US2126189A - Means for drilling wells - Google Patents

Description

Aug. 9, 193.8. v l o. B. GOLDMAN MEANS FORDRILLING WELLS Filed Deo. 30, 1935 5 Sheets-Sheet 1 5 Sheets-Sheet 2 o. B. GoLDMAN MEANS FOR DRILLING WELLS Filed Deo. 3o. 1935 Aug, 9, 1938.

o. B. GOLDMAN 2,126,189

MEAS FOR DRILLING WELLS Aug. 9, 1938.

Filed Dec. 50, 1935 5 Sheets-Sheet 5 APatented Aug. 9, 1938 UNITEDv STATES PATENT oFFicE MnANs'roa nnnmNG WELLS Otto Berger Goldman, Dallas, Tex. Application neeembell 3o, 1935, serial No. 56,607

` r3 claims. (crest-1o) This invention relates to new and useful improvements in methods of and means for drilling wells.

The inventionvis an improvement upon the method and means for well drilling set forth in my Letters Patent No. 1,913,752, issued June 13, 1933.

One object of the invention is to provide an improved method of drilling, wherein the drill bit is rotated at a substantially constant speed and preferably at the maximum allowable speed, which makes for the fastest possible, and thus most economical, drilling.

An important object of the invention is to provide an improved method of drilling which involves constant speed of rotation of the drill bit. and' wherein variations in the speed of rotation of the bit, due to variations in the character of formation being drilled, are reflected in propor.- 20 tional variations in the operation of the drill stem driving means and in the feeding means for the drill stem, whereby the speed of rotation of the drill bit is maintained substantially constant regardless of the character of the formation being attained than has heretofore been possible.

Another object of the invention is to provide an improved drilling method wherein the weight of `the drill bit on the bottom of the hole is automatically varied inversely with the hardness of the formation beingv drilled and wherein the; maximum allowable power is delivered to the bit at all times.

Still another object of the invention is to provide an improved method of rotary drilling wherein the operation of the feeding means for the drillstem is automatically controlled by the speed of rotation of the drill bit, whereby said means is operated to provide a continuous feed of said drill stem.

A further object of. the invention is to provide ,improved means for drilling, coring andreaming of wells, wher'ein the speed of rotation of the drill bit is maintained substantially constant, irrespective of the character of formation being drilled, while the drilling speed progresses in proportion to the variations in the character of the formation.

A still further object of the invention is to provide an improved rotary drilling, mechanism which includes a prime mover for rotating the `drill stem and bit, and a feeding means connected with and controlled by the speed of said prime mover for feeding the drill stem into the hole, the. prime mover being governed only by the load drilled and thereby a faster drilling speed may be f be compensated by an immediate adjustment in the feeding means, whereby a4 substantially constant speed of rotation of the drill stem and a substantially continuous feed thereof will be maintained.

.Another object of the invention is to provide r improved means for rotary drilling which includes a feeding means connected to the drill stem and. a counterbalance or compensating means connected to said feeding means and` exerting a torque equal to, or preferably greater, than the torque resulting from the weight of the' drill stem load, whereby said drill stem is counterbalanced; a motor connected with the feeding means for the operation of the same and serving to control the lfeed fof the drill bit into the formation being drilled, thereby eliminating the building up of a great momentum due to the weight of 'the drill stem load and thus eliminating the danger of overfeed.

A construction designed to carry out the in- -vention will be'hereinafter described, togethe with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by` reference to the accompanying drawings, in which an example of the invention is shown, and wherein: l

Figure 1 is a side elevation of an apparatus for carrying out'the improved method constructed in accordance with the invention,

Figure 2 is a plan view and electromechanical diagram of the complete device,

Figure 3 is an enlarged electromechanical diagram, and showing schematically the construction of the various portions of the electrical apparatus.

Figure 4 is an enlarged View, partly in elevation and partly in section of the worm, gear and brake, which control the feed of the draw works, and

Figure 5 is a view. similar to Figure 3, of a modified form of apparatus.

In the drawings, the numeral l0 designates the derrick floor on which the conventional drill'- ing rig is mounted. The rig includes theusual rotary table Il, through which the drill stem or string of pipe l2 extends. The drill Ybit (not shown) lis carried on the lower end of the`drill which is mounted in bearing brackets 24. As.

brackets 3 I. L

shaft. 'Ihis sprocket has connection through an.

stem and engages, or bears on, the bottom of the hole'A. The connection between the rotary table and drill stem is such that rotation of the rotary table will rotate the drill stem and the drill bit carried thereby. lEhe drill stem is freely movable vertically through the rotary toble and has its upper end secured to the usual travelling block (not shown) which is suspended by several runs of cable, the dead end of which is shown at I3. The live end I3' of the cable is wound on the ordinary draw works drum I4, and it will be seen that as' said drum is rotated to pay out the cable, the drill stem will be lowered into the hole A.

For rotating the table I I so as to rotate the drill stem and bit to perform the drilling operation, a suitable drilling engine I1 is provided. 'I'he engine has the usual admission or feed pipe I8 in which the throttle valve I9 is connected. It is obvious that adjustment of the valve I9 controls the power of the engine. The engine is provided with a driving sprocket 20 mounted on the engine shaft I1', and an 1endless chain 2I passes overv this sprocket. The chain also passes over a sprocket2 secured on a transverse 'jack shaft 23 shown in Figures 1 and 2, the shaft 23 is located substantially midway between the engine I1 and rotary table I I, but it is noted that the invention is not to be limited to any particular location of any of the parts.

