Method for handling column of drill pipe during drilling operations

[57] ABSTRACT

A method for removing or installing a column of drill pipe or tubing relative to a well bore during drilling or workover operations wherein the drill string is moved from the well bore preferably in one continuous piece without breaking it into shorter sections, and is moved in an upwardly and radially outwardly curved path from the well bore to a substantially horizontal attitude for storage preferably in a generally circular configuration on the ground or support means for later return to the well bore moving approximately along the same path, and as one piece.

Claims, 9 Drawing Figures

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SHEET 1 OF 4

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FIG.1

ATTORNEY

PATENTEDJUH 61972

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SHEET 2 OF 4

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PATENTEDJUH 61972

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SHEET 3 OF 4

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INVENTOR.

Eugene A. Smitherman

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FIG. 4

ATTORNEY

PATENTED JUS 6 1972

3,667,554

SHEET U CF 4

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FIG. 7

ATTORNEY

3,667,554

METHOD FOR HANDLING COLUMN OF DRILL PIPE DURING DRILLING OPERATIONS

RELATED APPLICATIONS

The present application is a continuation of application Ser. No. 859,634, filed Sept. 22, 1969, now abandoned, which was in turn a continuation-in-part of application Ser. No. 685,686, filed Nov. 24, 1967, by the same inventor, entitled “Method for Handling Column of Drill Pipe During Drill Operations,” which is now abandoned.

SUMMARY OF PROBLEM AND SOLUTION

Oil and gas wells are presently drilled by rotary drilling techniques wherein a column of drill pipe is assembled in the well bore with a cutting tool carried at the lower end of the column. The column of drill pipe is rotated and the cutting tool penetrates the earth to greater and greater depths during which operations additional sections of drill pipe are added to the column of drill pipe. Occasionally, the need arises wherein it is necessary to remove the column of drill pipe from the well bore and change or repair the drill bit, or for other reasons. More often than not, the column of drill pipe is thereafter returned to the well bore for a continuation of the drilling process. It will be appreciated that removal of the column of drill pipe from the well bore is a problem entailing substantial time and effort in solution, as will be described.

Consider, by way of example, a well bore and associated column of drill pipe, approximately 9,000 feet in depth, on the occasion of replacement of the drill bit. The column is made of approximately 300 joints of drill pipe which are removed from the well bore and broken into stands of approximately 90 feet, comprising three joints of pipe. In the stated example, 100 stands of the drill string are customarily stored temporarily in the derrick itself. In the routine course of events, this means that 100 separate operations are required wherein the column is rested on slips in the rotary bowl, the breaking of the joint, the unthreading of the stand, the maneuvering of the stand to the stored position, occasional re-connection of the mud line to the drill pipe, further upward movement of the drill string by use of elevators, and additional repetitive steps. The plurality of the above described steps require a substantial interval of time to disconnect one stand, let alone 100 stands of pipe. It is with this in view that the present invention is summarized as providing a method whereby the column of drill pipe is removed as preferably one continuous piece, not broken into shorter sections, from the well bore wherein it is moved generally upwardly and outwardly from the bore hole along a curved path to a substantially horizontal attitude for storage. Moreover, the present invention provides storage preferably in an essentially circular configuration, with multiple loops of drill pipe placed in the circle until the lower end of the column of drill pipe is lifted from the well bore. At this juncture, the lower end of the drill pipe including the drill tool is exposed for repairs or replacement as desired. Moreover, the column of drill pipe is placed in a position for easy return to the well bore by movement in the reverse manner.

The present invention solves the problem of retrieving the drill string to service the lower end, typically replacement of the drill bit, without the tedious problem of making up the drill string to return it to the well bore. In times past, this has been solved by stacking 90-foot stands of pipe in the derrick as the drill string is slowly disassembled and re-assembled. The present invention provides an apparatus for the method of retrieving the drill string, directing it upwardly in a vertical path as it emerges from the well bore and bending it toward the horizontal and curling the drill string in a circular storage container.

