US2734721A - zublin - Google Patents

Description

Feb. 14, 1956 J. A. zuBLlN, 2,734,721

` APPARATUS FOR DRILLING WELLS WITH ORIENTED CURVED BORES OF' LARGE RADII Filed June 4, 1953 2 Sheets-Sheet l Feb. 14, 1956 Filed June 4,J 1955 APPARATUS FOR CURVED J. ZUBLIN DRI NG WELLS WITH BORES OF' LARGE RADI ORIENTED I 2 Sheets-Sheet 2 mxmmw INVENTOR United States Patent APPARATUS FOR DRILLING WELLS WITH URI- ENTED CURVED BORES OR LARGE RADII John A. Zublin, Los Angeles, Calif.

Application June 4, 1953, Serial No. 359,562

2 Claims. (Cl. 25E-1.6)

The present invention relates to apparatus for drilling oil wells with oriented curved bores of large radii. It is the purpose and object of the invention to provide a method and apparatus by which oriented curved bores of large radii may be effectively drilled with but one round trip of the drilling equipment.

The need for the drilling of deecting bores having as their purpose the recovery of oil from points in a producing formation horizontally spaced a substantial distance from the point of initiation of the vertical well bore has become increasingly pronounced with attempts to recover oil from underwater formations. Indeed there are many instances where the real need for the drilling of a deflecting bore in a given azimuth is apparent.

It is the purpose and Iobject of the present invention to provide a method and apparatus by which such a deflecting bore may be produced through conventional rotary drilling technique as a direct continuation of an initiated vertical well bore.

The present invention is not concerned with the production of curved deviated bores of small radii such as drain holes drilled directly from a verticalbore laterally into the producing formation, but is rather concerned with the production of a deiiecting bore as a continuation of an initially straight well bore in the drilling of which the bore is deflected in a curved path of large radius on the order of 1000 to 2000 feet.

In the prior art practice of the drilling of deflecting bores the expedient of whipstocks has been primarily availed of. Generally speaking, tubular drill strings employed in rotary drilling have suicient inherent ilexibility to permit of their deviation from the vertical in an amount approximating about 3 per hundred feet of length Vof drill string. In general, whipstocks set in a vertical well bore for the purpose of causing a deiiection of the drill bit 'normally contemplate a deflection from the vertical of from around 3.to about 5. In practice it has been found that when drilling a deflecting bore through the medium of a whipstock, the drill string after it passes the whipstock tends to follow the path of least resistance and return to a straight line under the iniluence of gravity. In consequence of this inherent tendency of the conventional rotary drill string to follow the path of least resistance, it has been the prior art practice in the drilling of deecting bores through the use of whipstocks to drill a limited distance beyond the point of setting a particular whipstock; to then withdraw the drill string and bit from the well bore and set another whipstock at a lower depth to which the deecting bore has been drilled, and to repeat this procedure throughout the drilling of the deilecting bore. Such practice has entailed the necessity for a complete roundtrip each time a whipstock is set. Each roundtrip and each setting of the whipstock entails hazards that, -quite apart from the sheer-loss of time involved, render the drilling of the dellecting bores of large radii very costly. v-

ICC

It is the purpose and object of this invention to provide a simplified method and apparatus for drilling deilecting bores of large radii by which it is possible to eliminate the use of whipstocks and to complete the drilling of a deecting bore or a series of dellecting bores on one roundtrip of the drilling equipment.

More specically, it is the object of the invention to provide a method and apparatus for initiating and continuing the drilling of a deilecting bore at substantially the same fixed radius, said radius being sufficiently large to lie within the limits of the inherent ilexibility of the conventional rotary drill string.

From an apparatus standpoint, the purpose and object of the invention is to provide a unit suspendable from the lower end of a rotary drill string susceptible of manipulations in a manner requisite to elect the initiation and continued drilling of a curved deflecting bore of large radius without the use of instrumentalities other than those suspended from and carried by and insertable into the well bore by a conventional rotary drill string.

By the expression curved bores of large radii as employed in this application, it is intended to identify and define curved bores having degrees of curvature attainable through the inherent iiexibility of a normal rotary drill string. In general, the radii of deiiecting bores with which the present invention is concerned lie within the limits of about 1000 to about 3000 feet.