When the engine I1 is operated, the sprocket 20 is rotated, causing rotation of the jack shaft 23 through the medium of the chain 2I and sprocket 22. The jack shaft also carries a second sprocket 25 secured at one end, and this sprocket is connected to the driven sprocket 28 of the rotary table II by an endless chain 21. The driven sprocket 26 is keyed on one end of the rotary drive shaft 28, which is supported in suitable bearing brackets 29. The opposite end of the shaft 28 is operatively connected to the rotary table by means of bevel gears (not shown) so that rotation of said shaft will rotate said table. It will be seen that motion is transmitted from the engine I1 togthe jack shaft 23,*and from this shaft to the rotary drive shaft 28 through the endless chain 21 and sprockets 25 and 26, whereby' rotation of the rotary drive shaft 28 andthe resultant rotation of the rotary table and of the drill stem and bit is caused b y the engine, I1. It is pointed out that the engine I1 has no governor and its speed is controlled by the load imposed upon it which load results from the engagement of the drill bit with the formation being drilled and the resistance offered to the rotation by such formation.

The draw works drum I 4 is fastened on a transverse shaft 39 which is journaled in bearing A sprocket 32 is keyed on the drum endlesschain 33 with a sprocket 34 on a transverse line shaft 34, which is rotatably supported in bearing brackets 35. It will be obvious that rotation of the line shaft 34 will rotate the drum shaft to rotate said drum' I4, or rotation of said drum will impart rotation to said line shaft.

A second sprocket 36 is secured to the line shaft 34 and an endless chain 31 passes over this sprocket and also over a sprocket 38 which is fastened on the end of the shaft 39 of a worm gear 49. The gear 40 is mounted within a suitable case 4I which also has a worm 42 mounted ony a worm shaft 43 in its lower end. The worm is iny constant engagement with said worm gear 4I). One end of the worm shaft 43 extends outwardly from the case 4I and is connected by a coupling 44 with an electric feed motor 45. It will be obvious that when the motor 45 is operated, the worm 42 is rotated to drive the worm gear 49 and rotatethe gear shaft 39. Rotation of this shaft will rotate the line shaft 34 through the sprockets 36 and 38 and endless chain 31. 'Ihe line shaft 34 will, in turn, impart rotation to the drum I4 through the chain 33 and sprockets 32 and 34.

For counterbalancing the weight of the drill stern and its associate parts, a suitable compensating means or counterbalance may be mounted at any point between the feed motor 45 and drum I4. This compensating means has been shown in the form of a multiple disk brake 46 which is mounted in an extension 4 I formed on the Worm and gear casing 4I. The brake comprises a plurality of disks 41 rigidly attached to the inside of the extended portion 4I of the case, and a plurality of revoluble disks 48 which are secured on the extended end of the worm shaft 43 which is free to undergo axial movement. It is noted that the stationary disks are alternately mounted with relation to the rotating disks.

Since the drill stem is carried by the cable wound on the drum I4, the weight of said stem will tend to rotate the drum I4, whereby the worm will tend to be rotated by said drum. With the mounting of the multiple disk brake on the worm shaft, it will be seen that the torque resulting from the weight of the drill stem and its associate parts will cause the worm shaft 43 to move axially to press the disks 48 on the worm a shaft against the stationary disks 41 secured within the casing. The brake is so constructed that the torque of its friction is sufficient to more than neutralize that resulting from the weight of the stem and its associate parts, whereby said brake acts as a counterbalance. Therefore, since 'the stem is countcrbalanced, the rotation of the draw works drum I4 to pay out the cable I3 and lower the drill stem I2 into the hole is controlled entirely by the feed motor 45. The weight of the stem is not depended upon to feed the same in the hole.

It has been the usual practice, in hand drilling, to apply a brake to the drum I4 and to intermittently release the brake, thereby permitting the drum to be rotated to pay out th cable by the weight of the drill stem. An automatic brake-of this type is fully disclosed in my former patent, hereinbefore referred to. In such structure, the Weight of the stem is depended upon to lower the same, and due to the intermittent release of the brake, the feed of the stem into the hole isx intermittent. Also, when the brake is released, the weight of the stem and its associated parts give an active acceleration to the down feed of the stem,`which results in a high velocity and great momentum. Therefore, when the brake is again applied, immediate stopping 'of the downward movement of the drill stem is impossible, the result being that the drill stem over-feeds.

This active acceleration and resultant overfeed is overcome with the structure herein disclosed by the counterbalancing of the drill stem. The multiple disk brake 46 is of such size that it serves to not -bnly reduce the downward acceleration of the drill stem to zero, but preferably to make the same negative. Further, by overcoming the downward acceleration, it is possible to accomplish a continuous feed of the drill stem in the hole which is positively controlled by the electric 'feed motor t5. The rate of the feed may be faster or slower, but is nevertheless continuous.

