US3163217A

US3163217A - Method and apparatus for hanging pipe in an underwater well

Info

Publication number: US3163217A
Application number: US153470A
Authority: US
Inventors: John A Haeber
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1961-11-20
Filing date: 1961-11-20
Publication date: 1964-12-29
Anticipated expiration: 1981-12-29
Also published as: GB984061A

Description

3,163,217 METHOD AND APPARATUS FOR HANGING PIPE IN AN UNDERWATER WELL Filed Nov. 20, 1961 J. A. HAEBER Dec. 29, 1964 3 Sheets-Sheet 1 FIG-2 53 FIG. 4

INVENTOR J. A. HAEBER BY: Hak

HIS AGENT FIG. I

J. A. HAEBER Dec. 29, 1964 METHOD AND APPARATUS FOR HANGING PIPE IN AN UNDERWHTER WELL I5 Sheets-Sheet 2 Filed Nov. 20 1961 FIG. 7

FIG. 5

INVENTOR.

J. A. HAEBER HIS AGENT J. A. HAEBER Dec. 29, 1964 METHOD AND APPARATUS FOR HANGING PIPE IN AN UNDERWATER WELL 5 Sheets-Sheet 5 Filed Nov. 20, 1961 FIG.

INVENTOR J. A HAEBER BY: H

HIS AGENT United States Patent Ofice 3,163,217 Patented Dec. 29, 1964 3,163,217 METHOD AND APPARATUS FOR HANGING PIPE IN AN UNDERWATER WELL John A. Haeber, Houston, Tex., assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware Filed Nov. 20, 1961, Ser. No. 153,470 14 Claims. (Cl. 166-14) This invention relates to a method and apparatus for hanging a string of pipe in an underwater well and pertains more particularly to a method and apparatus for hanging, from an underwater wellhead assembly positioned on the ocean floor, a string of well casing which has been stuck in the well as it was being run into place.

A recent development in the field of well driliing has been the method of drilling wells at offshore locations where the wellhead assembly, including a casinghead, is positioned well below the surface of a body of water and preferably on the ocean floor. An oil or gas well may be drilled in the ocean floor and completed with all of the operations being carried out from a drilling barge which may be positioned on the surface of the body of water several hundred feet above the wellhead assembly which is positioned on the ocean floor. All of the operations are carried out from the drilling barge in a blind manner, that is, there is no diver on the ocean floor check ing the equipment as it is run together or connecting one piece of equipment to another.

In running one of the permanent strings of pipe into a Well which has been drilled in the above-described manner, the possibility exists that a string of pipe may become stuck in the drilled hole before the pipe hanger, secured to the upper end of the pipe string, is seated or hung from the casinghead positioned on the ocean floor. For example, in the event it is desired to run 4,000 feet of well easing into a well drilled in the ocean floor and hang it from a casinghead of a wellhead assembly positioned on the ocean floor, it may happen that after running 3,700 feet of pipe string into the hole, the pipe string or casing becomes stuck therein with the casing hanger at the top of the casing string positioned 300 feet above its seat in the casinghead. The well drilling personnel are then faced with the problem of attaching a casing hanger to the casing string within the casinghead which is positioned under several several hundred feet of water. When well casing becomes stuck in the above-described manner during the drilling of land wells, no problem exists since the casing is cut off at the casinghead and a casing hanger is manually attached to the top of the casing so that it is seated on the landing surface within the casinghead. However, it is impossible to use this or other land well methods for hanging pipe strings or casing in an underwater well wherein the casinghead is positioned on the ocean floor.

It is therefore a primary object of the present invention to provide a method and apparatus whereby pipe which has become stuck in a well prior to reaching its seated or hung position may be provided with another casing hanger which can be attached to the stuck casing from a remotely positioned drilling barge.

A further object of the present invention is to provide a method and apparatus whereby a string of well casing which has become stuck in a well may be hung in tension after being provided with an auxiliary casing hanger.

Another object of the present invention is to provide a method and apparatus whereby a faulty section of pipe or well casing may be removed from an underwater well and replaced with another section which is secured to the portion of casing left in the well.

