US3014533A - Permanent completion of wells - Google Patents

Description

Dec. 26, 1961 R JR 3,014,533

PERMANENT COMPLETION OF WELLS Filed Sept. 22, 1958 /3 H. Moore, z/r.

INVENTOR.

ATTORNEY 3,914,533 Patented Dec. 26, 1961 This invention relates to permanent completion Well installations and more particularly to the placement in a well hole and the embedment in a hole-filling solid cement column of conductor equipment through which all of the various working and reworking operations and the usual production of well fluids are accomplished.

In conventional well practices-and after a hole has been drilled through the earth from a surface location and to a production zone, the wall of the bored hole is lined throughout its depth by a large diameter hollow tubular casing. Thereafter a production conduit or string of tubing sections of smaller diameter is lowered through the casing in concentric relation thereto and usually a packer is set between the two strings for closing off the annular space from the production zone for well fluid flow through the inner string to the surface. A well liner casing and its enclosed annular space serve many useful purposes and, among other things, permit the production tubing string to be withdrawn for the performance of reworking operations. I

As distinguished from past procedures, it is here proposed to install a Well tubing assembly which has all the advantages of but does not employ the customary large diameter casing and which assembly, once installed, remains in place and yet permits all of the necessary working operations to be readily performed. Forcertain well conditions, considerable savings are effected not only in the simplification of maintenance and reworking operations but also in the original cost for the drilling of a well hole, inasmuch as a much smaller well hole can be bored, and one which is only slightly larger than the tubing string is entirely feasible and is desirable inasmuch as the work of bringing in a Well and the time required are considerably lessened, and since the tubing assembly is permanently cemented within the hole, at least for a considerable portion of its bottom length and on occasion throughout substantially its entire length, it follows that the smaller the hole, the less will be the volume of cement required to bridge the bore space surrounding the tubing string.

Reference is to be made to the accompanying drawing wherein FIG. 1 is a more or less diagrammatic illustration in exaggerated proportions of a Well installation in verti cal section according to the present improvement; FIG. 2 is an enlarged vertical section'of a parallel string mandrel having a side pocket in one of the string passages for removably receiving a retrievable tool for effecting control of a communicating opening between the mandrel passages; and FIG. 3 is a transverse section on line 3--3 of FIG. 2.

In FIG. 1 the conduit assembly of parallel tubing strings/ll and 2 extends in radially spaced relation with the wall 3 of a well hole drilled from the earths surface 4 to intersect a subterranean oil, gas or other well fluid production zone 5. Each tubing string consists of a large number of end to end connected pipe sections inelusive of several specially formed mandrels 6 common to both strings and located at preselected vertically spaced apart intervals. 7

Each mandrel 6, as shown in FIGS. 2 and 3, contains a pair of side by side vertical passages, one of which is afforded by a hollow or tubular pipe section 7 whose opposite ends are externally screw threaded for aligned coupling connection within and as a part of the tubing string or macaroni line pipe 1. The bottom of the tubular section 7, forming a part of the lowermost of a group of installed mandrels and which ordinarily will be within the production zone 5, as seen in FIG. 1, will be plugged or capped as a lower terminal of the tubing string 1 and this tubing string constitutes a passageway which can be utilized for purposes for which the conventional casing annulus space is often employed. The other tubing string 2 extends further downwardly a short distance below the lowermost mandrel d for eventual receptionof the conventional cement plug and float collar and constitutes a well production tubing conductor. Where the two strings rise above the ground surface 4, they will be provided with suitable control valving, aslshown at 8 and 9 in the respective tubing strings l and 2.

All of the production string tubing sections, inclusive of the passages through the several mandrels 6, are coaxial and are of approximately the same internal diameter for a full-open bore on a straight line and through which wire line tools may be passed. That hollow portion of each mandrel 6 within which is formed a straight through full-open production passage Ill has terminal internally threaded tubular extensions 11 for coupling with adjoining production string sections. Between these coupling terminals ll the mandrel wall is enlarged and oifset to one side from the tubing axis and conveniently is of oblong outline in transverse section to enclose a side pocket or chamber laterally displaced from the full-open straight through passage in. Welded or otherwise fixed within the lower portion of the offset pocket is a tube 12- open at opposite ends and affording a receiver for removably locating any selected one of a number of conventional Well tools lowered to or retrieved therefrom by the well known wire line equipment passaged through the straight through open bore string 2. The chamber space above the offset receiver 12 aifords working clearance for the manipulation of the wireline equipment in a manner well understood in the art.

Intermediate the open ends of the tubular receiver 12 there is formed an annular internal groove 13 and an intersecting radial port 14 in the wall of the receiver for communication with a lateral port 15 in the wall of the mandrel tube 7 and by way of a port connecting tube or side extension passage 16 whose opposite ends are sealed and welded to the tubes 7 and 18. Additional weldments join abutting walls of the mandrel tube 7 and mandrel housing 6 for securing the parts in unitary assembly. Above and below the internal groove 13, the interior surfaces of the receiver 12 are accurately machined and finished smooth for a close sealing fit to such packings as may be carried by any retrievable tool positioned therein.

