Control Line Installation For Down-hole Safety Valves

Abstract

In a side-by-side dual completion, 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 novel method to be performed to install the control lines in tension without kinking.

Description

BACKGROUND OF THE INVENTION

In most oil producing areas, each tubing string through which subterranean fluids are produced under pressure from a petroleum well is required to include a down-hole safety valve placed e.g. 200-300 feet below the surface. Typical of valves in current use are the Otis valve illustrated at page 3,883, 3,886 of the 1970-71 edition of the Composite Catalog of Oil Field Equipment and Services, Gulf Publishing Company, Houston, Tex., U.S.A. Note that the Otis valve as illustrated installed includes a 1/4 inch control line which proceeds to the surface beside the tubing string. At intervals the exterior control line is clamped to the tubing string. The use of such a control line prevents rotation of the tubing string during installation, as rotation would result in fouling of the control line. This and other installation mishaps can result in kinking or bending of the control line so it will not serve its only purpose. This necessitates additional drilling rig costs for control line repair. Also disadvantageous is the fact the tubing string having such an external control line cannot be raised or lowered through a stuffing box-type tubing hanger. Another sub-surface safety valve installation including an external 1/4 inch control line is illustrated under the Page Oil Tools section of the same Composite Catalog on page 3,997, 4,002. Such control lines are especially subject to kinking, while being threaded through an opening, either out of the outlet of a tubing head, through a port in a tubing hanger, or as illustrated on the above-mentioned pages 3,886 and 4,002 of the Composite Catalog. One solution is to eliminate having a small diameter control line and instead having plural coaxial tubing supplied with fittings and seals to define an annulus about the inner tubing through which hydraulic fluid may be selectively pressurized to operate the down-hole tubing safety valve. Such a construction permits the unit to be rotated without fouling the control means for the valve, permits the unit to be raised and lowered through a stuffing box-type tubing hanger and to be used in single or multiple completions. This type of control line installation is further described in the copending U.S. Pat. application of Phipps et al., Ser. No. 252,101, filed May 10, 1972. Although the coaxial tubing design of control line is believed to have broad applicability, there are undoubtedly instances where small diameter separate control lines will be preferred for use.

Sector-Shaped or diametrically split tubing hangers are disclosed in the U. S. Pat. of Allen, No. 2,794,505, issued June 4, 1957, in the U. S. Pat. of Watts et al., 3,080,181, issued Mar. 5, 1963, and Watts et al., 3,118,690, issued Jan. 21, 1964.

SUMMARY OF THE INVENTION

In conducting the method of the invention in its presently most preferred form:

1. The down-hole safety valve with 1/4 inch control line is run into the well through the blowout preventers, the control line being maintained in tension. The one of the sector-shaped tubing hangers is attached to the respective tubing and the 1/4 inch tubing is inserted in the slot in the flat face of that hanger.

2. A clamp is installed, maintaining the small tubing in tension.

3. The control line seal nipple lower section with O-ring seals is placed over the 1/4 inch tubing and threaded into the hanger, shouldering on the hanger.

4. Control line tubing slip seal is installed and set by means of a setting nut.

5. The setting nut and clamp are removed, control line tubing being in tension. The tubing upper end is now cut to dimension.

6. A blind plug and blanking cap are installed.

7. By means of a landing joint and landing sub, the first tubing hanger with its control line is lowered through the blowout preventer and landed in the tubing head.

8. The second down-hole valve is run, the control line for it being assembled, as previously done for the first one. The dual hanger pack-off is placed over the upper extension of the second tubing hanger and the control line seal nipple. The pack-off retainer ring holds the pack-off in position.

9. The second tubing hanger is landed through the blowout preventers, the pack-off being guided over the first landed tubing hanger.

10. The hangers having been landed, set screws are made up on top of pack-off, effecting a seal within the head and around the hanger and seal nipples. The blowout preventers are removed. The blind plug of stage 6 is loosened to determine if there is pressure inside the 1/4 inch tubing. (Tubing back pressure valves may be installed inside the tubing hangers.)

