US3007534A - Electric cable drum for rotary drilling - Google Patents

Description

Nov. 7, 1961 Filed July 16, 1958 l. S. SALNlKOV ETAL ELECTRIC CABLE DRUM FOR ROTARY DRILLING 4 Sheets-Sheet 1 IVAN s. SALNIKOV RICHARD L. CANNADAY 'NVENTQRS BY ATTORNEY Nov. 7, 1961 l. S. SALNIKOV ETAL ELECTRIC CABLE DRUM FOR ROTARY DRILLING Filed July 16, 1958 FIG-2 4 Sheets-Sheet 2 T/wo |2 ISO '58 L IVAN S. SALNIKOV INVENTORS RICHARD L. CANNADAY BY Q 7 ATTORNEY Nov. 7, 1961 l. s. SALNIKOV EI'AL 3,007,534

ELECTRIC CABLE DRUM FOR ROTARY DRILLING Filed July 16, 1958 4 Sheets-Sheet 3 z N 2 I80@ 0 v we N s. SALNIKOV FIG-3 HARD L. CANNADAY 'NVENTORS BY 7 ATTORNEY Nov. 7, 1961 l. s. SALNIKOV ETAL 3,007,534

ELECTRIC CABLE DRUM FOR ROTARY DRILLING Filed July 16, 1958 4 SheetsSheet 4 no (as:v us 7 100 j FIG-4 FIG-5 IVAN s. SALNIKOV RICHARD L. CANNADAY INVE'WQRS BY "(z/u t2 7 W ATTORNEY United States Patent C) 3,007,534 ELECTRIC CABLE DRUM FOR ROTARY DRILLING V Ivan S. Salnrkov, Scarsdale, and Richard Lee Cannaday,

New York, N.Y., assignors to Jersey ProductionflResearch Company, a corporation of Delaware Filed July 16, 1958, Ser. No. 748,869 12 Claims. (Cl. 175-104) This invention relates to drilling apparatus for deep bores such as oil wells. It relates particularly to drilling apparatus for performing the operation known as rotary drilling. It relates more particularly to rotary drilling apparatus in which the actual cutting elements are driven by electrical means, and it relates more particularly still to rotary drilling apparatus in which the cutting elements are driven by electrical means which are positioned immediately adjacent the cutting elements at the bottom of the hole being drilled.

In present day practice the drilling of a large proportion of bore holes in the earth for the production of crude petroleum from underlying oil-bearing strata is accomplished by a technique known as rotary drilling. In this technique a drill pipe string provided with a bit at its lower end is run into the full length of the bore hole. All elements of the drill pipe string'except for the upper most one are usually of circular cross section. The uppermost element known in the art as a kelly or grief stem is of non-circular'cross section, for example, square or fluted. The kelly has a sliding flt in bushings of' a rotary table located on the drilling platform at or above the earths surface. This table is driven through a gearing arrangement by a conventional primemover such as a steam or internal combustion engine.

As the rotary table is driven by the prime mover, the table bushings impart a torque to the non-circular kelly which is transmitted to all lower elements of the pipe string and finally to the drill bit. Then as-the drill bit realizes a cutting effect to deepen the hole, the entire pipe string is free to descend deeper intothe earth because of the sliding fit of the kelly in the bushings of the rotary table. During the course of these operations a drillingfluid commonly known as drilling mud is circulated down through the drill pipe, around and across the cutting elements of the drill bit, and back through the annulus between the drill pipe and the wall of the hole to lubricate any cutter hearings in the drill bit, remove heat and flush debris generated in drilling, and to seal the hole.

In the course of research for improved drilling methods it has been proposed that the driving means for the cutter elements be located immediately adjacent these elements instead of at the earths surface as is the case with the conventional rotary table mechanism described above. Among the proposals have been several calling for an electric power consuming means coupled directly to the cutter elements. This means might comprise a motor to drive cutters of conventional design, or it might comprise a transducer for employment in a magnetostrictive drilling technique. Whether this means be a motor, a transducer used for magnetostriction, or any other electric device, however, the problem of power supply to this means at the bottom of a bore hole must be met.

In general two possibilities exist for supplying power to an electric device at the bottom of a bore hole. One is to employ batteries which are packaged directly with the power consuming device. An example of such arrangement may be seen in U.S. Patent No. 2,643,087 to H. I. Ogorzaly et al. issued on June 23, 1953. Ogorzaly discloses a self-powered rotary drilling apparatus which dispenses with any pipe string from the earths surface.

3,007,534 Patented Nov. 7, 1961 have to be spliced or parted at theearths surface each The other possibility, and the one with which this invention is concerned, is to employ an electric cable running time that a pipe element is added to or removed from the drill string. Not only will the making and breaking of joints in the cable represent added steps in the procedure of lengthening or shortening the string, but also the very presence of such joints will introduce points of potential weakness in the cable itself.

