Tubing Hanger Assembly And Method Of Using Same

Abstract

A tubing hanger assembly and method of using same, wherein a continuous tubing having a smooth external surface which is to be left in a well after insertion is supported by the hanger assembly so that subsequent operations may be performed in the well through the tubing without leaving the usual wellhead equipment at the well.

Description

BACKGROUND OF THE INVENTION

The field of this invention is tubing hanger assemblies and methods of using same.

In recent years, tubing in continuous lengths without joints or collars has been introduced into wells through the usual well-head equipment, an example of which is illustrated in U.S. Pat. No. 3,313,346. So long as the wellhead equipment is in place, the tubing may be used for performing various operations such as the injection of gas to stimulate the flow of oil from a well and the injection of paraffin solvents and other chemicals. If only one or more of such operations is to be performed, the tubing and the wellhead equipment can simply be removed after the operation, but in some instances, periodic operations on a weekly or monthly basis are required, and it is therefore desirable to have the tubing in the well, but the wellhead equipment and injection apparatus are too expensive to leave in an idle condition for such extended periods between the operations.

SUMMARY OF THE INVENTION

The present invention relates to a method of supporting a continuous tubing having no joints or collars in a well during and after removal of wellhead equipment through which the tubing was originally inserted, wherein there is no well pressure in the tubing at the time of disconnecting the wellhead equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation of the apparatus of this invention in position during the injecting of tubing into a well casing;

FIG. 2 is a vertical sectional view of the tubing hanger assembly of this invention prior to the disconnection of the wellhead equipment therefrom;

FIG. 3 is a view of the tubing hanger assembly of this invention after the union has been disconnected therefrom and the permanent hanger components have been substituted in the apparatus;

FIG. 4 is a cross-sectional view taken on line 4--4 of FIG. 3; and

FIG. 5 is a cross-sectional view taken on line 5--5 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the drawings, the letter T designates generally the tubing hanger assembly of this invention which is adapted to be positioned above a well casing C (FIG. 1) and below the conventional wellhead equipment W. The typical wellhead equipment W illustrated in FIG. 1 includes blowout preventers and other controls which form no part of the present invention. Continuous tubing or pipe P which is formed without any joints or collars, and which is normally a metal pipe formed of steel or other alloy, is injected into the well casing C with any suitable apparatus such as schematically indicated by the letter A in FIG. 1, an example of which is shown in U.S. Pat. No. 3,285,485. Briefly, the present invention relates to the tubing hanger T and the method of using same so that when it becomes desirable to leave the tubing or pipe P in the casing C, the tubing T may be supported by the tubing hanger assembly T, and the wellhead equipment W as well as the injection apparatus A may be removed for use at another location.

Considering the invention more in detail, and particularly FIGS. 1 and 2, wherein FIG. 2 is an enlarged sectional view of the tubing hanger assembly T, such assembly T is positioned as illustrated in FIG. 1 above the casing C and below the wellhead equipment W prior to inserting the tubing or pipe P therethrough and into the well casing C.

The tubing hanger assembly T includes a body 10 which has a longitudinal bore 11 therethrough, through which the tubing or pipe P extends. A first counterbore 12 is formed in the body 10 above the bore 11, and a second counterbore 14 is formed in the body 10 above the first counterbore 12. The diameter or width of the second counterbore 14 is greater than the diameter or width of the first counterbore 12. A shoulder 12a is formed at the lower portion of the counterbore 12, between the bore 11 and the counterbore 12. A similar shoulder 14a is formed at the lower end of the second counterbore 14.

The lower end of the body 10 has any suitable means therewith for connecting same to the well casing C, and as illustrated in FIG. 2, such connecting means preferably includes an annular flange 15 which is threaded or is otherwise secured at threads 15a to the lower end of the body 10. The flange 15 is adapted to be bolted by means of bolts (not shown) which extend through bolt holes 15a in the flange 15 and also through a corresponding flange 16 (FIG. 1) on the well casing C, or an extension thereof, as will be well understood by those skilled in the art.

