US3472324A - Rotating ditch and method - Google Patents

Description

Oct. 14, 1969 E. A. MORI HOTATING DITCH AND METHOD 3 Sheets-Sheet l N. .MNHN

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Oct. 14, 1969 E. A. MORI ROTATING BITCH AND METHOD Filed DGO. 22 1967 United States Patent O 3,472,324 ROTATING DITCH AND METHOD Ernest A. Mori, Glenshaw, Pa., assignor to Gulf Research & Development Company, Pittsburgh, Pa., a corporation of Delaware Filed Dec. 22, 1967, Ser. No. 692,736

Int. Cl. E21b 21/00 U.S. Cl. 175-66 12 Claims ABSTRACT OF THE DISCLOSURE The invention comprises a ditch or return line for use in rotary methods of drilling wells in the earth with means to rotate the ditch about its own axis, and with various adjusting means to adjust height and angle, and to permit use of various size diameter ditches.

This invention relates to the art of drilling wells in the earth by the rotary method utilizing fluid circulation. As is known, in drilling wells to hydrocarbon bearing deposits, a long string of pipe carrying a drill bit on its lower end is employed. Fluid, known as drilling mud, is pumped downwardly through the drill pipe and out the drill bit, and is then returned to the surface in the annulas between the hole drilled and the drill pipe. The drilling mud is reconditioned on the surface and recirculated through the well. The drilling mud serves to carry cuttings up out of the well, constrain pressures that are encountered in the borehole, cool the bit, and other purposes well known to those skilled in this art.

The invention is directed to a portion of the uid handling apparatus for use in the rotary method of drilling above described, particularly, the ditch or return line which is positioned between the upper end of the surface pipe and the mud reconditioning equipment. Surface pipe is large tube or casing which denes the outside of the annulus between the borehole and the drill pipe through the upper end of the well up to and slightly above the surface. The surface pipe is provided with a flow nipple nears its upper end which extends out to one side away from the axis of the well and through which the return mud iiows. A return line or ditch comprising flexible tubing, a length of pipe, a trough, or other means is provided between the flow nipple and the first piece of mud reconditioning equipment. In place of the conventional ditch, the present invention provides a straight length of pipe which is rotatably sealed to the outer end of the flow nipple, with means to rotate the pipe about its own axis to thereby achieve advantages over and solve problems present in prior known return lines.

The rst piece of mud reconditioning equipment to which the outflow from the conventional ditch or the rotating ditch of the present invention is fed is a device known as a shale shaker. The shale shaker comprises a screen and means to vibrate the screen so that cuttings in the mud will be separated out. The cuttings, depending on their particular nature and the combination of their nature with the nature of the particular mud, may form clumps or slugs of material which can clog the ditch, which can be detrimental to normal operation of the shale shaker, which can cause backing up of fluid in the ditch, and which can cause overflow of mud from the ditch and/ or from the top of the surface pipe.

The clumping and clogging problem becomes intensied in the so-called hydraulic or jet drilling method, described in U.S. Patent No. 3,375,887, to Goodwin et al., Ser. No. 660,065, tiled Aug. l1, 1967, and assigned to the same assignee as the present invention. In said jet drilling method, a plurality of high velocity streams of abrasive laden drilling mud are utilized in drilling the well. The abrasive used may be sand, steel or iron particles such as shot, or other relatively small particles of relatively hard material. In jet drilling, signiiicant concentrations of the abrasive are included in the mud, and the abrasives themselves or in combination with the cuttings may increase the frequency of occurrence of clumps forming in the mud in the ditch. The mud used in jet drilling must be more viscous than the mud used in conventional rotary drilling to enable it to suspend or carry the abrasive particles. The higher viscosity mud may further increase the frequency of formationl of clumps or the like in the return line.

In conventional usage, the return line has a downward inclination from the surface pipe to the shale shaker. A possible solution is that by increasing the angle of inclination, the jet drilling mud may flow satisfactorily through a conventional ditch because of the increased gravitational pull. That solution is not practical because it is desirable, for reasons of safety, to keep the mud handling equipment as far from the well as possi-ble. With the rotating ditch of the present invention invention, the angle of inclination can be very close to horizontal, angles on the order of 3 have been successfully used, to thereby position the shale shaker and other mud handling equipment at a safe distance from the wellhead without special equipment to increase the height of the flow nipple above the shale shaker.