These and other objects of this invention will be understood from the following description taken with reference to the drawing, wherein:

FIGURE 1 is a diagrammatic view illustrating a drilling barge positioned on the surface of a body of water over a wellhead assembly positioned on the ocean floor during well drilling operations;

FIGURE 2 is a longitudinal view in enlarged detail of the casing hanger of FIGURE 1 being run into place;

FIGURE 3 is a longitudinal view diagrammatically representing an inside pipe cutter secured to the lower end of a running pipe string;

FIGURE 4 is a longitudinal view taken in cross section of an elongated tubular pipe hanger of the type employed in the method of the present invention; and,

FIGURES 5 through 10 are longitudinal views taken in partial cross section of an underwater well with various pieces of equipment positioned therein, the figures being arranged in sequence to illustrate the successive steps of the method of the present invention.

Referring to FIGURE 1 of the drawing, a drilling vessel 11 is shown as being positioned in an anchored manner on the surface 12 of a body of water 13. The drilling vessel or platform 11 is provided with a derrick 14 containing a conventional hoist system 15 provided with an elevator 16 which is adapted to be secured to the upper end of a running pipe string 17.

The running pipe string 17 is illustrated as being positioned in a marine conductor pipe 20 which is a large-diameter pipe made up in sections and having secured to its lower end auxiliary equipment such as blowout preventers 21 and a wellhead connector 22, the latter being adapted to be secured in a fluidtight manner to the top of a casinghead 23. The well casinghead 23 is fixedly secured to a base platform 24 of the wellhead assembly with a conductor pipe extending from the platform 24 down into the well and being cemented therein. The wellhead is also provided with guide columns 26 and 27 having

guide lines

28 and 29 extending thereinto with the upper ends of the

guide lines

28 and 29 being secured to the drilling barge 11.

Depending from the lower end of the running string 17 is a pipe or casing hanger 31 which is fixedly secured, as by welding or screw threads, to the upper end of a string of pipe or well casing 32 (FIGURES 1 and 2). If desired, the casing hanger 31 may be provided with a piurality of hold-down slips 33.

FIGURE 1 illustrates the operation of running a length, say 4,000 feet, of pipe or Well casing 32 down through the marine conductor pipe 20, casinghead 23, conductor pipe 25 and into the open well 34. At this stage of the operation, since the depth of the well was known to he, say, 4,000 feet, slightly less than 4,000 feet of well casing 32 was made up or connected together on the drilling barge 11 and the casing hanger 31 was then attached to the top of the well casing. The lower end of the running string 17 was then temporarily connected to the inside of the casing hanger 31, in any well known manner as by J-slots or by left-hand threads, and then additional sections of running string were connected together so as to lower the well casing string 32 and easing hanger 31 down into the casinghead 23 so as to seat the casing hanger 31 therein.

During the last stage of running the casing hanger 31 to its seated position within the casinghcad 23 the well casing 32 has become stuck in the well and the drilling crew is unable to lower it any further. It is also possible that the pipe might be stuck before the casing hanger is installed on the string. Since the decision has been made to leave the well casing 32 in the well, orin the event that it is not possible to withdraw it, it is necessary to cut oif the well casing 32 extending above the ocean floor and withdraw the cut-off portion upwardly to the drilling barge 11 together with the casing hanger 31 and the running string 17. Any suitable type of an inside or outside cutter may be employed to cut off the casing string 32 as long as the conductor pipe 25 in the well is not damaged during the operation. An outside cutter could only be used in the event the casing hanger 31 had not been attached. An inside pipe cutter 35 is schematically shown in FIGURE 3 as being provided with a plurality of radially-extending knives or cutters 36 which are adapted to cut through the wall of the casing string 32 when rotated at the lower end of a running pipe string 37. In FIGURE the inside pipe cutter 35 is illustrated as being run down through the well casing string 32 to a selected point therein where it is desired to cut off the well casing. The casinghead 23 is illustrated as being provided with a lower landing surface 40 on which the casing hanger 31 (FIGURES 1 and 2) should have seated.

In the event that the drilling personnel does not want to trust the well casing string 32 to stay supported at its stuck position after being cut by the pipe cutter 35, the string of well casing 32 may be cemented in place in a conventional manner, as by pumping cement down through the casing string 32 from the drilling barge 11. The well casing is subsequently cut after the cement has $61.

