US2784942A - Apparatus for simultaneously drilling and casing shot holes - Google Patents

Description

March 12,1957 R. v. PEcK Er AL APPARATUS FOR SIMULTANEOUSLY ORILLING AND CASINO SHOT HOLES 'Filed Jan. 11, 1955 .Usually such explosive charges are 'thus necessitating that the entire hole be cased.

United States Patent APPARATUS FOR SIMULTANEOUSLY DRILLING AND CASING SHUT HOLES Richard V. Peck and John N. Stoddard, Bakersfield, Calif., assignors, by mesne assignments, to California Research Corporation, Sau Francisco, Calif., a corporation of Delaware Application January 11, 1955, Serial No. 481,186 3 Claims. (Cl. Z55- 19) This application relates in general to earth boring, and relates more particularly to apparatus for simultaneously drilling and casing a shot hole for seismic exploration.

In the art of seismic prospecting, charges of explosives are detonated to produce seismic energy which is radiated back to seismic wave detectors for producing signals indicative of the paths of travel of the received energy.

which penetrate the weathered, low velocity upper crust of the earth to providemaximum transfer of energy lfrom the explosive to the earth. Such shot holes are usually drilled with a` portable, rotary drilling rig and, if possible7 the shot holes are not cased or lined. However, where the shot holes are to be drilled in terrain having loose rock formations, sloughing, caving sands or other poorly consolidated material, it is necessary to provide casing in the shot hole to prevent caving of the hole upon withdrawal of the shot hole drill.

Heretofore, numerous methods have been proposed for casing shot holes. Occasionallythe casing can be merely dropped into the hole, but the hole is seldom open enough to permit the use of this method. ln another of these proposed methods, the casing string isvused as a conventional drill string with the drill bit secured to the end of the casing string, and the-casing `is progressively inserted during drilling in a manner similar to that of conventional drill string. However, this method has the disadvantage that it is impossible to remove the drilling bitV from the shot hole without removing the entire casing string, since the bit is secured' to the casing string, This method has the further disadvantagesthat it requires the use of one bit for drilling the entire shot hole and necessitates the abandonment of the bit and the sub in the hole upon completion of the drilling. Many times'the bitl wears out long before theV hole is` finished or, at best, the last portion of the hole is drilled inetliciently because of the badly worn bit. Also, it is often desirable to change the type of bit being used, such as when changing from drilling in rock formations to drilling in clay, and this prior art method prevents such a change.

Broadly, thepresent invention contemplates methods and apparatus for simultaneously drilling and casing a shot hole for seismic exploration in which the drilling bit need not be withdrawn from the hole for the insertion of casing and in which the drilling bit maybe conveniently Withdrawn at any time during the drilling and casing of the hole and recovered upon completion of the drilling. More particularly, the present invention contemplates the use of a conventional shot hole drill provided with retractable underreamers for enlarging the drilled hole beyond the diameter of the drilling bit to a size suicient to permit casing to be inserted in thehole. The underreaming `is done concurrently with the drilling, and the casing is inserted in the hole as Vtheunderreaming progresses. `ln one embodiment of the invention, the drilling assembly is rotated bya rotary table having removable `slips or keys therein which, when removed, permit insertion `of a length placed in shot holes 2,784,942 Patented Mar. l2, 1957 of casing over the drilling assembly without withdrawing the drilling assembly. The casing is disposed concentrically of the drilling assembly, and the casing is forced or allowed to drop into the hole upon resumption of drilling so that the drilling and setting of casing occurs simultaneonsly.

l't is, therefore, an object of the present invention to provide new and improved methods and apparatus for simultaneously drilling and casing well bores.

lt is an additional object of the present invention to provide methods and apparatus for drilling seismic shot holes in which the hole is simultaneously drilled, underreamed, and the casing set in the underreamed portion.

lt is a further object of the present invention to provide methods and apparatus for simultaneously drilling and casing a seismic shot hole in which the entire drilling assembly may be recovered upon completion of the drilling or at any time during the simultaneous casing setting and drilling of the hole.

lt is a further object of the present invention to provide methods and apparatus for simultaneously drilling and casing a seismic shot hole in which the casing setting operation can be suspended and the drilling of the hole continued.

It is a further object of the present invention to provide methods and apparatus for simultaneously drilling and casing seismic shot holes in which the lengths of casing may be inserted into the hole without removing the drilling assembly from the bottom of the hole.

