US3434535A - Multiple tubing string support and safety valve installation - Google Patents

Description

J. S. PAGE March 25, 1969 MULTIPLE TUBING STRING SUPPORT AND SAFETY VALVE INSTALLATION e s T M Na w M M W 4 m 0 M W9 J3 m a 22 T A} a Ma w my J. S. PAGE March 25, 1969 MULTIPLE TUBING STRING SUPPORT AND SAFETY VALVE INSTALLATION Sheet 2 of 2 Filed April 5, 1967 J'uvsuroe Liou/v $5 0 PAGE firroeNe-s s.

United States atent 3,434,535 MULTIPLE TUBING STRING SUPPORT AND SAFETY VALVE INSTALLATION John S. Page, Lakewood, Calif.; Eulah N. Page, executrix of the will of said John S. Page, deceased, and sole heir of the estate of said John S. Page, assignor, by mesne assignments, to Cook Testing C0., Long Beach, Calif., a corporation of Nevada Filed Apr. 3, 1967, Ser. No. 627,893 Int. Cl. E21b 43/12 US. Cl. 166-72 7 Claims ABSTRACT OF THE DISCLOSURE The disclosure concerns installation in a well fluid pressurized tubing string of a control fluid pressure responsive sub-surface safety valve, without killing the well, and in such manner that the sub-surface string will not be disturbed despite great damage to the well head.

Background of the invention This invention relates generally to well protection and operation. More specifically, the invention concerns installation in a pressurized well tubing string and operation of a control fluid pressure responsive sub-surface safety valve.

In certain oil and gas producing regions it is desirable to install sub-surface safety valves in wells, as for example land wells, which are already drilled and in production. Such installation secures the wells against possible sabotage such as dynamiting of the well head, for in such event the safety valve will automatically close and shut in the well at a sub-surface location below the explosive blast. One method of installation involves injection of mud into the well and at high pressure to kill the well in order to allow safety valve connection in the string. However, it is a known fact that certain wells in those areas, as for example North Africa, are characterized by a type of producing formation which can be greatly damaged by such mud injection. Previous practice has shown that such wells, if killed in this manner, will not come back to their normal flowing stage.

Summary of the invention It is a major object of the present invention to provide unusually advantageous method and apparatus for installation of safety valves in well tubing strings without killing the wells with mud injection. Basically, and in its method aspects, the invention involves steps that include lowering a plug in the well tubing string for plugging it at a first location spaced below the top of the string; connecting a control valve in the string at a second location spaced above the first location, which step is made possible by the initial plugging step; also connecting concentric tubing strings in series with the well tubing string and above the valve to establish one path for control pressure communication to the valve via one of the concentric strings and another path for well production fluid flow upwardly from the tubing string below the valve to another of the concentric strings and via the valve; and thereafter elevating the plug through the valve and the other concentric string for unplugging well production fluid flow via the other path. Typically the control valve is lowered to a sub-surface location as a result of connecting the concentric string sections into the string, whereby the valve is not only inserted in the string but also it is lowered to a position below potential blast efiects, where the valve may automatically shut off should control pressure be sharply reduced as for example due to such a blast.

Additional steps of the novel method include sealing oif between the string and well bore during connection of the control valve in the string, one such sealing method advantageously including installing at the well head a pressure lock between the tubing and the well bore and elevating the top of the string through the lock for connection of the valve to the string at the exterior of the lock; connecting a settable support to the string proximate the valve location and prior to concentric string connection to the string, lowering the support and valve in the well during concentric string connection, and setting the support at a sub-surface location in the well to support the string; installing at the well head a pressure lock between the tubing and the well bore and lowering the valve and support through that lock; connecting a well packer in the string to be lowered with the support, and setting the packer; and sealing off between each of the concentric strings and the well bore, proximate the concentric string upper terminals, to maintain separation of the aforementioned flow paths at the well head.

In its basic apparatus aspects, the installed assembly includes tubing string means installed in the well and sub-surface valve means connected in the string, the latter including a lower tubing string extending below the valve means for flowing production fluid upwardly to the valve means, and inner and outer generally concentric upper tubing strings extending upwardly between the valve means and the well head, the valve means being responsive to control fluid pressure introduced into one of the upper tubing strings to control the upward flow of production fluid from the lower string to the other of the upper concentric strings; subsurface support means supporting the string means in the well; and structure at the well head to supply control fluid pressure to the one upper tubing string and to receive flow of well production fluid from the other of the upper tubing strings, that structure including a well bore extension receiving the upper tubing strings with the inner string projecting above the upper terminal of the outer string, first sealing means sealing off between the inner string and the bore extension above the upper terminal of the outer string, and second sealing means sealing off between the outer tubing string and the bore extension and spaced below the first sealing means. Typically, and as will be seen, the first and second sealing means may comprise spools respectively mounted on the inner and outer tubing strings.