This leads directly to consideration of the second disadvantage likely to obtain with a cable inside a pipe string'which is that the cable may be supported only at its upper end. Considering that bore holes for petroleum production may extend thousands of feet into the earth, it is evident that a cable of such length hanging under'its own weight will be highly stressed in tension near the earths surface and that there will be a strong parting force on any intrinsically weak or poorly made cable joints. Rupture of any joint with consequent loss of power for drilling would be a serious matter. Even if, contrary to the assumption stated previously, the cable connection with the power consuming device be of a sliding nature which allows the cable to be completely reeled out of the pipe string whenever pipe sections are to be added or removed whereby the cable may be continuous rather than jointed, there will still be potentially dangerous self-stressing in the cable body material.

According to this invention the foregoing disadvantages and difficulties in providing electric power at the bottom of a bore hole by means of a cable running inside of a drill pipe string are substantially avoided by extending the cable downward outside of the pipe string, that is, in the annular space between the pipe string and the bore wall. In'this case the cable may be paid out and reeled in as a continuous member without regard to addition or removal of pipe string elements, due provision being made to prevent the cable from becoming wrapped around the pipe string as the latter is rotated. Likewise, if local support of the cable along the pipe string be desired, simple, quickly released strap or clamp means may be applied to bind the electric cable to the pipe string as the string is lowered into the earth. I

It is a principal object of the present invention to provide a method and means whereby an electriccable may be extended down a bore hole in the annular space between a rotary drill pipe string and the bore wall.

Within the aforestated principal object, it is a particular object of this invention to provide a method and means whereby an electric cable may be extended down a bore hole linearly with a pipe string; that is, without becoming wrapped around the pipe string as the latter is rotated.

Within the aforestated principal object it is a particu-.

lar object of this invention to provide a method and means whereby an electric cable may be evenly unwound from a drum as it is paid out to enter a bore hole with a pipe string being lowered, and be evenly rewound onto this drum as it emerges from the bore hole upon withdrawalthe derrick floor on which a rotary table of substantially conventional design is supported.

These and other objects may be perceived and a fuller understanding of the present invention obtained by re ferring to the following description and claims taken in conjunction with the accompanying drawings in which:

FIG. 1 represents a partially sectioned elevation view showing a rotary table mounted on a derrick floor, a kelly passing through the rotary table, the cable drum of this invention with its winding flyer, and the sleeve providing support for the drum attached to the underside of the rotary table.

FIG. 2 represents a partially sectioned elevation view in axial continuation of FIG. 1 showing the stroking mechanism for the cable drum flyer and the blow out prevention and drilling fluid control means at the upper end of a bore hole.

FIG. 3 represents a partially sectioned elevation view in axial continuation from. FIG. 2, some intermediate length of pipe string being omitted, showing the lower end of a drill pipe string in a bore hole, an electric motor. attached to the pipe string, and cutter elements driven by the motor.

FIG. 4 represents a view taken in section along line 44 of FIG. 1 showing the ratchet means whereby the cable drum may be driven in the direction of normal motion of the rotary table.

FIG. 5 represents a view taken in section along line 55 of FIG. 1 showing details of the flyer cable snugger whereby the cable from the drum may be brought. in close to the kelly.

FIG. 6 represents a view taken in section along line 66 of FIG. 3 showing details of the strap and guard means used for securing the cable to the outside of the drill pipe string and protecting it from abrasion by the bore hole wall.

Referring now to FIG. 1, the floor of a substantially conventional drilling derrick is designated 10. This is upheld by structural elements 12 extending to the earths surface. A rotary table 14 is supported on a table bed 16 resting on the derrick floor. Table 14 is conventional except for the provision of a bottom flange whereto attachment may be made of apparatus to be described. The rotary table turns primarily on bearings 18 while bearings 20 prevent upsetting of the table by any lifting component of the table turning force. On the underside of the upper surface of table 14 there is a beveled ring gear 22 which meshes with a beveled pinion 24 on one end of shaft 26 which is supported in bearing housing 28. On the other end of this shaft there is a sprocket wheel 30. By means of sprocket 30, shaft 26, pinion 24, and gear 22, the arrangement of which is fully conventional, power may be transmitted to table 14 from a prime mover not shown whereby the table may be either positively driven, or else restrained from being turned by reactive drilling forces.

