mounting bracket 88 which also rises from table 68. Gear 89 secured to the rotor shaft of Selsyn receiver 46, is enmeshed with pinion 85 and imparts rotary motion to the pinion. This causes scriber 84 to move back and forth depending on the direction of movement of the rotor of Selsyn receiver 46.

Scriber 84 (FIGURE 9) consists of a spring loaded scribing element 90 whose extremity is in contact with the graph paper (or the like) on turntable 70. Spring 92 is located in a tube 93 and has one end seated on scribing element 90 and the other end seated on a stop 94 in tube 93. The tube is welded or otherwise fixed to pinion 85.

In the embodiment under discussion there is a source of electrical energy, for example battery 96 which is fixed in chamber 30. Vibrator 97 or an equivalent component or part for converting the nature of the electrical output from DC. to AC. is operatively connected with the output terminals of the battery. As shown in FIGURE 11 the source energized vibrator is wired with the Selsyn transmitters 36 and 34 by parallel networks. These are operatively connectedto multiple channel or frequency radio transmitters 100 and 102 respectively that are also carried by collar 20 and located in chamber 30. The

radio transmitters are short range transmitters whose signals are accepted at the antennas of radio receivers 104 and 106 located preferably adjacent to the Selsyn motors 46 and 56 with which they are wired. An A.C. power supply for the receivers of FIGURE is operatively connected to the Selsyn motor receivers.

As an alternative, the means which operatively connect the Selsyn transmitters with the Selsyn receivers may consist of metallic conductors that extend through-the drill stem. In such a modification the radio link schematically represented in FIGURES 10 and 11, would be omitted. Slip rings for the group of leads extending through the drill stem would be located at the top of the drill stem and could assume a number of configurations, one of which is shown in FIGURE 14. In either case the signals generated at the transmitters are conducted to the Selsyn receivers 46 and 56.

In operation, the drill stem iscontinuously rotated in the ordinary way. This causes the unit 18 to rotate since it is a part of drill stem 12. As long as the collar remains vertical and arm 42 is coincident with the vertical axis of rotation of collar 20, arm 42 of Selsyn transmitter 34 will remain fixed vertically in space it being apparent that suitable means for dampening uningly, arm 42 will be instantaneously displaced each revolution of its displacement plane because of the horizontal component of force introduced by gravity and The rotor of Selsyn transmitter 34 will be correspondingly moved with respect to the stator to generate a signal voltage that is transmitted by a radio link or by metal conductors to the Selsyn receiver 46. a An immediate correction takes place in receiver 46 causing its rotor to deflect an amount identical to the deflection of the rotor in Selsyn transmitter 34. Accordingly scriber 84 will make a radial excursion at a predetermined ratio to the deflection of arm 42 on turntable 70 capable of mounting a scale. The description of the operation so far discusses a useful sub-combination of the embodiment of FIGURE 1 in that only deflection (inclination) of drill stem 12 is sensed and information relatingthereto transmitted to the receiver 46. A more comprehensive apparatus utilizes the azimuth transmitter 36 and azimuth receiver 56. These operate by having the rotor of transmitter 36 held along a geographical reference direction as the unit 18 rotates. The holding is achieved by a magnetometer, magnetic compass or some other corresponding device. As the stator and rotor move with the axis of the gyro-compass, magnetic compass, magnetometer, etc., on the vertical axis of rotation, there will be a constant corrected speed signal transmitted from Selsyn transmitter 36 to Selsyn receiver 56. Turntable 70 ordinarily rotates at the same speed as the drill stem to instantaneously orientate deflection with respect to the well hole. Any deviation of the rotational axis is thus also shown by the correct aximuth direction on a scale graph as rotor of Selsyn receiver moves scriber 84. Reference is now made to FIGURES 6, 7, 12, 13 and 14. The equipment disclosed in these figures is principally intended to explore and record the condition of an existing hole. The Selsyn transmitter and receiver system of the previously described embodiment is essentially followed. The distinction is mainly in collar of the support that has a bottom 122 and closing top 124 at the ends of a cylindrical side wall. Ring gear 126 is in the top part of collar 120, and there is a pinion 128 enmeshed with ring gear 126. The pinion is fixed to the shaft of motor 130, the latter secured in a case 132. As seen in the wiring diagram of FIGURE 14, motor 139 is adapted to be energized by conductors which pass through slip ring assembly 136 and which attach to an external source of electrical potential (not shown). Case 132 has a side wall, a top wall 138 Within an opening of which slip ring assembly 136 is attached, together with a bottom wall 140. Anti-friction bearings 142 mount bottom wall 46 on the bottom 132 of collar 120 enabling the case 13?. to rotate freely within the collar. Selsyn motor transmitter is mounted with its rotor shaft 152 on a horizontal axis. Mounting bracket 154 supports the Selsyn transmitter 150 in case 132. Case 132 together with collar 120 constitute a support for the Selsyn transmitters, just as the collar 18 functions as a support for the Selsyn transmitters in the embodiment of FIGURE 1. Weight arm 156 is attached to the shaft 152, and it has weight 158 thereon which is attracted by gravity in a down, vertical position. Lateral deflections of the support are sensed by the Selsyn transmitter having its rotor move with respect to the three stator windings thereof and this information is transmitted in the form of an electrical signal through the electrical conductors (FIGURE 14), slip ring assembly 136 and cable 160 passing through the stem by which the support is lowered into the hole. Selsyn receiver such as receiver 46 in FIGURE 7 or such as receiver 180 of FIGURE 15, is operatively connected with the conductors that extend from Selsyn transmitter 150.