Additional structural aspects of the invention include the freedom of the tubing string means from vertical support at the well head, whereby in the vent of upward dynamiting of the well head the tubing will not be carried with it; the location of the sub-surface string support means on the lower string in the well; the provision of means packing off between the lower string and the well bore, and which cannot be disturbed in the event of blasting of the well head since the well head equipment does not support the string; and the provision of a first pipe outside the bore extension at the well head to communicate with the upper interior of the inner tubing string, and a second pipe outside the bore extension at the well head to communicate with the upper interior of the outer tubing string, one pipe supplying control fluid for operating the sub-surface valve and the other pipe receiving well production fluid flow.

These and other objects and advantages of the invention, as well as the details of illustrative embodiments, will be more fully understood from the following detailed description of the drawings, in which:

Brief description of the drawing FIG. 1 is a vertical elevation taken in section to show the assembly installed in a well;

FIG. 2 is an enlarged vertical section taken on line 2-2 of FIG. 1, showing a typical sub-surface valve in open state;

FIG. 3 is an enlarged view similar to FIG. 2 but showing the valve in closed state;

FIG. 4 is a section taken on line 44 of FIG. 3;

FIGS. 5 and *6 are vertical sections illustrating steps in the method of sub-surface valve installation;

FIG. 6a is a vertical elevation illustrating another step; and

FIG. 7 is a vertical section showing plug construction.

Referring first to FIGS. 1 and 2, a well bore 10 is shown as cased at 11 with tubing string means 12 installed in the well. The string means includes a lower tubing string 13 extending below valve means 14 connected in the tubing string, the latter also inner and outer generally concentric upper tubing strings 15 and 16 extending upwardly between the valve means and the well head.

Generally speaking, the valve means 14 is responsive to control fluid pressure introduced into one of the upper tubing strings 15 and 16 to control the upward flow of production fluid from the lower string 13 to the other of the upper tubing strings. In the example shown, the valve means is responsive to control fluid pressure introduced into the interior 17 of the outer one 16 of the upper strings, thereby to control production fluid flow from the lower string into the interior 18 of the inner one of the upper tubing strings.

The illustrated valve means includes a sub body 19 having interiorly threaded pin and box ends 20 and 21 respectively connected to the lower and upper strings 13 and 15. The body itself includes interconnected tubular sections 19a, 19b and 190, and the outer concentric string 16 is connected to the body at 22. Control pressure is applied from the interior 17 of the outer string, and

via side port 23 in the body section 1%, to a chamber 24 formed by the body and an axially movable valve sleeve 25. Such pressure exerted on piston surface 26 tends to urge the sleeve downwardly in a direction to displace the sleeve skirt 27 from closed position as seen in FIG. 3 to open position seen in FIG. 2. In FIG. 3, the skirt closes off access of production fluid flow to a by-pass channel 29 via an entrance side port at 30, whereas in FIG. 2 that port is open to pass the flow upwardly in the channel 29, the flow re-entering the interior of the sub body at 31 above a plug 32, for upward flow in inner string 15.

Plug 32 seals at 33 against the bore 34 of the cylindrical insert 35 suitably attached to the sub as by circularly spaced vertical webs 36. In this regard, the plug may be introduced to the inner string 15 via the lubrication unit '80 (to be described later) and lowered by wire line attached to plug nipple 37, for releasable attachment to the valve interior. Such attachment may be effected by reception of lugs 38 (on collet spring fingers 39) into the annular groove 40 formed by the insert 35. The plug is retrievable as by connection of a wire line lowered cup onto the spring finger serrated terminals 41, to collapse the fingers inwardly releasing the lugs from groove 40.

A helical spring 42 retained by sub section 190 urges the valve sleeve upwardly at 43, tending to maintain the port closed. Such closing action can be overcome by exertion of suflicient control fluid pressure downwardly in the outer concentric string 16, to open the valve; conversely, the valve can be closed by reducing the control fluid pressure exerted at 26.

It is an important feature of the invent-ion that the string assembly as described is supported in the well by sub-surface support means, whereby severe damage to the well head (as by explosives) will not result in disruption of string support in the well. In this regard, FIG. 1 shows the provision of sub-surface support means below the valve 14 and in the form of slips 47 which are set in response to fluid pressure exertion in the lower string. The pressure is applied to a suitable piston urging the slips axially against a cam surface which tapers to wedge the slips outwardly and against the bore 48 of the casing 11. Such a support means as described is disclosed in John S. Page application for US. Letters Patent Ser. No. 520,470, filed Jan. 13, 1966.