Further purposes and objects of the invention will become apparent as the description proceeds and will be described in connection with the accompanying drawings, in which Figure 1 is a fragmentary view and side elevation with parts broken away and illustrating a position of the drilling unit suitable for practicing the method and exemplifying the apparatus of the invention;

.Figure 2 is a fragmentary view and side elevation with parts broken away similar in nature to Fig. l, and illustrating an additional species of the apparatus of the invention and a position of such apparatus suitable for practicing the method of the invention;

Figure 3 is a detailed cross sectional View illustrating the manner in which the deiiecting force is applied to the drilling in the unit;

Figure 4 is a detailed cross sectional view taken along the line 4 4 of Fig. 3;

Figure 5 is a detailed cross sectional view taken on the line 5-5`of Fig. 3;

Figure 6 is a detailed cross sectional view taken on the line 6--6 of Fig. 3;

Figure 7 is a detailed cross sectional view through the clutch mechanism illustrating operational features of the apparatus; and

Figure 8 is a detailed cross sectional view illustrating the manner in which the drilling unit may be suspended from a conventional rotary drill string.

Referring to Figure 1, a conventional hollow rotary drill string is indicated at 10 which is adapted to extend to the surface of the well and to be rotated by conventional rotary equipment. Drilling uid is adapted to be passed down and through the drill string 10 from the lower end of which is suspended a unit assembly embracing an inner tubular rotary drive member 11 which carries a bit 12 at its lower end. Rotation of the rotary drill string 10 and the rotary tubular drive member 11 will effect a positive rotation of the bit 12. Surrounding the rotary drive member 11 is an elongated sleeve i3, the upper end of which is threadably engaged at 14 in a collar 15 carrying anti-friction means 16 for facilitating free rotation of the tubular drive member 11 within the sleeve 13 (see Fig. 8). The sleeve 13 is slidable longitudinally to a limited extent on the member' :arsenal 11. Adjacent the upper end of the sleeve 13 there is positioned a stabilizing collar 17 having ribs 18. The stabilizing collar 17 is carried by the sleeve 13 and functions to stabilize the apparatus in the well bore.

The stabilizing collar 17 acts as a fulcrum about which the portions of the apparatus below the collar 17 can be moved.

Atl a point intermediate the stabilizing collar 17 and the bit 12 there is provided an anchoring collar 19 ixedly held on the outer sleeve 13 by a set of screws 20 (see Fig. 4). Spaced below the collar 1.9 a slidable collar 21 having a keyway 23 for the accompanying key 22, is mounted for relative vertical movement on the exterior of the sleeve 13 (see Fig. 5). A heavy leaf spring 24 adapted to exert a predetermined lateral force on the drill unit has its upper end secured as indicated at 25 to the collar 19 opposite the gripping teeth 26 thereof. The lower end of the leaf spring 24 is secured as indicated at 27 to the slidable collar Z1 opposite the gripping teeth 23 thereof. Stop members 29 are carried by the sleeve 13 to limit the upper movement of the collar 21 on the sleeve 13.

Secured to the lower end of the sleeve 13 by the threaded connections 30 is the upper member 31 of the two-clutch member. The lower member 32 of the twoclutch member is secured to and carried by the inner rotary drive member 11. The spring 33 normally urges the clutch members 31 and 32 toward the disengaged position. When, however, an upper pull is exerted on the rotary drill string 10, the frictional resistance offered u by the stabilizing collar 17, the spring 24 and attendant mountings carried by the outer sleeve 13, against the well bore wall will hold the sleeve 13 thereby permitting limited vertical movement of the inner drive member 11 and engagement of the clutch members 31 and 32 to permit concurrent rotation of the inner drive member 11 and the sleeve 13 to facilitate orientation of the sleeve 13. and to insure deflection of the bit 12 in the desired azimuth.

It will be appreciated that as the drilling of the deecting bore continues the spring 24 tends to force the collars 19 and 21 toward the side of the bore with the smallest radius. When the teeth 26 and 28 of the collars 19 and 21 are pressed against the wall of the deilecting bore, the degree of deection will become stable and the bore will continue with substantially the same radius. The spring 24 continues to maintain proper friction between the collar 19 and the wall of the well bore whereby the member 13 is held against rotation as it advances in the bore. clutch members 30 and 31 with the forced rotation of member 13 will vary the azimuth of the deecting bore.

Only the closing of the It will also be appreciated that the weight of the sleeve f 13 and parts carried thereby is normally sufficiently in excess of the frictional resistance or drag created by spring 24 and the ribs on collars 17, 19 and 21 engaging with the well bore such that the sleeve normally moves along with the drill collar 11 and drill bit 12.

It may, in some instances, be advantageous to mount the collars 19 and 21 on the member 13 other than concentrically therewith to further facilitate orientation in the well.