Many objects and advantages of the present invention will become more readily apparent from a consideration of the following specification and drawings, wherein;

FIG. 1 shows the drill string removal apparatus of the present invention cooperative with an offshore drilling rig and derrick;

FIG. 2 is a sectional view taken along the line 2 — 2 of FIG. 1 illustrating details of construction of a drill pipe guide;

FIG. 3 is a partial view showing the derrick and conventional drilling apparatus with apparatus cooperative with the present invention moved aside to permit its storage and continued drilling by the derrick;

FIG. 4 illustrates in detail a pipe elevator system which removes the drill string from the well bore and directs it toward the apparatus of the present invention;

FIG. S is a sectional view taken along the line 5— 5 of FIG. 4 showing the elevator apparatus of FIG. 4 engaging the tool joint;

FIG. 6 is a sectional view taken along the line 6 — 6 of FIG. 4 illustrating details of construction of the pipe elevators;

FIG. 7 is a top or plan view showing the circular storage apparatus for the drill pipe in conjunction with the derrick;

FIG. 8 is a sectional view taken along the line 8 — 8 of FIG. 7 illustrating details of construction of the pipe storage means of the present invention; and,

FIG. 9 is a connector which is joined to the uppermost end of the drill string as it is removed from the well bore for pulling the drill string through the apparatus of the present invention to be stored.

Attention is first directed to FIG. 1 of the drawings. In FIG. 1, the numeral 10 illustrates a conventional drilling barge of satisfactory construction, having a derrick and associated drilling apparatus indicated generally at 11. The present disclosure will include an offshore drilling barge, although the apparatus of the present invention is readily useable on land, and the offshore barge constitutes no limitation on the present invention. The barge 10 carries the drilling equipment indicated generally at 11. The numeral 12 indicates the apparatus of the present invention which is an apparatus which stores the drill string, without regard to its length, as it is removed from the well bore. The whole drill string is pulled in a typical use of the present invention, whereupon it is serviced and thereafter returned to the well bore. The present invention enables the removal of the entire drill string without breaking it down into stands of pipe, which is both time consuming, tedious and dangerous. Considering the present invention more in detail, the numeral 10 indicates the offshore drilling barge which is of conventional construction and which provides the context for installation of the present invention. The numeral 11 indicates the drilling equipment which includes a conventional derrick 13, traveling block 14, swivel 15, and the necessary Kelly and rotary table. An elevator apparatus at 16 retrieves the drill string from the well bore when the conventional drilling operations are interrupted.

The present invention includes a suitable support structure 17 which extends above the drilling barge 10 for supporting the drill string 18 as it is retrieved from the well bore. The structure 17 provides support for the drill pipe 18 which tends to be quite heavy, and support for the means for guiding and redirecting the pipe 18 to the storage means, as will be described. Conventionally, the pipe emerges from the well bore pointing essentially directly upwardly. The support structure 17 is cooperative with a pipe guide means 20 as will be described with regard to FIG. 2, which redirects and slightly bends the pipe from the vertical preferably to the horizontal and then directs it tangentially toward a circular storage rack which can accommodate several turns or laps of the pipe. Of course, the pipe 18 may be stored in some other configuration or in some other plane.

The support means 17 is thus a structural steel frame which projects into the air and holds the pipe guide means 20 at various locations along its length. Each of the pipe guides is connected to and held up by the structural support 17. Hence, the structure 17 may take any form, but the pipe guides 20 carried at its upper edge as shown in FIG. 1 are located along the arc of a circle which is determined by the desired bending radius of the drill pipe 18. In further particular, a top view, as will be described with regard to FIG. 7, shows also that the structure 17 begins curving the drill pipe 18 for storage.

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FIG. 1 further includes an upstanding pipe 21 and a flexible pressure hose 22 which supplies drilling mud to the storage rack of the present invention. If desired, the drill string can be retrieved from the well bore in communication with the mud pump so that as the pipe is pulled from the well bore, additional mud is being forced through the entirety of the drill string back into the well bore. This is the safety factor which prevents a bubble of gas or pressure fluid from a geological formation from rising too rapidly in the well and creating a dangerous condition as would be the case if the well bore were left open, either in the annulus adjacent the drill pipe, or in the drill pipe itself.