From the foregoing, it will be seen that the engine drives the rotary table il through the chains 21A and 21, jack shaft 23 and drive shaft 28. 'I'he enginehas no governor and its speed is controlled only by the load imposed upon the drill bit, which load results from the resistance offered by the formation to the rotation of the bit. The-downward movement of the dril stem l2, or the feed'of said stem into the hole, is

controlled by the electric feed motor 45. If said motor operates at a faster speed, the drum I4 is rotated faster to pay out cable at a faster Similarly, if the feed motor slows, then the cable pay-out is lessened and the stemV is fed into the hole at a slower rate. The weight, or pressure,'of the bit on the bottom of the holeA is, of course, regulated by the rate of feed of the stem, relative to the rate at which the bit digs od.

For varying the speed of the electric feed mo- VAtor t5, which positively controls the draw works drum M, an electrical control generator 50 is provided (Figure 2). The armature shaft 5i of this generator is connected by a coupling 52 and ydriven by the shaft 53 of a feed generator t. This shaft 53 of this latter generator has a sprocket 55 on its outer end and this sprocket has a driving connection through an endless chain 56 with a sprocket 51 secured on the jack shaft 23. l

As has been explained, motion to the rotary table Il and drill stem l2 from the drilling engine' l1 .is transmitted through the jack shaft 23. Therefore, since the armature shaft 53 of the feed generator is connected with the jack shaft, it will be seen that the speed of the feed and control generators are controlled by the engine l1'. The feed generator 54 is electrically connected' with and drives the feed motor 45,

whereby the speed of said motor iscontrolled thereby. The worm 42, which is driven by said motor 45, regulates the paying out of the cable, and therefore, due to the connection of the parts as shown, it will be seen that the speed of the feed motor 45 and resultant pay out of the cable to feed the drill stem, is regulated according to the speed of rotation of the bit and stein, as transmitted to the jack shaft 23.

In drilling, the drill bit must perform two functions, first, it must penetrate the formation and, second, is must remove the material by a shearing or cutting action. The penetration of the bit is caused by the weight of the bit on the bottom of the hole, whilethe cutting or shearing is produced by the rotative power applied to the bit. If the penetration of the bit is too` deep, the resistance offered by the formation to the rotation of the bit is so great that the speed of rotation of the drill bit is -reduced,

` ythereby reducing the power input to the bit,

with a corresponding retarded rate of drilling, or else the rotation of said bit and stem may (rpbe stopped altogether by the deep penetration,

and a hang-up results.l On the other hand, if the penetration is not deep enoughfthere` is not suicient resistance to the rotation and the bit will rotate without properly performing its cutting or shearing action, which results in a reduction in the-rate of drilling. Thus, it is evi- .dent that for.maximum speed of drilling, the lpenetration ofthe bit must be neither too great nor too small.

Due to the various characters of formations vice versa;

. tained. That is, as the character of the forma-- tion changes, the weight ,on bottom must change to attain the proper penetration.` When drilling in a hard formation, the weight on bottom must be greater than in a soft formation and therefore, the weight on bottom must vary according to the formation being drilled, and this weight must be more or less inversely proportional to the hardness of the formation. In addition to the proper penetration, itis imperative, in order to attain the maximum rate of drilling, that the power input to the' drill bit be maintained substantially constant and preferably at the maximum allowable,

irrespective of the character of the formation through which it is passing. Since the power of the drilling engine, at a fixed position of the throttle, varies with its speed, it is obvious that constant speed of rotation of the bit, together with proper penetration is necessary to fastest to the speed of rotation of the-drill stem and bit through the jack shaft. In describing the operation of the electrical apparatus employed;

-reference is made to Figures 2 and 3, wherein a wiring diagram is shown. The several pieces of electrical apparatus which are employed are, with slight modification, standard equipment, and therefore, they have not been illustrated in detail. However, their main working parts have been illustrated and a brief description thereof is herewith given. For the sake offclarity the entire electrical hook-up will first be described, after which the various circuits will be set forth.

As has been stated, an electric feed motor 45, feed generator 54 and control generator 50 are provided. For exciting the fields of the motor and generator, a constant voltage direct current excitor generator 50 is provided, (Figure 3). This generator maybe either engine or motor Referring now in detail to Figure 3, it will be seen that the control generator 50 has an armature 6| which has one of its terminals connected to a binding post 62 by a lead wire Gla, and its other terminal connected with a binding post 63 by a wire Gib. The field 64 of this generator ,has one side connected by a conductor 64a with a binding post 65, while its other side is connected by a Wire 64b with a post 66.

The feed motor 45 is provided with an armature 61. one terminal of which is connected by a wire 61a with a post 68, while its other terminal is connected by a wire `61h to a terminal 69. The eld 10 of'this motor has one side connected with the binding post 66 by `a wire '1|Ja..A

, binding post 14, and its other terminal connected by a wire 13b 4with a binding post 15. l

'I'he exciter generator 60 is provided with an armature 16, one side of which is connected by a wire 16a with a binding post 11, the. other side of said amature being connected with a post 18 by a wire 16h. The eld 19 of this generator has one of its terminals electrically connected by a wire 19a to the post 11 ,while the other terminal thereof connects by a wire 19b with the binding post 18. A conductor 80 extends from the binding post 18 to the post 66, whereby one side of the exciter generator is electrically connected to one side of the field of the control generator through the wire 64b, and also to one side of the eld of the feed motor through the wire 10a. The other side of the exciter generator is connected to the other side of the field 10 of the feed motor by a conductor 8| which leads from the post 11 to the post 1|, to which the field 10 is connected by a Wire 10b.

