US2366547A - Fitting for use with oil well tubing or the like - Google Patents

Description

FITTING FOR USE' WITH OIL WELL` TUBING 0R THE LIKE Filed Jan. 1o, 1942 2 sheets-sheet 1 ATTORNEY.

D. P. OAK

Filed Jan. l0, 1942 2 Sheets-Sheet 2 FITTING FOR USE WITH OIL WELL TUBING OR THE LIKE Jan. 2,l 1945.

Zilli/42.474.

Ill'. IIIIII INVENTOR Y YD a d P Oa ATTORNEY Patented Jan. 2, 1945 FITTINGrr Fon UsE WITH oIL WELL TUBING i on THE LIKEI I A Donald P. oak, Tulsaokla. t Application January 10, 1942, Serial No.` 426,274 2 Claims. `(Cl. 16B- 2) `This invention relates to a fitting` for use in connection with well tubing, and has for its principal objects to provide a fitting which facilitates connection of asecondary string of tubing in case aleak develops in the original tubing; to provide a fitting which facilitates permanent or temporary plugging off wells or repair and reestablishment of abandoned'wells; and to provide a tting adapted for3facilitating certain well operations which must be carried on under high pressure or flowconditions. 3

4In accomplishing these and other `objectsof the invention hereinafter pointed out, I have provided improved details of structure, the preferred form of whichis illustrated in the accompanying drawings, wherein: I, I

Fig,` 1 is a schematic view of well arrangement in a field where fiow is effected through repressuring with a Iiuid such as water and in which wells the present invention is particularly adapted.

Fig. 2 is a sectional view through a portion of a well equipped with a tubing provided with a fitting in accordance with the present invention, the fitting and tubing being shown in section.

Fig. 3 is a `similar View illustrating an inner string of tubing which is inserted through the original string `and connected thereto by the fitting.

Fig. 4 is a `section similar to Fig.`2 but illusd trating insertion of a closure plug into thefitting preparatory to shutting off the well against bottom hole pressure. j

Fig. 5 is a section similar to Fig. 4 illustrating closure of the pressure relief openings through the plug. K I

Fig. 6 is a similar section operation is completed.

Fig. 7 is a cross-section on the line 1-1 lof Fig. 6.

Referring more in detail to thedrawings:

As above mentioned, the present invention is particularly useful in oil fields Where flow is effected through pressuring orrepressuring the production formation with hydrostatic heads of fluid sufdclent to effect fiow from the formation through selected wells. For example, natural formation pressure in `many production areas is depleted to such an extent that the wells are not self-owing and it is necessary to resort to pumping operations.` As the pressure is further reduced the production formation usually floods with water so that it is not economical to` pump the after the plugging It is the lpracticed to reestablish flow fromthe producing wells indicatedat I,` Fig. 1 of the drawings, by drilling holes 2 spaced from the producing wells and to run tubings 3 into the bore-holes which are cemented in at thelower ends adjacent the cap rock; as indicated at 4, so that the full I effect of a hydrostatic head of `liquid pumpedinto the tubing acts upon thefluid in the formation to effect fiow of the oil andwater mixture from the producing wells. I I d d L The tubing of such wells is subject to deterioration, failure `caused by e1ectrolysis,`"erosion`, and chemical reactions so that leaks develop andthey become useless for their intended purpose, For the same reason, leaks develop in the tubing of `the producing wells. It then becomes necessary to equip the wells with new tubing, but this is a difcult operation since the tubing of Vtheipressuring wells must beinserted against high hydrostatic pressures and that `of the producing wells under flow conditions. I