The objective of non-disturbance of the string, despite great damage to the well head, is further enhanced by reason of th characteristic that the tubing string means is free of vertical support at the well head. In the example shown, this characteristic is found in the structure at the well head by which control fluid pressure is applied to one upper tubing string (as for example string 16) and by which production fluid is received from the other tubing string (as for example string 15). Such structure includes a well bore extension, as for example casing section 50 of the casing head 51, which receives the tubing strings 15 and 16 with the inner string projecting at 15a above the upper terminal 16a of the outer string. First sealing means, as for example first spool 52 on string terminal 15a, seals olf between the bore 53 and the inner string upper terminal 15a; likewise, second sealing means, as for example second spool 54 on string terminal 16a, seals oif between the bore 53 and the outer string upper terminal 16a. Since the spools are in effect slidable with respect to bore 53, although sealing thereagainst, the casing head may be blown upwardly from the floor 56 and off the spools, without pulling the strings along to any extent.

The above mentioned structure may also be considered to include a first pipe 61 outside the well bore extension formed by the casing section 50 and communicating via a side port in the section 50 with the upper interior of the inner tubing string 15; similarly, a second pipe 62 communicates with the interior of the outer tubing string 16, spool 52 sealing off communication of the spaces above and below it and within the casing section 50. Pipe 62 supplies control fluid pressure from a source 63, and pipe 61 receives flow of production fluid. Valves 64 and 65 in pipes 61 and 62 are used for flow control. Note that the valve sleeve 25 will be closed to FIG. 3 position, by reduction of control pressure applied at chamber 24, in the event of rupture of line '62, the rating of spring 42 and the depth of the valve in the well being such as to serve this function.

To complete the description of FIG. 1, the tree at the well head includes casing head sections 66 and 67, the latter having branches 68 and 69 controlled by valves 70 and 71, for controlling fluid flow to and from the annulus 72, if desired. The casing head is capped at 73, as by section 74 mounting a shut-off valve 75. Finally, the lower string 13 carries means packing off between that string and the well bore 42. The packer 77 of FIG. 1 serves this function, and may have the construction as shown and described in the Page application Ser. No. 520,470 referred to above. As there described, the packer 77 is expanded against bore 48 in response to fluid pressure application in the tubing 13.

A further and important aspect of the invention has to do with installing the FIG. 1 equipment in a flowing well, without use of mud which might irrevocably kill the well or reduce its production to substantial degree. Such beneficial installation may be had in accordance with the following teachings, an understanding of which will be helpfully gained by reference to and study of FIGS. 5 and 6.

The method involves lowering a retrievable plug in the original string 13, which extends to the well head, as by Wire line 86, for plugging the string at a first location spaced below the top of the string. For example, the plug may be lowered to the location of a tubing coupling 87, for packing off proximate the interior recess provided by the coupling. The plug 85 may be of the construction as shown in FIG. 7 herein, having a tubular body supported by a collet 121 which engages body shoulder 120a in running position. The collet has spring fingers 122 with latch dogs 123 urged outwardly to engage the tubing bore 124 during running. A ram 125, supported by wire line 86, urges the plug downwardly in the string to desired depth, as by engagement with the tops 127 of the fingers, the ram also including a rod 128 of a length to hold the ball 129 in body 120 011 annular seat 130, during running. This allows the plug to pass well fluid relatively upwardly therethrough, during running.

Upon arrival of the plug at desired depth, the latch dogs 123 snap outwardly into the groove 131 inwardly of collar 87, to locate the plug and to resist its upward displacement. Also, ram 125 is retrieved. A spring 132 urges ball 129 against seat 130, and shut in well pressure urges body 120 upwardly relative to the collet, from a lower or extended posit-ion to the collapsed condition shown, in which fingers 122 are blocked against inward retraction. Shoulder 134 on the body then pressurizes the elastomeric seal ring 135 toward metal ring 136 retained beneath the collet. Seal 135 then expands and packs off between the body 120 and the bore 124. Retrieval of the plug is accomplished by wire line lowering of a retrieval cup 140 acting to collapse finger terminals 141 inwardly and to grip their serrations 142, followed by lifting of the cup and the plug. Such plug manipulation is aflorded by first attaching the lubricator 80 to the top of the flange 87 on the tree 51. The plug is lowered past open valve 88 and into lubricator tubular body 89, valve 75 being closed; thereafter, valve 75 is opened and valve 88 closed, enabling lowering of the plug by wire line into plugging position in the tubing 13. A top packing for the wire line is contained at 89a. Thereafter, the lubrication is removed, and the tree 51 is removed off flange 90. Note that the string is supported by a ring 91 attached to the tubing and seated at 92 in the casing head section 67.

