US2309905A - Device for surveying well bores - Google Patents

Description

Feb. 2, 1943. E. M. IRWIN ETAL 2,309,905

I DEVICE FOR SURVEYING WELL BORES Original Filed Jan. 27, 193 9 3 Sheets-Sheet 1 f6 EMA/77 M lEW/N 56065 A4 2015 650K615 .5. LEW/5 INVENTORS ATTORN Feb. 2, 1943. E. M. IRWIN ETAL 2,309,905

DEVICE FOR SURVEYING WELL BORES Original Filed Jan. 27, 1939 3 Sheets-Sheet 2 E6. 2' jg 5 i 65 v 64 r 67 v ,6! 0 J .59 Q

/6 55 EMMETTM/EWI/V azz/a' 64 Pfll' 0505655 45 /5 INVENTO E- ATTO EY.

Feb. 2, 1943. r E. M. IR-WIN ETAL 2,309,905

DEvICE FOR SURVEYING WELL BORES Original Filed Jan. 27, 1939 3 Sheets-Sheet 3 .ew/vzrr M mw/v EPA/6E H. EULE azoee: 5 LEW/5 INVENTORS.

- .ATTORNEY.

prescribed course: directed Patented Feb. 2, 1943 UNITED STATES DEVICE FOR SURVEYING WELLIBOBES Emmett M. Irwin and Bruce H. Rule, Pasadena,

and George E. Lewis, Alhambra, CaliL, assignors to- Cooperative Development 00., Los-Angeles, Calif., a corporation of California Continuation January 2 of application Serial No; 253,124, I, 1939. This application April 29,

1941, Serial No. 390,938

" Claims.

Our invention relates to oil well survey devices and has particular reference to an instrument which may be employed for the purpose of measuring the course ofa well bore by determining the deviation thereof from the true vertical and the direction which such deviation takes.

This application is a continuation of our previously filed application Serial No. 253,l24'. illed January 27, l939,'and entitled Device for surveying well boresg v Inioil well practice, the well bore is drilled from the ground surface, either in a true vertical direction from the ground surface toward -.an oil pool located vertically below the starting pointvof the well, or along a predetermined or toward an oil pool which maybe offset in a known direction from the point on the ground surface at which the well bore is started. In either event it is desired that the driller know from time to time whether or not the well bore is following the true prescribed course and for this-purpose :it is the present practice to employ survey instruments which may be lowered into and passed through the well bore to make measurements of the direction in which the well bore is traveling: that is,-whether or not the well bore has deviated from a true vertical line and the compass direction in which such deviation occurs as well as the extent or angle of such deviation.

Heretofore all of the survey instruments which have been found practicable for this use have included devices which are adapted to be lowered into a well bore upon a wire or cable and stopped therein. at a desired point in the bore, the instrument then being permitted. to makethe measurements, after which the instrument is.

withdrawn to the ground suface and there opened in order to permit the'record of the measurement made to be translated and read. One of the primary difllculties encountered in the pre-: vious devicesis that during the survey of a well, either in making a single angle of'deviation measurement and direction of deviation measurement at some one-predetermined point in the well or in making asurvey of the complete well by makingaserles of records'at different depths along the course of the bore, it is impossible 'for the person making thesurvey to determine whether ornot an actual measurement .and recording of the measurement has been made by the instrument so that after theinstrument has been withdrawn to the ground surface it is ';fre-.. quently found that no record has been made at one or more points along the survey.

Another deficiency of the previous devices is that operating mechanisms for causing them to make their records usually consist of electric circuits and requires the location upon the instrument of suitable sourcesof electric current such as dry batteries, so that it is impossible to determine, until the device has been withdrawn to the ground surface, whether such sources of current have been depleted or destroyed to ren- 10 der the instrument'inoperative at the very time it is desired-that it should make its measurements. It is an object of our invention, therefore, to provide-a survey instrument which maybe lowered to any desired depth in a well bore upon a cable which constitutes an electric conductor over which electric power at predetermined voltage maybe transmitted down through the cable to the instrument to supply operating current therefor and in which the measurements made by the instrument may be transmitted to the ground surface through the same electrical conductor. Another object of our invention is to provide an instrument of the character set forth wherein the measurements taken by the instrument at anypoint'along the course of the well bore may. be instantly transmitted ,to the ground surface and there received and translated or recorded so that the person making the survey 30 is constantly advised as to whether or not the instrument is in operative condition and is actudesired points.

Anotherobject of ourinvention is to provide 88 an instrument of the character described wherein the instrument may be lowered into a well bore without regard to the compass orientation of the instrument itself but in which theinstmment is provided with means for determin- 40 ing its varying orientation relative to the orientation of the drift of the well bore, and a means for determining the varying orientation of the instrument relative to a true north direction, both of which determinations will be transmitted Q to the ground surface to permit direct reception,

translation and recording thereof at the ground surface, permitting direct reading at the ground surface of the effective orientation of the drift .01 the well bore.

.Another object of our invention is to provide a device as set forth in the preceding paragraphs wherein novel means is employed to determine the orientations of the drift of the bore and the position of the instrument relative to the true north, which means requires a minimum of mechanical power for its operation.