\ In carrying out the present invention, the original'string of tubing`3 is, therefore, provided with a fluid-tight pressure resistant fitting 6 of sleeve-like form4 inset between selected points of tubing and made apart of the tubing system by welded or threaded connections at the time the d tubing is installed. In the illustrated instance,

the iitting has external threads I at the respective ends-thereof conforming to theinternal threads 8 of tubingcouplings-*s and ljwhich are attachedtothe threadedends of adjacent tubing sections II fand"`I`2. The interior of the fitting is provided with an internallyzthreadedaxial bore I3 to pass thehfluid and so that incase aleak develops in the tubing 3, a smaller string of tubing I4 having threads I5 on the lower end may be ireadedly engaged with threads I6 of the bore lIn orderto facilitate insertionof the tubing I4, the upper end of the fitting is provided with a bevelled counterbore I'I which tapers downwardly and inwardly toward` the axis of the bore to guide the threaded end of the tubing into engagement with the threads. `The oppositeend of the tting is also provided with a tapered counterbore I8` to facilitate flow of uid therethrough.

To install the fitting it is applied between selected sections of tubing and run .into the borehole 2 after which the'space between the tubing 3 and wall of the bore-hole is packed off at a point above the production formation soas to seal off upward flow around the tubing and maintain full effect of the pressuring liquidlin the tubing 3 whereby the oil and water mixture is caused to move toward a producing well and ow upwardly through the tubing thereof under hydrostatic heads carried within the tubing of the water wells. The tubing may be packed off in any suitable manner, however, it is desirable to effect a permanent seal of cement around the tubing in sufficient quantity and depth that the cement is retained in place and maintains the desired seal. The fitting 6 is also preferably located so that itis containedwithinthe cement ,packing as shown inFig.2.`

After the tubing has been in use for some time leaks may develop therein so that the head of liquid leaks therefrom and it becomes necessary to insert another string of tubing l4.- This is readily effected by making lup the string ofiI smaller sized tubing and inserting it through the original tubing, the thread of the rst section of tubing being of the same diameter, direction,

pitch, and type of 'thread as the thread within the bore of the tting 6. The new tubing is lovv4 ered through the original tubing until the end encounters the tapered counterbore or bevel surface at the upper end of Vthe fitting which guides and Vcenters the inner tubing relatively kto the bore, then by turning the inner tubing in proper direction, `the threads thereon screw into the threadsv of the bore making up the joint and providing a leakfproof connection therewith. If desired, another fitting 6 may be installedr between selected yjointsof the inserted tubing so that an additional string .may b'e run thereinto when the second string'A becomes unserviceable for its in ytended purpose..y However, I find that in most installations, the second string maybe readily removed fromthe iitting 6 and withdrawn from the outer string of tubing and a new stringof tubing inserted in its place. y v `.'[n the operation of the wells, .itsometimes becomes desirable to plug olf, one of the wells and this may be readily accomplished by screwing a plug `or properly closed pipe section intothe bore ofthe fitting. Thismay be effected while maintaining hydrostatic pressure in the other wells withaspecialplug designed to be set against fluid pressure in thetubing 3. ThelpluglS comprises al cylindrical Abody having external threads conforming in diameter, direction andpitch with the threads Il; in .the bore of the iitting. The plugV i9 has apolygonal-shaped head 20 conforming in shape to a socket 2l formed within a t wrenchelike head 22 of a'lowering-in tool v,23 whe-rewith the plug may be lowered through the tubing landinsertedin. the l'ittingfas later described.'4 l Y i I Thev body of the plug including the head I9 has a,r central axial bore v24 provided Vwith internal threads 25 in which is threaded the shank 26 of a cap-screw 21 having a head 2'8 conforming in shape to the lhead 2li` and which is alsoadapted to be received in the socket 26 of the lowering-in tool. The head 2li ofl the plug Ahas lateral opent ings 29 that are spaced from theupper end thereofso that the shank of thecap-screw may be started Ainto thethreaded bore without covering the lateral openings12 9,;as shown in Fig. 4.

When applyingY the plug,4 the shank of thecap-- screw is threadedinto theupper end of the bore of the plug so that the end thereof is just above the openings 2'8 as shown in Fig. 4.. The flat sides of the cap-screw are aligned wththe corresponding sides of the head 20 and the assembly inserted into the socket 2l where the cap-screw is secured bya shear pin Sil that is extended through open;- ing's v3`Iv inthe wall of the socket and .through atran'sverse opening S21-n thehead ofthe screw.

