US3347319A

US3347319A - Large diameter casing

Info

Publication number: US3347319A
Application number: US439760A
Authority: US
Inventors: Robert L Littlejohn
Original assignee: Fenix and Scisson Inc
Current assignee: Fenix and Scisson Inc
Priority date: 1965-03-15
Filing date: 1965-03-15
Publication date: 1967-10-17
Anticipated expiration: 1984-10-17

Description

Oct. 17, 1967 R. L.. LxTTLEJQHN .3,347,319

l v LARGE DIAMETER GASING Filed March 15, 1965 2 Sheets-Sheet l INVENTOR ROABERT L. l. TTLEJHV BY y ATTORNEYS Oct. 17, 1967 R. L. LITTLEJOHN LARGE DIAMETER CASING 2 Sheets-Sheet 2 Filed March l5, 1965 INVENTOR ROBERT L. L/TnEJoH/v BY Ma] ATTQRNEYS L United States Patent Office 3,347,319 Patented Oct. 17, 1967 3,347,319 LARGE DIAMETER CASING Robert L. Littlejohn, Las Vegas, Nev., assigner to Fenix & Scisson, Inc., Tulsa, Okla., a corporation of Gklahonra Filed Mar. 15, 1965, Ser. No. 439,760 4 Claims. (Cl. 166--242) ABSTRACT OF THE DISCLSURE This invention relates to large diameter casing for positioning in a borehole in the earth. The casing includes a string of smaller diameter tubing removably supported to the exterior thereof and affording means of delivering cement around the exterior of the casing and including brakets exterior of the casing slidably receiving the tubing. The tubing has at the lower end thereof an enlarged external diameter shear collar formed of shearable material. The tubi-ng is slidably supported to the exterior of the casing by means of a tattletale bracket affixed to the exterior of the casing having an internal conguration to slidably receive the tubing but smaller than the external diameter of said shear collar. The shear collar is detachable from the tubing by upward pull on the tubing whereby said tubing may be removed, the engagement of the shear collar with the tattletale bracket indicating that the lower end of the tubing is adjacent the shear collar.

This invention relates to large diameter casings. More particularly, the invention relates to supporting large diameter casings in a drill hole and in another sense to the configuration of large diameter casings adaptable for support in a borehole.

Many types of underground work require the provisions of large casings in boreholes to afford access to subterranean formations, such as underground chambers for storing liquefied petroleum products and for general mining operations.

While the suspension of casings in boreholes is a common practice in the oil industry, such installations are limited to small diameter casings. When access must be provided for men and equipment to work below in ground installations the diameter must be much larger, varying from 30 inches LD. to 10 feet I.D. and even larger.

First a borehole of large diameter must be drilled in the earth. The borehole must then be lined by a steel casing to prevent cave-ins. It can be seen that the steel casing must be cemented in position and it is apparent that lowering into position, suspending and cementing in place a large diameter casing is an extremely diicult job.

Others have provided means for placing into position and cementing casing in boreholes and have described some of the problems in connection therewith. Examples of the prior disclosed means of solving the problem of lining boreholes with large diameter casing can be had by referring to the following United States patents:

An object of this invention is to provide means for hanging `in a borehole large diameter casing including means for cernenting the casing in position.

Another object of this invention is to provide improved large diameter casings of a` configuration particularly adaptable for telescopic mounting in a borehole.

Another object of this invention is to provide a means of cementing sequentially telescoped lengths for large diameter casing in a borehole including means for indicating when the cement has fully filled the annulus surrounding each length of casing. i

These and other objects and a better understanding of the invention will be had by referring to the following description and claims taken in conjunction with the attached drawings in which:

FIGURE 1 is a cross-sectional view of three lengths of large diameter casing hung in a borehole according to this invention.

FIGURE 2 is an enlarged cross-sectional View taken along the line 2-2 o-f FIGURE 1 of a portion of two lengths of large diameter casing constructed according to this invention. t

FIGURE 3 is a cross-sectional view taken along the line 3-3 of FIGURE 2.

FIGURE 4 is a cross-sectional view taken along the a typical installation is shown. First, a borehole 10 isi provided in the earth. In the upper portion of the borehole, which may be for instance to a depth of 200 feet, a large diameter casing 12 is positioned; this casing may be termed the surface casing. The upper open end 14 of the surface casing 12 communicates with the atmosphere at or adjacent to the earths surface. Welded to the interior of the surface casing 12 near the lower end thereof is an interior hanging ring 16 having anrinwardly sloped surface 18. The surface casing 12 is held in position in the borehole 10 by means of cement 20 in the annulus between the exterior surface of the casing and the borehole.

