Patent Grant
8479824
A wellhead can be damaged when the exposed casing becomes bent. To fix the problem, operators remove the existing wellhead and cut-down the exposed casing so that a new wellhead can be installed. However, installing the new wellhead presents several challenges. For example, some wells have inner tubing disposed inside the outer casing exposed at the well. In this situation, the operators need to install a “no-weld” casing head (also known as a sleeve-type casing head) on the cut-down casing and need to isolate the inner tubing from the outer casing.
In other problem situations at a well, a wellbore tubular (e.g., drill pipe, collar, casing, or other tubular) may become stuck during drilling, running, or hoisting. Because operators cannot pull the stuck pipe from the casing, the operators must use slip hangers to support the stuck pipe so the pipe can be left in place. Unfortunately, operators must set the slips to support the stuck pipe even though the wellhead (e.g., BOP, diverter, casing head, etc.) is already installed on the surrounding casing.
In one conventional method of setting such slips, operators unbolt the BOP/Diverter from the wellhead's casing head and raise the BOP/Diverter slightly so the operators can gain access inside the casing head. At this point, the operators can set the slips in the casing head and pull on the stuck pipe to engage it further on the slips. Once set, operators bring the BOP/Diverter back down and bolt it to the casing head. As expected, performing this operation by suspending several tons of equipment overhead while operators set slips and test the integrity of seals is time-consuming and difficult. Some other methods of setting slips to suspend a stuck pipe are disclosed in U.S. Pat. Nos. 4,982,795 and 5,301,750, which do not require the removal of the BOP/Diverter.
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
A wellbore tubular slip apparatus is used for a wellhead when operators install a “no-weld” casing head (also known as sleeve type casing head), on a casing and inner tubular at a well site. To install the no-weld casing head, operators need to be able to secure and extend the existing inner tubular so that the casing head can be installed on the casing at the well. Also, operators need to be able to isolate the inner tubular from the surrounding casing.
To do this, operators attach the slip apparatus to a joint tubular that will extend the inner tubular. The slip apparatus has an inner sleeve that threads onto the joint tubular. Operators then fit collet members on this inner sleeve onto the inner tubular so the joint tubular extends from the inner tubular. A groove for an O-ring seal and a shoulder can be defined inside the inner sleeve where it fits onto the inner tubular.
Operators also fit an outer sleeve of the slip apparatus onto the inner sleeve and thread a collet onto the inner sleeve. Preferably, the outer sleeve and the collet are separate components that when assembled together allow the collet to rotate while the outer sleeve does not. Although other arrangements are possible, the collet and outer sleeve can have interlocking lips in a tongue-and-groove or shoulder-to-shoulder arrangement.
When the collet thread onto the inner sleeve, the collet forces the outer sleeve to engage the collet members around the inner tubular. The collet members on the inner sleeve preferably have wedged outer surfaces that help to force the collet members into the inner tubular when pushed by the outer sleeve. In addition, the collet members preferably have teeth on their inner surfaces that bite into the inner tubular when forced against it. To lock the outer sleeve to the inner sleeve, threaded holes in the outer sleeve can receive bolts or the like that engage the inner sleeve to hold the two sleeves together.
Once the slip apparatus extends the joint tubular from the inner tubular, operators mount the no-weld casing head on the outer casing at the well site so that the joint tubular extends through the bowl of the casing head. Then, operators install a pack-off element, such as an H-plate, around the joint tubular in the casing head and install a second pack-off on a distal end of the joint tubular. Finally, operators install other wellhead components, such as a tubing spool, on the casing head. The second pack-off element on the end of the joint tubular engages inside the tubing spool to complete the isolation of the inner tubular from the surrounding casing at the well.
An outer casing 16 in
As shown in
As noted previously, installing the no-weld casing head 12 and isolating the inner tubing 18 from the outer casing 16 can prove difficult for operators in the field. To alleviate problems, operators use a power slip assembly 50 shown in
Operators use the power slip assembly 50 with the “no-weld” casing head 12 on the casing 16 and the inner tubing 18 by performing the following steps. First, when the damaged casing head (not shown) originally on the casing 16 is removed, operators cut and prep the casing 16 and inner tubing 18 to the proper lengths and finish. Prior to attaching the “no-weld” casing head 12 to the outer casing 16, operators first fit the power slip assembly 50 onto the inner tubing 18. In particular and as best shown in
Next, operators fit the distal end of the inner sleeve 60 over the exposed stub of the inner tubing 18. Using an appropriate tool, operators then lock the power slip assembly 50 onto the inner tubing 18 as described in more detail below. At this point, the joint tubular 20 extends vertically from the inner tubing 18. As best shown in
As noted above, the power slip assembly 50 allows operators to secure and extend the existing inner tubing 18 with the joint tubular 20 so the casing head 12 and other components can be isolated from the casing 16 once installed. Further details of how the power slip assembly 50 couples the joint tubular 20 to the inner tubing 18 are discussed below with reference to
The inner sleeve 60—shown in detail in FIG. 3—has inner thread 62 that threads onto external thread 22 on the end of the joint tubular 20. The inner sleeve 60 also has an inner groove 66 for an O-ring seal (not shown) and has a shoulder 67 that engage the distal end of the inner tubing 18 when positioned thereon (See
Outer wedge profiles 65 on these collet members 68 allow the members 68 to be forced against the inner tubing 18 so that teeth 69 on the inside of the collet members 68 bit into the tubing 18's outer surface. These inner teeth 69 can take many forms. For example, the teeth 69 can be vee-thread and can have concentric grooves, as shown in
As noted previously and shown in
The sleeve 70's lipped upper end 74 mates with a lipped lower end 84 of the collet 80—shown in detail in
As the collet 80 is threaded onto the inner sleeve 60, the collet 80 moves the outer sleeve 70 down along the inner sleeve 60 and forces the collet members 68 into the tubing 18. The collet 80 threads onto the inner sleeve 60 by rotating the collet 80 counter-clockwise using an appropriate tool. Actually rotating the collet 80 can be performed in a number of ways. For example, operators can use a spanner or bar inserted into holes (not shown) provided in the sides or top of the collet 80 so it can be rotated.