Azimuth deviation detection Selsyn transmitter 164 is attached, for example by bracket 166, to the case 132. The orientation of the Selsyn transmitter 164 is such that the rotor shaft- 163 thereof is vertical and in alignment with arm 156 and also in alignment with'the nominal axis of rotation (vertical) of the case 120 or the entire support for the Selsyn transmitters. Shaft 168 is held fixed by a symbolically illustrated gyro device 170 that is operatively connected to the shaft 168.- The gyro device including conventional follow-up means as is-well known in the art is electrically operatedwith a wiring connection being made by slip ring assembly 172 (FIG- URE 14). Azimuth deflections, therefore, are sensed by causing a relative rotation between the rotor and stator of Selsyn transmitter 164. This information is transmitted in the form of an electrical signal to the azimuth receiver 56. Thus turntable 70 rotates at the same speed as case 132 driven by motor 130 for existing hole exrecording instrument is illustrated. Recording instrument 16a is composed of a stand 60a that has table 68a thereon. Levelling equipment such as spirit levels can be attached to the table 68a or can be separately used therewith. Instrument 16a is used for vertical deviation only, therefore, no azimuth indication nor compass is necessary.

Selsyn deflection receiver 180 is mounted on a bracket 182 that rises from table 6811. The axis of rotation of Selsyn receiver 180 is horizontal with the rotor shaft 184 having gear 186 secured to it. This gear is enmeshed with pinion 188 that follows the gear 186 and hence, fol lows the rotor of Selsyn receiver 180. Spindle 190 that is mounted in a bearing or bearings carried by bracket 182, positions the pinion 188 above the graph paper 192 that is moved beneath scriber 194. The scriber is attached to pinion 188 and has its scribing element in contact with the surface of a graph 192.

The graph is in the form of a continuous strip whose ends are on rolls 194 and 196 mounted in bearings suspended below the table 68a. Motor 198 is drivingly connected to one of the roller spindles to propel the strip from the supply roller to the take-up roller, during which deflections in a hole are transmitted in the form of excursions to the scriber 194. Information regarding these deflections can be transmitted from the unit of FIGURE 13 or the unit of FIGURE 1 or other modifications.

In FIGURES 18 and 19 there is a further arrangement. Table 200 responds to table 68 and 68a and has a deflection Selsyn receiver 202 supported above and on a mounting bracket 204. The axis of rotation of receiver 202 is horizontal, and there is a rotor shaft 206 to which arm 208 is attached. The arm is swung in a down, vertical position and will remain there until deflected in response to deflection of a similar or corresponding motion of a Selsyn transmitter linked with a Selsyn receiver 202. Any of the previously described Selsyn transmitters can be used to do this.

