US3420308A

US3420308A - Well casing hanger

Info

Publication number: US3420308A
Application number: US661039A
Authority: US
Inventors: Samuel W Putch
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1967-08-16
Filing date: 1967-08-16
Publication date: 1969-01-07
Anticipated expiration: 1986-01-07
Also published as: GB1194102A; FR1579713A

Description

Jan. 7, 1969 5, w, PUTCH 3,420,308

WELL CASING HANGER Filed Aug. 16, 1967 Sheet Of 4 FIELI INVENTOR. SAMUEL W. PUTCH BYE/MW ATTORNEYS Jan. 7, 1969 s. w. PUTCH 3,420,308

WELL CASING HANGER Filed Aug. 16, 1967 Sheet 2 of 4 F'IE .I=

INVENTOR. SAMUEL w. PUTCH BYJWW AT TORNE YS Jan. 7, 1969 s. w. PUTCH 3,420,308

WELL CASING HANGER Filed Aug. 16, 1967 Sheet J of 4 F IB E INVENTOR. SAMUEL w. PUTCH BYJWM ATTORNEYS Jan. 7, 1969 s. w. PUTCH 3,420,308

WELL CASING HANGER Filed Aug. 16, 1967 Sheet 4 of 4 F'II3 E INVENTOR. SAMUEL w. Pu'rcH ATTORNEYS United States Patent Office Patented Jan. 7, 1969 3,420,308 WELL CASING HANGER Samuel W. Putch, Harris County, Tex., assignor to FMC Corporation, San Jose, Calif., a corporation of Delaware Filed Aug. 16, 1967, Ser. No. 661,039 US. Cl. 166-208 Int. Cl. E21b 17/046 7 Claims ABSTRACT OF THE DISCLOSURE Background of the invention The field of art to which this invention pertains includes devices for suspending pipe or casing in wells or shafts bored into the earth, and more particularly to such devices for suspending an inner casing at a predetermined position inside an outer casing. More particularly, the invention relates to devices commonly known as casing hangers, and to those hangers which include an expansible and contractible element adapted to expand into a predesignated section of the outer casing to preclude downward travel of the inner casing within the outer casing.

In the practice of drilling wells for the recovery of valuable fluids such as oil and gas, it is customary to line the well bore with a series of concentric pipes, called casing strings, suspended from the top of the well by a hanger device that fastens an inner casing to the next adjacent outer casing. Where wells are drilled in off-shore locations, and particularly in deep water, it has been found desirable to support the several casing strings at the ocean floor to take advantage of the earths lateral and vertical support, rather than at the waters surface which leaves the casing highly susceptible to damage or loss as a result of surface storms, tidal fluctuations, strong currents, and sometimes just the great weight itself of an extensive length of heavy pipe. To overcome this problem, hangers that can be positioned at any desired place in an outer casing string have been developed to suspend the inner casing string at any level in the well, including at the ocean floor.

Although in general these hangers operate satisfactorily, many contain a plurality of spring-biased locking elements that are expanded into the landing section of the outer casing to secure the inner casing to it, and these springs can break or otherwise fail to perform. Another problem with hangers of this type is that they usually contain a number of parts which are rather intricate and therefore expensive. Further, the more complex the hanger the greater chance there is for it to malfunction, requiring a halt in well operations until the problem is corrected. Applicants present invention is designed to overcome each of these problems, and in so doing provides a new type of hanger that has fewer parts, is simpler to operate, and is less susceptible to malfunction than prior devices for this purpose.