The next step in the hanging of the large diameter casing according to this invention includes the positioning of a second length of casing 22 in the borehole. In the illustration of FIGURE 1 the surface casing 12 and casing `22 have been previously lowered into the borehole, hung in position and cemented. The outside diameter of the second length of casing 22 is less than the interior diameter of the interior hanging ring 16. Afiixed to the exterior of the second length of casing 22 is an exterior hanging ring 24 having an outwardly sloped surface 26. The upper end of the second length of casing 22 is beveled at 23 so that the O.D. of the beveled portion is slightly less than the I.D. of the surface casing 12. Welded to the interior of the second length of casing 22 adjacent the lower end thereof is an interior hanging ring 16A having an inwardly sloped surface 18A as previously described with reference to the surface casing 12. The second length of casing 22 is shown having been aliixed in position bycement 20 in the annulus surrounding the casing. i

In FIGURE 1 a third length of casing 30 is shown having been lowered in the borehole and is shown in the process of being cemented in position. The third length of casing 30 is constructed identically to the second length of casing 22 except that the O.D. of the third length of casing is smaller than the LD. of the interior hanging ring 16A. The third length of casing 30 has an exterior hanging ring 24B and an interior hanging ring 16B for the same purposes as previously described. In addition, as shown, the third length of casing 30 is provided with a drillable shoe 32 in the lower end thereof which serves The flushing tubing 34 is used as a means of injecting a Cement slurry 36 into the annulus between the exterior of the third length of casing and the borehole 1t). Affixed to the lower end of the flushing tubing 34 is a shear collar 38. The shear collar may be of metal lightly Welded to the tubing or heldfon the tubing by shearable adhesive such as epoxy resin, or the shear collar may be formed of some shearable material such as concrete or plastic. Holding the ushing tubing 34 in proper position on the exterior of the third length of casing 30 is a lower bracket 4) and a top or tattletale bracket 42.

Referring to FIGURE 2 the details of the casing lengths and the flushing tubing of this invention are best shown. The interior hanging ring 16A is welded to the interior of the second length of casing 22, the ring serving two purposes. The first and main purpose is to afford a projection on which the succeeding length of casing may be hung. The second purpose is to reinforce the casing to prevent its failure by outward pressure.

Afixed to the exterior of the third length of casing 30 is shown the exterior hanging ring 24B having its outwardly sloped surface 26 which engages the inwardly sloped surface 18A of the interior hanging ring 16A to hang the third length of casing 30. The exterior seating ring 24B is welded to the third length of casing 30 and serves the dual role of providing means of hanging the casing and reinforcement of the casing.

In FIGURE 2 it can be seen that the exterior hanging ring 24B is provided with an opening 44 through which the liushing tubing 34 passes. The diameter of the opening 44 is such as to freely pass the shear collar 38 affixed to the lower end of the fiushing tubing. In like manner the upper beveled portion 28A of the third length of casing is provided with an opening 46 which receives the flushing tubing 34.

As previously indicated, to retain the iushing tubing 34 in its proper position exterior of the third length of casing 30 as it is lowered in the hole a lower bracket 40 and a top bracket 42 are provided. These are best shown in FIGURES 3 and 4. As seen in FIGURE 3 the top or tattletale bracket 42, which is welded to the exterior of the third length of casing 30, is of a configuration to freely pass the casing 30 but is too small to pass the shear collar 38. The importance of this feature will be described subsequently. In contrast, the lower bracket 40, as shown in FIGURE 4, is large enough to freely pass the shear collar 38.

Method of hanging large diameter casing As previously indicated, FIGURE 1 shows the surface casing 12 and the first length of casing 22 having previously been hung and cemented into position. This view further shows the third length of casing 30 having been hung in position and is in the process of being cemented into place. According to the method of this invention, the third length of casing 30 is first hung in position having the drillable shoe 32 closing the lower end thereof. As the third length of casing 30 is placed in position it has afxed exteriorly thereof the flushing tubing 34 which extends to the surface. Cementing of the third length of casing 30 is accomplished by filling the interior of the third length of casing 30 with water, which may be pumped directly into the exposed upper end of the casing, to gradually ll the interior of the casing. At the same time, a cement slurry is pumped down through the flushing tubing 34 passing out the bottom of the tubing string and filling the annulus 36 around the casing. As the slurry is pumped into the annulus the string 34 is gradually withdrawn and at the same time the interior of the casing is filled with water. Optimumly, the level of water is maintained at approximately the same level as the cement slurry in the annulus. The function of the water is twofold. First, the weight of the water within the casing prevents it from being oated out by the cement slurry and second, the hydrostatic force of the water counteracts the eXteriOrly applied hydrostatic force of the cement slurry to eliminate the possibility of collapse of the casing.