11. Pressure, if any, has been released from the 1/4 inch tubing, the blind plug and blanking cap removed. Control line nipple upper section installed.

12. The control lines and seals are tested.

13. A packing retainer and chevron packing are placed over the control line nipple upper section. The packing retainer shoulders on the control line nipple lower section, assuring the proper position of the chevron packing, as well as transmitting load directly to the tubing hanger when testing the packing.

14. The tubing bonnet of the christmas tree assembly is landed, sealing on the upper extensions of the tubing hangers and the chevron packing. The packing is tested. A test port and relief port may be provided in the tubing head top flange, which would allow the testing of the tubing hanger pack-off and the ring joint seal between the tubing head and the tubing bonnet.

A primary feature of this type dual setting is the slot in the tubing hanger which allows simple, fast installation of the control line. The improvement of the sector-shaped hanger and the method of installation differs from other well completions that have down-hole safety valves.

A split packing element may be provided rather than a unitary one. In other words, each tubing hanger carries its sector-shaped packing unit. The sealing element is sandwiched between upper and lower metal plates. Upon the landing of both tubing hangers and seals in the tubing head, the set screws are made up against the bevel on the top plate, forcing the seal elements to compress and expand, effecting a seal between all parts.

The completion illustrated is suited for use with the head shown in the copending United States patent application of McGee et al., Ser. No. 236,755, filed Sept. 6, 1972, and is adaptable to other configurations, e.g. to a triple side-by-side completion with three 120-degree sector tubing hangers.

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

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a side elevation view of one tubing hanger, control line and tubing string at stage (2) of the completion described in the summary. A portion is broken away to expose interior detail;

FIG. 2 is a top plan view of the tubing hanger of FIG. 1;

FIG. 3 is a side elevation view of the completion shown beginning in FIG. 1, at stage (6) described in the summary;

FIG. 4 is a side elevation view of the same completion at stage (11) described in the summary;

FIG. 5 is a side elevation view of the same completion at stage (14) described in the summary; and

FIGS. 6, 7 and 8 are respectively perspective, top plan and longitudinal vertical sectional views of the split packing variation of the tubing hanger.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS OF THE INVENTION

In FIG. 1, there is shown a first tubular tubing hanger 10 having a semicircular sector-shaped enlarged portion 12 intermediate the longitudinal extent thereof. As seen in plan, the portion 12 includes a relatively narrow circumferentially extending flange 16 about the tubular barrel 14 of the hanger that extends in two generally triangular regions 18 having a common flat face 20. On its underside, the portion 12 is provided with a semicircular downwardly facing support shoulder 22. Generally centered in each generally triangular region 18 there is shown a vertical bore 24 that is internally helically threaded at 26 adjacent and leading to the upper end thereof. Below the shoulder 22, two oppositely outwardly opening recesses 28 are provided on an axis parallel to the face 20. At the base of each recess 28 an internally helically threaded horizontal bore 30 is provided that intersects with the respective bore 24 in the lower, non-threaded region thereof. Each horizontal bore 30 threadably receives a set screw 32 actuable from exteriorly of the hanger to partly obstruct the respective bore 30.

As an important feature, the flat face 20 is vertically slotted normal to the face in line with each bore 24. These slots 34 intersect the respective bores 24 and are of widths adequate to permit the lateral through-passage of a vertically oriented 1/4 inch tubing string 36; also referred to herein as the control line. Usually, each valve will have but one control line, the other opening and slot in the same hanger functioning as an alternate and/or permitting access to the well to check for obstructions. The unused opening may be suitably capped.

In the instance depicted, the tubing hanger barrel terminates at its upper end in an upwardly tapering, sealing frusto-cone 38 and at its lower end in a threaded connector 40 for securing the hanger 10 on the upper end of a tubing string 42.