Since the distance between the drilling vessel 11 and the platform 24 of the wellhead assembly on the ocean floor is known at all times, then by knowing the length of running pipe 37 on which the pipe cutter 35 is depending at the time the pipe is cut it is quite simple to determine the distance A (FIGURE 6) from the landing surface 40 within the casinghead to the top of the pipe 41 at which the lower stuck section of pipe 32 was positioned at the time it was cut. However, since the entire pipe string or casing string 32 may have been in tension at the time it was being run down into the well, after it was cut the top of the pipe 41 relaxed to the illustrated position shown at 41a. At the same time the top of the stuck section of well casing 32 remaining in the well would fall over against the inner wall of the conductor pipe 25 (FIGURE 6). Thus, the unsupported pipe or casing string 32 would relax a distance B. After cutting off the pipe or casing string, the upper portion 32a thereof would be withdrawn upwardly to the barge, as by a running string 17 as illustrated in FIGURE 1. In FIG- URE 6 the upper portion 32a of the casing string is shown as being withdrawn upwardly.

Knowing the distance A (FIGURE 6) from the landing surface 40 of the casinghead 23 to the cut off point at 41, and being able to estimate the distance B which is the amount the casing string 32 has relaxed in the well, an elongated tubular pipe hanger 42 (FIGURE 4) is made up. The upper end of the elongated tubular pipe hanger assembly 42 comprises a landing head or pipe hanger 43 having an annular seating shoulder 44 which is preferably provided with an annular seal 45 adapted to seal against the landing surface 40 of the casinghead 23 (FIGURE 6). If desired, a plurality of hold-down slips 46 actuated by springs 47 may be provided on the outer surface of the pipe hanger 43 for holding the assembly in place once it is seated in the casinghead. The inner wall of the pipe hanger 43 is preferably provided with suitable slots, notches or an annular groove 48 by which a running head may be connected to the pipe hanger assembly 42.

Fixedly secured to the pipe hanger 43 is an auxiliary pipe section 50 having an over-shot section at the lower end thereof, that is, a section 51 which has an internal diameter greater than the external diameter of the well casing 32 left in the well. The lower edge of the overshot section 51 is tapered outwardly from the bore 52 thereof, as at 53, to facilitate sliding the lower end of the assembly 42 over the upper end of the casing 32 left in the well. A plurality of pipe-hanging slips 54 are mounted for limited vertical movement along tapered surfaces 55 above an annular ring 56 which is adapted to be forced downwardly by the slips 54 to compress an annular ring of packing material 57 positioned below the ring 56. The arrangement is schematically illustrated without any attempt to show the actual construction of the unit whereby the ring 56 and slips 54 are readily installed in the unit. It is to be understood that other suitable types of packing 57 and pipe-hanging elements 54 may be employed. It is essential that the distance between the top of the slips 54 and the swaged portion 58 of the assembly, as represented by distance C in FIGURE 4, be slightly greater than the distance B which the well casing 32 relaxed (FIGURE 6). The length of the pipe section 50 is selected so that the pipe-hanging slips 54 are below the top of the well casing 32 in the well when the seating shoulder 44 of the hanger assembly 42 is hung from the landing surface 40 (FIGURE 6) of the casinghead 23.

After the cut-off section of pipe casing 32a is withdrawn from the well, as illustrated in FIGURE 6, the elongated tubular pipe hanger assembly 42 of FIGURE 4 is run or lowered through the marine conductor pipe 20 (FIGURE 1) and into the casinghead 23 (FIGURE 7) on a running pipe string 60 which has a running tool 61 aflixed to the lower end thereof. The running tool 61 is provided with a plurality of radially extending latches or dogs 62 adapted to be seated in the annular groove 48 on the inner surface of the casing hanger 43. In FIG- URE 7 the casing hanger 43 is shown about to be seated on the landing surface 40 of the casinghead 23. At this time the large-diameter or over-shot section 51 of the hanger assembly 42 has been forced down over the top of the stuck pipe or casing string 32 which remained in the well. The casing section 32 is at this time in its relaxed position.

After the running tool 61 (FIGURE 7) has seated the hanger assembly 42 in the casinghead 23, the dogs 62 of the running tool 61 are retracted and the running pipe string 60 and the running tool 61 are withdrawn from the well to the drilling barge 11. A suitable releasing spear 63 of any type well known to the drilling art, is then run into the well through the auxiliary pipe hanger assembly 42 and into the top of the well casing 32 standing free in compression within the well. The spear 63 is provided with suitable pipe-engaging elements, such as slips 64, which may be spring-loaded or otherwise operative to engage the inner wall of the Well casing 32 when forced therein on the lower end of a running pipe string 65. The spear 63 may be provided with a downwardlyextending short pipe section 66 having radially-extending centralizer fins 67 extending therefrom to aid in centering the spear 63 when it is run into the top of the casing string 32.