An electric circuit 210 merely schematically represents means for transmitting signals to the drilling rig controls such as brake, throttle, etc. Electric circuit 210 has a pair of time- delay switches 212 and 214 connected in parallel and arranged to energize relay 216 when either of them is closed. Time delay switches 212 and 214 are mounted on table 200 and are operated by being contacted by arm 208 as it deflects. Relay 216 closes a circuit having motor 218 in it and this can actuate any control, an alarm, visual signal, an audible signal or some control part of the actual drilling rig. It is specifically pointed out that the time- delay switches 212 and 214 need not be connected in the same circuit 210. Individual circuits, one controlled by each switch 212 and 214, could be provided and thereby obtain discrimination between clockwise and counterclockwise oscillation of the Selsyn receiver rotor.

In FIGURE 20 there is a further modification of the instrument by which signals from the subterranean unit are received and used. The apparatus in FIGURE 20 has table 230 on which levelling instruments, for example spirit levels 232, 23 3 and compass 234 are mounted. Turntable 236 is mounted for rotation in a horizontal plane and by an azimuth Selsyn receiver (unshown) similar to receiver 56 of FIGURE 7. Circuit 210a is arranged to control motor 218a and these function the same as circuit 210 and motor 218 of FIGURE 18, respectively. Instead of switches 212 and 214, though, there are concentric rings of microswitches 240, 241 and 242 and each switch is a time-delay (slow release) type of microswitch connected in parallel to slip ring unit 266.

Deflection information Selsyn receiver 244 is mounted on an upstanding bracket 246 attached to table 230 and holds the Selsyn receiver 244 in a position with its rotor horizontal. Gear 250 that is fixed to the shaft 252 of the receiver rotor, is enmeshed with a pinion 254. The

pinion is secured to a supporting oscillatory shaft 258, and this has scriber 260 secured to it. The scriber can either make a mark on a graph located over switches 240, 241 and 242 or can be used as means for closing the microswitches, this being the principal function of scriber 260. As the Selsyn receiver 244 receives its electrical signals from the remotely located Selsyn transmitter, deflections in the hole are proportionately reproduced by deflections of the scriber 260. Since turntable 236 is rotating continually as the subterranean support with the azimuth Selsyn transmitter causing the rotation, individual switches are presented to the scriber 260 for closing and for time-delay actuation of circuit 210a and all other circuits like it, there being a plurality of such circuits (only one shown) that are controlled by the rotary mounted microswitches 240, 241 and 242. A single circuit can be controlled by a plurality of these switches. Circuit 210a is attached to slip ring unit 266 in such a manner that when any switch in the concentric ring of parallel connected switches 240, 241, 242, etc., is closed the relay in circuit 210a is energized thus causing motor 218a to function.

Slip ring assembly 266 on the axis of rotation of turntable 236, and these are used for energizing the microswitches. The purpose of control device shown in FIG- URE 20 is directional drilling control other than vertical. The concentric circle of microswitches 240, 241, 242 is placed and secured upon turntable 236 in the position described by the scriber 260 when the unit described in FIG- URES 2, 3, 4 and 5 is rotated along its vertical axis while being held in the desired direction as to azimuth and angular deflection from the vertical. Thus control of drilling in the desired direction is predetermined and maintained after drilling operations begin.

It is understood that various changes and modifications may be made without departing from the following claims.

What is claimed as new is as follows:

1. An apparatus to detect deflection and azimuth deviations of a hole during or after drilling, said apparatus comprising a support, means for continuously rotating said support in the hole about an axis of rotation, a single deflection sensing Selsyn transmitter secured to said support and having a rotor shaft mounted at right angles to said axis, a deflection Selsyn receiver having a rotor shaft, means operatively connecting said Selsyn receiver to said Selsyn transmitter for providing signals to said receiver for moving said rotor of said receiver in proportion to movement of said rotor of said transmitter with respect to the axis of rotation, an azimuth deviation detecting Selsyn transmitter carried by said support and having a rotor means for rotationally fixing said rotor, an azimuth Selsyn receiver having a rotor, means for transmitting signals produced by relative movement of said rotationally fixed rotor and the stator of said azimuth transmitter to said azimuth Selsyn receiver to move said azimuth receiver rotor in proportion to movement of said rotor of said transmitter.