At the stage depicted in FIG. 1, a down-hole safety valve (not shown, below the view) has been run into the well (not otherwise shown in this figure) through the blowout preventers (not shown, below the view). The down-hole safety valve is run incorporated in the tubing string 42 at the same time as control line 36, which has its lower end secured to the down-hole safety valve for actuating the latter. During the running step, the control line is maintained in tension by continuously exerting an upward pull on it. Most of the tubing string and control line are down in the well at the stage depicted in FIG. 1 to the point where the tubing hanger 10 has been installed on the upper end of the tubing string and the control line 36 has just been displaced laterally through one of the slots 34 into one of the bores 24. The tensioned control line 36 has been clamped via a clamp 44, with respect to the tubing hanger 10, below the enlarged portion 12, in order to maintain the tension without further need for pulling upwardly on the upper end of the control line 36. The superfluous upper end portion of the control line 36 (above the cut that is shown in FIG. 3) may be cut off. Then a tubular control line seal nipple lower section 46 is slipped over the upper end of the control line, lowered into the bore 24 and threaded via its exterior helical threading 48 with the threads 26. The seal nipple lower section 46 shoulders on the upper end surface 50 of the hanger enlarged portion 12 at 52. The part of the throughbore 54 of the seal nipple lower section 46 that extends above the shoulder 52 includes an internal upwardly flaring portion 56 leading upwardly to an internally threaded portion 58. In its lower region, which in the instance depicted emerges below the lower end of the bore 54, the seal nipple lower section is provided with internal O-ring seals 60 which seal against the exterior of the control line 36. The flaring portion 56 functions as a bowl for slips 62 whose internal serrated surfaces 64 grip the exterior of the control line 36 after the slips are conventionally set by temporarily threading a setting nut into the threads 58 and down upon the slips. After the task of holding tension on the upper region of the control line has been taken over by the slips 62, the clamp 44 may be removed and the control line cut off to the level depicted in FIG. 3. An exteriorly threaded blanking cap 66 is threadably installed at 58 and has its bleeder port 68 closed by a blind plug 70 which may be unscrewed as few turns to open the control line to the atmosphere via the bleeder port 68, as will be explained below. The seal nipple lower section 46 is secured against rotation by running in the set screw 32.

By means of a conventional landing joint and landing sub (not shown), the tubing hanger 10 with the tubing string and down-hole safety valve (not shown) depending therefrom, and the control line 36 extending up alongside the tubing string from the safety valve to its tension-maintaining mounting in the tubing hanger, just described, are lower as a unit through the blowout preventer and landed at 22 on the landing shoulder 74 in the throughbore 76 of the tubing head 78 of the well.

A second down-hole safety valve (not shown) for the other half of the dual completion is then run on the second tubing string 80 with a respective control line maintained in tension and mounted to the second tubing hanger 82, just as described in relation to the first string, (like numbering is used to show like parts), except that a dual hanger pack-off 84 is placed over the upper end of the second tubing hanger and its control line lower seal nipple before the second tubing hanger is landed in the head 78 through the blowout preventers. As the second tubing hanger is landed, the pack-off 84 is guided to fit over the first-landed tubing hanger 10. (If seen in plan, the pack-off 84 is a unitary circular body having two respective openings for receiving the barrel portions of the hangers 10, 82 and two respective openings aligned with those of the bores 24 being used for receiving the upper portions of the two control line lower seal nipples. Both the tapered sealing frusto-cones of the hanger barrels and the blanking caps 66 extend upwardly from the upper surface 86 of the pack-off. The pack-off 84 is of three-layer sandwich construction, having a layer of resilient gasketing material 88 received between hard metal layers 90, 92. The upper outer corner of the upper layer 90 is chamfered to provide a wedging surface 94. The three layers 88, 90, 92 are held together by bolt means (not depicted) which allow the layers to be secured together.)

Set screws 94 having tapered noses 96 are then screwed in through the radiating set screw ports 98 in the upper flange 100 of the tubing head. These noses 96 bear down on the wedging surface 94, squeezing the layers 90 and 92 toward one another. This compresses the resilient gasketing layer 88 causing it to spread laterally and effect seals against the bore of the tubing head and the exteriors of the tubing hanger barrels and control line lower seal nipples. The blowout preventers may then be removed.