Summary of the invention Broadly considered, applicants invention comprises a hanger for connecting an inner pipe or casing to an outer concentric pipe or casing at a pre-designated location to prevent further downward movement of the inner casing in the outer casing, but permit upward movement of the inner casing with respect to the outercasing, and includes a tubular hanger body adapted for connecting to the upper end of the inner casing, a self-expandable hanger ring surrounding the hanger body and retained on it by a system of upper and lower stops, and a shear ring and pin assembly that responds to the weight of the casing to allow the hanger body to lock the hanger ring in its expanded condition. The hanger cooperates with a hanger coupling that can be positioned in the outer casing at any desired level, the hanger ring being resiliently retracted and having an outer configuration complementary to the inner configuration of the hanger coupling. Thus when the inner casing is lowered through the outer casing and the hanger ring comes into position opposite the hanger coupling, the ring automatically expands into the coupling without further manipulation. The shear ring and pin assembly retains the hanger ring in proper position on the hanger body while the hanger is being lowered in the outer casing, and includes a shear ring circumscribing the hanger body above the hanger ring, and a plurality of frangible shear pins that releasably secure the shear ring to the hanger body. The pins are severed by the shear ring when the weight of the inner pipe is allowed to bear on it, thereby permitting the shear ring and the hanger ring to move upwardly on the hanger body into a final locked position preventing further downward movement of the inner casing. However, from this position the inner casing can be moved upwardly, and in fact withdrawn from the outer casing, simply by lifting up on the hanger body, thereby causing the hanger ring to move back to its former position on the body where it can contract as restrictions in the outer casing are encountered and allow the inner casing to continue its upward travel. Applicants casing hanger thus provides all of the desirable functions and the advantages of the prior devices for this purpose without several of the more aggravating disadvantages thereof.

Brief description of the drawings FIGURE 1 is a view in side elevation, and partially broken away, of the casing hanger of this invention, connected at its lower end to a string of well casing and at its upper end to a conventional running string.

FIGURE 2 is a view in section, taken along the line 22 of FIGURE 1, through the shear ring and the hanger body.

FIGURE 3 is a view in section, taken along the line 3-3 of FIGURE 1, through the hanger ring and the hanger body.

FIGURE 4 is a view in side elevation, and partially broken away, showing the casing hanger of FIGURE 1 as it is being lowered in an outer concentric casing string.

FIGURE 5 is a view in side elevation, and partially broken away, showing the hanger after it has reached the hanger coupling in the outer casing string of FIGURE 4.

FIGURE 6 is a view similar to FIGURE 5, but illustrating the hanger in its subsequent locked position in the hanger coupling.

Description of the preferred embodiments Referring now to the drawings, the casing hanger 10 of the present invention includes a tubular body 12, a resiliently expandable and contractible hanger ring 14 circumscribing the body 12, a shear ring 16 above the hanger ring 14 and circumscribing the body 12, and a plurality of frangible shear pins 18 that releasably hold the shear ring 16 in position on the body 12. The upper portion 20 of the body 12 is provided with an internal set of acme threads 22 for connecting the casing hanger to a running string (not shown) through a landing sub 24, this connection being fluid tight by virtue of the seals 26. The lower portion 28 of the hanger body 12 is provided with external threads 30 to facilitate joining the body 12 through a coupling 32 to the upper end of a casing string 34.

The hanger body 12 has an inner cylindrical surface 36, an upper outer cylindrical surface 38, and a lower outer cylindrical surface 40 of lesser diameter than the surface 38. In its preferred form, the inner surface 36 has an annular groove 42, and is relieved above the groove 42 to form an upwardly-facing stop shoulder 44, the groove 42 and shoulder 44 providing landing means for suspending another string of casing inside the hanger body 12 with another hanger of this type. It is to be understood that the inner surface 36 may be provided with other configurations, or may have no grooves or shoulders, as desired.

The upper outer surface 38 of the hanger body 12 is provided with an upper stop shoulder 46 having an outer cylindrical surface 48 and a downwardly facing radial shoulder surface 50 for contacting the shear ring 16 and preventing further downward movement of the body 12 therein, the shoulder 46 being separated into a plurality of segments by axially extending grooves 52 in the surface 38. Projecting outwardly from the hanger bodys lower outer surface 40 is a lower stop shoulder 54 for retaining the hanger ring 14 on the body 12, the shoulder 54 having an outer cylindrical surface 56, an upwardly facing, inverted generally conical surface 58, and an inner, upwardly facing radial shoulder surface 60, the shoulder 54 likewise being divided into a plurality of segments by grooves 62.