During the initial mounting of the tubing hanger assembly T on the well casing C, which is prior to the insertion of the tubing or pipe P therethrough, the tubing hanger assembly T includes a male union fitting 20 which fits within the second counterbore 14 with its lower end 20a resting upon the shoulder 14a. The union fitting 20 has a longitudinal bore 20b therethrough which is in alignment with the bore 11 of the body 10, and through which the tubing or pipe P extends. The fitting 20 extends upwardly and is integral with, or is otherwise suitably joined to the wellhead assembly W by any known manner. The union fitting 20 is secured to the body 10 by a union nut 21 which is threaded by its threads 21a to external threads 10a on the body 10. The nut 21 holds the union fitting 20 in the seated position illustrated in FIG. 2, and preferably, a seal ring such as an O-ring 22 formed of rubber or other similar material is disposed on the union fitting 20 in sealing contact with the counterbore 14. It can be seen from FIG. 2 that the unthreading of the union nut 21 upwardly serves to release the nut 21 from the body 10 and to also permit upward movement of the union fitting 20 relative to the body 10. Such separation of the nut 21 and the union fitting 20 from the body 10 occurs when it is desired to remove the wellhead assembly W and the injector apparatus A thereabove from the position over the well casing C, while leaving the tubing T in the well casing C.

When the union fitting 20 has thus been moved upwardly a sufficient distance to expose the tubing P above the body 10, the body 10 is then in a position to receive a gripping and supporting means G (FIGS. 3 and 5). The gripping and supporting means G includes at least two gripping members 25 which together form a cylinder with a central bore 25a having gripping teeth 25b thereon. The teeth 25b are adapted to bite into and thus grip the external surface of the tubing P which is smooth so as to firmly attach the semi-cylindrical gripping members 25 to the tubing P. The gripping members 25 are clamped tightly on the tubing P so that the gripping teeth or slips 25b engage the external surface of the tubing T by means of cap screws 26 which extend through openings 25c in one of the members 25 and into threads 25d in the other of the members 25. It should be pointed out that the gripping members 25 are attached to the tubing T at a point above the upper end of the body 10 after the union nut 21 and the union fitting 20 have been released and moved to an upper position so that the gripping member G is actually below the union fitting 20.

After the gripping member G is secured to the tubing T it is lowered downwardly with the tubing T into the counterbore 12 to the position shown in FIG. 3 where the lower end of the gripping members 25 rest upon the annular shoulder 12a to thereby support the pipe or tubing P on the body 10.

After the tubing P is thus hanging in the tubing hanger body 10, a split seal member 30 having a split 30a therein (FIG. 4) is forced on to the tubing P above the body 10 and below the union fitting 20. Then the seal member 20 is moved downwardly on the tubing P into the counterbore 14 to seat upon the annular shoulder 14a so as to provide a fluid-tight seal between the tubing P and the body 10.

For increasing the sealing action of the seal member 30, a split bushing 32, which is preferably formed in two halves which are longitudinally divided, is disposed around the tubing T above the seal member 30 and it fits downwardly into the second counterbore 14 in contact with the upper surface of the seal member 30. The split bushing 32 has a lateral shoulder 32a at its upper portion which is engaged by a flange 33a on a locking nut 33 (FIGS. 3 and 4). The nut 33 has threads 33b which are adapted to engage the threads 10a on the body 10 so as to tighten the nut 33 downwardly on the body 10 for compressing the seal member 30 as the bushing 32 is moved downwardly with the nut 33. It is to be noted that the nut 33 has a longitudinal slot 33c (FIG. 4) which is wide enough to enable the lateral movement of the tubing P through such slot 33c so that the nut 33 may be positioned on the body 10 while the tubing P is extending above the bushing 32.

In carrying out the method of this invention, the tubing hanger T is disposed in the position illustrated in FIGS. 1 and 2 prior to the insertion of the tubing P through the wellhead assembly W and the casing C. At such time, the tubing hanger T has the union connection with the wellhead assembly W through the union fitting 20 and the union nut 21.

When it becomes desirable to remove the wellhead assembly W, as well as the injection apparatus A and the other surface apparatus, while leaving the tubing P in the casing C, the first step is to disconnect the union nut 21 from the body 10 so that the union can be separated and the union fitting 20 can be removed upwardly out of the counterbore 14 to a position so as to expose a substantial length of the tubing T above the body 10.

In carrying out the method of this invention, it is assumed that there is no pressure in the tubing P in the vicinity of the tubing hanger T.