Another object of our invention is to provide a measurement of the character set forth wheren a plurality of angle inclination measuring devices are employed, each of which is responsive to the tilting of the instrument a diflerent predetermined amount away from the vertical and in which an electriccircuit is completed by each of the angle measuring devicesto produce an indication at the ground surface of the number of such devices that have been so positioned as to complete their respective circuits.

Another object of our invention is to provide an instrument of the character set forth and a system for receiving the indications or measure.-

ings of the measurements may be instantly made.

Other objects and advantages of our invention will be apparent from a study of the following specification, read in connection with the accompanying drawings, wherein:

Fig. 1 is a diagrammatic view of a well here and the manner in which 'our instrument may be employed for'surveying the course of the bore;

Fig. 2 is a vertical sectional view taken through an instrument constructed in accordance with our invention and illustrating the various angle measuring devices, sequence switching apparatus, borehole orientation analyzing device and compass point orientation analyzing device, and the required electrical apparatus such as rectiflers and resistors which are required for the making of. the measurements and the translation of the intelligence to the ground surface;

Fig. 3 is a diagrammatic perspective view of a portion of the apparatus contained in the instrument shown in Fig. 2 including the sequence switching device, the motor or motive means required for operating the same, the bore hole orientation analyzing device and the compass point orientation analyzing device, and illustrating the mechanical connections therebetween;

Fig. 4 is a schematic wiring diagram illustrating the electrical connection required between the apparatus at the ground surface and the connections for the apparatus of the instrument itself;

Fig. 5 is a detailed perspective view of one form of recording device which may be employed at the ground surface for the reception and translation of the indications produced by the instrument in the well; and

Fig. 6 is a view of section of record chart which will be produced by our instrument and with our equipment.

Referring to the drawings, illustrated in Fig. 1 is a typical oil well which may be either a completed oil well or an oil well bore in the process of drilling. The bore is illustrated at i as extending from the ground surface 2 in a substantially true vertical line to the point 3 at which the course of the well bore deviates from the vertical and continues along thenon-vertical path to the lowest point or bottom of the hole indicated at 4. For purposes of illustration only we have shown a derrick structure 5 disposed above th'e upper end of the well bore and through which the drilling Y tools and other apparatus required therefor may be handled.

Assuming that it is desired to survey the course of the well bore l and to determine the angle to which the hole has deviated from the true vertical as well as the compass direction in which deviation occurs, we employ our survey instrument generally at G mounted at one end of an indicated electric conductor cable 7 which may be and prefshown) carried in a erably is disposed upon a suitable drum (not service truck indicated at I:

which service truck may also include as ,a part of its equipment the necessary electric current genand the recording apparatus;-

erating apparatus for receiving and translating the indications or measurements produced by our. instrument. For purposes of convenience in lowering the instrument into and raising the instrument out of the well, be suspended in any suitable manner within the derrick 5 and over which the cable 1 may extend.

By referring particularly to Fig. 2 it will be observed that our instrument includes a suitable case or housing III which may be constructed'as ments at the ground surface wherein visual readshown the instrument an elongated tubular housing preferably open at both ends, the lower end H thereof being closed by a suitable nose piece I! preferably rounded in order to permit the same to pass readily about any obstructions the hole. skilled in lowered into the open hole, it is preferable to lower the instrument into and through a casing or other pipe contained within the hole. For'purposes of illustration herein we have, however, being lowered into the open hole in which event the instrument will be considerably smaller in diameter than the diameter of the well bore, and in order to maintain the longitudinal axis of our instrument and its casing accurately aligned with the longitudinal axis of the well bore, we provide 'a plurality of spring shoes I3 disposed about the lower end of. the housing l0 and a similar plurality or series of spring shoes l4 disposed about the upper end of the housing l0, such spring shoes extending into contact with the walls of the bore and holding the instrument substantially centered within the bore.

A suitable compass i5 is secured within the housing I ll and is illustrated herein as a gyroscopic compass, though it will be understood by those skilled in the art that any other character or type of compass may be employed so long as it has the characteristic of holding an indicating element directed toward the true north ortoward any other selected point of the compass, or if desired, a simple gyroscope may be used which will have some portion or indicating element thereon movable at a known rate of speed and from which a calculation of the compass direction at any given instant may be made.