The rotating ditch of the present invention comprises a length of straight pipe, and means to rotate the pipe. Actual use has shown that the rotating ditch of this invention will maintain a clump-free and steady llow of heavy, viscous, abrasiveladen jet drilling mud therethrough. Conventional return lines have failed to operate succesfully with jet drilling mud because of the relatively high viscosity of the mud itself, and the relatively heavy weight of the mud with the abrasive therein.

The return line of the invention requires no balies, paddles, screws, or other extraneous agitation means inside it. By not providing such agitation means, the cost of fabricating the invention is kept to a minimum. Further, such bales, screws, paddles, or the like agitation means would in fact be a disadvantage in the rotating ditch of the invention because it is desirable to always have as little mud in the ditch as posible. Any internal agitation means must hold some additional mud in the ditch, requiring that the amount of mud in the overall mud system be increased. The additional mud makes the ditch heavier and more diiicult to support and rotate. In jet drilling additional mud requires additional abrasive to maintain constant abrasive concentration further increasing the desirability of always having at little mud in the ditch as possible. Abrasive in the ditch is not in use and the abrasive is a relatively expensive material. Still further, any such internal agitation means would form regions of mud movement of differing speeds, and settling of abrasive in the slower moving mud would form regions of high abrasive concentration in the ditch which would disrupt or destroy the abrasive concentration of the system. Jet drilling produces cuttings which are generally larger than the cutting produced in conventional rotary drilling, and the larger, heavier cuttings further increase the tendency of a stationary ditch to form clumps or plug or overflow. Thus, the rotating ditch of the invention avoids all of the above problems, while permitting a relatively low cost of fabrication.

let drilling mud will suspend the abrasive particles at cutting speed velocities of the mud and when the mud is not moving. However, when the mud :is moving slowly, as in a return line, the abrasive particles will settle out. Thus, in a stationary ditch, the abrasive concentration balance of the system is impaired by the abrasive settling at the bottom of the ditch. The abrasive concentrated at the bottom of a conventional ditch adds to the problems of ditch plugging, overfiowing, backing up, and the like, described above. The rotating ditch of the invention overcomes the settling problem by not permitting abrasive to build up at the bottom of the return line due to the rotional motion, which causes uniform mixing of the abrasive, and other solids, cuttings, in the mud in the return line. An additional advantage of the invention is that the rotational motion reduces friction and thereby aids mud `flow down the return line.

The rotating ditch of the invention is particularly advantageous in both conventional and jet drilling rigs where a soft or easily drilled formation is encountered. Such formations, soft shale for example, produce relatively large quantities of cuttings in relatively short periods of time, which cuttings, if not smoothly delivered by the rotating ditch of the invention, can seriously foul the mud handling equipment.

Other advantages of the invention will be pointed out or will become evident in the following detailed description and claims, and in the accompanying drawing also forming a part of the disclosure, in which: FIG. 1 is a partial elevational view of a drilling installation utilizing the rotating ditch of the invention; FIG. 2 is an enlarged view of a portion of the showing of FIG. l; FIG. 3 is a top plan View of the means to rotate the ditch; and FIG. 4 is a front end view of the showing of FIG. 3.

Referring now in detail to the drawing, designates the sub-structure of a well drilling derrick, 12 designates the rotating ditch of the invention, and 14 designates the mud handling equipment. Sub-structure 10 comprises a plurality of support members 16, the exact configuration of which are unimportant. The derrick floor 18 carries a rotary table 20 in which is fitted the drill pipe 24. Conventional means, known as a Kelly, not shown, are interposed between rotary table 20 and drill pipe 24 to turn the drill pipe about its axis for drilling. It will be understood by those skilled in this art, that FIG. 1 is somewhat diagrammatic in that many usually provided portions of the derrick are not shown.

The derrick, not shown, which is carried by the substructure 10, is disposed over the well being drilled, the outside of which is defined by surface pipe 22. Surface pipe 22 is provided with a flow nipple 26, which comprises a short length of pipe welded into a suitably formed opening in the wall of surface pipe 22. The rotating ditch of the invention comprises a flow pipe 28, the upper end of which is joined to flow nipple 26 by a rotating iluid tight seal connecting member 30, which is known as a Chiksan joint, made by The Chiksan Co. of Brea, Calif. The high or Well end of pipe 28 is supported on an idler roller support assembly 32. The low or mud tank end of pipe 28 is carried by a power drive and supporting assembly 34. Pipe 28 may have a diameter in the range of about 8 inches to about 16 inches, with a diameter of 12 inches being suitable for most applications.