As the iiushing tubing 34 is gradually withdrawn, the shear collar 38 freely passes through the lower bracket 40 which held it in its proper position as the casing and tubing were lowered into position. In like manner the shear collar freely passes through the opening 44 in the exterior hanging ring 24B but the shear collar cannot pass through the top bracket 42. When this is reached resistance to further upward extraction of the tubing occurs indicating to the cementing crew that the bottom of the tubing string is at the top of the third length of casing. If the tubing string has been withdrawn at the same rate the annulus is filled then the engagement of the shear collar 33 with the top bracket 42 is an indication that the annulus surrounding the third length of casing 30 has been filled. A more forceful upward pull on the tubing string shears the collar 38 allowing the tubing string to be extracted. The extraction of the tubing string completes the steps of cementing the third length of casing 30 in position.

The shoe 32 may be then drilled out, opening the lower end of the third length of casing 30 for the next phase of work. The method by which the third length of casing 30 has been hung and cemented in position can be repeated as often as necessary until the final depth is attained, each succeeding length of casing being smaller in diameter.

The method has been described to illustrate the steps of cementing the third length of casing 30 in position. The same steps would have been previously followed in hanging and cementing the second length of casing 22 in position.

Referring to FIGURES 5 and 6 an alternate method of cementing the casings of this invention into position is shown. In this method a shoe 50 closing the lower end of the third length of casing 30 is provided having an axial opening 52 therein. A latch-in tool 54 is lowered into position and stabbed into the openings 52 in shoe 50. A crown slip spear assembly, generally indicated by the numeral 56, is lowered into position having an expansion joint 58 which connects to the latch-in tool 54. Preparatory to the cementing operation, the expansion joint 58 is actuated to provide a side door opening through which the interior of the third length of casing 30 is filled with water. The side door opening is closed and then a cement slurry is pumped down the drill pipe 54 and through the opening 52 in shoe 50 to till the annulus with a cement slurry 36. After the annulus has been completely filled the crown slip spear assembly 56, the latch-in tool 54 and the side door expansion joint 5S are removed. The shoe 50 may then be drilled out exposing the end of the casing for the next sequence of drilling. The steps may be repeated with each additional length of casing until the ultimately desired depth is achieved.

The method of FIGURES 5 and 6 utilizes casing having the same structure as far as the hanging rings 16 and 18 are concerned but do not require the

brackets

40 and 42 of the previously described method. In addition, the method of FIGURES 5 and 6 does not require any openings inthe exterior hanging ring 24B.

The casing `structure of this invention and method of using same results in a substantial reduction of time and material costs normally encountered in hanging and cementing large diameter casings.

While this invention has been described with a certain degree of particularity it is manifest that many changes may be made in details of construction and the arrangements of components described without departing from the spirit and scope of this disclosure.

What is claimed is:

1. A large diameter casing string comprising:

a rst length of open ended casing positioned uprightly and cemented in the earth, the upper end communicating with the atmosphere;

an internal annular inwardly tapered hanging ring affixed to the first length of casing adjacent the open bottom end thereof;

a second length of open ended casing having an outupper end terminating at the earths surface and the lower end terminating at the lower end of said second length of casing, said tubing affording means of delivering cement around the exterior of said secside diameter smaller than the internal diameter of 5 ond length of casing; and said internal hanging ring aiiixed to said rst length including successive additional lengths of casing terof casing, said second length of casing vertically teleminating in a lower smallest diameter length of casscopically positioned in said first length of casing; ing, each successive length having an external outan external annular outwardly tapered hanging ring wardly tapered annular hanging ring adjacent the aflixed to said second length of casing adjacent the 10 upper end and an inwardly tapered internal annular upper end thereof, the outwardly tapered hanging hanging ring adjacent the lower end, each succesring engaging the internal hanging ring aixed to said sive length of casing being of an external diameter first length of casing whereby said second length of smaller than the internal diameter of said internal casing is suspended from said iirst length, said sechanging ring of the above adjacent length of casing, ond length of casing having the top end thereof ilared the upper end of each length of casing ared to an outwardly to near proximity of the internal wall of said rst length of casing, said external annular hangexternal diameter near the internal diameter of the above adjacent length of casing, the external hanging ring and said flared end portion of said second length of casing having an aligned small diameter opening therein; a string of smaller diameter tubing removably supported to the exterior of said second length of casing ing ring and flared top of each length of casing having an aligned tubing receiving opening therein.