In order to connect this side of the exciter with the other 'side of the field 64 of the controlr generator, a conductor 82 leadsfrom the binding post 1| to a binding post 83. 4A'variable resistance 84 is arranged to connect the post 83 and binding post 65 which latter is connected by a wire 64a with the field 64 of said control generator. The resistance includes a handle 85 (Figure 2) rigidly attached to a pivoted lever 86, which is adapted to move along an electrical resistance 81. The inner end of the lever is electrically connected with the post 83,.-while the resistance 81 has one end connected to the post 65 by a wire 81a. Thus, it will be seen that current passing through the conductor 82 must pass through the resistance to reach the field of the control generator 50.

From the above, it will beV seen that opposite sides of the fields 64 and 10 on the control' generator and feed motor are electrically connected to opposite sides of the exciter generator, whereby said fields are excited thereby. The eld 13 of the feed generator is also connected with and excited by said exciter generator but is connected through a reversing switch 88, and controller 90- the details of which will be described later.

As has been hereinbefore stated, the armature 12 of the feed generator 5l is rotated by its shaft which carries the sprocket 55 (Figure 2), whereby said generator is operated by the rotation yof the jack shaft 23. The operation of the control generator 50 is, of course, also controlled by the jack shaft because its armature shaft 5| is connected by the coupling 52 with the armature shaft of the feed generator. The actuation of the feed 'motor 45 1s controlled by the feed gen- 4wire 9|a to the binding post 83 which has connection by wires 82 and 8| to post 11 which con-- nects to one terminal of the exciter generator 60. The other terminal of the solenoidisfconconnected. Of course, energization of said solenoid electrically disconnects the contacts.

relieve the pressure. the resistance ||9 is connected by a wire |09a The contact 91 has a lead wire 91a which is connected with the binding post 68 to which one side of thearmature 6| of the control generator is connected. A conductor 98a leads from the Contact 98 to one side of a solenoid 99 lwhich forms a part of the controller 90. 'I'he opposite side of the solenoid 99 is connected by a conductor 99a with the binding post 62 to which the other side of the armature of the control generator 50 is connected. From the above, it will be seen that with the solenoid 92 de-energized, current will flow from the armature 6| of the control generator to the solenoid 99 of the controller, and as the output of said generator varies according to the speed of the jack shaft 28,'the magnetic attraction of said solenoid 99 is varie When the solenoid 99 is energized, it is adapted to attract oneend of an armature bar |00 which is pivotally mounted on a pivot pin |0|. The other end of the bar carries a counterweight |02 which -is adjustable thereon. This end of the bar also has a rod |08 pivoted thereto and the lower end of the rod carries a. piston |04 which is slidable within a cylinder |05, so as to form a dash pot and suitably dampen the movement of the bar. 'I'he cylinder has an opening |06 in its lower end and the size of this opening may be varied by a needle valve |01, whereby the speed of movement of the piston may be regulated. v

"`end of the bar which is arranged to be attracted by the solenoid 99, has an insulated bar |08 pivoted thereto. The lower end of this bar carries a pair of coiled springs |08' which engage terminals |09 and ||0 which rest on the carbon pile resistances H3 and IH. The lower ends of these resistances are connected to each other by a wire H5. The resistances 3 and IM are arranged to decrease when the solenoid 99 attracts the bar |00 so as to increase the pressure on said resistances. Similarly, the resistances increase as said bar moves away from the solenoid 99 to The contact |09 carried by with the post 18 which is connected with one side of the exciter generator, while the contact |I0 is connected by a wire ||0a with a binding post H6.

It will be evidentithat the power output of the control generator 50 regulates the energization of the controller solenoid 99. This solenoid controls the swinging of the armature bar |00, which in turn increases or decreases the resistances ||3 and IM.

As was above stated, the ileld 13 of the feed generator is excited by the exciter generator through an electrical reversing switch 88. Also the resistances ||8 and ||4 are connected in the feed generator circuit so that variation of these resistances will vary the power output of the feed generator 54 to vary the rate of feed of the bit into the formation.

The reversing switch 88 includes an actuating arm |20 which is pivoted to swing on a pin |2|. 'I'he upper end of a rod |22 is pivoted to one end of the arm |20, while the lower end of the rod v|22 is pivoted to the end |08 of the amature bar |00 of the controller, whereby when said bar is' swung, through energization of the solenoid 99, the actuating bar |20 is also swung.

The opposite end of the actuating bar |20 has a rod |26 slidable theret ough and the bar has insulated cross bars |21 an `|28 at its upper and lowe'r ends. 'Ihe rodis providedwith collars |28' 75 'i arcaico thereon, and coiled springs |23' surround the rod post H3, which post is connected to the contact i3 of the carbon pile resistance ||3. The contact |33 is connected by a wire |3|la with the ybinding post I3 which has connection with one side of the ileld '|3 of the feed generator, A wire |3|a connects the contact|3| with the post 13, which postV is connected to the other side of Ithe eld of the generator 53.

The upper bar |21 of the rod |26, carries a pair of contacts |33 and |33. 'Ihe contact |33 is connected by a lead wire |33a with one side of a resistance |35, and the opposite side of this resistance is connected by a wire '|33a to the binding post '|8 which leads to one side of the exciter generator. The contact |33is directly connected by a lead wire |33a with the post T5. The contacts |33 andY |33 are arranged to frictionally engage contacts |36 and |311, the former having connection by a wire |36a with the binding post 33, while the latter is connected by a wire |3f|a with the conductor `3| at the point |32.