In the form of the device illustrated herein, the gyroscopic compass l5 has one of its gimbals I I supported for rotation upon a mounting plate I! extending-across and rigidly secured near the lower end of the housing l0, while the opposite bearing for the gimbal it comprises a suitable bearing member i8 carried by a mounting I! disposed immediately above the gyroscopic compass l5. We employ in our instrument an analyzing which may be contained within While it will be understood by those the deviation of the well bore, one part of which comprises a compass point orientation analyzing device Illa, the device Ha including a .gimbal shaft I 9b mounted for rotation, on the bearing member I8 so that an arm or'wiper 20 rigidly connected thereto may be held in fixed angular relationship relative to a meridian passing through the instrument while the instrument rotates there'about. The wiper 20 carries an arm or pointing member which projects downwardly to engage a wiping contact or ball 2| arran ed to we provide a pulley structure 9 whichmay this art that our instrument may be By referring particularly to Fig. 3, it will be observed that the contact plate 22 is constructed with a metal disk-like portion 23 preferably with a ring 24 of insulating material surrounding the periphery of the same, and acting as a spacer in spacing a resistance ring 25 away-from the pe- V riphery of the disk 23. The ring 25 is preferably formed of some suitable high resistance material such as a carbon ring and the insulation ring 24 is preferably undercut slightly below the upper a depression 23 constituting'the trackway about which the ball contact 2i-may travel. The effect of the' gyroscoplc compass l5 will he to mainsurfaces of the disk 23 and the ring 25 to provide 7 ner and arranged to rotate the shaft 34 through suitable reduction gearing 33. The motor 33' is also arranged to simultaneously rotate another vertically extending shaft 43 disposed above the motor 33 and journaled for rotation in suitable bearing members 4| and 42 carried in transversely extending plate members 43 and 44 secured to the side walls of the casing iii. The. shaft 40 is drivably connected to the shaft of the motor 33 by means of reduction gearing 45. For reasons to be explained hereinafter the reduction gearing 33and 45 are so arranged that the contact arms 32 and 33 will make two complete revolutions tain the wiper arm 2| and its ball contact directed in a predetermined compass direction; for example, true north. irrespective of the retation of the casing ill during its passage upwardly and downwardly in the well bore.

Disposed immediately above the compass point always contact both thermetallic plate 28 and the resistance ring 23, 'and by reason of the conical shape of the surface of the plate. 23 the ball will always assume a position representing orientation analyzing device 2| is a bore hole while the shaft 43 is making one complete revolution.

The shaft 40 carries .a contant arm 45 which is rotatable therewith, being suitably secured to the shaft 43 and insulated therefrom by means of suitable insulating material 41. The contact arm 45 is arranged to contact a commutating and transfer device 410. carried in an insulating sleeve 43 secured to the side walls of the container l0.

As illustrated particularly in Fig. 3, the transfer mechanism "414; is preferably constructed in a ring shape and provided with alternate contact segments 43 separated .from each other by insulating segments 50; .The insulating segments are thelow side of the casing"! as it -'is disposed within the well bore. This low point of the casing III is, oi course, diametrically opposed to the direction taken by the well bore as it deviates from the true vertical.

Cur analysing means also includes a device for comparing the position of the gyroscope contact 2| (maintained at a fixed angle to a meridian by the gyroscope 15) with the position of the contact 3| which ,representsthe direction of the deviation of the well bore so that the direction of the well bore may be referred to the meridian. This means may include a pair of contact arms or rotary -membersf32 and 33 associated respec tively with theresistance rings 25 and 23. These contact arms are arranged'to engage theirrespective resistance rings and be rotated therearound while being maintained in a fixed angular relationship relative to each other by means of a vertically extending shaft member 34 to which each of the arms 32 and 33 may be secured.

In order that the proper electrical connections may be established, we prefer to interpose insulating material 35 between each of the arms 32 and 33 and the shaft 34 to which they are secured. The shaft 34 may be secured against downward axial movement by means of a collar 33 secured to the shaft 34 in a position to engage a transversely extending plate: member 31 secured to the side walls of the casing III.

In order that the contact arms 32 and 33 may be rotated about the periphery of the resistance rings 25 and 23 in order to compare the relative positions of the ball'contacts 2| and 3|, we provide a synchronous motor 33 which may be secured within the housing ill in any suitable manpreferably made slightly wider than the width of the contacting end of the rotary contact memher 45 so that this member will contact only one,

of the plurality of contact-segments 43 at any one time. A plurality of these segments, together with their interposed insulating segments 53 are distributed over appoximately one-half of the full circle provided by the commutating member 4111, the remaining half of the circle comprising a semi-circular slip ring 5| of electrically conducting material.

Secured within the casing i0 and disposed immediately above the plate member 43, we provide a pair of resistance units 52 and 53 and a pair of rectifying units 54 and 55. These units may be of conventional construction and suitably secured within casings adapted in turn to fit within the casing in and be secured thereto.

Directly above the rectifier unit 55 we provide a plurality of inclined plane and rolling ball type of angle measuring units 55. These units may be constructed as disclosed and described in a copending application filed by Emmett M. Irwin, et al., Serial No. 162,792, on September 7, 1937, and. each may include a body member 51 which is provided with a conically depressed upper surface 53 upon which is rested a spherical metal ball 53. A suitable contact ring 53 may bev supported in an insulating sleeve 5| in a position above the conical surface 55 suchlthat when theball 53 is rolled from the central depression in which it is rested to the outer edge of the supporting member 51, an electrical circuit will be established between the contact ring 53 and the supporting member 51.

The included angle between the sides oi the .conical surface 53 is made different for each of the plurality of angle measuring units 53 provided, beingpreferably arranged in regular angular steps of 1, the uppermost surface having electrical circuit between its contact ring and the supporting member upon which it rolls, If these cone-shaped supporting surfaces are arranged in such manner that the included angle of the cone of one of the members is 1 smaller than the next member above, the number of balls which will roll out of the central depression into contact with their associated resent the number of half degrees that the instrument is inclined from the vertical.