Rotary table 14 is provided with the customary inner or driving bushings 32 and outer or table bushings 34. These bushings are sized in combination with the rotary table to provide a snug but sliding fit on kelly element 36. For purposes of this invention the kelly is considered of square cross section, a conventional shape, and to have the usualaxial hole here designated 38 for passage of drilling fluid. What is unconventional about kelly 36 is an external longitudinal groove 40 whose function will be discussed presently. Supporting the kelly and all lower pipe string elements in the derrick, and supplying drilling fluid thereto are conventional swivel, hook, hoisting block, cable and hose means not shown.

Attached to the lower flange of rotary table 14, and

extending axially downward therefrom is a sleeve element designated generally as 42. According to FIG. 1 this attachment is made by means of bolts 44 passing through an upper flange 46. of the sleeve. Any other appropriate attaching means may be used. In addition to upper flange 46, sleeve 42 is characterized by another flange 48 about midway its length, and by a longitudinal slot 50 below flange 48. The bore of sleeve 42, while not necessarily identical with that of the rotary table, must, like that of the table, be sufficient for clear passage therethrough of the widest element of the drill pipe string including the drill bit assembly itself.

On sleeve flange 48 sets of bearings 52 support a cable drum designated generally as 54 which is coaxial with and has diametral clearance on sleeve 42. This drum is characterized by an upper flange 56 and a lower flange 58. It is characterized further by a false flange 60 below the upper flange. The purpose of the false flange is to provide an upper limit for cable turns on the drum. A spur gear ring 62 is fitted to the rim of flange 56, and a ratchet tooth ring 64 is fitted around flange 58. This ratchet ring is engaged by a ratchet pawl 66 pivoted on a pin 68 set in a boss on intermediate flange 48 of sleeve 42. Further details of the ratchet mechanism are shown in FIG. 4.

In radial line with spur gear ring 62 is pinion 70 on the output shafit of electric motor 72 which is mounted on bracket 74. This bracket is provided with guide and support rods 76 and 78 which pass through combination bearing and limit stop brackets 80 and 82 on the underside of derrick floor 10. Guide rod 76 comprises an extension of the piston rod of hydraulic cylinder 84 which is likewise supported from derrick floor 10. Hydraulic lines 86 and 88 lead away from cylinder 84 to appropriate manifolding and pressure and exhaust reservoirs not shown. Likewise, electric cable 90 leads away from motor 72 to appropriate switching and a power source. By means of hydraulic cylinder 84, bracket 74 and motor 72 may be shifted to bring pinion- 70 into mesh with gear ring 62. Normally the ring and pinion are out of mesh as shown. The circumstance in which they are meshed and motor 72 energized will be described presently.

Sur-mounting cable drum 54 and coaxial with it is a sleeve 92 of electrical insulating material. This is fitted on and stiffened by another sleeve 94 which may be of conducting material. Set in sleeve 92 are three slip rings 96 to which electric power may be supplied by well known brush means not shown. Power input to the rings, taken as alternating three-phase for example, is indicated generally byarrows. Penetrating sleeve 94 in the planes of the slip rings are three insulating bushings 98 through which lead wires from the slip rings may be passed.

The cable wound on drum 54 is designated 100. The inside end of the cable is anchored in the drum, passing vertically upward through an internal passage of the drum as shown and finally secured by an appropriate compression fitting 102. The actual conducting elements of cable 100, shown as three wires 104, are led through insulating bushings 98 and connected electrically to slip rings 96. Cable 100 is coiled down and up on drum 54 between the underside of false flange 60 and the upper surface of lower flange 58, and is eventually passed out between sets of upper guide rollers 106 and 108 on cable drum flyer arm 1.10.

The cable drum flyer comprises two arm members 110 and 112 each having vertical and horizontal segments and both mounted on a circular base element 114 which is closely but slidably fitted to sleeve 42. Base element 114 is characterized by an internal radial projection 116 which extends with a sliding fit into slot 50 in sleeve 42, and acts to prevent rotation of the cable drum flyer with respect to this sleeve. While flyer arm 112 has no cable guiding function such as that of arm 110, it will be useful as a means for balancing arm 110 not only in rotation as sleeve 42 turns with rotary table 14, but also statically to prevent binding of base element 114 on sleeve 42.

From upper guide rollers 108, cable 100 passes downward along flyer arm 1110 to lower guide rollers 118 between which it goes to enter an internal passage in the horizontal segment of arm 1-10. Slidably mounted in this horizontal arm segment and on base element 114 and its projection 116 is a cable snugger 120 which carries a set of guide rollers 122 betweenwhich cable o passes, and beyond which the cable turns downward. The snugger has two operating handles 1-24 of which one appears inFIG. 1.