Mud handling equipment 14 comprises a shale shaker 36, of the type described above, which is positioned over a mud tank 38, shown in end view in FIG. l. It will be understood that various other additional pieces of equipment such as pumps, stirrers, and the like are associated with mud handling equipment 14, but that they need not be shown or explained further here.

Referring to FIG. 2, there is shown the apparatus of the invention in detail. Idler assembly 32 comprises a bottom support 40, which comprises a base made up of four pieces of angle iron 42, each of which disposed with one fiange facing upwardly and one flange resting on the earth or other surface supporting the ditch and disposed in* wardly. The pieces 42 are cut on a 45 angle and are joined together by any suitable means such as welding. In each of the corners within the base formed by angle irons 42, is an upright member 44 which comprises a length of pipe. The four uprights 44 are joined together, intermediate their ends, by angularly disposed struts 46, one strut 46 being provided between each two uprights 44. The upper end of support 40 is joined together by suitable top members 48 which may comprise rod or pipe. Each upright 44 is provided with a row of openings 50, which are used to adjust the height of the upper member, as will appear more clearly below.

Adjustably mounted in support 40 is an upper idler assembly 52 made up of four uprights 54 formed of pipe having a diameter that will snugly and slidingly fit within uprights `44 of support 40. In spaced relation to its lower end each upright 54 is formed with three closely spaced openings 56. The space covered by the three openings 56 is equal to or less than the space between two openings 50 in uprights 44, whereby fine and coarse adjustment of the height of the idler rollers is provided, coarse adjustment on holes 50, and fine adjustment on holes 56 in cooperation with one set of holes 50. A locking nut and bolt assembly 58 is provided in each corner to pass through the openings 50 and 56. The uprights 54 are joined together by struts `60 welded or otherwise joined to them in spaced relation to their upper ends. The upper ends of uprights 54 are joined together by lengths of angle iron 62 and form a structure similar to the base formed by angle irons 42 described below. A roller supporting strap 64 is welded or otherwise joined to a pair of the angle irons 62. Referring to FIG. 2, a pair of heavy duty casters 66, or other suitable anti-friction roller means, are mounted on strap 64 by means of nut and bolt assemblies, not shown, which cooperates with suitable slots in the strap 64. Thus, 4the casters 66 may be adjusted toward and away from each other to accommodate various sizes of pipe to be used as the ditch.

Referring to FIG. 2, drive assembly 34 comprises a lower support identical to support 40 in idler assembly 32. The provision of identical supports for the drive assernbly 34 and the idler assembly 32 gives the invention the advantage of interchangeability of parts.

Drive assembly 34 comprises an upper assembly 70 which comprises four uprights 72 similar in structure and operation to the uprights 54 of upper assembly 52. The lower ends of the uprights 72 are provided with openings 56d and nut and bolt assemblies 58a similar to the parts 56 and 58 described above. The upper ends of the uprights 72 are joined together by four pieces of angle irons 74 to strengthen the structure. A vertically disposed angle iron 76 secured to the upper end of each upright 72 and extends thereabove. The upper end of the four angle irons 76 support a frame made up of four horizontally disposed angle irons 78 formed with mitered corners, see FIGS. 3 and 4. The angle irons 74 extend only between the flanges of the vertically disposed angle irons 76 so that the inside corner of each angle iron 76 is disposed directly against the upper end of the uprights 72 and is welded in place thereon. A strap 80 is disposed across and is suitably secured to the frame formed by the angle irons 78. A pair of ditch supporting casters or rollers 82 are adjustably supported on strap 80 for movement thereon towards and awayl from each other by means of slots 84 formed in the strap. Nut and bolt assemblies 86 secure the rollers 82 to the strap 80. Thus, the two ditch supporting rollers 82 can be moved closer together or further apart to accommodate various diameters of rotating ditches 28 which may be used depending on the demands of the particular installation.