Under normalV operation, the rod |26 is in a lower position with the contacts |28 and |23 frictionally engaging the contacts |33-and |3|.

However, ifthe armature bar |33 is swung, it will be seen that the arm |23 is also swung. Due to the frictional engagement of the contacts |23 and |23 with the contacts |33 and |3|, and also due to the springs |23', the arm |2||must move a predetermined distance, that is until the upper spring |23 is under sucient pressure to break the frictional engagement of the contacts. When this occurs, the arm is swung to the opposite direction to engage the upper contacts |33 and |33 with the contacts |33 and |33. A similar action takes place on the reverse actuation of the arm |23.

Assuming the contacts |23' and |23 are in engagement with the contacts |33 and |3|, the field '|3 of the feed generator is excited bythe exciter generator 6B. The current flows from the generator 33, through the conductor 3|, to the point |32, through the wire |22a, through con-A tacts |23 and |33, wire |3311, post '|3,'wire '33a to the eld 73. The current then passes through the wires '|311 and |3|a to contacts |3| and |23, then through wire |2911,post H3, wire ||||a, con-- act through the resistance 3, wire ||3 and resistance ||3, contact |09, wire |39a, post 'i3 and then through wire 1Gb to the other side of the exciter generator 6U.

oi.' will aifect the excitation of the field 13 of the feed generator to increase or decrease the power output of said generator. Since this feed generatorcontrols the feed motor, it is obvious that the speed of said motor is regulated by the re-l sistances H3 and H4 which, in turn, are controlled by the energization of the solenoid 99 of the controller. This solenoid is energized by the power output oi' the control generator 50, which is actuated by the jack shaft 23.- .Igherefore, .it

4 Since the resistances H3 and ||4 are connected directly in this circuit, it is obvious that an increase or decrease there-v is obvious that the speed of the jack shaft regulates the speed of the feed motor. and since the speed of the jack shaft variesin accordance with the load imposed on the drill bitpassing `through the formation, it is manifest that the speed of the feed motor 35, which regulates the feed of the cable from the draw works drum |3,

`is regulated in accordance with the formation being drilled. I

As has been stated, in normal operation `the rod |23 of the reversing switch is lowered as shown and the field 33 of the feed generator is excited as above set forth. However, when the actuating arm |23 is swung oppositely by increased swinging of the armature bar |03, then the contacts |23' and |23 at the lower end of the rod are disengaged from the contacts |33 and |3|,` while the contacts |33 and |33 at the upper end oi said rod engage the contacts |33 and |3'|.'.

In such event, the electrical current owing from the exciter lgenerator B3, passes through the conductor 3| to the point |32, then through the wire |3'|a, through the contacts |33 and |33,

through the wire |33a to the post l5, and then y through the wire |317 to one terminal' of the field 'H3 of the feed generator. vThe current then flows through the field, through wire 13a, post 113, Wire |3311, contacts |33 and |33, then through wire |33a, resistancey |33, wire |3311, post '|3 and finally throughwire '|311I to the opposite side of the generator 33. Thus, it is seen that the terminals of the generator till are connected to the reverse sides of the eld '|3 to cause the generator to reverse the direction of its current output, thereby operating the feed motor in a reverse direction to cause the motor to rotate the draw Works drum |3 so as to wind, instead of unwind, the cable i3 around said drum and thus lift the drill stem. Y

To control energization of the solenoid switch 3|, which latter interrupts the ilow of current bef tween the control generator 53 and the solenoid 33 of the controller 33, a time delay device |33 is employed. This device includes a solenoid 3| which when energized, attracts an arma,- ture |32 carried on one arm |33 of a pivoted bell 'crank |33. The other arm |33 of said crank is connected by a link |33 with a pivoted bar |33. This bar carries a gear segment |33. It is obvious that when the .solenoid is energized, the bell crank is swung which actuates the bar |3`| to swing the segment. When the solenoid |3| is del-energized, a counterweight '|33 returns the bar |37 to its normal position.

The segment |33 is in constant engagement with a gear wheel |33 which is attached to a larger gear by a ratchet connection (not shown) which permits the wheel |53 to rotate reversely without rotating the large gear E The gear |5| is in constant engagement with a smaller gear |52 which is rigidlyv attached to a ratchet wheel |53. An escapement mechanism |53 engages the ratchet wheel 1 and this escapement carries a pendulum |55 which has Weights |56 adjustably secured thereon. By adjusting these weights, the periodicity of the swinging movement may be varied,which varies the length of time required for the segment to swing from one extreme position to another. The. intricate details of the time switch are intentionally omitted as this is a standard switch which may be purchased on the open market. The General Electric switch bearing catalogue ,number Cr 2953-3 has been found suitable.