Attention is next directed to FIG. 2 of the drawings which shows a pipe guide means 20. The pipe guide means 20 is located at the upper parimeter of the support structure 17. The numeral 17α and Ylb in FIG. 2 indicate various and sundry legs of the support structure 17 which carries the pipe guide means 20. Inasmuch as the guide means 20 is duplicated at various points along the path of the drill pipe 18, only one such guide means may be described and the others will be sufficiently similar thereto, differing substantially only in location, and a detailed description of all the pipe guides is not needed. The pipe guide means 20 includes a fixed body 23 which supports a first roller 24 and a second roller 25. The rollers 24 and 25 are free wheeling guide rollers which are carried on suitable axles which are supported in the body 23. As shown in the drawings, the rollers 24 and 25 have an outer surface which is shaped to accommodate the drill pipe 18. The drill pipe 18 is thus cradled by the rollers 24 and 25. In addition, the upper portion of the guide means includes a body 26 which is hinged both at the right and at the left. The body 26 is hinged at 27 and 28 and a suitable pin is placed in the hinges to join the body 26 to the body 23. The body 26 incorporates a roller 29 carried on a shaft 30, which shaft 30 is forced toward the pipe 18 by a spring 31. The spring 31 maintains the roller 29 in contact with the pipe 18. Moreover, the spring 31 bears against a U-shaped bracket 32 which straddles the roller 29 and bears against the shaft 30 at both ends. Suitable bearings are included in the rollers 24, 25 and 29 to permit their free rotation. As the shaft 30 is forced toward the pipe by the Ushaped bracket, the roller 29 is kept in constant contact with the drill pipe 18. As the upsets on the pipe pass through the guide means 20, the spring 31 is compressed and the roller 29 moves upwardly as shown in FIG. 2. This permits the guide means to keep constant pressure on the drill string 18, and, as a consequence, the several guide means along the length of the support structure 17 redirect the drill pipe from the vertical to the horizontal and at a level approximately coincident with the drilling platform for storage in a circular storage means as will be described.

Attention is next directed to FIG. 3, which shows the conventional drilling apparatus as it is customarily used. The drilling apparatus is shown with the Kelly engaged by the rotary table during conventional drilling operations. The elevators 16 are moved aside inasmuch as they do not contribute to the drilling process, but are best used during retrieval and return of the drill string to the well bore. Of particular interest in FIG. 3 is the location of the elevators 16. They can be moved to the side and stored indefinitely. In addition, FIG. 3 illustrates the location of a certain connector 36 carried on a wire rope 37 which is threaded through the various and sundry guide means 20 of the present invention. The connector 36 is connected to the upper end of the drill string as it is retrieved. The wire rope and connector 36 are then used to pull the upper end of the drill string through the apparatus of the present invention for storage. Once the drill pipe 18 is snaked into the apparatus of the present invention, the apparatus is then free to pull the drill string rapidly from the well bore.

Attention is next directed to the elevators 16, best illustrated in FIG. 4. In FIG. 4, the drill string is indicated by the numeral 18 as it emerges from the rotary table. In conventional operations, the drill string has collars located approximately every 30 feet. The collars are engaged and lifted by the elevator means 16 which is a dual track conveyor belt vertically directed for withdrawing the drill pipe. Briefly, the elevators 16 include a support structure 38 which is of suitable framing members for holding the conveyors in their proper position relative to the drill pipe 18. The support structure 38 is somewhat in the form of an A-frame and supports vertical structural members 39 and 40 about which the traveling conveyors move. The frame member 39 supports a lower sprocket which is engaged with the left-hand chain 42. The structural member 39 also supports an upper sprocket 43. The chain 42 feeds over the sprocket 44 and thus travels vertically upwardly adjacent to the drill pipe 18 when retrieving the pipe.

Attention is momentarily directed to FIG. 6 of the drawings, which is a sectional view through the lower portions of the pipe elevators 16. In FIG. 6, the lower sprocket 41 is shown to be a trio of sprockets which are nested on a common shaft adjacent to one another, and which are rotated by a suitable motive source 44. Typically, the source 44 is an electric motor which has an output shaft, a suitable coupling 45, and gear box 46. The gear box 46 is connected to the sprocket 41 for driving the conveyor belt 42.

As shown in FIG. 6, the elevator means 16 is supported on separable platforms 47 and 48 which divide along the center line. It will be understood that one conveyor belt is positioned on one side of the drill pipe 18, and the other is positioned on the other side. Hence, it is quite convenient to divide the apparatus so that it may conveniently sit on or above the drilling platform, centered at the rotary table.

It will be noted that the right-hand portions of the elevator means shown in FIG. 6 are identical to the left-hand portions. It is believed that a detailed description of this additional apparatus is not necessary, and would be unduly burdensome on the disclosure.