3. A large diameter casing string according to claim 2 including a tattletale bracket axed adjacent the upper exterior end of said smallest diameter length of casing and extending through said aligned opening in said said bracket slidably receiving said tubing string, whereexterior hanging ring and flared end, said tubing exin said tubing string has a shearable collar at the lower tending interiorly of said first length of casing, the end thereof, of an exterior diameter larger than the inupper end terminating at the ear this Surface and the terior diameter of said bracket, said bracket serving to relower end terminating at the lower end of said seC- tain said tubing as said smallest diameter length of casond length of Casing, Said tubing aifOrding means Of ing and attached tubing are lowered into position, said delivering cement around the exterior of said secshearable collar detachable from said tubing by upward ond length of casing; and pull on said tubing whereby said tubing may be removed,

a tattletale bracket affixed adjacent the upper exteIiOr the engagement of said shearable collar with said tattleend of Said Second length of Casing, Said bracket tale bracket indicating that the lower end of said tubing is slidably receiving said tubing string, and wherein Said adjacent the top of the smallest diameter length of casing. tubing string has a shearable collar at the lower end 4, A casing string comprising:

thereof, 0f an exterior diameter larger than the in- 35 a length 0f large diameter casing positionable in an terior diameter of said bracket, said bracket serving earth borehole to bo cemented in position;

t0 retain Said tubing aS Said Second length 0f Casing a length of tubing slidably supported to the exterior and attached tubing are lowered into Position, Said of said casing and extending to the earths surface,

shearable collar detachable from said tubing by upsaid tubing affording means of pumping cement in ward Pull on Said tubing whereby Said tubing may be the earth borehole exterior said casing;

removed, the engagement 0f said shearable lnollar a shearable collar of diameter greater than said tubing with said tattletale bracket indicating that the lower affxod to the lower ond of Said tubing;

end 0f Said tubing iS adjacent the top of the second and a tattletale bracket aixed to the exterior of said length of Casing. casing at the elevation desired for the top of cement -2- A large diameter Casing string Comprising? 45 to be injected around the casing, said bracket having a iirst length of open ended Casing Positioned upright' a diameter to slidably receive said tubing but of 1y and cementeri in the earth, the upper end Comsmaller diameter than said shearable collar, said munieating with the atmosphere; bracket serving to retain said tubing as said length an internal annular inwardly tapered hanging ring af* of casing and attached tubing are lowered into posiiiXed to the iirst length of Casing adjacent the Open tion, said shearable collar being detachable from said bOttOm end thereof; tubing by upward pull on said tubing whereby said a second length of open ended casing having an outtubing may be removed, the engagement of said side diameter Smaller than the internal diameter of shearable collar with said tattletale bracket indicat- Snid internal hanging ring affixed to Said rst length ing that the lower end of said tubing is adjacent the of casing, said second length of casing vertically telebracket scopically positioned in said nrst length of casing;

an external annular outwardly tapered hanging ring affixed to said second length of casing adjacent the upper end thereof, the outwardly tapered hanging References Cited UNITED STATES PATENTS a string of smaller diameter tubing removably supported to the exterior of said second length of casing and extending through said aligned opening in said exterior hanging rring and ared end, said tubing extending interiorly of said rst length of casing, `the CHARLES E. OCONNELL, Primary Examiner.

I. A. CALVERT, Assistant Examiner.

Claims

4. A CASING STRING COMPRISING; A LENGTH OF LARGE DIAMETER CASING POSITIONABLE IN AN EARTH BOREHOLE TO BE CEMENTED IN POSITION; A LENGTH OF TUBING SLIDABLY SUPPORTED TO THE EXTERIOR OF SAID CASING AND EXTENDING TO THE EARTH''S SURFACE, SAID TUBING AFFORDING MEANS OF PUMPING CEMENT IN THE EARTH BOREHOLE EXTERIOR SAID CASING; A SHEARABLE COLLAR OF DIAMETER GREATER THAN SAID TUBING AFFIXED TO THE LOWER END OF SAID TUBING; AND A TATTLETALE BRACKET AFFIXED TO THE EXTERIOR OF SAID CASING AT THE ELEVATION DESIRED FOR THE TOP OF CEMENT TO BE INJECTED AROUND THE CASING, SAID BRACKET HAVING A DIAMETER TO SLIDABLY RECEIVE SAID TUBING BUT OF SMALLER DIAMETER THAN SAID SHEARABLE COLLAR, SAID BRACKET SERVING TO RETAIN SAID TUBING AS SAID LENGTH OF CASING AND ATTACHED TUBING ARE LOWERED INTO POSITION, SAID SHEARABLE COLLAR BEING DETACHABLE FROM SAID TUBING BY UPWARD PULL ON SAID TUBING WHEREBY SAID TUBING MAY BE REMOVED, THE ENGAGEMENT OF SAID SHEARABLE COLLAR WITH SAID TATTLETALE BRACKET INDICATING THAT THE LOWER END OF SAID TUBING IS ADJACENT THE BRACKET.