The larger lubricator 93 together with upper and lower rams 94 and 95 is next installed on flange 90. The rams are of known gate type, operable to open and close the passages in tubular bodies 94a and 95a. Next, a spare joint of tubing 13a is hoisted as at 96 and the pin end thereof is lowered through the lubricator and open rams, and threaded into the ring 91 as seen in FIG. 6a (tubing 13 being plugged off as described above). The rams are then closed about the adding tubing 13a and the lubricator 93 is pressured to equal well pressure in the annulus 72, as via pressure line 97. Lower ram 95 is then opened, and the string is hoisted to ele vate ring 91 to a position in the lubricator and between the rams.

Thereafter, the lower rams 95 are closed about the hoisted tubing 13 and the upper rams are opened away from tubing 13a. The tubing as again elevated to raise the ring 91 clear of the top of the ram 94, following which the ring 91 and tubing 13a are removed from tubing 13.

The unit embodying the packer 77 and slips 47 is next attached to the exposed tubing. These elements are then lowered through the lubricator, with opening and closing of rams 94 and 95 to maintain lock action. Thereafter, the valve 14 is added and concentric strings 15 and 16 attached and lowered through the lubricator and rams to desired depth, although a depth of 100 feet for the valve 14 would normally not be exceeded, or needed to protect against explosive damage. The packer is then extended or set, at such time that the upper terminals 15a and 16a of the concentric upper strings terminate in the casing as seen in FIG. 1, and as also seen in broken lines in FIG. 6. Also, the slips 47 are set. As explained in the referred to Page application Serial No. 520,470, fluid pressure may be exerted from the surface, and communicated via strings 15 and 13, for setting of the packer and slips. Well pressure exerted upwardly against plug bore 129 is suflicient to prevent opening of the ball off seat 130.

The annulus is now shut in by the packer, and the tubing 13 still remains plugged at collar 87, so the lubricator 93 and rams 94 and 95 can then be removed. Spools 52 and 54 are attached, in the position as seen in FIG. 1, and the stacked tree elements 50, 74, and 89 attached to the casing head section 67, as seen in FIG. 1. The auxiliary equipment 63 including booster pump and pilot valve are attached along with piping 61 and 62.

Finally, the retrieval cup is lowered by wire line 86 to latch onto the plug terminals 141, the line is pulled removing the plug from tubing 13, and the valve plug 33 previously described is lowered and installed. The wireline tools are then removed, and the installation is completed in the configuration described in FIG. 1.

I claim:

1. In a well assemby,

tubing string means installed in the well and sub-surface valve means connected in said string means, said string means including a lower tubing string extending below the valve means for flowing production fluid upwardly to the valve means and inner and outer generally concentric upper tubing strings extending upwardly between the valve means and the well held, the valve means being responsive to control fluid pressure in one of said upper tubing strings to control the upward flow of production fluid from the lower string to the other of said upper tubing strings,

sub-surface support means supporting said string means in the well,

and structure at the well head to supply control fluid pressure to said one upper tubing string and to receive flow of well production fluid from the other of said upper tubing strings, said structure including a well bore extension receiving said upper tubing strings with the inner string projecting above the upper terminal of said outer tubing string, first sealing means sealing oft between the inner string and the bore extension above said upper terminal of said outer string, and second sealing means sealing off between the outer tubing string and said bore extension and spaced below said first sealing means.

2. The assembly of claim 1, wherein said first and second sealing means comprise first and second spools respectively mounted on the inner and outer tubing strings.

3. The assembly of claim 2, wherein said structure includes a first pipe outside the bore extension communicating via said extension with the upper interior of the inner tubing string, and a second pipe outside the bore extension communicating via said extension with the upper interior of the outer tubing string, one of said pipes supplying said control fluid pressure and the other of said pipes receiving said flow of production fluid.

4. The assembly of claim 1, in which the tubing string means is free of vertical support at the well head.

5. The assembly of claim 4, in which said sub-surface string support means is on said lower string in the well and includes a slip engaged with the well bore.

6. The assembly of claim 1, including means packing ofl? between said lower string and the well bore.

7. The assembly of claim 1, wherein said bore extension is defined by a casing head.

References Cited UNITED STATES PATENTS Re. 26,149 1/ 1967 Sizer et a1. 166-72 3,065,794 11/1962 Page 166-72 X 3,156,300 11/1964 Page et a]. 166-72 X 3,351,133 11/1967 Clark et al 166-72 X DAVID H. BROWN, Primary Examiner.

U.S. Cl. X.R.

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