By way of example, one such tool is shown .at 17 in FIG. '2 and may be considered. as an ordinary gas lift valve which controls the passage of pressure gas from the conwhich block communication, can similarly be received at each mandrel and in any desired combination for the performance of a given job. When no such tool is fitted to the offset receiver, the two parallel tubing string passages in the mandrel common to both strings are in free communication with one another through the ports 14 and 15 and the vertically spaced apart open ends of the receiver l2. 7

Because the retrievable tool receivers are laterally offset from the production passages It}, a full-open and straight line bore is maintained for the'whole length of the well and tools can be installed in and removed from any mandrel selectively. Furthermore, with the string intercommunicating controls offset from interference, other conventional tools may be located within the fullopen bore of the production string 2 according to known practices. By way of illustration, there is shown a conventional landing nipple 18 incorporated in the tubing string 2 just above the mandrel 6 next above the production zone 5, and such nipple, for example, can mount a removable choke or the like. Such nipple can also be employed for suspending a downwardly projecting extension tube of smaller diameter than the production string, to co-operate therewith in providing an internal passage and an external passage as upward and downward fiow paths below the next to the lowermost mandrel as may enable circulation or pump-down in one string and exhaust in the other, as, for example, in performance of cementing and washing operations. For centralizing the conductor assembly dur-- ing its installation, use is made of one or more sets of the usual spring centralizers, as shown at 19.

For closing the upper end of the well hole, there is employed the known casing head and hanger equipment generally indicated at 2- at the upper end of a short length of easing tubing 21 which preferably is employed to extend through a surface layer and at least the weathered stratum of the earth. According to the'drawing, a solid cement column 22 extends into and overlaps the bottom of the surface casing 21 and otherwise completely fills the Well hole and embeds the parallel tubing string and mandrel assembly. After the cement, introduced as a slurry within the open bore hole, has set, it is perforated in the usual manner, as shown at 23, into the production zone 5 and from within the production string 2 by means of conventional perforating equipment lowered from the surface. The long column of cement 22 seals the face of the uncased bore wall and permanently encases therein the conductor assembly. In bulk, the cement required is kept fairly small by drilling a slim hole to a diameter only slightly greater than the maximum diameter of the double string and mandrel assembly. Thus an open hole of approximately six inches across can be fitted with a production conduit of two inches, a parallel line pipe of about one and a quarter inches and connecting mandrels having a maximum transverse dimension of about five inches for an annular working clearance of about one-half inch, which is ample for accommodating installation.

When the tubing assembly is to be set in a previously bored hole, the tubing sections are made up in the usual fashion at the surface and lowered through the bore in increments as succeeding sections are coupled in end to end succession. Usually, before each mandrel is added to the string, the communication opening between the two passages 7 and 10 is closed off by the insertion of a blanking plug within the receiver 12. Also, at spaced apart intervals, the parallel string sections are preferably tied or banded together, as shown at 24, for keeping the parallel strings in proper assembly. After the complete string has been lowered, it is ready to be cemented in place. The cement slurry sent down through the conductor tube 2, is forced out at the bottom and rises in the drilled hole back up toward the top of the hole to the desired level. Performance of the cementing operation through the tubing string employs the usual equipment, such as a fioat collar and a pump-down plug, shown above the guide shoe in FIG. 1, at the bottom of the tubing string. For washing operations, such as the removal of cement from within the bottom of the production string following a cementing job, the string intercommunicating passage at the lowermost mandrel can be opened for circulation of liquid directed downwardly in one of the tubing strings and returned to the surface in the other tubing string. By properly controlling communication between the tubing strings and at different levels selectively, various operations can be taken care of as desired. In addition to enabling the well to produce by itself or by means of either mechanical pumping apparatus or gas lift equipment, there can be readily performed all of the other conventional procedures, including melting of paraflin by circulating hot oil, the injection of chemicals and the like, all without need for erecting a large working rig. Communication between the strings can be established selectively at different levels, either by removal of the initially installed blanking plugs in the mandrel receivers 12 or by the substitution of flow control units, and every necessary well job can be easily handled with equipment on a wire line service truck.

What is claimed is:

In a permanently completed gas lift well installation, a production string of end to end connected tubing sections projected through a well hole between the surface and a production zone, a plurality of retrievable tool receiving mandrels incorporated in the string as sections thereof at vertically spaced apart intervals and provided with fullopen passageways in axial alignment with the passageways through the other tubing sections, each such mandrel having a side chamber offset laterally from the full-open passageway therethrough and provided with a chamber side wall opening, a lift gas delivery macaroni line pipe extending from the surface in parallel side by side relation with the production string and having passageway means communicating in parallel flow relationship with the side wall openings of all of said chambers and being otherwise closed at subsurface levels, lift gas supply means connected with the pipe line at the surface level thereof, a tool locating receiver in each offset chamber for retrievably positioning a tool in flow control relation with the chamber side wall opening, a series of wire line tools to be passaged through the tubing string and to be selectively and retrievably positioned in the receivers of said mandrels and held thereby in flow control relationship with said side wall openings and a column of cement filling the annular well hole space around said tubing string and said line pipe and said column of cement and the production string having intercornmunicating flow perforations therethrough at and in communication with the production zone.

References Cited in the file of this patent UNITED STATES PATENTS 171,563 Hardison Dec. 28, 1875 2,605,637 Rhoades Aug. 5, 1952 2,749,989 Huber June 12, 1956 2,781,098 Bielstein Feb. 12, 1957 2,785,753 Spearow- Mar. 19, 1957 2,785,754 True Mar. 19, 1957 2,847,072 Lebourg Aug. 12, 1958 2,923,357 Daflin Feb. 2, 1960

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