Extending downwardly from the upper stop shoulder 46 is a cylindrical locking surface 64 that serves to look the hanger ring 14 in its fully expanded condition, and extending upwardly from the lower stop shoulder 54 is another cylindrical surface 66. A radially-extending surface 68 joins the two

surfaces

64, 66, providing a stop 70 that prevents the hanger ring 14 from being accidentally forced upwardly on the hanger body 12 as it is being lowered through the outer casing.

The hanger ring 14 has an inner cylindrical surface 72, an outer cylindrical surface 74, and upper and lower

annular end surfaces

76, 78, respectively.

The outer edges of the upper and lower ends of the ring 14 are beveled to provide

camming surfaces

84, 86 for retracting the ring 14 when it encounters obstructions as the hanger 10 is moving through an outer casing. Extending outwardly from the upper end of the outer cylindrical surface 74 is a downwardly facing annular radial shoulder surface '88 that, in combination with the cylindrical surface 90, provides a stop shoulder 92 which cooperates with an upwardly facing surface 138 of the stop shoulder 94 (FIGS. '5 and 6) in a hanger coupling 96 to preclude further downward movement of the hanger ring 14 in the coupling.

The lower portion of the hanger ring 14 has an outer cylindrical surface 98 and a downwardly and outwardlyextending upper surface 100 that, together with the lower beveled surface 86, form an annular boss 102. The boss 102 prevents the hanger ring 14 from expanding into a groove or other relieved area in the outer casing until the ring is properly positioned in the hanger coupling 96, as shown in FIGURE 5. The diameter of the cylindrical surface 98 is greater than that of the cylindrical surface 90 of the shoulder 92, and as a result when the hanger 10 is within an outer casing 104 (FIGURE 4) only the surface 98 is in contact with the outer casings inner surface 106.

The hanger ring 14 is split axially throughout its length,

and therefore has axially extending opposed surfaces 108, 110, as is perhaps best illustrated in FIGURE 3. The ring 14 also is divided into a plurality of rigid segments 14a, b, c, etc. (FIG. 3), by a plurality of axial slots 112, but has an annular web 114 that joins the several segments together. The web 114 is dimensioned to permit the ring 14 to expand and contract as required for passing obstructions in the outer casing as well as for proper seating of the ring in the hanger coupling.

When in its rest position as illustrated in FIGURES 1, 2, 4 and 5, the shear ring 16 is mounted on the locking surface 64 of the hanger body 12 immediately above the hanger ring 14 through frangible shear pins 18 that preclude axial movement of the shear ring 16 on the body 12. The shear ring 16 has upper and lower annular

radiallyextending surfaces

116, 118, respectively, the surface 118 functioning as a stop for preventing the hanger ring 14 from moving toward the upper portion 20 of the hanger body 12. When the casing hanger 10 is fully set and locked, as shown in FIGURE 6, the surface 116 bears against the radial surface 50 of the upper stop shoulder 46, so that the forces tending to move the hanger 10 and the inner pipe 34 further downwardly are transferred through the shear ring 16 to the hanger ring 14, and thence to the hanger coupling 96 in a secure, positive manner. As shown best in FIGURE 2, the shear ring 16 is axially split at 120 and is provided with a plurality of inner axially extending slots 122, for imparting the resilient expandability and contractibility required to install the ring on the hanger body 12 by slipping it over the shoulder 46.