Generally cable snugger 120 comprises a hollow head element in which guide rollers 122 are carried, and two side pieces running in grooves in flyer arm 110. The purpose of the snugger is to bring cable 100 in close to kelly 36 as shown in FIG. 1 during paying out operations, guiding the cable into kelly groove 40. A lip on the lower edge of the head of snugger 120 extends the cable toward the kelly groove, compensating for the relative set back the cable would have otherwise due to grooving of rollers 122'. In its retracted position, that is, when cable snugger 120 is shifted outward away from the kelly axis, there must be sufiicient clearance beyond guide rollers 122 and the head element lip that the widest element of the drill pipe string including the drill bit may pass freely through the bore of sleeve 42. The sense of this requirement for snugger retraction applies, of course, to the amount by which projection 116 offlyer base element 114 may extend inside sleeve 42. Further details of the cable snugger are shown in FIG. 5.

The entire cable drum flyer structure is upheld on bearings 126 which in turn are carried by a support ring 128 which, like ring element 114 of the cable flyer, has.

a close sliding fit on sleeve 42. Support ring 128 is itself supported by two hydraulic plungers 130 which work in cylinders 132. Buffer elements 134 atop the cyinders provide shockless seating thereon of the support ring. More complete views of thesecylinders and themeans for actuating the plungers appear in FIG. 2. It may be appreciated presently, however, that vertical motion of plungers 130 will cause or permit up and down stroking motion of the cable drum flyer with respect to cable drum 54.

Finally in FIG. 1 notice the platform 136 mounted on vertical support 12 of derrick floor 10 about even with lower flange 58- of the cable drum. This platform which may be considerably above ground level and accessible by suitable ladder means will provide a convenient point from which to observe the condition of cable windings on drum 54 and, correspondingly, a convenient station at which to locate the controls of electric motor 72, and hydraulic cylinders 84 and 132.

Refer now to FIG. 2 which is an axial continuation of FIG. 1. The ground surface on which the drilling derrick is supported is designated 138. A Well cellar 140 has been excavated to a convenient sub-surface floor level 142. Well casing 144 terminates at level 142. In line with the well casing are customary blow out prevention and drilling fluid control means designated generally as 146. Pipe 148 leading away from these means is a return line for conveying drilling fluid as indicated by an arrow to appropriate screening and conditioning apparatus not shown. Flow of drilling fluid downward through the bore 38 of kelly 36 and upward between the kelly and casing 144 is indicated also.

Supported on stanchions 150 extending upward from the cellar floor is a platform 152. which carries the hydraulic cylinders 132. Each of these cylinders is provided with a supply line 154, an exhaust line 156, an overflow line 158, and an O-ring seal 160. Direction of oil flow is indicated by arrows. Supply lines 154 should join beyond the discharge of whatever hydraulic pump is used so that pressure will come onto the two cylinders evenly. Likewise, exhaust lines 156 should enter a common exhaust main. Overflow lines 158 are installed at points corresponding to-the uppermost level of designed stroke of plungers 130, and serve to prevent accidental overtravel of these plungers. Features of the hydraulic system not shown such as the pump and reservoir, which may serve hydraulic cylinder 84 as are taken as conventional.

drill string from the drill bit upward may be inspected by -a drilling crew member or members on platform 152 as the string is" lowered intoor withdrawn fromthe hole. Spacing S also provides working access to the drill string elements for strapping cable onto or unstrapping it from them.

Refer now to FIG. 3 which is in axial continuation from FIG. 2, some intermediate length of pipe string being omitted. In thisfigure, 162 designates the lowest element of the pipe string, for instance the drill collar, short of the drill bit and the electric driving means immediately adjacent thereabove. The bottom of thehole being drilled is 164 and the bore wall 166. A frustro:

conical drill bit and electric motor driving means are shown. The bit comprises cutter elements 168 rotatably mounted on a head 170 which is fixed to the hollow output shaft 172 of a motor whose relatively stationary structure is designated 174. This structure is provided with a threaded neck region 176 whereby connectionis made to the drill collar.

So far as internal structure is concerned, the motor shown in- FIG. 3 may be similar to that of Ogorzaly in many respects. Desirably it will have gear reductionmeans' for providing proper relative rotational speed of drill bit head 170, and it must have a continuous internal passage for the flow of drillingfluid. It need not have the internal pump of Ogorzaly since the present invention contemplates that fluid circulation pressure will be provided by traditional means at the earths surface. In FIG. 3 arrows indicate the passage of drilling fluid down the bore of drill collar 162 and into neck region 176 of motor element 1.74, out of motor shaft 172- and diverging toward cutters 168, and up in the annular space between the motor and drill collar on the one hand and the bore wall 166 on the other.