The instrument iscapped by means of a cap member 82 which may be secured to the casing It by means of a threaded adapter unit 88 threadedly engaged with the casing l and providing also a threaded engagement for the cap 82. The cap 82 is provided with a packing and clamping member 88, for securing and sealing the supporting and electri al conductor cable 1. In order that proper connection vmay be established between a central electrical conductor 88 forming a part of the cable 1 and the equipment previously described, we provide a. connection block 88 which is secured to the cap member 82 and provided with a terminal contact 81 to which the electrical conductor-may be attached.

The connection block 88 is provided with a spring contact member {88 connected electrically to the terminal contac 81 and arranged toengage-a' complementary contact member 88 carried by and insulated from the adapter member 83. The contact member 88 is provided at its lower end, which is disposed within the interior of the casing II, with a contact terminal 18 from which all of the power for operating the previously described electrical mechanisms carried by the casing Iliisderived. v r g The equipment which is'- maintained at the round surface and carried in the service truck 8 includes an alternating current generator 1| which is arranged to be driven from any suitable source of power such as the engine of the truck 8, a disconnect switch 12 connected in the main circuit of the generator 1| for disconnecting the equipment from the generator, a starting switch- 18 which may be operated in a manner to be described hereinafter to place the equipment in operation; and a receiving illustrated herein as a dual recording ammeter 14. /The ammeter 14 may be of a common type such as is illustrated in Fig. and includea' synchronous electric motor 15 which is connected by suitable belting or gearing (not shown) for feeding a chart 18 through the instrument at a substantially constant rate of speed.

The recording ammeter 18 includes a pair of load responsive elements or ammeters 11 and 18 which are each arranged to move associated needles 19 and 80 over scales 8| and 82. The needles 19 and 88 are provided with pens 83 and 88 for scribbing contact -rings,'will repand translating means being taken,

'ductor portion 88 of and assuming certain operating. conditions and describing the manner in which each of the associated mechanisms operate and cooperate with the other associated mechanisms to transmit to the ground surface the angle of inclination of the well bore at the point where the reading is together with the compass direc tion which-such deviation assumes. The equipment is placed in operation by starting the alternating current generator 1|, one terminal of which may be connected to the outer sheath or grounded portion 81 of the cable Tand the other terminal of which may be connected by means of a conductor 88 to the line switch 12; The starting switch 13 and the line switch 12 are then closed to transmit power over conductors 98a and flllbconnected in parallel with each of the meters 11 and "to the electrical conductor portion 85 of the cable 1. The closing of the starting switch 18 prevents the momentary high W of. current required to start the motors for the gyroscope I 5 and the synchronous motor 88 from passing through the sensitive windings of the ammeters 11 and 18. It the ammeters 11 and 18 are so constructed as to be able to withstand this relatively high current, the switch 13 need not-be employed. After these motors have been started the switch 18 is opened andleft in the open position to allow the current and 18. which are connected by means of parallel circuits and 98 between the electrical conthe cable 1 and the load side ofthe line switch 12.

The circuit 88 includes the ammeter 11 and its associated rectifier 85 while circuit 88 includes the ammeter 18 and its associated rectifier 88. Power then flows down conductor 88 to the instrument 8 where the conductor 85 is connected to one terminal of the gyroscope motor ii, the other terminal of which isconnected to the grounded circuit 81. Upon closing the switch 12 the gyroscope'motor is causedto revolve and if the instrument is of the gyroscopic compass type the gimbal l8 and the shaft i8 securedthreto will assume a fixed angular position relative to the meridian passing through the location of the instrument. We prefer, for the sake of convenience, to secure the contact arm 28 to the shaft l8 in such position that the arm 28 will point to the true north.

- scope i8 isput a line on the chart 18 as the chart 18 is moved "past. these instruments.

As illustrated particularly in Fig. 4, rectiflers 85 and 88 are respectively associated with the ammeters 11 and 18 and are connected in series therewith. The rectiflers 85 and 88 are of the half wave type and so connected that each of the ammeters 11 and 18 respond only to onehalf of each of the cycle of in the alternating current generated by thegenerator 1| In order that the ammeter 11 may respond to one-half of each of the cycles while the ammeter 18 may respond to the alternate half, we connect the rectiflers 85 and 88 ins-everse relationship relative to each other.

. The manner in which the equipment operates may best be understood by referring to Fig. 4

clined 1 to .the

II, on the other hand, the gyroscopic instrument II the contact arm 28 may be oriented relalowered in the well bore. As soon as the gyrointo operation,- the instrument is lowered into the well bore to the desired depth at which time readings of the angle 01' inchdirection of deviation may be determined from recordings made upon the chart 18at that time. 1 g Y Let us assume that atthe point at which the measurement is being taken, the well bore is invertical and drifts northwest.

. It the bore is inclined at an angle of 1 to the vertical/two of contact with their associated contact. rings 88 and complete an electrical circuit between the two associated base members 51 and rings 88.