The ,pivoted bar Il-'l has a non-conductor rod |51 connected to one of its ends as shown and this rod carries aaconductor plate |58 at its lower end. 'I'he plate has a pair of contacts |59 and |60 which are arranged to engage contacts I6I The contact I6| is connected by a wire I6Ia.I

with the binding post 93, which, it willbe remembered,'is connected to one side of the solenoid 92. -The other contact |62 is connected by a wire |620. to the binding post 18 which is connected with the exciter generator. Therefore, when the solenoid I4I is energized to engage the contacts |59 and |60 with the contacts I6I and |62, an electrical circuit to the solenoid 92 is completed to energize this solenoid. Energization of the solenoid 92 will attract its armature 94 to disengage the contacts 95 and 96 from the contacts 91V and 98 which breaks the circuit between the control generator and solenoid 99 of the controller to render both inactive. When the solenoid 99 is de-energized the armature bar |00 is swung away from the solenoid which causes the resistances II3 and II4 to increase to stop the feed motor 45 and thereby stop the feed of the drill stem I2. Itis noted that under normal conditions, the solenoid I4I of the time delay is deenergized, in which case. the solenoid switch 9| is holding the circuit to the solenoid 99 closed.

For energizing the solenoid |4I of the time delay, a pressure controller |63 is provided. This is a conventional apparatus and includes a pointer |64 which has an electrical contact |65, said' A'contact being insulated from the pointer.

` This contact is connected by a wire I65a with one side of the solenoid I4|. The other side of the solenoid is connected by a wire .I4Ia to the wires I62a which leads to the post 18.

The pointer |64 is rigidly secured on a pivot pin |66 which is operatively attached to a Bourdon tube (not shown) so as to be rotated by pressure variations in a tube |61 (Figure 2) which communicates with the Bourdon tube. A block IIiiy has a toothed segment |69 concentric with the pivot pin |66, and this segment is in lconstant engagement with a pinion |10l which is secured on a pin having a hand knob I1I on itsV outer end. On one side of the block |68, an arm or second pointer |12' is pivoted and a coil spring |13 has one end secured to the pointer and its other end fastened to the block, whereby said spring exerts its tension to hold the pointer in engagement with the block. Thus, the position of the arm or pointer |12 with relation to the dial |14 may be readily varied by rotating the knob I1I and changing the position of the block. The arm |12 is provided with an insulated contact |15 which is arranged to engage the contact |65 of the pointer |64 when said pointers `move into engagement with each other. The contact |15 is connected by a wire `I15a with the binding post 11 which has connection with the exciterl generator 60. It is obvious from the above that the pointer |12 is manually adjustable while the pointer |64 is ,moved or swung by the pressure within the tube |61. When the contacts of the.

,l through the post 11, through wire I15a, through the contacts |15 and |65, and then through the wire I65a to one side of the solenoid I5I. Then from the other side of the solenoid through the wire I4 la through the wire |62a, post 18, and then through wire 16b to the other side of the generator 60, whereby the solenoid I4I is energized. Therefore, this solenoid is energized only when the pointers |64 and |12 have their contacts engazing.

For varying the pressure in the tube |61 to swing the pointer |64, the tube |61 is connected to a translating device |16 (Figure 2) which is engaged with the dead end I3 of the cable carrying the drill stem and which device is responsive to the variations in the tension of said cable. The

details of the translating device are clearly shown,

in my former Patent No. 1,766,782, issued on June 24, 1930.` Suflice it to say, therefore, that as the tension on the cable decreases, the pressure in the tube |61 decreases, which causes the movable needle |64 to move toward the adjusted or. stationary needle |12. If this tension decreases sufflciently, the pointerswlll move to engage their contacts, which will close the electrical circuit to thesolenoid I4 I, as has been explained.

In operation, the power to be delivered by the drilling engine I1 is determined bythe adjustment or setting of the admission valve I9 in the line I8. Operation of the engine rotates the jack shaft 23, which, in turn, drives the rotary table I I to rotate the drill stem I2 and bit, as has been explained. The engine is ungoverned except by the load imposed on the drill bit, and therefore, a fixed amount of power is delivered by said engine so long as its speedremains constant.

The exciter generator 60 excites the fields of the feed motor 45, feed generator 54 and control generator 50. The jack shaft 23 drives the feed generator 54 and since its field is excited by the exciter generator, said feed generator delivers power to the feedv motor because of its connection with said motor through the leads 12a and 61a and 12b and 61h. Thus, the feed motor is actuated which drives the worm 42, andtherefore, the draw works drum I4 is rotated to pay out the cable and thereby lower the drill stem I2 into the hole, which feeds the bit into the formatlOIl.

'I'he resistance oiered by the formation to the rotation of the bit determines the load on the engine I1 and thus, governs its speed. If the resistance increases, thereby increasing the load, the speed of rotation of the bit will decrease, whereby the engine speed is decreased. This decrease will cause a decrease in the speed of rotation of the jack shaft'23, which decrease will be transmitted to the feed generator 54 and the control generator 50 to slow up the same.

Reduction in the speed of thefeed generator 54 will reduce its power output, and this will result` in a decrease of the speed of the feed motor; also, the reduction in the speed of the control generator 50 will reduce the energization of the coil 99 of the controller 90 and thereby increase the resistances I I3 and I I4 in series with the field 13 of the feed generator 54, thus further decreasing the` speed of the feed motor 45. As a result, the draw works drum I4 will be'rotated at a slower rate which reduces the rate of downfeed of the drill stem. This reduction in the rate of down feed will reduce the load on the drill bit, which reduction will be reflected by a decreased load on the engine. As soon as the engine load `is. decreased the jack shaft 23 will again be mation which increases the load, the feed motor' is immediately slowed down to reduce the rate of feed of the drill stem until such time as the drill bit again attains its original speed of rotation.