Coming down alongside the drill collar is electric cable 100 to make appropriate connection at its lower end to the electric motor. A compression fitting 178 providesa fluid tight seal around the cable. The connection of cable 100 to the motor shouldbe of a relatively easily separable nature consistent with other requirements. Furrther in respect of cable 100, notice strap 180 binding the cable closely to the drill collar. Additional details of this strap and other cable securing and protecting means will appear upon consideration of FIG. 6.

Refer now to FIG. 4 which provides plan details of the ratchet connection between intermediate flange 48 of rotary table sleeve 42' and lower flange 58 of cable drum 54. In this figure, 1'82 designates a leaf spring affixed to sleeve flange 48 which bears on ratchet pawl 66 to turn it about pivot pin 68 in a manner tomaintain it in engagement with ratchet ring 64 of flange 58. An arrow indicates the normal direction of rotation of flange 48 as this rotation is imparted to it by the driving means of rotary table 14, and it may be seen that when. ratchet ring 64 is engaged by pawl 66 the cab-1e drum will be driven in the same direction as flange 48, sleeve 42, and the rotary table.

184 and 186 designate holes in pawl 66 and sleeve flange 48 respectively which are at the same radius from the axis of pivot pin 68. Accordingly, if the pawl be moved out of engagement with the ratchet ring against the influence of leaf spring 182, holes 184 and 186 may be aligned and a pin dropped through them to maintain the disengagement of pawl 66 and ratchet ring 64. With the pawl so disengaged, the cable drum may be turned counterclockwise with respect to sleeve flange 48 and the rotary table.

Refer now to FIG. which provides plan details of the cable snugger element of the cable drum flyer assembly. The structure of snugger 120 comprising a head piece and two side pieces is apparent. In the condition shown, corresponding to FIG. 1, the snuggcr is extended inwardly to guide cable 100 closely into groove 40 of kelly 36. With the snugger so extended, the cable will tend to be in close along all pipe string elements below the kelly. Locally, groove 40 will provide control and protection of the cable by preventing sway of the cable run in way of the kelly and possible abrasion of it against any surface enclosing the kelly. Snugger handles 124 may be of the spring-loaded, pull out kind having tips of reduced section to enter holes in the horizontal segment of flyer arm 1-10, and so provide detent action for maintain-. ing the snugger in either its extended or retracted posi-.

tion.

Refer now to FIG. 6 which provides plan details of means for securing and protecting electric cable 100 along the pipe string. An arrow indicates the normal direction of rotation of the pipe string. Drill collar 162 shown in section is formed or fitted with a longitudinal fin 188 which serves as a guard and alignment means for cable .100. This fin is so configured that cable 100 may be held closely within it and that if the drill string should wipe against bore wall 166 abrasion will be taken by the fin and not by the cable.

Fin 188-extends the full length of drill collar 162, and tins of similar configuration maybe appliedto or formed on all other pipe string elements for attachment below the kelly inthe rotary drilling apparatus of this invention. Since screw threads on pipe elements for rotary drilling are very carefully cut for predetermined angular starting points of and number of turns for engagement of adjacent elements, there will be no difliculty in obtaining substantially continuous alignment of cable guard fins from one end of a pipe string to the other. Such fins should, of course, align not only with each other but also with cable groove 40 in kelly 36 and the cable terminal fitting in motor element 174.

'Cable strap 180 is characterized by several attachments. One is a cable crowding block 190 which has surfaces configured to the general curvatures of the drill collar or other pipe string element and cable 108 as shown. The function of block 190 is to hold cable 100 snugly against guard fin 188 when strap 180 is joined around drill collar 162. The surface of block 190 conforming to the cable has a facing of compressible material 192 which actually bears against the cable.

Other fittings on strap 180 are the joining blocks 194 and 196 which have faces even with the ends of the strap. Block 194 has a surface conforming to the curvature of the leading side of guard fin 188 while block .196 conforms to the general curvature of the drill collar, and their faces which are even with the ends of the strap are intended to abut. Block 194 may be considered to have a tongue and block 196, a groove to accommodate this tongue, and the tongue of block 194 and the body of block 196 drilled to pass a pin 198 whereby the strap ends; are joined. Any other suitable joining means may be used.

Besides. being fitted with blocks 190, 194 and 196, strap 180:.v has. a. lining of compressible material 200 extending substantially'f'rom block 190.to block 196. When the tongue and groove joint is made up, compression is taken. in this liner between the strap and the drill collar so that the whole strapassembly is a tight fit on the collar, not likely to slide out of place. It is evident that there will be friction forces between compressible facing 19; and the.- inside. surface of guard fin 188. on the one hand and electric cable on the other. These forces will act to support the cable on the drill collar or other pipe string element, at least to the extent of counteracting the tendency of the cable to become stressed by its own weight.