Means are provided to drive the rotating ditch 28, and to provide a third roller above the first two rollers 82 to` provide a three-point contact against the ditch, while at the same time maintaining sufi'icient flexibility to permit the use of different sizes of pipe for the ditch. To thisend, a motor and idler supporting sub-assembly 88 is adjustably mounted on a pair of the vertical angle irons 76. Sub-assembly 88 is supported on a short, vertically disposed angle ion 90 and a long, vertically disposed angle iron 92, each provided with a plurality of openings which may be brought in registry with any of several similarly spaced openings formed in a contact-` ing flange of two of the angle irons 76 and secured thereto by suitable nut and bolt assemblies 94. Thus, the entire motor and idler sub-assembly 88 may be moved vertically with respect to upper assembly 70, and secured at various heights thereon.

A pair of relatively large motor supporting angle irons 96 extend outwardly, one from the upper end of short angle iron 90 and the other from mediately the ends of long angle iron 92. The horizontal iianges of the two angle irons 96 carry a motor base supporting underplate 98, on which is mounted a commercial universal motor mount 100. The outer ends of the large angle iron 96 are joined together and the structure rigidified by an angle iron 102, and the motor supporting structure further strengthened by a pair of angularly disposed struts 104 which may be formed of angle iron, or rod, or the like. The inner ends of the large angle irons 96 are joined together by an angle iron 106. Mounted on the top of universal mount 100 for adjustment to the left and right (looking at FIG. 4) is a bottom plate 108, which carries a pair of front end uprights 110, and a rear yoke 112. An upper swinging plate 114 is mounted on uprights 110 and yoke 112 by means of a pair of front end journal members 116. A pin 118 passes through suitably formed openings in uprights 110 and journal members 116 to rotatably mount plate 114 about the axis of pin 118. A threaded member 120 has its lower end rotatably mounted within yoke 112 and its upper end provided with double suitable nuts and washers which are received within a cutout in the rear end of swinging plate 114. A gear-motor 122 is secured to swinging plate 114 by suitable means not shown, and comprises an output drive pinion 124. It will be understood that gearmotor 122 comprises suitable speed controls, on-o controls, and an electrical supply cable, all conventional and not shown. Thus, the angular position of output pinion 124 may be adjusted so that its axis is parallel to the axis of rotating ditch 28 by means of changing the position of swinging plate 114 on threaded member 120. The angle of the ditch is controlled by the overall, adjustable, heights of the idler and drive assemblies 32 and 34 with respect to each other.

Subassembly 88 further comprises an angle iron 126 which extends upwardly from angle iron 106 to a height equal that of long angle iron 92. The upper ends of angle irons 92 and 126 are joined together by an angle iron 128. A roller supporting plate 130 is joined to the up- -wardly extending frame formed by angle irons 92, 126 and 128, and carries an upper ditch guiding roller assembly 132.

To complete the drive chain, a split clamp ring 134 is provided. The two halves of the clamp ring are secured tightly to the rotating ditch at a position thereon close to the plane of pinion 124. Spaces are provided between the halves of the clamp ring 134 so that the tightening nut and bolt assemblies 135 will bridge the spaces to assure that the clamp ring tightly grasps the rotating ditch. A drive sprocket 136 is slipped over the ditch 28 and secured to the clamp ring 134 by bolts 138. A suitable drive chain 140 interconnects pinion 124 and sprocket 136.

If it should be desired to change the size of the return line 28 because of larger or smaller uid flow demands, the only changes required are that a suitably sized clamp and sprocket 134 and 136 be provided, the two rollers 82 moved to provide a larger or smaller space between them, the subassembly 88 slid up or down to bring the roller 132 in contact with the ditch, the length of the chain 140 corrected, and the conversion is completed.

While the invention has Ibeen described in detail above, it is to be understood that this detailed description is by way of example only, and the protection granted is to be limited only within the spirit of the invention and the scope of the following claims.

Iclaim:

1. In a rotary method of drilling wells in the earth comprising the use of a fluid which circulates through the well from the surface to the bottom of the well, returns to the surface and is delivered to reconditioning equipment through a return line extending from the top of the well to surface drilling fluid handling and recondi tioning equipment, the improvement comprising rotating the return line about its own axis.

2. The method of claim 1, and disposing the rotating return line at an angle of about 3 olf horizontal with the high end of the return line at the well.