In FIGURE 8, the pipe spear 63 is shown as having been positioned in the top of the well casing 32 which is still in its relaxed position standing free within the well. In FIGURE 9, tension has been applied to the running string and the spear 63 attached thereto by means of the hoist system on the barge 11 so that the running string 65 and well casing 32 are drawn upwardly a distance B which is substantially equal to that which the well casing 32 relaxed when the casing was cut off. The pipe-hanging dogs or slips 54 are in contact with the outer surface of the well casing string 32 at all times so that when the spear 63 is disengaged from the inner surface of the well casing 32 and withdrawn upwardly to the barge as shown in FIGURE 10, the slips 54 are forced downwardly a small amount against ring 56 which expands the annular seal 57 to close the space between the inner wall of the pipe hanger assembly 42 and the outer wall of the Well casing 32. The movement is slight so that the well casing 32 still hangs in tension within the well, pulling the casing hanger assembly 42 downwardly so as to compress the seal 45 against the landing surface 40 in a fluidtight manner.

It is quite apparent that at a later time during the life of the well, in the event that a leak should develop in a casing string so that it is necessary to replace the casing string, the method of the present invention could be employed to cut off the damaged section of well casing within the well, withdraw it from the well, measure it and make up an elongated tubular pipe hanger assembly similar to 42 of FIGURE 4 which was slightly longer than the measured section, lower the new section of pipe into place, and then connect and seal the new section to the old section in the well and place the two in tension by the method and apparatus described hereinabovc.

I claim as my invention:

1. A method of installing a pipe section in a well and hanging it from a wellhead assembly, said method comprising the sequential steps of cutting off a pipe string in the well at a point below the landing surface of the wellhead assembly, withdrawing the top cut-off portion of the pipe string, running into the Well an auxiliary pipe section, permanently hanging said auxiliary pipe section in said wellhead assembly with the lower portion of the auxiliary pipe section in telescopic relationship with the upper end of the remaining portion of the pipe string in the well, sealing off at a point between the pipe sections between the lower end of the auxiliary pipe section and the top of the pipe string, and anchoring the top of the remaining portion of said pipe string to the lower end of said auxiliary pipe section.

2. The method of claim 1 including the step of applying a lifting force to the upper end of the remaining portion of pipe string in the well to place the pipe string in the well in tension before anchoring the upper end of the remaining portion of said pipe string to the lower end of said auxiliary pipe section.

3. A method of removing a portion of pipe string from within a well and connecting the remaining portion of said pipe string to an auxiliary pipe string in a well which is hung from a landing surface in the wellhead assembly, said method comprising the sequential steps of cutting oil a pipe string within a well at a point below a landing surface in the wellhead assembly, withdrawing the upper cut-off section of the pipe string from the well, running an auxiliary pipe string into the well into telescopic fluidtight relationship with the upper portion of the lower section of said cut-off pipe string remaining in the well, and hanging said auxiliary ipe string from a landing surface in the wellhead assembly.

4. A method of hanging, from a landing surface of an underwater wellhead assembly, a pipe string which has become prematurely stuck in a well with the pipe hanger at the upper end of the pipe string being positioned above its normal seated and hung position in a wellhead assembly, said method comprising the steps of cutting off the stuck pipe string at a point below the landing surface of the wellhead assembly and above the point where the pipe string is stuck in the well, withdrawing the top cut-off portion of the pipe string from the well, running into the well an auxiliary pipe section into telescoping relation with the pipe string portion remaining in the well, hanging said auxiliary pipe section in said wellhead assembly with the lower portion of the auxiliary pipe section in telescopic relationship with the upper end of the remaining portion of the stuck pipe string, sealing off the space between the lower end of the auxiliary pipe section and the top of the stuck pipe string, extending a pipe-engaging tool down through the wellhead assembly and said auxiliary pipe section and into said stuck pipe string, bringing the pipe-engaging tool into lifting contact with the inner wall of the stuck pipe string, applying a lifting force to said pipe-engaging tool to pull the stuck pipe string upwardly in tension, anchoring the top of said pipe string in tension to the lower end of said auxiliary pipe section, disconnecting the pipe-engaging tool from said stuck pipe string, and withdrawing the pipeengaging tool from the wellhead assembly.

5. The method of claim 4 including the step of cementing the lower portion of stuck pipe string in the well prior to cutting the pipe string.