By reference to Figure 1, it will be observed that the drilling unit shown has three points of contact with the well bore, point A being the contact of the stabilizing collar 17 with the well bore; point B being the contact of the drill bit 12 with the well bore; and point C being the contact of the spring 24 with the well bore. The bit 12 rotates and its sharp teeth cut sidewardly into the well bore under the force supplied by spring 24 which tends to pivot the bit about the collar 17 at point A as a fulcrum. Thus, after a few rotations of the drill string with the parts in the position shown in Figure. l, the bit initiates the drilling sidewardly under the force of the spring 24. The bit is lowered simultaneously with this sideward drilling tendency with the result that there is initiated the drilling of a curved bore of largev radius determined by the three-point Contact of the unit within the well bore.

A generally equivalent structure is shown in Figure 2 which is identical with the structure shown in Figure l with the exception that the relative location of the stabilizing collar 17 and of the collar 19 and associated parts, including the spring 24 and the slidable collar 21, is reversed. That is, the apparatus shown in Figure 2 partahes of the characteristics of a rst class lever whereas the apparatus of Figure 1 partakes of the characteristics of a lever of the third class. More specilically, in the apparatus shown, in Figure 2 the spring 24 having its contact point C with the well bore acts as a torce :o pivot the apparatus around the contact point A of the collar 17 which functions as a fulcrum and so to direct the bit 12 making Contact at B with the well bore to drill a deflecting bore of the desired radius.

it will be understood that this invention contemplates, both with respect to method and apparatus, all relative rotations at the points A and B, and more specically of the collar 17 which functions as a fulcrum and the collar 19 and associated force applying spring 24 and slidable collar 21.

It will be understood that the eiective pressure applied to the bit will depend somewhat on the relative location of the points A, B and C, and that by variation of the relationship of the points A, B and C and the degree of pressure applied by the spring 24 at the point C, the degree of deection of the bit can be quite accurately controlled within the limits of elasticity of the rotary drill string 10.

While the invention is primarily intended to effect drilling of a deflecting bore as a continuation of an initiated vertical bore, it is possible to take off from a vertical bore that has been previously drilled and drill a deecting bore in a predetermined azimuth from said vertical bore.

Indeed, it is even possible to drill a second deecting bore after a rst bore in a given azimuth has been drilled. A slight pull on the drill string 10 with limited partial rotation will elfect engagement of the clutch members 31 and' 32, following which the unit may be oriented in a new azimuth.

This application is a continuation-in-part of Zublin application Ser. No. 328,679- led December 30, 1952.

Having thus described my invention, what I claim is:

l. Apparatus for controlling the direction and extent of deviation of a well bore by the rotary drilling method comprising an elongated relatively iniiexible tubular section, an elongated drill collar rotatably mounted in said tubular section, a drill bit carried at the lower end of and rotatable with said drill collar, means at the upper end of said drill collar for connecting same to the lower end of a rotary drill string for rotation therewith, a collar rigidly secured to said tubular section adjacent the lower end thereof and having outwardly projecting ribs engageable with the well bore wall to provide a fulcrum about which said tubular section can pivot, and well bore. engaging deecting means carried by said tubular section at a point spaced above said collar acting to urge said inexible tubular section and said drill bit to pivot about said collar in a predetermined radial direction.

2. Apparatus for controlling the direction and extent of deviation of a well bore by the rotary drilling method comprising an elongated relatively inexible tubular Section, an elongated drill collar rotatably mounted in said tubular section and capable of limited longitudinal movement relative to said tubular section, interengaging clutch elements carried by said tubular section andv said drill collar respectively, means normally. holding said clutch elements. in disengaged position while permitting engagementof said. clutch elementsupon limited longitudinal' movement of said drill collar within said tubular sec 5 tion, a drill bit carried at the lower end of and rotatable with said drill collar, means at the upper end of said drill collar for connectng same to the lower end of a rotary drill string for rotation therewith and which said tubular section can pivot and well bore engaging deecting means carried by said tubular section at a point spaced above said collar acting to urge said iniiexible tubular sectionand said drill bit to pivot about whereby said drill collar may be moved longitudinally 5 Seid 0011er in e predetermined radial directionrelative to said tubular section by lifting of the dn'll string for engagement of said clutch elements, a collar rigidly secured to said tubular section adjacent the lower end thereof and having outwardly projecting ribs engageable with the well bore wall to provide a fulcrum about Anderson July 25, 1939 Diehl et al. Sept. 14, 1943

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