' In order that this angle of inclination may be transmitted to the ground surface, we con-' nect each of the supporting members 81 to the grounded casing 18 ofthe instrument, such connection being indicated on the wiring diagram to flow through the ammeters 11 the simple gyroscope type,

the ball members so will lie in km} 4) as by} conductor 9|. Each of the contact rings 69 isonnerited to a corresponding commutator segment 49by means of conductors 92a, 92b, etcs, as many conductors being provided a as thereare contact rings 99 and commutator segments 49.

r .-The contact arm 46 which associated with the commutating device 410 is electrically con- :nected by meansoi 'a conductor .93 to one ter- =.minal of the rectifier 55. The connection between the conductor 93 a'nd'the contact arm 46 bore deviates from the vertical atthe point being surveyed by 1". e i,

As previously described, substantially one half of each full circle of revolution ofv the conmay be established by means of a brush member 7 94 secured to the insulating sleeve 43 in a posi- 55 is connected by means'of a conductor 96 to one-terminal of the resistor 53, the other tertion to wipe a cylindrical hub portion 95 of the a @contact arm 46. The other side oftherectifler minal of which is connectedto' the electrical conductor 65 forming a part of thecable I.

It will be observed thatii the contact arm isis rotated past its plurality of segments 49 me counter-clockwise direction,'asviewed in Fig. 4, an electrical circuit will lee-completed and interrupted between. the conductors 91 and 65 through the rectifier 55 and the resistor 53 as,

many times as there are ball members 59 in tact arm 49 is employed in transferring the conductor 93 sequentially to each oithesegments 49, the remaining half circle of revolution establishing a connection between the conductor 93 and the slip. ring portion 5|. We prefer. to use this remaining half of the revolution of the contact arm 46 for the determination of the azimuth of the line along which the well bore is-deviating. We accordingly connect the slip ring 5I to the contact arm33as by means of a conductor I99 and the plate portion upon which the ball member 3I rests to the gro'undedouter case I9 ofthe instrmnenh'siich connection being indicated on Fig. 4 by conductor I9I.

In a similar manner the plate member 23 of the unit associated with the gyroscope I5 is connected to the grounded case I9, such connection being indicated diagrammatically in Fig. 4 as conductor I92, while the movable arm 32 associated therewith is connected by means of a.

contact with the contact rings 69' associated therewith. Rotation of the arm 46 in order to and the ball members 59 included in this circuit. The rectifier 55 is so placed in the circuit 93 that the current'fiowing therethrough w ll also flow through the rectifier 86 and the am- 'meter 19. During such time as the contact arm L 46 is in contact with a segment 49 to which a circuit has been completed by one of the balls 59, a full metallic circuit will be completedfrom the generator H through the ammeter I9 which includes only the resistance unit 53 as a load. The. magnitude of current flowing through the ammeter at this time is, therefore, determined by theresistance of the resistor 53.

We preferably choose this resistance of such valuethat the ammeter 18' will move its needle 19 through approximately halt of its total allowable travel. In the assumed case then it will be seen that as the contact arm 46 is rotated' past its contact segments 49 in response to the rotation of the motor 39, the circuit will be completed through the ammeter I8 twice corresponding to the two balls 59 which have been moved .into contact with their contact rings 69 as a, result of the instrument 6 being disposed at a 1? angle to the vertical. These' conductor I93 to the rectifier 54,.the otherside of said rectifier being connectedby'means of a conductor I94 to. the resistor 52. The resistor 52 has its other terminal connected tothe electrical conductor 65.

As previouslym'entioned, the 'gearingwhich is interposed, between the shaft of the motor 39 and the shaft-carrying contact arms 32 and 33 and the gearing interposed between the motor 38 and the shaft'connectingthe contact arm 49 is so arranged that the arms 32 and 33 are caused to make one complete revolution during the time the arm 46 is traversing ahalf of a revolution.

Referring first to the contact 32, it will be noted that the electricalcircuit is completed from conductor 91 through conductor I92 to the base member 23 of the gyroscopically contro ed unit, thence through the ballcontact 2 I to e .cuit will vary from a maximum, at the point resistance ring 25 where the circuitsplits, one

part travelling around the resistance ring in a I clockwise direction, the other part travelling therearound in a counter-clockwisedirectio'n, these two parts meeting at the junction between the contact arm 32 and the resistance ring. The circuit then extends from the contact arm 32 via conductor I93 through the rectifier 54 and resistor'52, to the other line conductor 65.

We have arranged the rectifier '54 relative to conductors I93 and I94 in such manner that the half cycle of the alternating current which flows through this rectifier is the same half cycle which flows through the ammeter 11- so that the ammeter 11 will respond to changes in re sistance in the previously described circuit.

It will be noted that the resistance of this cirwhere the contact arm is diametricaliytop posed to the position of the ball contact 2| or when the arm 321s pointing due south, to' a minimum when the arm 32 has'rotated one half vof. a, revolution from the previously described the ball contact 2| therefor comprise a variable load means operable to impose a load on the generator "II which variesin correspondence with the determinations of the analyzing means,

' where the path divides,

curve such as the curve I03 indicated in Fig. 6.