The blind plugs 70 are next loosened to check whether there is pressure within the tubing strings. (The down-hole safety valves, especially ball valves, are normally run in a closed condition.) For additional tubing safety, tubing back pressure valves may be installed inside the tubing hangers. See the copending United States patent applications of Holbert, Jr., Ser. No. 123,805, filed Mar. 12, 1971, Ser. No. 124,411, filed Mar. 15, 1971, and 167,784, filed July 30, 1971.

After any pressure has been released by loosening the blind plugs 70, the blind plugs 70 and blanking caps 66 are removed and are replaced by control line nipple upper sections 102. This involves placing an annular ferrule spacer 104 over each control line upper end and lowering it to rest upon the respective set of slips, installing an annular ferrule 106 upon each spacer, then threading the exteriorly threaded lower end region 108 of each tubular control line nipple upper section into the threads 58 until the upwardly tapering internal seat 110 in the lower end of the throughbore 112 thereof engages the upwardly tapering external seat 114 on the upper end of the respective ferrule. The upper end region of the respective control line 36 projects upward into the respective throughbore 112 and is sealed therein by an O-ring seal 116 mounted in a circumferential groove in the throughbore. The upper ends of the control line nipple upper sections are internally helically threaded at 118 to permit temporary connection thereto of control line nipple test adapters for pressurizing the control line at this point to determine the integrity of the various seals and the operability of the valves. The pressurizing adapters (not shown) are then removed.

Next (FIG. 5), packing retainers 120 and chevron packing 122 are placed about the control line nipple upper sections. The retainers 120 shoulder on the respective upper ends of the control line nipple lower sections, assuring proper positioning of the chevron packing as well as transmitting load directly to the tubing hanger when testing the packing.

Then the tubing bonnet 124 of the christmas tree assembly is landed, sealing with the respective sealing frusto-cones at the upper ends of the tubing hanger barrels, and with the chevron packing. The chevron packing is activated by injecting packing compound through the ports 126, and the packing is tested. Although not shown, a test port and relief port may be provided in the tubing head top flange, such allowing the testing of the tubing hanger pack-off and the ring joint seal 128 between the tubing head and the tubing bonnet.

In FIGS. 6, 7 and 8, there is shown a variation of the pack-off described above in relation to FIG. 4. In the earlier version, the pack-off is a single unit of circular section which covers both hangers 10 and 82. In the FIGS. 6, 7 and 8 variation, the pack-off is itself a plurality of sector-shaped units also, corresponding in angular extent to the sector-shaped tubing hangers. As shown, the units are semicircular in extent. Each is assembled onto its respective hanger and carried into the tubing head therewith, in a non-compressed condition. Each pack-off unit 130 is shown including a lower compression plate 132, a compression seal 134 of resilient gasketing material, and an upper compression plate 136 having a beveled upper outer corner 138. These are surmounted by a retainer plate 140 having an outer portion 142 which extends down into the gap created by beveling the upper compression plate region 138, except for slots 144. These parts are maintained assembled by a retainer ring 146 which surmounts the retainer plate 140 and fits in a circumferential groove 148 in the exterior of the barrel of the tubing hanger. The lower outer corner of the lower compression plate 132 is beveled at 150. The sandwiched elements 132, 134, 136 and 140 include aligned openings 152 for the hanger barrel 154 for the control line securement and support and 156 for an access port, the latter being closed with a blot 158.

When the hangers 10, 82 are to be used in a tubing head having a top flange provided with radiating set screws, the noses of the set screws are advanced into the slots 144 to bear down on the beveled surface 138 to compress the material 134 between the plates 132 and 136 to seal against the tubing head, control line, access port bolt and with the other pack-off. When the hangers 10, 82 are to be used in a tubing head having a Grayloc (T.M. Gray Tool Company, Houston, Texas) flange (Composite Catalog of Oil Field Equipment and Services, 1970-71 Edition, Gulf Publishing Co., Houston, Tex., pages 2,235, 2,242, 2,243), the set screws enter the notch provided radially adjacent the beveled surface 150 on the lower compression plate. When these set screws are run in they bear upwardly on the surface 150 and thus compress the sealing material 134 between the plates 132 and 136 to seal as described above.