As illustrated in FIGURES 5 and 6, a hanger coupling 96 connected at the desired level into the outer casing 104 provides a landing device for suspending the inner casing 34 in the outer casing. The upper end of the hanger coupling 96 preferably has acme threads 124 to releasably join it to a landing sub 126 which, in turn, is threaded at its upper end into the outer casing 104. The internal cylindrical surface 128 of the hanger coupling 96 has an annular groove 130 with an axially extending cylindrical surface 132 and upper and lower inwardly diverging end surfaces 134, 136, respectively. Above the groove 130 a radial surface 138 extends outwardly from the cylindrical surface 128 to another cylindrical surface 140.

Also, as shown in FIGURES 5 and 6, if it is desired to suspend the outer casing 104 in still another casing of larger diameter (not shown), the hanger coupling 96 may be provided with a stop shoulder 142, a shear ring 144, and a hanger ring 146, all analogous to the corresponding elements of the hanger 10, i.e., the hanger coupling 96 may be shaped like casing hanger 10, but of larger diameter. Of course, it should be understood that the hanger coupling 96 needs only an internal configuration that will cooperate with the hanger 10 and hold it securely, so that hanger couplings other than the type illustrated at 96 are also within the scope of this invention.

As is apparent from the foregoing description, suspending a string of inner casing in an outer casing with the hanger 10 involves merely lowering the hanger and the inner casing in the outer casing, i.e., no rotation or other manipulation procedures are required. As explained previously, while the hanger 10 and the inner casing 34 are being lowered the cylindrical surface 98 of the hanger ring 14 remains against the inner surface 106 of the outer casing 104, as illustrated in FIGURE 4, holding the hanger ring 14 sufficiently retracted to prevent its shoulder 92 from contacting restrictions that might be present in the outer casing and stopping the downward travel of the inner casing and hanger. As the hanger 10 reaches the level illustrated in FIGURE 5, the hanger ring 14 expands into the coupling 96, the boss 102 entering the coupling groove 130 and the stop shoulder 92 moving outwardly toward the couplings inner cylindrical surface 140. When the hanger ring 14 is expanded fully (FIGURE 5), its

cylindrical surfaces

90, 98 bear against the couplings cylindrical

surfaces

140, 132, respectively, its entire radial end surface 76 is beyond the couplings stop shoulder 70, and the surface 88 of its stop shoulder 92 extends over the radial surface 138 of the couplings stop shoulder 94.

The holding tension on the running string is then relaxed, transferring the weight of the inner casing string 34 to the coupling 96 through the shear ring 16 and hanger ring 14. This shears the pins 18 and pulls the hanger body 12 downwardly within the shear ring 16 until the radial surface 50 of the hanger body stop shoulder 46 comes to rest on the shear rings upper surface 116, as is illustrated in FIGURE 6. Simultaneously, the shoulder 70 and the locking surface 64 of the hanger body 12 move down inside the hanger ring 14, preventing the ring 14 from retracting and releasing its grip on the hanger coupling. Thus, in the condition shown in FIGURE 6, the hanger is set and locked in the coupling 96 to suspend the casing 34 from that point.

Although setting and locking the hanger 10 in the coupling 96 precludes further downward movement of the hanger and its attached inner casing 34, one of the advantages of this invention is that the hanger and inner casing can be raised out of the coupling 96 and the outer casing simply by lifting on the hanger body 12. As the body 12 moves upwardly and the first restriction is encountered by either of the hanger rings beveled surfaces 84, 100, such as when the upper surface 134 of the hanger couplings groove 130 is encountered by the surface 100, the hanger ring 14 is held by the restriction until the lower stop shoulder 54 contacts the rings lower end surface 78. The ring 14 then continues upwardly With the body 12, and in doing so retracts inwardly in response to the camming action of the beveled surface that is bearing against the restriction. In similar manner the

beveled surfaces

84, 100 cam the ring 14 past subsequent restrictions in the outer pipe. Thus neither rotation nor any other procedure except lifting is required to withdraw the hanger 10 from its coupling.