The point of maximum deflection of the ammeter corresponding to the ammeter reading at the time the contact arm 32 is pointing due north establishes peaks such as that indicated at I03 in Fig. 6. Simultaneously with the rotation 01' the arm 32 to establish the peak I on the chart I6 to indicate the true north position, the arm 33 is caused to revolve about its associated resistance ring 23. to cause a recording upon the chart I6 indicating the lowermost position ofithe track upon which the ball contact 33 travels. Current for this measurement flows from the grounded conductor 31 through conductor IM and ball contact 3| to the resistance strip 23 one path leading in a clockwise direction around the resistance ring 29, while the other path leads in a counter-clockwise direction therearound, these pathsmeeting at the Junction between the contact arm 33 and the resistance strip 20. The current then flows from the arm 33 over conductor I00 to the slip ring 5|, through the movable arm 46 in contact therewith and conductor 03 attached to said movable arm-and thence through rectifier 55 and resistor 53 to the other side. of the line 65.

As has been pointed out, through "the rectifier current flowing the time the contact arm 33 is adjacent the ball contact II. This ammeter will thus draw an extension of the curve 39, such as that indicated at I01 in Fig. 6, having a peak I08 correspond I1 and the alternating 55 is measured by the ammeter 13 so that as the-resistance in the preing to the point of maximum current and representing the time at which the movable contact 33 is angularly disposed relative to a predetermined reference point on the housing estabtrue north position corresponding to one of the j peaks I06 and at a later time the arm 33 will arrive at a point adiacent the ball contact 3I corresponding to the low side of the track upon which it travels on a direction diametrically opposed to the direction of deviation of the well bore.

Since the position assumed by the'ball contact 3I is diametrically opposite to the direction of deviation of the well bore, we prefer to locate the arm 33 in a position diametrically opposed from the position of the arm 32 so, that after the arm 32 has assumed the true north position, the amount of angular displacement required to move the arm ,33 into a position pointing in a direction diametrically opposite to the direction from the meridian,- a distance II 0 (see Fig. 6) Y separating the peak I03 corespondingto the true north from the peak I 03 corresponding to the direction of deviation of the bore may be meas- I ured and compared to the previously mentioned distance I 09.

If, as in the assumed example, the well is deviating northwest, the distance I I0 will equal exactly one-eighth of the distance I00, and since the distance I09 represents 360", the distance IIO will represent one-eighth of 360or 45 from the north. Since the synchronous motor 33 is arranged to rotate the arms 32 and 33 in a coun-' ter-clockwise direction when viewed from above or from north through west to south, it follows, since the peaks I00 occur at a time later-than the peak I03, the well bore must be deviating west of north by 45 or in the direction northwest.

Our device also provides means for determining the angular position of the instrument housing relative to a predetermined reference direction independently of determinations of the compass direction assumed by the well bore.

After the instrument has transmitted to the ground well bore'to the vertical, no current will flow through the ammeter I3 and the line 33 drawn thereby on the chart .13 will be a straight line indicating this, zero current condition. Assoon,

lisl'ied by the beginning or; end of the cummut'ator segment ii, in exactly the same fashion as the ball contact 3I is angularlydisposed rela-'- tive to this reference point.

Since the'synchronous motor 15 is employed to drive the chart l3 and the synchronous motor 33 is employed to drive the contact arms 32 and 33, it"-follows that a specified length of chart will always correspond to one complete revolution of the arms 32 and 33 independently of the speed at whichthe arms are rotated and the chart is fed. It will be further observed that this distance is the distance separating the two peaks I00 in the curve I05 and represents an angular displacement of the arms 32 and 33 of exactly 360. This distance is indicated on Fig. 6 by the-dimension line bearing the reference character I09.

It will be further observed that since we prefer, as previouslymentioned, to rotate the contact arms 32 and 33 in a counter-clockwise ,direction, the arm 32 will, under the assumed conditions as illustrated in Fig. 4, first arrive at the however, as the wiper arm 40 arrives at the predetermined referencepoint on the housing and establishes an electrical connection with the slip ring segment ill, the line 03 drawn by the am meter 18 will have a break in it suoh'as that in-.-

dicated at ,IIIIin Fig. 6 at which time the ammeter 11 indicatesthe amount of current flowing through the resistance ring 20. The break or point of discontinuity III in the line 03 indicates the instant at which'the movable arm 43 came into contact with the predetermined reference point on theinstrument .housing. If then a dimension II: is measured from the break III to the peak I06 of the curve I06 representing the relative location of the true north direction, the comparison between the dimension H2 and the dimension I09 will give the angular position of the reference point on the instrument housing relative to the true north south line.

It will be noted, therefore, that with this arsurface the angle of inclination of the housing relative to a predetermined reference direction, the angular disposition of the housing relative to the direction taken by the deviation of the well bore from the vertical, the angular direction of the deviation of the well bore rela:

tive to a predetermined reference direction, and

the angle of inclination of the well bore to the vertical;

It will be apparent to those skilled in the art that with all of this data, together with depth measurements which may be taken by measuring the amount of cable payed out from thecable reel in lowering the instrument lnthe well bore, the precise course of the well bore may be accurately mapped and other useful data tabulated.

It will be observed that with this arrangement, a single cable comprising an insulated electrical conductor and a grounded cable sheath may be employed with the previously described apparatus to determine, whenever desired at any point in a well bore, the angle which said'bore deviates from the vertical and the angular position of such deviation referred to any selected horizontal reference line.