2. An apparatus to detect deflection and azimuth deviations of a hole during or after drilling, said apparatus comprising a support adapted to be disposed in the hole and having an axis of rotation, a deflection sensing Selsyn transmitter secured to said support and having a rotor shaft mounted at right angles to said axis, a Selsyn receiver operatively connected to said Selsyn transmitter to provide signals proportional to the deflection of said support, an azimuth deviation detecting Selsyn transmitter carried by said support and having a rotor, means for rotationally fixing said rotor, an azimuth Selsyn receiver, means for transmitting signals produced by relative movement of said rotationally fixed rotor and the stator of said azimuth transmitter to said azimuth Selsyn receiver to thereby produce a signal proportional to azimuth deviation of said support, said support including a casing, a collar, means mounting said casing for rotation in said collar and means drivingly connected to said casing and collar for continuously rotating said casing and both Selsyn transmitters with respect to said axis of rotation.

3. An apparatus to detect deflection and azimuth deviations of a hole during or after drilling, said apparatus comprising a support, means for continuously rotating said support in the hole about an axis of rotation, a single deflection sensing Selsyn transmitter secured to said support and having a rotor shaft mounted at right angles to said axis, a Selsyn receiver operatively connected to said Selsyn transmitter to provide signals proportional to the deflection of said support, an azimuth deviation detecting Selsyn transmitter carried by said support and having a rotor, means for rotationally fixing said rotor, an azimuth Selsyn receiver, means for transmitting signals produced by relative movement of said rotationally fixed rotor and the stator of said azimuth transmitter to said azimuth Selsyn receiver to thereby produce a signal proportional to azimuth deviation of said support, said support comprising a drill stem collar having a drilling mud passageway, a chamber in said collar and accommodating said Selsyn transmitters, and a wall in said collar isolating said chamber from said passageway.

4. In an apparatus to detect deflection and azimuth deviations in a hole, the combination of a sensing unit adapted to be lowered in the hole and having a first Selsyn transmitter therein including means for enabling said first transmitter to detect deflection, a first Selsyn receiver remote from said unit, means operatively connecting said transmitter and said receiver, an instrument for recording information from said transmitter and received by said receiver, said instrument including a scriber, means mounting said scriber for movement, means connected to said scriber for moving said scriber in response to and in proportion to the received deflection signals of said first receiver, and means for rotatably supporting a graph in contact with said scriber, said last named means including a second Selsyn receiver remote from said unit, said sensing unit including a second Selsyn transmitter operatively connected to said receiver, means for enabling said second transmitter to detect azimuth deviations by simultaneous rotation of both transmitters whereby said graph may be rotated proportional to rotation of said transmitters.

5. Equipment for detecting both deflection and azimuth deviations from a vertical reference, said equipment comprising a sensing unit that has Selsyn motor transmitters at right angles to each other, means for continuously rotating said sensing unit means responsive to continuously changing deflection for actuating one of said transmitters, means responsive to azimuth deviations for actuating the other of said transmitters, Selsyn motor receivers remote from said transmitters, means for applying electrical signals generated by said transmitters to said receivers, a turntable, means drivingly connecting the azimuth receiver with said turntable to vary continuous movement of said turntable as a function of the signal produced by deviation of said transmitters in an azimuth plane, a scriber, means mounting said scriber for movement with respect to the turntable and for drivingly connecting said scriber to said Selsyn deflection receiver so that said scriber is moved in excursions whose magnitudes are proportional to the signal received by said Selsyn deviation receiver.