It should now be apparent that the control line installation for down-hole safety valves as described hereinabove possesses each of the attributes set forth in the specification under the heading "Summary of the Invention" hereinbefore. Because the control line installation for down-hole safety valves 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. A well pipe hanger for hanging at least one string of well pipe from shoulder means in a head, said hanger including:

a tubular barrel portion having a throughbore extending between the upper and lower ends thereof;

means defining an enlarged band on the exterior of the barrel extending a significant portion about the circumference of the barrel intermediate said ends thereof;

securement means on said barrel lower end for securing a string of well pipe to the barrel lower end in sealed communication with the throughbore of the barrel;

circumferential sealing means provided on the barrel adjacent said upper end thereof for sealing with well head equipment to be imposed thereupon;

means defining a passageway through said enlarged band extending generally parallel to the throughbore of the barrel;

means defining a laterally opening slot in the enlarged band communicating between the exterior of the well pipe hanger and said passageway along the length of the passageway, the slot being more narrow than the passageay is wide; and

securement means provided on the enlarged band circumferentially of the passageway for mounting a tubular element to extend within the passageway to restrict lateral exit from the passageway to the exterior of the well pipe hanger through the slot.

2. The well pipe hanger of claim 1 further comprising a second passageway through said enlarged band extending generally parallel to the first-mentioned passageway therethrough; means defining a second laterally opening slot in the enlarged band, this slot communicating between the exterior of the well pipe hanger and said second passageway along the length of the second passageway, the second slot being more narrow than the second passageway is wide; and

securement means provided on the enlarged band circumferentially of the second passageway for mounting a second tubular element to extend within the second passageway to restrict lateral exit from the second passageway to the exterior of the well pipe hanger through the second slot.

3. The well pipe hanger of claim 1 further including a tubular element having securement means provided thereon engaging the last-mentioned securement means of claim 1, the tubular element extending within said passageway of the enlarged band of the well pipe hanger to restrict lateral exit from that passageway to the exterior of the well pipe hanger through the slot.

4. The well pipe hanger of claim 2 further including a first tubular element having securement means provided thereon engaging said securement means provided on the enlarged band circumferentially of the first-mentioned passageway, the first tubular element extending within the first-mentioned passageway to restrict lateral exit from the first-mentioned passageway to the exterior of the well pipe hanger through the first-mentioned slot; and

a second tubular element having securement means provided thereon engaging said securement means provided on the enlarged band circumferentially of the second passageway, the second tubular element extending within the second passageway to restrict lateral exit from the second passageway to the exterior of the well pipe hanger through the second slot.

5. The well pipe hanger of claim 3 further including means defining a circumferentially extending shoulder on the tubular element within the throughbore thereof; and

annular gripping and support means supported upon said shoulder for hanging a second string of well pipe from said shoulder.

6. The well pipe hanger of claim 5 further including securement means provided on the tubular element and a cap secured on the last-mentioned securement means and extending over the upper end of the tubular element for closing the latter.

7. The well pipe hanger of claim 5 wherein the shoulder is an upwardly flaring slip bowl surface; and wherein the annular gripping and support means comprises a set of pipe slips.

8. The well pipe hanger of claim 1 wherein the enlarged band has, in plan view, generally the shape of a sector of a circle including a substantially circularly curved peripheral portion and a substantially straight-sided peripheral portion extending between the angularly opposite ends of the circularly curved peripheral portion; said tubular barrel lying intermediate these two peripheral portions.

9. The well pipe hanger of claim 8 wherein it is through the substantially straight-sided peripheral portion that the slot means meets the well pipe hanger exterior.

10. The well pipe hanger of claim 9 wherein the substantially circularly curved peripheral portion subtends an angle of substantially 180.degree..

11. The well pipe hanger of claim 2 wherein the enlarged band has, in plan view, generally the shape of a sector of a circle including a substantially circularly curved peripheral portion and a substantially straight-sided peripheral portion extending between the angularly opposite ends of the circularly curved peripheral portion; said tubular barrel lying intermediate these two peripheral portions.