If, on the other hand, the drill enters a formation where the load on the drilling engine is reduced, said engine will be speeded up. This increased speed of the engine increases the speed of the jack shaft 23 which increases the power output of the feed generator 54 to increase the speed of the feed motor also, this increases speed of the control generator which causes increased energization of the solenoid 99, whereby the resistances I3 and ||4 in series with the field 13 of the feed generator are decreased, which furlther causes speeding up of the feed motor. The resultant increase in the speed of the motor increases the rate of down feed of the drill stem |2 which immediately increases the load on the` engine 1, whereby said engine is slowed down to its original normal speed. Therefore, it is manifest that irrespective of the character of formation throughwhich the drill is passing, the speed of the drill bit is maintained substantially constant by varying the rate of feed of the drill stem.

' In drilling, part of the weight of the drill stem 2 is supported from above by the travellling block (not shown) while the remainder of this weight is supported' on the bottom of the hole. Thus, the upper part of the stem is in'tension, but the lower part having a length whose weight is equal to the weight With'which the bit presses onthe bottom of the hole is in compression. As

the weight .of the 'bit on bottom increases, they length of drill stem which is in compression increases, until nally a'length so great is had that this portion of the stem buckles, in which case a crooked hole results. The revolution of the drill stem in a crooked hole results in fatigue failure, or twist-offs due 'to the back and forth bending which follows when said stem is rotated in a' crooked hole. To remove from the Well parts which have been so broken off involves a great deal of expense and often results in the loss of the well.

To avoid this expense, and hazard, it is necessary to limit the weight of the bit on the bottom to such extent that the drill stem |2 will not buckle. 'Ihis is automatically accomplished by means of my controller and its associate parts.

With the bit olf the bottom of the hole, the movable pointer |64 of the pressure controller |63, indicates the total weight of the drill stem.

. The stationary pointer |12 is then set at an amount less than this total weight, this difference being equal to the maximum weight of the bit on bottom that will be allowed. For example, if the pointer |64 indicates 50 tons with the bit off of bottom and the maximum weight of the 'bit on bottom is to be limited to 3 tons, then the pointer |12-is set at 50 less 3 tons or at 47. The drilling equipment is then put into Ioperation and the bit feeds down. As the `bit presses on bottom, the weight on the hook is reduced and as a result the pointer |64 lowers on the dial. Should it ever lower as'much as three points, the contact |65 goes into circuit closing engagement with the contact |15 of the pressure controller with the result that the solenoid 4|` is energized drawing the armature |42 towards it and causing the convmotor is operated in the opposite direction.

and after a certain interval, the contacts |59 i and |69 engage the contacts |6| and |62 and thus cause the solenoidv 92 to be energized. The energizing of the coil 92 causes the contacts 95 and 95 to separate from the contacts 91 and 98 opening the circuit which energizes the solenoid 99'of the controller 90 and causing the switch 88 to go into the reversing position to cause the feed motor 45 to lift the drill stem and thus to relieve the weight of the bit on the bottom of the hole. But as soon as the weight of the bit on the bottom of the hole is again less than the limit set, the contacts |65 and |15 again separate, de energizing the coil |4| and the contacts |59 and and contacts |6| and |62 again separate due to the action of they counterweight |49 of the timing mechanism with the result that the solenoid 99 is again energized, which returns the reversing switch 88 to its original Aposition so that the feed motor operates to feed the stem doWn-' wardly. It is pointed out that when the switch 88 is `in a reverse position, the resistances ||3 and H4 are not in the circuit of the field 13 of the feed generator but the xed resistance |35 is in the circuit. The purpose of this resistance is to cause the feed motor to operate at a predetermined rate of speed whereby the drill stem is lifted at a predetermined rate. It is pointed out that the time delay prevents the solenoid 92 from being energized by the momentary engagement of the contacts and |15 which may be caused by bouncing of the bit.

The construction of the controller 99 and its associated parts is such as to prevent the bit from hanging up. When the load of the engine reaches a predetermined amount, due to reduction in speed of the drill stem, the solenoid 99 of 'power output of the control generator 59, due to the reduced rotation of the jack shaft 23. Thus, the bar |00 is swung sufciently to increase the resistance of the carbon pile to the maximum, whereby the yspeed of the feed motor 45 is reduced to zero. Any further reduction in the speed of the stem |2 permits further swinging of the armature bar |80. This additional swing of the bar, swings the actuating bar |20 to swing the switch 88 to a reverse position so that the feed It is noted that the springs |20 and the frictional engagement of the contacts permits the bar to be swung a predetermined distance before actul ating the reversing switch, after which time the switch is snapped into reverse position.

When the motor 4 5 is operated in the reverse direction, the drill stem is hoisted whereby the bit is freed sufficiently from its engagement with the formation so as to permit the speed of rotation of the bit to again increase. As soon as this increaseoccurs the reversing switch is returned 'to its normal position to operate the motor 45 so as to again feed the stem l2 downwardly. It is pointed out that the switch 88 may be operated either by the pressure controller |63,A or bythe controller 90. In "either case, it serves to hoist the drill stem.