It may be noted that the structure shown in plan and cross section in FIG. 6 would not be dynamically balanced about the axis of the drill pipe string. As will be brought outpresently, the rate of rotation of the pipe string iscontemplated to be quite low, and any side thrust on it resulting from unbalanced masses such as those of fin 188, the fittings on strap .180, and cable 108 itself would not likely be large. However, it should be understood that this invention contemplates that such side thrust may be eliminated altogether by appropriate balancing means such as fins formed or fitted on the drill collar and other pipe string elements opposite fin 188 and other cable guarding fins. Likewise, attachments on strap 180 and similar straps may be provided to balance the cable crowding and the joining blocks.

The component parts of an apparatus embodiment of this invention having been described individually and in their relation one to another, the overall operation of this apparatus will now be considered.

Assume the apparatus to be in substantially the condition shown in FIGS. 1, 2, and 3. Kelly 36 and all drill pipe string elements below it including motor element 174 are being. turned clockwise (looked at from above) as indicated by rotational arrows by the prime mover of rotary table 14. The turning speed of these elements will be comparatively low, say 5-10 r.p.m., little more than sutficient-to insure that the pipe string will not become frozen to bore wall 166. Drilling fluid is being circulated down through passage 38 of the kelly and all succeeding pipe string elements including the cutter driving motor, across the cutters and bottom face 164 of the hole being drilled, up the annular space between the pipe string and the bore wall into the blowout prevention and fluid control apparatus 146, and out the return pipe 148 for appropriate treatment.

Electric power transmitted through cable 100 is activating the motor at the lower element of the drill pipe string, causing bit head and cutters 168 to turn clockwise as shown by an arrow in 'FIG. 3 ahead of the relatively stationary motor element 174. Relative to the earth formation being drilled, the speed of bit head 170 may be 300 r.p.m. or thereabouts, that is, normal rotary drilling speed. It should be noted that the full drilling reaction torque will be transmitted from motor element 174 to the pipe string, and so on up to the rotary table. Accordingly, the table turning means must at least be capable of developing full drilling torque at the low speed at which the table and pipe string are being driven ahead.

As the rotary table is turned, table sleeve 42 and the cable drum fiyer assembly will be turned with and by it and at precisely the same speed, the flyer assembly turning on bearings 126 on support ring 128. Cable drum 54 will also be turning, being driven at least at the speed of the table by the action of ratchet pawl 66 on ratchet ring 64. However, as all of the foregoing action proceeds, cutters 168 will be deepening the bore hole, and the entire drill pipe string will be descending with kelly 36 sliding downward through driving bushings 32. Descent of the, drill string will cause a pull to be exerted on cable 100, at least in the run above the highest cable strap. This pull in turn will exert a torque on cable drum 54 to turn it ahead of sleeve flange 48 on bearings 52 against the rather light drag imposed by the ratchet mechanism.

Of course with relative rotation between the cable drum 54 on the one hand and flange 48, sleeve 42., and table 14 on the other there will be a net unwinding of cable from the drum. This will be observed by the control man on platform 136 who will see the level of coils ou the outer winding decend, taking conditions initially.

as they are shown in FIG. 1. To prevent unnecessary stressing of the cable, it is desirable that the cable coming off of the drum pay out in a horizontal line to guide rollers 106 on flyer arm 110. Accordingly the flyer assembly will have to be continuously lowered until the level of the outermost cable coils on drum 54 has descended to the drum lower flange 58.

. Lowering of the flyer can be effected by bleeding hydraulic fluid out of cylinders 130 from under plungers 132 through lines .156. As the fluid is bled, the flyer. assembly, support ring. 128, and the plungers will come down of their own weight. After the cable has unwound down to drum flange 58, it will commence unwinding up toward false flange 60 with continued lowering of the drill string. To maintain horizontal payout of the cable in this circumstance, hydraulic fluid must be admitted under pressure to cylinders 130 through lines 154 to drive the plungers, the support ring, and the cable drum flyer upward. Up and down stroking of these elements will be continued as long as the drill string descends.

At some time after the commencement of drilling operations as hereinsupp'osed, the drill string will. have descended so far that no working length of kelly 36 remains above therotary table. Atthis point a new pipe section must be added to the string. Power to the cutter driving motor being transmitted through cable 100 is shut off; the rotary table prime mover and the drilling fluid circulating pump are stopped; rotary table bushings 32 are withdrawn, and hoisting of the drill string is commenced and continued until the joint between the lower end of the kelly and the uppermost pipe section is above the table. e

The technique of adding a pipe section to a drill string is well known in the art, and need not be recounted here. In connection with the handling of electric cable'during hoisting of the string, however, certain procedures may be noted. When the string is raised cable which would otherwise go slack should be rewound on drum 54, and to do this the cable drum must be turned backward with respect to the rotary table. Access is had by temporary ladder or otherwise to pawl 66 which is disengaged from ratchet ring 64, and held out of engagement by dropping a pin through holes 184 and 186. Pressure is relieved from hydraulic line 86 and applied to line 88 actuating hydraulic cylinder 84 to shift motor bracket 74 against stop bracket 80, and thereby bring pinion 70 on the shaft of motor 72 into mesh with gear ring 62 on the drum upper flange 56. Cable snugger 120 is retracted by appropriate operation of handles 124.