Any form of shear pin may be used such as an ordinary cotter pin, wire, or the like.

The assembly is then lowered through the tubing with the aid of a string of sucker rods or the like 33, the lowering-in tool being threaded upon the lowermost rod as indicated at 34, Fig. 4. When the plug reaches the tting it is guided by the tapered counterbore thereof into registering alignment with the threaded boreand Aupon turning the rods in the properdirectiori the plug is threaded into the bore ofthe fitting, during which time pressure therebelow is being relieved through the plug openings 24 and 29. Therefore, the plug ,is-readily lowered,l against pressure carried in the Aproducing formation. When the plug is in proper position the pin 30 is sheared off by exerting an upward pull on the lowering-in rods and the socket is: raised sufficiently so that it clearskthe head 20 of the plug. The cap-screw is then rotated into the bore 24 of the plug so that the threaded shank thereof closes the .lateral openings ,29 and stops flowthroughfthe tubing.

When old iield's are to Vb'e're'vived byfrepressuring the formation with hydrostatic heads of fluid. selected wells in, the field may' loe used fior' the repressuiin'g wells and in conditioning thereof my improved fitting `'forms ,ari important .part as it enables` cementing in of the tubing under pressure carried in `the .producing formation. ,"The bore-hole to be usedlis cleared of tubing, debris and the like and tlibilg eqlippedVS/'IH proved fitting is lowered into thlbore-hle-t l with aid `of the provide relief of `pressure whilefthe, cement is being pleoed around the tubing to sealtiie `upper formations from' the producing formatiorifa'nd so that the full static head created in the'tubing" acts directly upon the iiuid contained in the .produoing formation. A. y l

since the flow through the tubing relievesltlie pressure while thev cement sets, the `c'errir'it forms a positive s'eal and is retained in its desired seal*- ing position. If it'. is desired to close offiioivlfroi the productionfor'mat'ionoompletely', ;`a...clo'sil re` plug may be readily Screwed'ito the boreofthe fitting in the manner 'just described, after which nine olosure 'is' only temporsry;zth Itusingindy be left in position and tlie 'nlug' later 'removed lowering-inltool. ,i improved iittirlg' also-desirable wlieredt is necessary to reduce the oros'sfsee'tioiial ,e .of the' flow tubing. The smallerljtubing is'readily inserted through the flow tuliiiigend threaded into tnebore of the ritt'iiigso ,that-flow rioni e well is diverted through the srnanerA tubing.v

From the foregoing it is obvious that lhaife provided o ntting wriioii 'is particularly adoptedt for use` in connection with wllsproducing'--uid as well estrie wells which establish the' hydro-v static heads so astofmaintain desired controliof such welis'wlile maintaining hydrostatic p'ress'ule on `trie nrojduoi g formation. j i what I claim anddesirejto' s'eoiirebytnetjters Potent is: 'jj I A Y Lin opnreztus ofthe @noreste descrilied in combination witlre. well tubing. e.' nttirglleving fluideti'ght connection with trie ltubirigjmearttlie lower eridtl'lerei and provided with a'ilow o ing therethrough. Land ,.prinzided`` with internal threads, a plug menib having' external 4tlireedsj for engaging the tiire sof seid eiid having" .en axial port' ,pr'oizided wi n 'internal'- tliree'ds, e. heed onjsaid plug ineiiioer having lateral ,ports connected with .saidgalii oft,'=`a' n l 2,366,5474 v v 3, screw member having a shank adapted `to `he l aplug having an axial bore and lateral ports conthreaded into the axial port:` to close said `lateral nectedwith said bore. a polygonal head on said ports, a head onthe screw member, said heads p1ug,a sha-nk threaded into said bore. a polygonal having socketengaging portions, and `a socket head on said shank, a polygonal socketmember member having portions to engage said portions 5- engaging said heads, and shear means connectof the heads to rotate saidmembers. n ing one of said heads with `the socket member.

2. In anapparatus of the character described, v l DGNALD P; OAK.

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