6. In an apparatus for detecting deviations in azimuth and deflection wherein there is a unit having a pair of Selsyn transmitters at right angles to each other, means for continuously rotating said transmitters to actuate said transmitters in response respectively to continuously changing deflection and azimuth deviation of both transmitters, an instrument remote from said unit and having a pair of Selsyn receivers thereon, means operatively connecting said Selsyn transmitters with said Selsyn receivers to impress signals on said receivers from said transmitters, and means including a plurality of switches for actuating at least one external device, said switches operatively con- It) nected to said azimuth receiver, and means connected with said deflection Selsyn receiver for actuating said switch.

7. Apparatus for detecting and indicating deflection and azimuth deviations in a hole comprising a sensing unit adapted to be lowered into the hole, said unit including first and second Selsyn transmitters simultaneous continuous movement, means for imparting said first transmitter having a first rotor shaft extending perpendicular to a rotational axis of said unit, said second transmitter having a second rotor shaft extending parallel to said rotational axis, deflection detecting means connected to said first rotor shaft for enabling it to detect instantaneous deflection in a rotating plane containing said rotational axis, means connected to said second rotor shaft for enabling it to continuously detect azimuth deviation of said rotational axis and angular displacement of said deflection detecting means with respect thereto, a first Selsyn receiver including a rotor shaft disposed remote from said unit, a second Selsyn receiver including a rotor shaft disposed remote from said unit, means operatively connecting said first transmitter to said first receiver and said second transmitter to said second receiver so that said respective receiver rotor shafts move in proportion to movement of said respective transmitter rotor shafts, and indicating means continuously driven by said receiver rotor shafts.

8. The combination of claim 7 wherein said indicator means includes a scriber operatively connected to said first receiver rotor shaft for movement thereby and a turntable adapted to be contacted by said scriber operatively connected to said second receiver rotor shaft for rotative movement thereby.

9. Apparatus for detecting and indicating well hole deflection and deflectional direction comprising, rotatable casing means having a first rotational axis and disposable in the well hole, means for imparting continuous rotation to said casing means about said first axis deflection sensing means pivotally mounted by the casing means about a second axis perpendicular to the rotational axis of the casing means for pivotal movement relative to the casing means in response to rotation of the casing means to detect instantaneous deflection regardless of angular position of said second axis, transmitter means operatively connected to and responsive to pivotal movement of the deflection sensing means relative to the casing means to provide surface indication of deflection, deflectional direction indicating means operatively connected to said transmitter means and said casing means for continuous rotation thereof about the rotational axis to provide positional reproduction of the casing means in the Well hole so as to furnish directional orientation for the deflection indication.

10. A well survey instrument comprising, continuously rotating casing means, means for imparting continuous rotation to said casing means, gravity responsive deflection means angularly displaceable about a deflection axis fixed in said casing means and disposed perpendicular to a rotational axis of the casing means for reflecting instantaneous inclinations of said rotational axis with respect to a gravitationally vertical line during each revolution of the casing means about said rotational axis, rotation responsive means for reflecting rotational movement of said deflection axis, and azimuth detecting means operatively connected to said rotation responsive means and responsive to displacement of said rotational axis to vary rotational movement of said rotation responsive means to reflect azimuth orientation of the deflection axis.

11. The combination of claim 10, including surface located deflection indicating means operatively connected to said gravity responsive deflection means for indicating angular displacement of the gravity responsive deflection means and scale means operatively connected to said rotation responsive means for displacement thereof in proper phase relationship to deflections of said deflection indicating means.

12. The combination of claim 11, wherein said azimuth detecting means comprises, means rotatably mounted by the casing means about said rotational axis operative to remain locationally fixed with respect to the surface of the earth.

13. The combination of claim 10, wherein said azimuth detecting means comprises, means rotatably mounted by the casing means about said rotational axis operative to remain locationally fixed with respect to the surface of the earth.

References Cited in the file of this patent UNITED STATES PATENTS Anschultz-Kaernpfe Dec. 19, 1916 Johnston Oct. 3, 1933 Goble et a1. Dec. 27, 1949 Kothny Apr. 8, 1952 Noxon et a1. Sept. 23, 1952 Arps Nov. 10, 1953 Chenery Mar. 16, 1954 Hinchman Apr. 20, 1954

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