Objects and advantages other than those outlined above will be apparent from the following detailed description when read in conjunction with the accompanying drawing, in which:

Fig. l is a view, partly in cross-section, diagrammatically illustrating apparatus for carrying out the present invention; and

Fig. 2 is a cross-sectional view ll-ll of Fig. 1.

Referring to Figs. l and 2 by character of reference, numeral 11 designates suitable means, such as a truck bed, for supporting the drilling equipment used in the present invention. Bed 1l is provided with a rotary table 12 driven by suitable means, such as a shaft i3, as is well known in the art. Rotary table l2 is provided with an opening in the central portion thereof through which the drilling assembly and casing are adapted to pass. The drilling assembly includes a conventional hollow kelly 16, at one end of which is connected a swivel i7 and a mud hose 1S for supplying drilling lluid to the bit through the hollow center of the kelly and the drill string. The other end of kelly 16 is provided with sui*- able means, such as a conventional oil field tool joint, for securing lengths of drill string to the kelly.

The kelly is also provided with four longitudinal grooves 20 which engage guide pins or keys 2l, either directly or through a drive bushing. Keys 2l are also removably secured to rotary table l2 to transmit the rotational movement of table 12 to kelly lo and the attached drill string, as is well known in the art. Keys 2l are preferably provided with handles 22 for removing the keys from the rotary table. With keys 2l removed, the opening in rotary table 12 is of sulicient size to permit passage therethrough of a length of casing 25 for casing the walls of the shot hole. Kelly 16 may also be provided at the lower end thereof with suitable means for applying force from the kelly to the length of casing 25. Such means may be a thrust block secured to kelly lo and riding on casing 2S, but preferably is a coupling 27 having one end secured to kelly lo by set screws 28 and having the other end secured to the upper end of the casing. The rotational movement of kelly 16 is thus taken along plane transmitted through coupling 27 to casing 25 to aid in inserting the casing in the shot hole.

The drilling assembly also includes a suitable drilling bit 3l secured to the lower end of the drill string. The drilling assembly further includes retractable underreamer cutters or fingers 32 which are actuated by drilling uid pressure acting on a piston 35 which is restrained by a spring 34. When the iiuid pressure inside the drill string is of suicient magnitude, piston 33 is forced downwardly against the action of spring 34 to force underreaming cutters 32 into the expanded position shown in Pig. l to underream or enlarge the diameter of the hole beyond that of bit 31. A rubber rotating ange 3i) may be provided on the drill pipe above the underreamer iingers to prevent drilling uid from passing up between the drill pipe and casing and to force the fluid up between the casing and the bore hole wall to thereby lubricate the casing during its insertion.

Assuming that a shot hole is being drilled, with underreaming cutters 32 expanded by the action of the mud pressure to underream the shot hole to an enlarged diameter, and that a formation is encountered which requires casing to keep the hole open after withdrawal of the drill, the method of operation of the invention is as follows: Swivel i7 and mud hose i3 are disconnected from the upper end ot the kelly, and keys 21 are removed frorn the rotary table. Bit 3l is resting at the bottom at this time so that there is no necessity to insert slips in the rotary table to hold the drilling assembly. Coupling 27 may then be either withdrawn Iup through the rotary table and over tue free end of the kelly, or, if coupling 27 is too large to pass through the rotary table, the coupling may be disconnected below the rotary table. A length of casing ZS is then slipped over the free end of the kelly and into the hole, with the upper end ot casing 2.5 below the rotary table. The components at this time occupy the positions shown in dotted lines in Fig. l. The casing is then made up with as many lengths as can be inserted under the lever of the rotary table. A slush pit 36 or other suitable depression is preferably provided under the rotary table to enable a maximum length of casing to be inserted at one time.

Coupling 27 is then secured to the kelly and to the upper end of casing 25, and keys 2l are inserted into the rotary table and into the grooves of kelly lo. With swivel i7 and mud hose Il@ reconnected, the simultaneo-us drilling and casing setting commences. As kelly i6 and coupling 27 rotate, casing 2S is also rotated and forced into the underreamed hole. it will be understood that, in practice, suitable means7 such as pull-down chains, are usually provided to apply a thrust on the kelly to torce the drilling assembly downward and that this pull-down force will also be applied through coupling 27 to casing rthus, casing Z5 advances in the shot hole simultaneously with the drilling assembly. Alternatively, a simple thrust block connected to the drill pipe and bearing on the `upper end of casing 25 may be utilized in conjunction with a pulldown device it it is Ydesired to merely force casing 25 down rather than rotate it as in the embodiment of Fig. l.