With the foregoingaccomplished, hoisting of the drill string may be started. The cable control man on platform 136 actuates motor 72 to rotate drum 54 counterclockwise as the string comes up, at the same time minding the hydraulic stroking controls for the flyer to insure an even rewinding of the cable. Meanwhile crewmen on platform 152 will be watching the upward passage of the drill string through access opening S. It will be no problem to strip cable 100 out of groove 40 in the kelly, but after the joint of the kelly and the uppermost pipe section has come into sight, men on platform 152 must be alert to remove all cable straps such as 180 passing them, and to see that the cable is stripped clear of any guard fin such as 188.

After a new pipe section has been added and the string is ready for lowering, the foregoing operations will be reversed. Pinion 70 will be shifted out of engagement with gear ring 62; pawl 66 will be reengaged with ratchet ring 64; cable snugger 120 will be extended, and as the string descends past access opening S, cable 100 will be tucked inside the guard fins and cable straps applied at appropriate intervals. When cutters 166 have reached the bottom of the hole, driving bushings 32 been reinstalled, drilling fluid circulation started, and proper compressive load let onto the drill string, operation of the drill motor and rotary table may be started with accom- 10 panying paying out of cable according to procedures given already.

So far as cable handling is concerned, the foregoing procedures are applicable when the entire drillstring must be pulled above the rotary table for replacement of a drill bit or cutter driving motor. In this-case table bushings 34 as well as driving bushings 32 must be removed from the rotary table, and the connection of the cable to the motor will be broken. A structural feature of this invention which it is desired to point out because of the significant, if negative, effect which it has on drilling operations'is that all electric cable handling apparatus is located below the derrick floor on which the rotary table is supported. Space on this floor is at a premium for pipe handling purposes, and pipe handling techniques well known in the art need not be modified be cause of any obstacles imposed by the apparatus embodiment of this invention which has been disclosed.

Although this invention has been described with a certain degree of particularity, it is to be understood that the present disclosure has been made only by way of example, and that numerous changes in the details of con-v struction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of this invention as hereinafter claimed. It should be understood in particular that the disclosed method and means for paying out and reeling in an electric cable are fully applicable in connection with use at the lower end of a drill pipe string of power consuming devices and earth-penetrating means other than an electric motor and rotary cutters.

What is claimed is:

1. An apparatus for drilling holes in the earths strata which comprises (1) a rotary table, (2) support means for said table whereby said table is positioned with respect to earth strata to be drilled, (3) a drill pipestring extending substantially centrally and perpendicularly through said table and so engaged by said table that it may slide longitudinally therethrough and be driven in rotation thereby and being characterized and by an end portion adapted to enter holes in earth strata, (4) earthpenetrating means and electrically energized actuating means therefor attached to said drill pipe string at said end portion, said actuating means being disposed to drive said earth-penetrating means with respect to said drill pipe string, (5) a drum member disposed coaxially with respect to said drill pipe string intermediate said rotary table and said earth-penetrating means, said drum member being adapted for rotation with respect .to said drill pipe string and to have an electric power cable wound thereon, (6) a' flyer assembly disposed adjacent said drum, said flyer assembly being characterized by a plurality of cable guide elements, (7) an electric power cable at least partially wound on said drum with one end secured thereon and extending therefrom over said guide elements of said flyer assembly to a point in closely spaced relation to the outer surface of said drill pipe string and thence at least part way along said drill pipe string to said actuating means for said earth-penetrating means, said electric power cable being secured at its other end to said actuating means in a fashion whereby electric power for energizing said actuating means may be supplied through said cable, (8) support means for said flyer assembly, said support means providing for relative rotary motion of said assembly with respect to said drum to unwind said electric power cable therefrom and bring it into closely spaced relation to the outer surface of said drill pipe string and parallel to the axis thereof as said drill pipe string slides longitudinally through said rotary table in a direction of deeper penetration into earth strata, and (9) means whereby electric power may be furnihsed to said electric power cable while said drum performs rotary motion about its own axis.