Returning again to FIG. 4, it will be noted that the left-hand elevator system has engaged the drill pipe 18 on a pipe carrier 49. Additionally, the right-hand conveyor system is shown moving a pipe carrier 50 to engage the next collar in the drill string 18. The alternating engagement of the left- and righthand conveyors should be understood to provide a means whereby first one collar is engaged by one conveyor and the collar next emerging from the well bore is engaged by the other conveyor. Drill pipe is customarily manufactured in 30foot lengths. Hence, the spacing between collars is approximately 30 feet. Because of the 30-foot spacing of collars on the drill string in the conventional drill pipe use today, it will be understood that the elevator means 16 of FIG. 4 extends somewhat taller than 30 feet. The preferred range is 35 to 40 feet, with the conveyors extending the full length of the apparatus. The lower sprocket 41 can be located immediately above the rotary table with perhaps a foot or so clearance. It is not mandatory that the lower sprocket 41 be right on the drilling platform. Consequently, the upper sprocket 43 should be at least 30 feet above the lower sprocket 41. This, then, permits the pipe lifts 49 and 50 to grasp the pipe as it emerges from the well bore.

Attention is directed to FIG. 5 which shows the lower pipe lift 50 in greater detail. The pipe lift 50 projects laterally from the chain as it moves vertically. It engages the drill collar in its nether shoulder, and lifts the drill pipe 18 upwardly. As shown in FIG. 5, the pipe lifter 50 has a U-shaped slot which fits snugly against the side wall of the pipe. As the pipe lift 50 moves faster, it lifts the collar from its lower shoulder and helps draw the drill string from the well bore. As shown in FIG. 5, the pipe lift 50 is carried on at least two or three pins to various chain lengths comprising the lift chain of the elevator, and hence, extends rigidly to the left, and is guided and maintained in this posture by a channel formed in the structural member 40. This is a suitable means for engaging the pipe 18, and pulling it from the well bore.

Without regard to the size of the motor, it can be geared down to provide sufficient pulley power for withdrawing the drill string 18 from the well bore.

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It should be noted that the two conveyors alternate in grasping first one collar and then the next of the drill pipe 18 as it emerges from the well bore. When one side loads up, there is a tendency for the motor to slow down, and that side travels a little slower because of the load. The other conveyor will be unloaded at this juncture and the motor will tend to speed up, rushing the pipe lift means of that elevator to a position immediately adjacent to the drill pipe for lifting purposes. Thus, as shown in FIG. 1, when the pipe lift 49 reaches the top of its travel and tends to rotate to the left and withdraw from the collar of the pipe 18, the pipe lift 50 at the lower portions of FIG. 4 will come into engagement with its drill collar. The motors may be controlled by hand or suitable speed controllers. In this manner, the pipe lift 50 tends to overtake the drill collar, and this sequence is repeated throughout the entire drill string.

To this juncture, sufficient structure has been described for withdrawing the drill string from the well bore and guiding it on the structural support member through the use of the means 20. Attention is now directed to FIG. 7 wherein the means for storing the pipe in a horizontal loop is described. In FIG. 7, the numeral 11 indicates the drilling apparatus which is conventionally found in conjunction with the present equipment. The numeral 17 indicates the structural support member previously described for holding the drill string 18 as it is bent from the vertical toward the horizontal, and forced to a horizontal point approximately parallel with the deck of the drilling barge 10. In FIG. 7, it will be noted that the structural support 17 incorporates several guide means 20 which continuously bend and redirect the drill pipe 18 tangentially toward a circle. As was discussed in regard to FIG. 1, the structural support 17 provides compound bending to the pipe 18 as it is redirected to the storage means as will be described.

In FIG. 7, a circular storage means is indicated by the numeral 55. It preferably comprises a completely encircling storage rack best illustrated in FIG. 8. In FIG. 8, the means 55 will be observed to include a side wall 56 and a bottom wall 57, and an internal side wall 58. The walls 56 and 58 are parallel to one another, and are concentrically located. The wire line 37 is threaded through the various pipe guide means 20 shown in FIG. 7, and one or two revolutions of the line 37 are stored in the circular storage means 55. The connector 36 (see FIG. 9) connects through the drill string 18 for the purpose of pulling the drill string 18 from the well bore through the various guide means and then to the storage container 55. The circular storage trough or rack is rotated to pull the lead line 37, the connector 36 and then the drill string through the various pipe guides 20 and into the storage trough or rack. As the drill pipe 18 is stored and the storage trough or rack is rotated, additional drill string is pulled from the well bore into the storage rack 55.

