Well Head Set Screw Port Exit Of Control Line For Down-hole Safety Valve

Abstract

Valves fittings and flexible tubing for connection to the upper ends of one or more control lines for down hole safety valves are connected to these upper ends above the tubing hangers and seals and communicated to the exterior of the head through one or more ports conventionally used for set screws, using disclosed fittings in the ports. Assembled parts may be tested for leaks before the tubing bonnet and remainder of the christmas tree are installed.

Description

BACKGROUND OF THE INVENTION

The subject matter hereof grew out of continuing efforts to provide alternatives or improvements upon the apparatus and procedures disclosed in the co-pending U.S. Pat. application of McGee et al., Ser. No. 286,754, filed Sept. 6, 1972 and to improve upon the apparatus and procedures currently marketed by others. For instance see page 3,960 of the 1968-69 edition of the Composite Catalog of Oilfield Equipment and Services, Gulf Publishing Company, Houston, Texas; and pages 3,302 and 3,504 of the 1972-73 edition thereof.

In contrast with the equipment disclosed in the abovementioned co-pending application that of the present invention does not require a special tubing bonnet, may more readily be incorporated in existing wells, can permit continued production from a well while the control line power source is being serviced or repaired.

SUMMARY OF THE INVENTION

Valves fittings and flexible tubing for connection to the upper ends of one or more control lines for down hole safety valves are connected to these upper ends above the tubing hangers and seals and communicated to the exterior of the head through one or more ports conventionally used for set screws, using disclosed fittings in the ports. Assembled parts may be tested for leaks before the tubing bonnet and remainder of the christmas tree are installed.

The principles of the invention will be further hereinafter discussed with reference to the drawing wherein a preferred embodiment is shown. The specifics illustrated in the drawing are intended to exemplify, rather than limit, aspects of the invention as defined in the claims.

BRIEF DESCRIPTION OF THE DRAWING

IN THE DRAWING

FIG. 1 is a top plan view of a tubing head provided with an installation in accordance with the principles of the present invention, part of one set screw port being broken away to expose interior details; and

FIG. 2 is a vertical cross sectional view taken substantially along the line 2--2 of FIG. 1.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT

The aforementioned co-pending application of McGee et al describes a side-by-side dual completion wherein two semicircular tubing hangers are provided with slots on their flat faces leading to bores for the receipt of control lines for respective down-hole safety valves. The slots facilitate the carrying out of a method described therein for installing the control lines in tension without kinking. All of the disclosure in that application is hereby incorporated into this one to avoid needless repetition of matters already described therein. Attention will be paid to differences.

In conducting the method of the invention in its presently most preferred form: Assembly and running of the tubing strings, down hole valves, control lines, tubing hangers and packing assembly may be carried out substantially as set forth in the aforementioned co-pending application of McGee et al.

At the stage shown in FIGS. 1 and 2, the hanger 10 has shouldered in the tubing head 12, the pack-off 14 has been installed and compressed by running in conventional set screws 16 (one shown, of several used.) A dual completion is shown (note the two sealing cones 18 at the upper ends of the respective tubing strings), but since they are alike, the following description will deal with a representative one.

The control line 20, a one-fourth string of tubing that protrudes up through a bore 22 in the pack-off 14 is secured and sealed in place via a control line seal nipple 24 that screws into the tubing hanger at 26 to abutment at 28 and has its exterior sealed with the pack-off 14 at 30. The nipple 24 has a longitudinal bore 32 up through which the control line 20 extends. The upper end of the bore 32 is enlarged to receive, in ascending order, a lower ferrule 34, a spacer 36, an upper ferrule 38, and a setting nut 40 (all annular parts). The setting nut is exteriorly threaded to screw into internal threads in the enlarged upper end of the nipple 24 at 42. The tightening of the nut 40 seals the exterior of the control line 20 with respect to the throughbore of the nipple 24, i.e. the ferrules 34, 38 provide metal to metal seals. The upper end of the control line is disposed within the throughbore of the setting nut. At an intermediate stage, earlier than that depicted in the figures a blind plug and blanking cap may be installed on the setting nut via the internal threads 44 in the upper end of the throughbore thereof.