As explained heretofore, after the union fitting 20 and the nut 21 have been moved upwardly so as to expose a portion of the tubing P above the body 10, the gripping means G is clamped onto the tubing P, using the cap screws 26, or any other suitable means for forcing the slip teeth 25b into gripping engagement with the external surface of the tubing P. Thereafter, the gripping means G and the tubing T are lowered to position gripping means G in the first or lower counterbore 12 as shown in FIG. 3. The seal means 30 is positioned above the gripping means G in the counterbore 14, and it is compressed into sealing engagement and is held in such compressed condition by a split bushing 32 which is secured to the body 10 by the nut 33.

After the nut 33 is thus in position, the tubing P is hanging on the body 10 of the tubing hanger T and is sealed by the seal means 30. The portion of the tubing P which is extending above the bushing 32 is then cut off to form an upper end 35 to which is attached a valve 36 for thereafter controlling fluid flow into and out of the tubing P. The valve 36 may be connected in any suitable way to the upper end 35 of the tubing P, but as illustrated in FIG. 3, the tubing P has a collar 37 welded or otherwise attached thereto, and the valve 36 has a nipple 36a which is threaded or is otherwise suitably connected to the collar 37.

After the valve 36 has been installed, the well is again completely under control and none of the surface apparatus, such as the wellhead assembly W and the injector apparatus A are required. Periodic well operations may be performed by reason of having the tubing P thus supported in the well casing C. For example, some wells need stimulation periodically which can be accomplished by injecting gas periodically into the well to start the flow of oil again. Oil or other well fluid may be produced externally of the tubing P through any suitable outlet valve (not shown) in the casing C which is below the tubing hanger assembly T, the construction of which is well known to those skilled in the art. The present invention may also be used after it has been assembled as shown in FIG. 3 to introduce corrosion inhibitors into the well periodically, which is desirable in connection with wells which produce gas having substantial amounts of hydrogen sulfide therewith. In other instances, paraffin solvents and other chemicals may be introduced through the tubing P for performing various well treatments or operations which are known in the art.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape, and materials as well as in the details of the illustrated construction may be made without departing from the spirit of the invention.

Claims

We claim:

1. A method of mounting a tubing in a tubing hanger having a bore therethrough, first and second counterbores, and a union at the upper end, comprising the steps of:

disconnecting said union from said tubing hanger to permit raising of a wellhead assembly thereabove to expose the tubing above the hanger;

thereafter raising the wellhead assembly while supporting the tubing to expose a portion of the tubing between the tubing hanger and the wellhead assembly;

inserting a gripping and supporting means laterally onto the exposed tubing between the hanger and the wellhead assembly while the tubing is supported from above;

attaching the gripping and supporting means to the tubing and then lowering the tubing with the gripping and supporting means to position the gripping and supporting means in said first counterbore so that the tubing is thereby supported by the tubing hanger;

inserting seal means laterally onto said tubing in said second counterbore;

confining and tightening said seal means to seal around said tubing;

thereafter cutting said tubing at a point above said tubing hanger to permit removal of said wellhead assembly and said union hanger and the tubing support thereabove; and

installing a control valve on the upper end of said tubing after it has been cut.

2. The method set forth in claim 1, wherein said step of confining and tightening said seal means includes:

positioning a split bushing around the tubing above said seal means; and

thereafter disposing a nut having a longitudinal slot therein for permitting the nut to pass laterally relative to the tubing in a position for threading onto the upper end of said body for forcing the bushing relative to the seal means to increase the sealing action between the seal means, the tubing, and the body.

3. The method set forth in claim 1, wherein said gripping and supporting means includes a split cylinder having slip teeth on the inner surface for engagement with the tubing, and said step of attaching the gripping and supporting means on the exposed tubing includes:

securing the split cylinder on the tubing with the slip teeth thereof in gripping contact with the external surface of the tubing.

4. The method set forth in claim 2, wherein said gripping and supporting means includes a split cylinder having slip teeth on the inner surface for engagement with the tubing, and said step of attaching the gripping and supporting means on the exposed tubing includes:

securing the split cylinder on the tubing with the slip teeth thereof in gripping contact with the external surface of the tubing.