Froml the-above, it win be obvious'that withl the improved method herein-set forth, the speed of rotation of the drill bit is maintained substantially constant, irrespective of the character of formation through which said bit is drilling. The

controlled in accordance with the load imposed on the drill bit in rotation, and since this feed is positively controlled by the feed motor 45, a continuous feed is had. All danger of the bit hanging up, or being stopped in rotation due to too gre'at a resistance, is eliminated by means of they reversing mechanism. By means of the pressure controller |63, excess weight which causes the drill stem to buckle, resulting in crooked holes and twist-offs, is prevented. By means of the time delay apparatus, it will be obvious that bouncing of the bit which may occur during drilling will not affect the normal operation of the entire apparatus. Therefore, it will be seen that the i'mproved method permits constant speed of rotation of the drill bit, whereby the maximum allowable power may be delivered to the bit which greatly increases the speed and economy of the drilling.

It is pointed out that the reversing switch 88, which raises the drill stem I2 in the event that there is an excess weight on bottom of the bit, or too deep penetration, may be eliminated. In such case, the electrical hook-up would be as shown in Figure 5. By observing this iigure and comparing it with the wiring diagram Figure 3, the differences in the hook-up may be readily seen. When the switch is eliminated, the field 13 I of the feed generator 54 has one terminal connected by a wire 13o `to the conductor 8| at the point 8|'. -The otheJterininal of the field 13 is connected by a wire 13d with the terminal or binding post I I6, which post is connected by the wire ||0a with the contact ||0v which is carried by the resistance |I4. With this arrangement,-

it will be obvious that the reversing switch and its associate wiring is entirely eliminated. The field 13 of the feed generator is then energized in the following manner: The current flows from one side of the exciter generator 60 through the conductor 8| to the point 8|', then through the wire 13e to the eld 13. From the field 13 the electrical current passes through the wire 13d to the binding post I6, through a wire I I0a, Contact I I0, through t'ne resistance II-3, wire ||5 and resistance H4, then through contact |09, through wire |09a to the binding post 18, from which post the current passes through the wire 16h to the opposite side of the exciter generator 6|). In this way it will be obvious that the`field 13 of the feed generator is constantly excited by the exciter generator. 'I'he operation of the other parts when the reversing switch has been eliminated. is exactly as -has been described.

It is further notedthat although it is most desirable to utilize the time delay switch |40, it is possible to eliminate this switch. For purposes of illustration, this switch has been eliminated in Figure 5. In such case, the solenoid 92 of the solenoid switch 9| is directly connected and arranged to be energized by the engagement of the contacts |65 and |15 on the pointers |64 and |12 of the pressure controller 9|. A lead wire |80 has one end connected to the contact |65 and leads to one side of the so1enoid92.' The other side of the solenoid is connected by a Wire |8I with the binding post 18 which leads to one -side of the exciter generator. When the contacts |55 and |15 move into engagement with each other, it will be seen that the current will how from one side of the exciter through the wire 16h, post 18 y and through the wire |8| to the solenoid. From the solenoid the current will flow through the wire |80 to the contact |65, through the contact |15, through a wire |1511, and finally through the post 11 and wire 16a1tothe other side of the exciter generator. Thus, it will be seen that when the time delay switch |40 is omitted, the energization of Athejsolenoid 02 is controlled directly by the contact en the pointer of the pres' sure controller |63. It h'as been found that this structure will operate, but. it is more desirable to have the time delay switch because many times the contacts of the pointer move into engagement with each other due to bouncing of the bit and in such case it would not be desirable to actuate the solenoid 92. However, such cases are not very frequent and the apparatus will operate without said switch.

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

1. A well drillingapparatus including, a restrainedly suspended drill. stem having a drill bit at its lower end vin the well, a prime mover.

for rotating the drill stem and governed by the load imposed upon it by the drill bit rotating through the formation, means actuated by the prime mover for releasablyfeeding the drill stem downwardly as the hole is drilled, drill stem weight self-applied brake means associated with the feeding means for,- counterbalancing the weight and decelerating the downward movef ment of the drill stem so as to prevent said stem over lfeeding by gravity, and time controlled means for automatically reversing the operation of the feeding'means to hoist the drill stem and bit when the drillingload on said bit exceeds a predetermined point.

2. A well drilling apparatusincluding, a hoisting and lowering drum having' a cable wound partially thereon from one end, the cable carried movably over a support, and a drill stem suspended from the opposite end of the cable, said stem having a. bit at its bottom to drill the hole, a prime mover for continuously rotating the drill stem, a retainable feeding device including a worm wheel geared to said drum whereby the one is rotatable by the other, a worm screw engaging said worm wheel, a brake on the shaft of said worm screw and constantly set in effective braking condition by endwise movement of the shaft brought about by the weight of the drill stem tending to unwind its' supportlng cable from the drum, and a feed motor for continuously rotating said worm screw shaft, said motor being actuated by electrical controlling elements coordinated with the prime mover whereby variations in the speed of the drill stem is refiected in the feed controlling means and the feeding of the drill stem is continuous but varied proportionately to the change in-.character of the formation being drilled and the stem is rotated continuously at substantially a constant speed.

3.1The apparatus as set forth in claim 2 and further including means time delayed in operation for automatically reversing the feed motor to operate the drinn to lift the drill stem when the drilling load on said bit inthe formation reaches a predetermined point.

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