2. An apparatus according to claim 1 in which said 11 drum is in fixed vertically spaced relation to said rotary table.

3. An apparatus according to claim 1 in which said drum is supported by said rotary table.

4. An apparatus according to claim 1 in which said flyer assembly includes a shiftable mounting for at least one of said cable guide elements whereby said element may be moved with respect to said drill pipe string to withdraw said electric power cable from said point which is in closely spaced relation to the outer surface of said drill pipe string.

5. An apparatus for drilling holes in the earths strata which comprises a rotary table, support means for said table whereby said table is maintained substantially horizontal and is positioned with respect to earth strata to be drilled, a drill pipe string characterized by upper and lower end portions extending substantially centrally and perpendicularly through said table and so engaged by said table that it may slide longitudinally therethrough and be driven in rotation thereby, earth-penetrating means and electrically energized actuating means therefor attached to the lower end portion of said drill pipe string, said actuating means being disposed to drive said earth penetrating means with respect to said drill pipe string, a sleeve member secured to the underside of and coaxially with said rotary table and enclosing said drill pipe string for at least part of the length thereof, said sleeve member being characterized by an outwardly extending flange at a point intermediate its length and by at least one longitudinal slot extending through at least part of the region of said sleeve below said flange, a drum member so supported on said sleeve flange to be rotatable with respect thereto, said drum enclosing at least part of said sleeve above said sleeve flange and being itself characterized by upper and lower flanges, a flyer assembly including a base ring surrounding said sleeve and having a projection extending within said sleeve slot and adapted to move longitudinally with respect to said sleeve in the region thereof below said sleeve flange, at least one arm member surmounting' said base ring in line with said slot and extending outwardly beyond said sleeve flange and said drum lower flange and thence upwardly for a distance approximately equal to the length of said drum, a first cable guide element at the upper end of said flyer arm member, a second cable guide element at the region of said arm whereat the upward extension thereof commences, and a third cable guide element at the inner end of the outward extension of said arm in line with said sleeve slot, support means for said flyer assembly whereby said flyer may be raised and lowered with respect to said sleeve and said drum, an electric power cable at least partially wound on said drum with one end secured thereon and extending outwardly therefrom and successively over said first, second, and third cable guide elements, and thence downwardly along the outside of said drill pipe string to said actuating means for said earth-penetrating means, and being secured at its other end to said actuating means in a fashion whereby electric power for energizing said actuating means may be supplied through said cable, and means whereby electric power may be 1 2 furnished to said cable while said drum performs rotary motion about its own axis.

6. An appaartus according to claim 5 in which said earth-penetrating means comprises at least one rotary cutter element and said electrically energized actuating means comprises at least one motor.

7. An apparatus according to claim 5 in which said support means for said flyer assembly comprises at least one hydraulic plunger and cylinder assembly.

8. An apparatus according to claim 5 in which said drill pipe string comprises at least one pipe element provided with an external fin whereagainst said electric power cable may be positioned for protection of said cable from abrasion by the wall surfaces of a hole being drilled.

9. An apparatus according to claim 5 in which said flyer assembly includes a shiftable mounting for said third cable guide element whereby said element may be extended inwardly to a position closely adjacent the outer surface of said drill pipe string, and therefrom withdrawn outwardly to at least a position substantially within the boundaries of said slot in said sleeve member.

10. An apparatus according to claim 5 including means whereby saiddrum member may be driven in rotation with respect to said sleeve member for rewinding' said electric power cable on said drum, said means comprising a gear ring disposed outwardly about said upper flange of said drum member, and a motor having an output pinion adapted to mesh with said gear ring, said motor being so mounted on said support means for said rotary table that it may be controllably shifted in position to effect meshing of said pinion with said gear ring.

11. An apparatus according to claim 5 including means whereby said drum member may be restricted to unidirectional rotation with respect to said sleeve member, said means comprising a ratchet ring disposed outwardly about said lower flange of said drum member, a ratchet pawl pivotably mounted on said flange of said sleeve and disposed to engage said ratchet ring, and spring means whereby said pawl is biased to be maintained in engagement with said ratchet ring.

12. An apparatus according to claim 11 including releasable locking means whereby said ratchet pawl may be maintained out of engagement with said ratchet ring against the bias of said spring means, thereby allowing said drum member to perform multi-directional rotation with respect to said sleeve memberr References Cited in the file of this patent UNITED STATES PATENTS 974,305 Stewart Nov. 1, 1910 1,391,626 Gilthorpe Sept. 20, 1921 1,461,713 Gilman et al July 10, 1923 2,105,091 'MacKay Jan. 11, 1938 2,314,560 Scharpenberg Mar. 23, 1943 2,326,556 Opsal Y Aug. 10, 1943 2,355,342 Van Wormer Aug. 8, 1944 2,370,818 Silverman Mar. 6, 1945 2,643,087 Ogorzaly et al June 23, 1953

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