When coupling 27 and the upper end of the casing section 2S have reached the lower surface of the ground, as shown by the solid-line positions of these elements in Fig. i, an additional length of casing may be inserted by detaching coupling 27 from the upper end of the casing section and removing the coupling from the kelly after removal of keys 2i and the swivel and mud hose assembly. The next section of casing may then be lowered over kelly i6 through the opening in the rotary table and threaded or otherwise secured to the upper end of the preceding casing section. Coupling Z7, keys 2l, swivel Q27, and mud hose assembly i3 are then replaced and driiiing and casing setting resumed. it will be understood that additional lengths of drill pipe may be added to the drilling assembly in the usual manner without interfering with the position of the casing being set.

it will be seen from the above that the method and apparatus of this invention permit simultaneous drilling and setting of casing without the necessity of withdrawing the bit and drill string from the bottom of the hole or trom the hole itself to add additional casing lengths, and that this invention permits the bit and the remainder of the drilling assembly to be easily removed from the hole upon completion of the drilling operation or at any time during the drilling operation.

It will be obvious to those skilled in the art that various changes and modifications may be made in the illustrated embodiment without departing from the spirit of the invention. For example, if the opening in the rotary table is not of sufficient size to permit the casing sections to be inserted therethrough, the method of this invention may be carried out by withdrawing the drilling assembly from the hole up to the level of the rotary table and inserting a casing length between the rotary table and the surface of the ground. The drilling assembly may then be lowered through the casing and drilling operations resumed. This method of operation also permits simultaneous drilling and vsetting of casing and enables the drilling assembly to be recovered from the hole upon completion of drilling.

We claim:

l. Apparatus for simultaneously drilling and inserting lengths of casing in a seismic shot hole comprising a string of drill pipe, a drilling bit secured to one end of said drill string, underreaming means in said drill string for enlarging the opening produced by said bit to a diameter sutlicient to accommodate said casing, a rotary table having an opening therein of suicient diameter to accommodate said casing, a kelly connected to the upper end of said drill string and passing through said opening in said rotary table, removable keys in said rotary table for engaging said kelly to transmit the rotary movement of said table to said kelly and said drill string, a length of said casing being insertable through said opening in said rotary table when said keys are removed, the upper end of said length of casing being positioned below said rotary table after insertion, and coupling means secured to said kelly below said rotary table for connecting said kelly to said length of casing to transmit the movement of said kelly to said casing length, whereby said casing length is inserted in said hole as said drilling and underreaming progress.

2. Apparatus for simultaneously drilling and inserting lengths of casing in a seismic shot hole comprising a string of drill pipe, a drilling bit secured to the end of said drill string, underreaming means in said drill string for enlarging the opening produced by said bit to a diameter suicient to accommodate said casing, a rotary table having an opening therein of suflicient diameter to accommodate said casing, a kelly connected to the upper end of said drill string and passing through said opening in said rotary table, removable keys in said rotary table for engaging said kelly to transmit the rotary movement of said table to said kelly and said drill string, a length of said casing being insertable through said opening in said rotary table when said keys are removed, the upper end of said length of casing being positioned below said rotary table after insertion, and means secured to said kelly below said rotary table for transmitting force from said kelly to a length of said casing, whereby said casing length is inserted in said hole as said drilling and underreaming progress.

3. Apparatus for simultaneously drilling and inserting lengths of casing in a seismic shot hole comprisinga string of drill pipe, a drilling bit secured to the end of said drill string, retractable underrearning means in said drill string for enlarging the opening produced by said bit to a diameter sucient to accommodate said casing, hydraulic means for operating said underreaming means, a rotary table having an opening therein of suhcient diameter to accommodate said casing, a hollow kelly connected to the upper end of said drill string and passing through said opening in said rotary table, removable keys in said rotary table for engaging said hollow kelly to transmit the rotary movement of said table to said hollow kelly and said drill string, a length of said casing being insertable through said opening in said rotary table when said keys are removed, the upper end of said length of casing being positioned below said rotary table after insertion, and coupling means secured to said hollow kelly below said rotary table for connecting said hollow kelly to said length of casing to transmit the movement of said hollow 6 kelly to said casing length, whereby said casing length is inserted in said hole as said drilling and underreaming progress.

References Cited in the le of this patent UNlTED STATES PATE-NTS 224,182 Hammett Feb. 3, 1880 1,908,227 Dodds May 9, 1933 2,227,763 Santiago Jan. 7, 1941 2,338,093 Caldwell Jan. 4, 1944 2,485,826 Harinck Oct. 25, 1949 2,688,465 Birdwell Sept. 7, 1954

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