The installation depicted is further completed by rotatatively running an annular nut 46 into one of the otherwise extra set screw ports 47 until it engages the stop shoulder 48 therein. A packing gland nut 50, a spacer 52, packing 54 and and a lock nut 56 are assembled on the neck 58 of a needle valve 60 and inserted in the port 47 until the gland nut 50 threadably mates with the threads 62 sufficiently to establish seals at the packing, at 64, and at the tapered nose 66 where the inner end of the valve 60 housing fits in a corresponding taper in the outer end of the bore of the annular nut 46.

By means of e.g. "Swagelok" fittings 68, 70 secured on its opposite ends, a length of flexible tubing 72 is connected between the inner end of the nut 46 and the upper end of the setting nut 40. Close tolerances for the tubing 72 are not involved because it is somewhat flexible and may either be pre-cut to length at the factory or field cut to length for installation in the orientation substantially as depicted in the figures.

A pressure line 74 may now be connected to the inlet port 76 of the valve 60 and the latter opened (if not already open) by manipulating the stem 80 to test the control line and its actuation of the down-hole safety valve (not shown) at the lower end of the control line 20. Note that this may be done before the bonnet or any further christmas tree equipment that would obscure the ports is installed. If testing and inspection indicates proper assembly and sealing, a conventional tubing bonnet and further christmas tree equipment installed.

Note these advantages over the equipment of the aforementioned co-pending application of McGee et al.:

1. A special design of tubing bonnet is not required.

2. If a down hole valve is to be installed in an existing well, the only change in equipment is the use of the control line passing type of tubing hanger and pack-off(e.g. per McGee et al.) and the installing of the various parts between the control line 20 upper end and the pressure line 74 as described above.

3. Possible greater economy

4. Pressure can be maintained in the control line while the pressure generating and controlling equipment upstream of the valve 60 is repaired or serviced by closing the valve 60.

Note that the critical seals are preferably metal-to-metal ones. Note also that the invention may be used with single, dual, triple, or other multiple completions, subject only to the corresponding availability of otherwise un-needed set screw ports in the tubing head and space for the flexible tubing and its fittings between the tubing head and the tubing bonnet that will be mounted on the tubing head. As an optional feature, note that the fitting 70 could be closed during running of the tubing hangers to eliminate the need for temporary installation of a blind plug and blanking cap as disclosed under item 11 in the summary of the invention in the aforementioned co-pending application of MeGee et al.

It should now be apparent that the well head set screw port exit of control line for down-hole safety valve as described hereinabove possesses each of the attributes set forth in the specification under the heading "Summary of the Invention" hereinabove. Because the well head set screw port exit of control line for down-hole safety valve of the invention can be modified to some extent without departing from the principles of the invention as they have been outlined and explained in this specification the present invention should be understood as encompassing all such modifications as are within the spirit and scope of the following claims.

Claims

What is claimed is:

1. An installation for controlling down hole, control line-operated equipment such as a safety valve of a petroleum well, comprising:

a tubing head having a plurality of set screw ports of the sort normally provided for respective receipt of set screws to compress a pack-off down against a tubing hanger;

a tubing hanger mounted in the tubing head for suspending a string of tubing in the well and pack-off means for sealing between the tubing head and the tubing;

a control line extending up through the tubing hanger, up past the pack-off means and being exteriorly sealed with respect to the tubing head by the pack-off means;

one of said set screw ports lacking a set screw and instead thereof being provided with: openable and closable valve means sealed therein and being operable from exteriorly of the tubing head;

fluid-tight conduit means interconnecting the control line with said one set screw port down stream from said valve;

and means exteriorly of the tubing hanger for connection of a pressure line to the one set screw port upstream from said valve.

2. The installation of claim 1 wherein the fluid tight conduit means includes a flexible tube having fittings at each end thereof for said interconnecting.

3. The installation of claim 2 further including an annular adapter nut received in the one set screw port ahead of said valve, the respective of said fittings being secured to said adapter nut.