3. In apparatus for drilling wells by the rotary method, the combination comprising a return line extending from the well surface pipe to drilling lluid handling equipment, a flow nipple extending from said surface pipe, rotary sealing means to connect one end of said return line to said llow nipple in fluid liow communication therewith, and means to support said return line and to rotate said return line about its own axis.

4. The combination of claim 3, said return line cornprislng a straight length of about plain pipe having a diameter in the range of about 8 inches to about 16 inches.

5. The combination of claim 3, said support means comprising an idler assembly and a drive assembly, said idler assembly and said drive assembly comprising a similar bottom support, and said bottom support comprising a plurality of tubular uprights adapted to adjustably receive the upright portions of a cooperating upper member.

6. The combination of claim 5, said idler assembly comprising an upper member having upright portions receivable within the tubular upright portions of said bottorn support, said idler assembly comprising a pair of rollers on the top thereof and means to change the distance between said rollers, said adjusting means between said nesting uprights of said bottom support and said upper member comprising a plurality of openings spaced apart vertically on Said tubular uprights of said bottom support by a lirst distance, and a second set of openings spaced apart vertically on said uprights of said upper member vwith the overall distance between the highest and the lowest of said openings in said uprights of said upper member being lsubstantially equal to said iirst distance.

7. The combination of claim 3, said return line rotating means comprising a bottom support and an upper member, a pair of rollers on the top of said upper member adapted to rotatingly support said return line and means to change the distance between said rollers, a drive and upper idler sub-assembly, means to adjustably mount said drive and upper idler sub-assembly on said upper member of said drive assembly, said sub-assembly comprising vertical portions adapted to be secured at varying heights with respect to vertical portions of said upper member, support means extending laterally from said vertical portions of said subassembly to the side thereof opposite the side on which said return line is disposed, drive means, means to mount said drive means on said support portions of said sub-assembly, said drive means comprising a power pinion, said drive means mounting means comprising means to dispose said power drive pinion in a plane substantially perpendicular to the axis of said return line, a sprocket, means to mount said sprocket on said return line, and power transmission means interconnecting said pinion and said sprocket.

8. The combination of claim 7, said means to mount said sprocket on said return line comprising a clamp, said return line clamp comprising a pair of semicircular clamp members, means to clamp said clamp members to said return line, and means to secure said sprocket to said clamp.

I9. The combination of claim 7, said drive means comprising a gear motor, said means to mount said gear motor with said pinion thereof in a plane substantially perpendicular to the axis of said return line comprising a bottom plate, a top plate swingably mounted on said bottom plate with said gear motor thereon, and means to dispose said top plate at an adjustable angle with respect to said bottom plate.

10. The combination of claim 9, said bottom plate comprising a pair of uprights and a yoke, said top plate comprising a pair or journal members disposed in juxtaposition to said bottom plate uprights respectively, a pin rotatably interconnecting said uprights and said journal members, a threaded member swingably received within said yoke of said bottom plate, said upper plate being formed with a cut-out adapted to receive the upper end of said threaded member, and nut and bolt means on said threaded member adapted to move the notched end of said upper plate with respect to said threaded member around said pin member.

11. The combination of claim 7, said bottom support of said drive assembly comprising a plurality of tubular upright portions, said upper member of said drive assembly comprising upright portions receivable within said tubular upright portions of said bottom support, height adjusting means between Said nesting portions of said bottom support and said portions of said upper member received therein, said adjusting means comprising a first set of vertically spaced openings on said tubular uprights of said bottom support, a second set of vertically spaced openings on said uprights of said upper member, and the distance between the highest and the lowest of said second set of openings being substantially equal to the distance between any two adjacent openings of said rst set of openings.

12. The combination of claim 7, a third roller on said vertical portions of said sub-assembly, whereby by adjustment of said sub-assembly on said upper member, said third roller is brought into Contact with said return line adjacent the top thereof to provide a three-point contact between said rollers and said return line to hold said return line in position on said rollers.

References Cited UNITED STATES PATENTS 2,302,112 11/1942 Eddy 209-113 X 2,576,283 11/1951 Chaney 175-66 2,657,016 10/1953 Grable 175-206 X 3,135,685 `6/1964 Tanner 175-206 X 3,292,384 12/1966 Rubin 209-113 X NILE C. BYERS, JR., Primary Examiner U.S. Cl. X.R.

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