6. The method of claim 4 including the step of anchoring the auxiliary pipe section in the wellhead assembly against upward movement therein.

7. A method of hanging, from a landing surface of an underwater wellhead assembly, a pipe string which has become prematurely stuck in a well with the pipe hanger at the upper end of the pipe string being positioned above its normal seated and hung position in a wellhead assembly said method comprising the steps of cutting off the stuck pipe string at a point below the landing surface of the wellhead assembly and above the point where the pipe string is stuck in the well, withdrawing the top cut-off portion of the pipe string from the well, determining the distance between the top of the cut-off stuck pipe string in the well and the landing surface of the wellhead assembly, making up an auxiliary pipe section greater in length than the determined distance and having a pipe hanger at the top thereof and a lower end of an internal diameter greater than the external diameter of the top of the stuck pipe string in the well, lowering said auxiliary pipe section into said wellhead assembly and hanging it therein with the lower portion of the auxiliary pipe section in telescopic relationship with the upper end portion of the remaining portion of the stuck pipe string, sealing off the space between the lower end portion of the auxiliary pipe section and the top portion of the stuck pipe string, providing the lower end of the auxiliary pipe section with pipe-hanging slips in the telescoped portion thereof, extending a pipe-engaging tool down through the wellhead assembly and said auxiliary pipe section and into said stuck pipe string, connecting the pipe-engaging tool to the inner wall of the stuck pipe string, applying a lifting force to said pipe-engaging tool to pull the stuck pipe string upwardly in tension, anchoring the top of said pipe string in tension to the lower end of said auxiliary pipe section to pull the hanger thereof. in sealing engagement with the landing surface of the wellhead assembly, disconnecting the pipe-engaging tool from said stuck pipe string, and withdrawing the pipe-engaging tool from the wellhead assembly.

8. An auxiliary pipe hanger assembly for hanging from a well casinghcad a string of pipe the upper end of which is below the landing surface of said casinghead, said pipe hanger assembly comprising:

(a) an elongated tubular body member,

(b) the upper portion of said body member being of enlarged outer diameter forming a seating shoulder thereon of a size to seat on the landing surface of said casinghead,

(c) the lower portion of said body member having an internal diameter of a size to fit telescopically on the upper end of a string of pipe freely standing within the well, and

(d) annular seal means carried on the lower end of said body member for sealingly engaging the wall of said free standing pipe string.

9. The apparatus of claim 8 including pipe-hanging means carried near the lower end of said body member. 10. The apparatus of claim 7 wherein said pipe-hangmg means are a plurality of downwardly-moving slips mounted on the wall of said body member above said annular seal means, and a ring member axially slidably mounted on said body member between said slips and said seal means and in compression therebetween causing expansion of said seal means on actuation of said slips.

ll. The apparatus of claim 8 including annular seal means carried near the top of said body member on the outer surface thereof for sealing the space between said body member and said casinghead.

12. The apparatus of claim 11 wherein said annular seal means are carried in an annular recess formed in the seating shoulder of said body member.

13. The apparatus of claim 8 including hold-down anchoring means carried outwardly on said upper portion of said body member for engaging the inner wall of said casingheadi 14. A method of removing a portion of a pipe string from within a well and connecting the remaining portion of said pipe string in the well to an auxiliary pipe string which is hung in the well from a landing surface in the wellhead assembly, said method comprising the steps of cutting off a section of pipe from a pipe string within a well at a point below a landing surface in the wellhead assembly, withdrawing the upper cut-off section of the pipe string from the well, running an auxiliary pipe string into the well into telescopic fluidtight relation with the upper portion of the lower section of said cut-oil pipe string remaining in the well, hanging said auxiliary pipe string from a landing surface in the wellhead assembly, applying a lifting force to the upper end portion of said lower section of cut-01f pipe string to raise it relative to said auxiliary pipe string after the latter is hung from the landing surface in the wellhead, and interconnecting said pipe strings with said lower section in raised position to prevent downward movement of said upper portion of 5 the cut-off pipe string relative to said auxiliary pipe string.

References Cited by the Examiner UNITED STATES PATENTS 2,017,451 10/35 Wickersham 166-14 X 2,134,311 10/38 Minor et al. 166-47 2,261,564 11/41 Robichaux et al 166-46 x 2,495,352 1/50 Smith 166 14 2,607,422 8/52 Parks et al 166--67 X 15 CHARLES E. OCONNELL, Primary Examiner.

NORMAN YUDKOFF, Examiner.