In FIG. 8, the storage rack 55 is shown including the means which rotate the storage rack as the drill string 18 is accumulated in several turns or revolutions. The storage means 55 is carried on a pair of rails 60 and 61. Wheels 62 and 63 earned on a common axle 64 support the storage rack on the rails 60 and 61. The wheels and associated axle are located at several points about the circumference of the storage rack 55 to support the entirety of the circular structure on the rails. Additionally, a circular rack 65 is located immediately inboard the outer rail 60. The rack 65 is engaged by a pinion 66 which is common to the axle 64. The pinion 66 is keyed to the axle 64 and in response to operation of a motor 67, the storage rack is rotated. The motor 67 is provided with a conventional coupling, gear reduction box, and suitable gears at 68 for imparting the rotation to the common axle 64 and the pinion 66. As the motor 67 operates, the storage rack 55 is rotated at a rate of speed determined by operation of the motor 67.

As mentioned above, a suitable number of wheels are arranged about the pipe storage rack 55 to carry the rack and maintain it level as it rotates on the rails 60 and 61. The axle 64 is supported by a pair of downwardly extending journals 69 and 70 which are appended to the lower side of the storage rack 55.

The length of the lead line 37 should be so calculated that when it is fully retrieved and placed in the storage rack, it positions the connector 36 of FIG. 9 immediately adjacent to an opening in the side wall 58 of the storage rack 55. As shown in FIG. 8, this permits the mud line 22 to connect through the side wall 58 so that the mud line is then connected with the drill pipe 18 through a T-connection provided in the means 36 as shown in FIG. 9. The apparatus can be interrupted in its operation and the storage rack stopped while this connection is made once the first few hundred feet of drill pipe 18 have been retrieved from the well bore.

Strong emphasis should be placed on the fact that the drill pipe is not bent to the extent that it takes a set. The stresses in the drill pipe are kept below the elastic limit, and as a consequence, the pipe is first bent, then straightens out of its own accord and returns to its original straight posture. Consequently, the pipe that is handled by the present invention is returned to the well bore without the use of pipe straighteners or like apparatus.

In operation, the method of the present invention includes the steps of disconnecting the drill string from the Kelly and connecting it with the adaptor 36. The adaptor 36 is pulled through the various pipe guides 20 as shown in FIG. 7 with the upper end of the drill string being forced through the various pipe guides. As the wire rope 37 is retrieved into the circular rack 55, the drill pipe 18 is pulled into the storage rack. As shown in FIG. 1, the drill pipe 18 is angled downwardly at its point of entry to the storage rack 55. This tends to force the pipe toward file bottom, and indeed, it is stored on the bottom plate 57 as shown in FIG. 8. If the storage rack 55 is rotated at a speed slightly faster than the speed of withdrawal of the elevators 16 as shown in FIG. 1, the drill pipe 18 will be drawn toward the inside wall 58. Thus, the combination of the speed of rotation of the circular storage rack in conjunction with the downwardly directed pipe at the point of entry forces the pipe to the bottom and inside of the storage rack 55. In a sense, these two factors aid and assist the order in which the several turns or revolutions of the drill pipe go into the storage rack as opposed to a random means of coiling the pipe in the storage rack.

The present apparatus functions both for retrieval of the drill string and return of the drill string to the well bore. When it is time to return the drill string, the rack 55 is reversed in direction of rotation and the elevators 16 as shown in FIG. 4 are likewise reversed to lower the drill string back into the well bore. The full length of the drill string is retrieved from the circular storage rack 55 and returned to the well bore to permit the drilling operation to resume. On retrieval, the pipe is uncoiled from file circular storage rack until the connector 36 feeds back through the various and sundry pipe guides, and is returned to the position of FIG. 3. As shown in FIG. 3, the connective swivel 36 is then disconnected from the drill string, which is then connected to the conventional draw works in the derrick and the drilling process is then resumed. The several method steps of the present invention have likewise been included in the description heretofore.

The vocabulary adapted in the specification is applied to the claims which are appended hereto, the foregoing being directed to the preferred embodiment of the present invention.