It is apparent that all sources of error, such as the resistance of the cable or changes in the re-- sistance of the various elements employed due,

, 2. In an oil well survey device, an, instrument housing insertable in a well bore'with its axis aligned with the axis of said bore, said housing containing the following instrumentalities;

orientation means for determining the angular orientation of said housing with respect to the direction of inclination of said well bore, compass means for determining the angular orienta-- tion of said housing with respect to a predetermined compassdirection, timing, means defining a repeating time cycle, and transmitting means actuated by said timing means andco'upled to said orientation means and said compass means for simultaneously transmitting to the ground surface a pair of signals of varying amplitude, the positions of the maximum amplitude of which in each of said time cycles are a measure of the determinations made by said orientation means V and said compass means; and translating means to temperature or pressure changes, are obviated through the use of this system, which depends upon the synchronous timing between the speed of feed of the chart and the speedof rotation of the analyzing devices 22 and 2I.

The indications do not depend upon the value of current indicated by the ammeter charts but upon the location of well defined peaks in these curves relative to each other. In the case of the vertical angle, the magnitude: is determined purely by the number of peaks irrespective of their relative positions.

It is accordingly apparent that we have provided a survey instrument which may be lowered to any desired depth in a well bore upon a cable of the character described and which operates to transmit to the ground surface readily translatable indications of the angle of deviation of the well bore from the vertical and the direction which such deviation assumes relative to a horizontal reference direction line.

While we have shown and described the preferred embodiment of our invention, we do not desire to be limited to any of the details of construction shown or described herein, except as defined in the appended claims.

We claim:

1. In an oil well survey device, an instrument housing insertable in a well bore with its axis aligned with the axis of said bore, said housingcontaining the following instrumentalities; orientation means for determining the angular orientation of said housing with respect to the direction of inclination of said well bore, compass means for determining the angular orientation of said housing with respect to a predetermined compass direction, and transmitting means for simultaneously transmitting to the ground surface a pair of comparable signals, one for each of .the' determinations of said orientation means and said compass means; and translating means at the ground surface including means for receiving said signals, and means actuated by said signals for visibly indicating said signals in'a comparable relation to each other whereby said signals may be visually compared to determine the direction of inclination of said well bore with respect to said predetermined compass direction,

at the ground surface including means for receiving said, si nals, and recording means for recording said signals with the maximum amplitude thereof in a linear spaced relation to each other corresponding to the positioning of said maximum amplitude in said time cycle, whereby the" linear distance separating said maximum amplitudes of said recorded signals may be com pared with the .linear distance separating the maximum amplitudes of one recorded signal from the repetition thereof to determinethe direction of inclination of saldwell bore with respectto said predetermined compass direction.

3. In an oil well survey device, an instrument housing insertable in a well bore with its axis aligned with the axis of said bore, said housing containing the following instrumentalities;

means defining a reference point, orientation means having a gravity actuated member movable by inclination of said housing to a position indicating the angular relation of said reference point to the direction of inclination of said well bore and including one rotary member mounted for rotation independently of. said gravity member, compass means having an indicating member capable of assuming a predetermined compass direction and including another rotary membermounted for rotation independently of, said indicating member, means for synchronously rotating said rotary members to define one time cycle for each full 'circle rotation thereof, and

-- transmitting means coupled to said rotary memcycle.

bersfor transmitting three signals to the ground surface during one time cycle, one signal when said one rotary member is moved to angular coincidence with said gravity member, another signal when said other-rotary member is moved to angular coincidence with said indicating member, and a third signal when said rotary members are moved to angular coincidence with said reference. point; and translating means at the ground. surface including means for receiving said signals, and recording means for recording said signalsin the same linear spaced relation to each other as said signals are spaced in said time 4. In an oil well survey device, an instrument housing insertable in a well bore with its axis aligned with the axis of said bore, said housing containing the following instrumentalities;-

means defining a reference point, orientation means for determining the angular'orientation of said reference point with respect to the direction of inclination of said well bore, compass means for determining the angular orientation of said reference point with respect to a predetermined compass direction, timing meansdefining a repeating time cycle, and transmitting means actuated by said timing means and coupled to said orientation means and said compass means for simultaneously transmitting to the ground surface a pair of signals of varying amplitude, the positions of the maximum amplitude of which in each of said time cycles are a measure of the determination made by said orientation means v and said compass means; and translating means at the ground surface including means for rev ceiving said signals, a record chart, indicating means actuated by said signals to make marks on said chart representative of the varying amplitude' of said signals, and means for moving sad chart past said indicating means in synchronism with the operation of said timing -mean's,- whereby the relative linear positions of the maximum signal amplitudes represented by said marks on said chart are identical with the positioning of said maximum amplitude in said time cycle.