12. The well pipe hanger of claim 11 wherein it is through the substantially straight-sided peripheral portion that the second slot means meets the well pipe hanger exterior.

13. The well pipe hanger of claim 12 wherein the substantially circularly curved peripheral portion subtends an angle of substantially 180.degree..

14. The well pipe hanger of claim 3 wherein said engaging securement means on the tubular element and on the enlarged band are constituted by helical threading.

15. The well pipe hanger of claim 5 further comprising circumferentially extending sealing means in the throughbore of the tubular element for sealing with the exterior of the second string of well pipe.

16. In a well completion:

a head having means defining a vertical throughbore having shoulder means facing upwardly therein;

a well pipe hanger for hanging at least one string of well pipe from said shoulder means, said hanger including:

a tubular barrel portion having a throughbore extending between the upper and lower ends thereof;

means defining an enlarged band on the exterior of the barrel extending a significant portion about the circumference of the barrel intermediate said ends thereof;

securement means on said barrel lower end for securing a string of well pipe to the barrel lower end in sealed communication with the throughbore of the barrel;

circumferential sealing means provided on the barrel adjacent said upper end thereof for sealing with well head equipment to be imposed thereupon;

means defining a passageway through said enlarged band extending generally parallel to the throughbore of the barrel;

means defining a laterally opening slot in the enlarged band communicating between the exterior of the well pipe hanger and said passageway along the length of the passageway, the slot being more narrow than the passageway is wide; and

securement means provided on the enlarged band circumferentially of the passageway for mounting a tubular element to extend within the passageway to restrict lateral exit from the passageway to the exterior of the well pipe hanger through the slot;

said hanger being received in said throughbore of the head and being supported via said enlarged band upon said shoulder means of said throughbore of said head; and

a first string of well pipe having the upper end thereof secured to the lower end of said barrel by the securement means on the lower end of said barrel.

17. The well completion of claim 16 further comprising a second passageway through said enlarged band extending generally parallel to the first-mentioned passageway therethrough; means defining a second laterally opening slot in the enlarged band, this slot communicating between the exterior of the well pipe hanger and said second passageway along the length of the second passageway, the second slot being more narrow than the second passageway is wide; and

securement means provided on the enlarged band circumferentially of the second passageway for mounting a second tubular element to extend within the second passageway to restrict lateral exit from the second passageway to the exterior of the well pipe hanger through the second slot.

18. The well completion of claim 16 further including a tubular element having securement means provided thereon engaging the last-mentioned securement means of claim 16, the tubular element extending within said passageway of the enlarged band of the well pipe hanger to restrict lateral exit from that passageway to the exterior of the well pipe hanger through the slot.

19. The well completion of claim 17 further including a first tubular element having securement means provided thereon engaging said securement means provided on the enlarged band circumferentially of the first-mentioned passageway, the first tubular element extending within the first-mentioned passageway to restrict lateral exit from the first-mentioned passageway to the exterior of the well pipe hanger through the first-mentioned slot; and

a second tubular element having securement means provided thereon engaging said securement means provided on the enlarged band circumferentially of the second passageway, the second tubular element extending within the second passageway to restrict lateral exit from the second passageway to the exterior of the well pipe hanger through the second slot.

20. The well completion of claim 18 further including means defining a circumferentially extending shoulder on the tubular element within the throughbore thereof; and

annular gripping and support means supported upon said shoulder for hanging a second string of well pipe from said shoulder, said second string of well pipe extending down through the passageway within the tubular element and being engaged by said annular gripping and supporting means and supported thereby from said shoulder within the throughbore of the tubular element.

21. The well completion of claim 20 further including securement means provided on the tubular element and a cap secured on the last-mentioned securement means and extending over the upper end of the tubular element for closing the latter.

22. The well completion of claim 20 wherein the shoulder is an upwardly flaring slip bowl surface; and wherein the annular gripping and support means comprises a set of pipe slips.

23. The well completion of claim 16 wherein the enlarged band has, in plan view, generally the shape of a sector of a circle including a substantially circularly curved peripheral portion and a substantially straight-sided peripheral portion extending between the angularly opposite ends of the circularly curved peripheral portion; said tubular barrel lying intermediate these two peripheral portions.