Once the inner pipe is hung (FIG. 6), the running string is rotated to back the landing sub 24 out of the hanger body 12, and then lifted from the well. Other well operations then can be conducted in the conventional manner, including lowering and setting another string of easing within the inner casing 34 by using the hanged body 12 with its groove 42 and stop shoulder 44 as the coupling. When it is desired to remove the inner casing 34, a running string with a landing sub is lowered, rotated in the opposite direction to connect the sub to the hanger body 12, and then lifted back out, bringing the hanger 10 and the inner casing 34 with it.

The casing hanger 10 can be employed to suspend casing at any desired location in the well merely by properly positioning the cooperating hanger coupling 96. For example, this hanger is ideally suited for on-bottom suspension of the casing in an underwater well where there is adequate support so that the surface conductor, which extends from the ocean floor to the surface of the water, does not have to bear the weight of the inner strings of casing and thus is not subjected to undue compressive load. The hanger also serves unusually well for suspending casing strings in a telescoping manner, i.e., each string suspended from the bottom of its immediately adjacent outer string, thereby reducing casing expense. Since no slips are used in this hanger, the attendant disadvantages thereof, such as casing distortion, are avoided. Conventional cementing procedures can be carried out through this hanger, the

slots

52 and 62 providing ample fluid bypasses.

Although the best mode contemplated for carrying out the present invention has been herein shown and described, it will be apparent that modification and variation may be made without departing from what is regarded to be the subject matter of the invention as set forth in the appended claims.

I claim:

1. A pipe hanger assembly for suspending an inner pipe within and from an outer pipe, comprising: an elongated tubular hanger body with upper and lower ends, said upper end adapted for releasable connection to a well tool and said lower end adapted for connection to a pipe, upper stop means extending outwardly from the outer surface of said hanger body intermediate said ends, lower stop means extending outwardly from the outer surface of said hanger body intermediate said upper stop means and said lower end, a resiliently expandable and contractible hanger locking ring circumscribing said hanger body and axially slidable thereon between said upper and lower stop means, said ring adapted for self-movement from a contracted condition into an expanded condition to preclude downward movement of said hanger body in said outer pipe while facilitating upwand movement of said hanger body therein; locking means on the outer surface of said hanger body intermediate said upper and lower stop means and adapted to lock said 'hanger locking ring in its expanded condition, and releasable stop means on the outer surface of said hanger body intermediate said upper stop means and said locking ring for preventing said locking means from locking said locking ring in said expanded condition.

2. The pipe hanger assembly of claim 1 wherein said hanger locking ring is split axially and is provided with a lower outwardly-extending annular boss and an upper outwardly-extending annular locking shoulder.

3. The pipe hanger assembly of claim 2 wherein said annular boss has a larger outside diameter than said annular locking shoulder, for providing a bearing surface for said locking ring with respect to said outer pipe.

4. The pipe hanger assembly of claim 3 wherein said locking ring is divided into a plurality of rigid axially extending segments by a plurality of axial slots.

5. The pipe hanger assembly of claim 4 wherein said locking means comprises a cylindrical locking surface extending from said upper stop means towards said lower stop means, and having a diameter sufiicient to hold said locking ring in expanded locking condition with respect to said outer pipe when said ring is circumscribing said surface.

6. The pipe hanger assembly of claim 5 wherein said releasable stop means comprises an annular shear ring circumscribing said locking surface and releasably secured thereto by frangible shear pins.

7. The pipe hanger assembly of claim 6 wherein said lower stop means includes an outer axially extending retainer flange for retaining said locking ring in position on said hanger body.

- References Cited UNITED STATES PATENTS 3,017,931 1/ 1962 Jackson et a1 166-208 3,086,590 4/1963 Jackson et al 166--.6 3,227,218 l/l966 Fisher et a1 166-208 3,305,015 2/1967 Brown et al 166.6

JAMES A. LEPPINK, Primary Examiner.

US. Cl. X.R. 285-