Because the outer sleeve 70 and collet 80 are connected together by lipped ends 74 and 84, the collet 80 is allowed to rotate even though the outer sleeve 70 may not rotate. Rotating the collet 80, however, drives the outer sleeve 70 downward, allowing its inner surface 72 to engage the wedge profiles 65 of the collet members 68 on the inner sleeve 60. As the collet members 68 are forced inward by the downward moving outer sleeve 70, the member's inner teeth 69 bite into the tubing 18. The left side of
For exemplary dimensions, the casing 16 may have a diameter of 8⅝-in, while the inner tubing 18 may have a diameter of 5½-in. The inner sleeve 60 may have an overall outside diameter of 6.375-in and a length of 7.33-in. The internal thread 62 may accept a 5½-in tubular. The depth of the slots for the collet members 68 may extend a length of 2.33-in, and the wedged profile 65 on the outside of the collet members 68 may be angled at about 5-degrees. The outer sleeve 70 may have an outer diameter of 7.25-in, an inner diameter of 6.535-in, and an overall height of 3.75-in with the lip 74 being 0.25-in. The collet 80 may similarly have an outer diameter of 7.25-in, an inner diameter of 6.25-in for its thread 82, and an overall height of 2.00-in with the lip 84 being 0.25-in. Each of these components can be made of suitable materials for use in a well environment. These dimensions are exemplary. Other implementations for different sized casing or tubular would use different dimensions.
As shown in
In general, the power slip assembly 50 can be used in any application where conventional slips are used to secure and/or extend an existing conductor, casing, or tubing. For example, the power slip assembly 50 can be used in place of conventional slip hangers and can connect to tubing through the BOP/Diverter if needed in various situations. One such situation is when a wellbore tubular (e.g., drill pipe, collar, casing, or other tubular) becomes stuck during drilling, running, or hoisting.
As shown in
To deal with a stuck pipe situation, the end of the stuck pipe 100 can be cut and prepped using techniques known in the art while the wellhead (not shown) remains installed uphole. For example, depending on how accessible the end of the stuck pipe is, a motorized cutting tool, chemical techniques, or radial cutting torches can be used. Operators then attach the power slip assembly 50 on the joint tubular 104 and pass the assembly 50 and joint tubular 104 through the BOP/Diverter without needing to disassemble it. When passed to the stuck pipe 100, the collet members 68 of the inner sleeve 60 fit onto the exposed end of the stuck pipe 100. Then, a running tool (not shown) runs through the BOP/Diverter and engages the collet 80 to rotate it so that it threads onto the inner sleeve 60. As the collet 80 is rotated and threads onto the inner sleeve 60, the outer sleeve 70 forces against the wedge profiles of the collet members 68 causing their teeth to bit into the outside of the stuck pipe 100. When coupling is complete, the running tool (not shown) is removed through the BOP/Diverter, leaving the joint tubular 104 connected to the end of the stuck pipe 100 by the power slip assembly 50. Various pack-off components, slips, and hangers can be installed as needed to isolate and suspend the pipe 100 and the joint tubular 104 in the casing 102.
In this sense, the power slip assembly 50 can be set in a less time-consuming and less precarious manner than used for setting conventional slips in such situations. Moreover, the power slip assembly 50 can be set in place even though a drill collar may be in the way. As is known, having a collar stuck in the bowl of a casing head prohibits the use of conventional slip hangers, which require operators to spear and stretch the casing first. Ultimately, the power slip assembly 50 is less costly, easier, and quicker to set than convention slips used in the art.
The foregoing description of preferred and other embodiments is not intended to limit or restrict the scope or applicability of the inventive concepts conceived of by the Applicants. In exchange for disclosing the inventive concepts contained herein, the Applicants desire all patent rights afforded by the appended claims. Therefore, it is intended that the appended claims include all modifications and alterations to the full extent that they come within the scope of the following claims or the equivalents thereof.
This is a non-provisional application of U.S. Provisional Appl. Ser. No. 61/102,056, filed 2 Oct. 2008, which is incorporated herein by reference and to which priority is claimed.
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| Number | Date | Country | |
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| 61102056 | Oct 2008 | US |