24. The well completion of claim 23 wherein it is through the substantially straight-sided peripheral portion that the slot means meets the well pipe hanger exterior.

25. The well completion of claim 24 wherein the substantially circularly curved peripheral portion subtends an angle of substantially 180.degree..

26. In the well completion of claim 16, a second well pipe hanger for hanging another string of well pipe from said shoulder means, said second hanger including:

a tubular barrel portion having a throughbore extending between the upper and lower ends thereof;

means defining an enlarged band on the exterior of the barrel extending a significant portion about the circumference of the barrel intermediate said ends thereof;

securement means on said barrel lower end for securing the other string of well pipe to the barrel lower end in sealed communication with the throughbore of the barrel;

circumferential sealing means provided on the barrel adjacent said upper end thereof for sealing with well head equipment to be imposed thereupon;

means defining a passageway through said enlarged band extending generally parallel to the throughbore of the barrel;

means defining a laterally opening slot in the enlarged band communicating between the exterior of the second well pipe hanger and said passageway along the length of the passageway, the slot being more narrow than the passageway is wide; and

securement means provided on the enlarged band circumferentially of the passageway for mounting a tubular element to extend within the passageway to restrict lateral exit from the passageway to the exterior of the second well pipe hanger through the slot;

said second hanger being received in said throughbore of the head and being supported via said enlarged band upon said shoulder means of said throughbore of said head;

said other string of well pipe having the upper end thereof secured to the lower end of said barrel by the securement means on the lower end of said barrel wherein it is through the generally straight-sided peripheral portion of the second well pipe hanger that the slot means thereof meets the exterior of the second well pipe hanger;

the circularly curved peripheral portion of the second well pipe hanger subtending an angle of substantially 180.degree.;

the generally straight-sided peripheral portions of the first-mentioned and second well pipe hangers being presented against one another.

27. The well completion of claim 26 further including a tubular element having securement means provided thereon engaging the last-mentioned securement means of claim 26, the tubular element extending within said passageway of the enlarged band of the second well pipe hanger to restrict lateral exit from that passageway to the exterior of the second well pipe hanger through the slot.

28. The well completion of claim 27 further including means defining a circumferentially extending shoulder on the tubular element within the throughbore thereof; and

annular gripping and support means supported upon said shoulder for hanging a second string of well pipe from said shoulder, said second string of well pipe extending down through the passageway within the tubular element and being engaged by said annular gripping and support means and supported thereby from said shoulder within the throughbore of the tubular element.

29. The well completion of claim 28 wherein the first and other strings of well pipe are constituted by respective strings of production tubing.

30. The well completion of claim 29 wherein the second string of well pipe is constituted by a down-hole safety valve control line.

31. The well completion equipment of claim 26 further including:

pack-off means over the enlarged bands of the two well pipe hangers within the throughbore of the head; the pack-off means having respective opening means therethrough for receiving the barrels of the two well pipe hangers and said tubular elements, and including a lower compression plate means, an upper compression plate means and an intermediate layer of resilient gasketing material, and means on said head for squeezing the two compression plate means together to cause said layer of resilient gasketing material to circumferentially seal with the throughbore of the head, the exteriors of the two barrels and the exteriors of the two tubular elements.

32. The well completion equipment of claim 31 wherein the pack-off means is diametrically split into two complementary pack-off units, one coordinating with each well pipe hanger and the gasketing material, upon being compressed also sealing between said two complementary pack-off units.

33. The well completion equipment of claim 32 further including retainer means on each well pipe hanger barrel for maintaining the respective pack-off unit, disposed thereabout, in assembled condition.

34. The well completion equipment of claim 33 wherein each retainer means comprises a snap ring mounted in means defining a circumferential groove in the exterior of the respective barrel.

35. The well completion equipment of claim 27 further including laterally opening internally threaded set screw port means in each enlarged band and set screw means threadably received therein, bearing against the respective tubular element to lock the same in place.