5.'I n an oil well survey device, an instrument housing insertable in a well bore withits axis aligned. with the axis of said bore, saidhousing containing the following instrumentalities: means defining a reference point, orientation means having a gravity actuated member movable by inclination of said housing to a position indicating the angular relation of said reference point'to the direction of inclination of said well bore and including one rotary member mounted for rotation independently of said gravity member, compass means having an indicating member capable of assuming a predetermined compass direction and including another rotary member mounted for rotation independently of said indicating member, means for synchronous- .s 1y rotating said rotary members to define one time cycle for eachfull circle rotation thereof,

signal identifying the beginning of each of said time cycles and a pair of signals during one of said cycles, the positions of which in said time cycle is a measure of the determinations made byv said orientation means and said 'compass means and translating means at the ground surface including means for receiving said signals, a record chart, indicating means actuated by said signals to make marks on said chart, and means for moving said chart past said indicating means in synchronism with the operation of said ,tim-

ing means, whereby the relative linear positions of said marks on said chart are identical with the positioning of said signals in said time cycle.

7. In an oil well survey device, an instrument housing insertable in a well bore with its axis aligned with the axis of said bore, said housing containing the following instrumentalities; inclination responsive means for determining the angle of inclination of said well bore, means defining a reference point, orientation means for determining the angular orientation of said reference point with respect to the direction of inclination of said well bore, compass means for determining the angular orientation of said reference point with respect to a predetermined compass direction, timing means defining a repeating time cycle, and a transmitting means 3 actuated by said timing means and coupled to and'transmitting means coupled to said rotary members for transmitting three signals to the ground surface during one time cycle, one signal when said one rotary member is moved to angular coincidence with said gravity member, another signal when said other rotary member is moved to angular coincidence with said indicating member, and a third signal when said rotary members are moved to angular coincidence with said reference point; and translating means at the ground surface including means for receiving said signals, a record chart, indicating means ac-' tuated by said signals to make marks on said chart, and means for moving said chart past said indicating means in synchronism with the rotation of said rotary members, whereby the relative linear positions of said marks on said chart are identical with the relative angular positions of said gravity actuated member, indicating membe:- and reference points 6. In an oil well survey device, an instrument housing insertable in a well bore with its axis aligned with the axis of said bore, said housing containing the following instrumentalities;

means defining a reference point, orientation means for determining the angular orientation of said reference point with respect to the direction of inclination of said well bore, compass means for determining the angular orientation of said reference point with respect to a predetermined compass direction, timing'means defining a repeating time cycle, and transmitting means actuated by said timing means and coupled to said orientation means and said compass means for repeatedly transmitting to the ground surface a said inclination responsive means, orientation means and compass means to simultaneously transmit to the ground surface during one time cycle a pair of comparable signals corresponding to the determinations of said orientation means and said compass means and to transmit during a subsequent time cycle a plurality of other signals, the number of which is representative of the determination of said inclination responsive means; and translating means at the ground surface including means for receiving said signals, and recording means actuated by said signals for visibly indicating said comparable signals in a, comparable relation to each other and recording the number of said other signals, whereby visual comparison of said signals'indicates the angle of inclination of said well bore and the compass direction of said inclination.

8. In an oil well survey device, the'combination of: a survey instrument insertable in a well bore with its-axis aligned with the axi of said bore including orientation means for determining the angular orientation of the deviation of said well borerelative to the angular position of said instrument, and compass means for determining the angular orientation of said instrument position relative to a predetermined reference direction; a source of alternating current at the ground surface: electric motor driven timing means carried by said instrument cooperating with said orientation mean and said compass means for repeatedly transmitting to said ground surface a pair of signals both embraced within one' time cycle, one signal representative of the determination of said orientation means-and ana housing insertable in a well bore and having an axis alignable with the axis of said bore and means defining a reference point on said housing, a device for measuring the angular disposition of said reference point relative to the direction of deviation of said well bore from the vertical, comprising: an electrically conductive supporting plate in said housing disposed perpen dicularly relative to the axis thereof; an electrically conductive resistance element encirclin said plate and insulated therefrom. for defining a circular trackway; an electrically conductive rolling member carried on said plate and movable by gravity around said trackway to the low side thereof to define a housing low point by electrically connecting the low side of said resistance strip to said plate when the axis of said housing is disposed at an angle to the vertical; a rotary member engaging said resistance strip to forman electric circuit between said rotary member and said plate through said resistance strip and said rolling member;' means mounting said rotary member for movement about said resistance strip from a position corresponding to said reference point to said low point totraverse an angle corresponding to the angle between said points and to thereby vary'the resistance of said electric circuit; and means in said circuit responsive to variations in the resistance thereof for indicating the magnitude of the angle traversed by said rotary member.

10. In an oil well survey instrument including a housing insertable in a well bore and means defining a reference point on said housing, a compass device for determining the compass direction of said reference point, comprising: an

electrically conductive resistance ring carried by said housing and insulated therefrom; a pointing member of electrically conductive material-engaging said ring, a compass means in said housing for moving said pointing member about said resistance ring to a position defining a predetermined compass direction; a rotary member of electrically conductive material engaging said resistance ring to form an electric circuit between said rotary member and said pointing member through said resistance ring, means mounting said rotary member for movement about said resistance ring from a position corresponding to the location of said reference point to a position corresponding to the position of said pointing member to traverse an angle corresponding to the angle between said reference point and said pre determined compass direction and to thereby vary the resistance of said electric circuit; and means in said circuit responsive to variations in the resistance thereof for indicating the magnitude of the angle traversed by said rotary member.

EMMETI M. IRWIN. BRUCE H. RULE. GEORGE E. LEWIS.

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