US2304394A - Oil well tubing coupling - Google Patents

Description

Dgc. 8,}942- J. G. A. M. BVIERMANN ETAL 2,304,

OIL WELL TUBING COUPLING Filed Nov. 7, 1939 3 Sheets-She et s Fig-VIII.

InvQmbr-s: Josephus Georg'uus Anionius Maria Efzrmann Patented Dec. 8, 1942 UNITED- STATES 1 PATENT OFFICE on. wan. roams. cournno Josephus Georgina Antonius Marla Biermann and Richard Schiel. Campinas, Bumania; vested in the Alien Property Application November 7, 1939, Serial No. 303,284

In Romania November 19, 1938 i 4 Claim; (Cl. 103-232) The present invention relates to couplings for oil well tubing and pertains more particularly to couplings or tool pins for use in oil wells which contain an auxiliary string or tubing extending into the well along with the producing or main string, but not enclosed within the latter.

The purpose oi an auxiliary tubing string is usually to-provide a conduit for passing fluids to the bottom of the borehole. For example, steam may be conducted down such a tubing string, which is clamped to the usual producing string, to prevent paramn deposition within the producing string with resultant plug ing thereof. In another instance, liquids, air, or other gases may be forceddown under pressure to aid in bringing 7 oil to the surface through the producing string, as, for example,in fluid pressure pumps, in gaslift pumping operations, etc. However, independent or separate Joining of the single lengths of the auxiliary tubing and the single lengths of the producing string leads to cumbersome structures and causes a considerable loss of time dur- Fls re 6 is a verticalsectional view taken along the line VIVI of Figure 5.

Figure 'l is a vertical sectional view taken along the line'VII-VII of Figure 5. v

Figure 8 is a perspective elevation of a modiiled arrangement or the bottom coupling shown in partial cross-section along the line VII-VII of Figure 5, and Fig. 9 is a perspective view 01. another modified arrangement.

Referring to Figure 1 of the drawings, the

singielengths of a producing string of tubing l and an auxiliary string ofjtubing I are respecv tively joined together by .means or the .present coupling device which comprises upper and lower cylindrical members 8 and l. A special bottom coupling or tubing joint I is attached between.

two lengths or the producing string 1 audio the lower end, preferably, .of the auxiliary string.

Now referring to the more detailed Figures 2- and 8; the upper cylindrical member I or the coupling has an axial bore 6, enlarged and ining withdrawal or insertion of the tubing strings.

It is, therefore, the object of the present invention to provide a device for simultaneously joining both the single lengths of the producing.

string of tubing and the single lengths of the auxiliary string of tubing.

' A fin-ther object is to provide an arrangement comprising a special bottom coupling containing three longitudinal channels connected with each other by cross channels, which serve to connect ternally threaded at thepper end to receive the externaliythreadedendoi'alena h laofthepmducing string I. The'lower transverse face I of this member 3 has a ring-shaped groove 8 cut therein and an externally threaded shank 8 proiecting therefrom about the bore I. A vertical channel 10 penetrates from the ring-shaped the bores of the auxiliary hrbing and oil-producgroove 8 tothe upp r face of the member 3.

The lower cylindrical member 4 of the coupling assembly has a ring-shaped groove I! in the upper transverse race to match the groove 8 in the upper member 3. An axial bore it in said member l is internally threaded at its upper end to receive. the threaded shank 9 and at its lower end toreceive the externally threaded end of a length lb I 01' the producing string I. Member 4 likewise has Figure 2 is a detailed verti in section of the 7 coupling device.

Figure 3 is a transverse sectional view along the line III-III of Figure 2.

Figure 4 is a verticalsectional view of a modifled portion of the coupling device.

taken Figure 5 is a transverse sectional view of the bottom coupling taken along theline V-V. of Figure l, and shown to an enlarged scale. 1

a vertical channel II from the ring-shaped groove i 2 to the lower transverse face.

Thus, an axial passage is provided by means of bores 8 and it between the lengths in and lb of the producing string to allow unrestricted flow V therethrough. Further. on attaching a length In of the auxiliary string 2 to the'channel il in the upper face of the'upper'member I and a similar length 2b to the channel ll in'the lower face of the lower member 4, a passage is obtained between the lengths in and 2b by means of channel ll, whichenters ring-shaped groove I, which forms a ring-shaped channel in conjunction with the ring-shaped groove II, which in turn has the vertical channel ll extending therefrom to the auxiliary tubing length 22:, attached at the lower face oi the lowermemberl. A gasket i8 is inserted between the lower face of the u p r member 3 lower portion thereof as I v or both.

and the upper face of the lower'member 4 in order to prevent leakage from the ring-shaped channel to the axial bore or vice versa.

Preparatory to lowering into the well, a section of combined producing string and auxiliary string is assembled by attaching a coupling member 3 to one end and a coupling member 4 to the other end of a length of the producing string. The vertical channels ill and I4 of the coupling members are co-axially aligned and a length of auxil iary tubing inserted therebetween.

The lengths of auxiliary tubing may be butt welded between the coupling members on each end of a length of the producing string (as shown in Figure 1) or they may be threadably connected to the coupling member at one end and butt welded to the coupling at the other end of the length of the producing string (as illustrated in Figure 2). The auxiliary tubing may likewise be attached between the coupling members by enlarging one (as shown in Figure 4) or both of vertical channels Ill and M in the coupling assembly, then slipping the tubing segment 2b through one such enlarged channel I4a, after the coupling members are attached to each end of the producing tube, and fastening the tube 2b to the coupling member 4 by means of an internally and externally threaded ring or nipple l 1 adapted to be threaded into the enlarged channel Ma and around the tubing length 2b.

Sections madeup in this manner can be quickly joined together in one operation by threading the externally threaded shank 9 ofa coupling member 3 into the upper internal thread of bore l3 in a lower coupling member 4. Hence, simultaneously or jointly connected but separate producing and auxiliary tubing strings can be placed in the hole quickly 'and easily to form a conduit for bringing up oil and another conduit for passing fluid down into the well. i

However, it is to be understood that the term ring-shaped'groove includes. also grooves in the a form of partial rings as it is evident that grooves forming an arc slightly greater than half a circle will, when placed together as described, communicate with each other at some pointand permit' flow therethrough. This being sufficient for thepurpose of the present invention, it is intended that said term he so construed throughout this specification and the appended claims.

It is likewise intended that the coupling members may be modified so as to have more than one independent groove with vertical channels extending from each, while retainingat least some of the advantages of the present invention.

It is often desirable to inject the downwardly flowing fluid from the auxiliary tubing string into the producing string or into the space within the borehole casing. These desirable features may be obtained from an arrangement of the present invention comprising a special bottom coupling in conjunction with a producing string, an auxiliary string and couplings as described above. Serving to couple together lengths of the producing string, the bottom coupling maybe internally at both ends to receive the threaded ends of lengths la and lb of the producing string and has a boresubstantially equal to the size of the bore of the tubing in the producing string. Longitudinal channel 22 has a bore about the size of that of the auxiliary string tubing and has internal threads at each end of said bore, adapted to receive the threaded ends of lengths ,2a and 2b of the auxiliary string, or when thebottom coupling is attached to the lower end of v wise manner from both ends toward the cross channel 26 and by means of internal threads is thereby adapted to receive various threaded minating in an enlarged and threaded bore 24a normally closed by plug 32 therein.

With a tubing co'uplingor joint of thistype any desired connection or shutting oil? may be obtained. Thus, for example, when it is desired to prevent parafiin precipitation in the tubing by introducing steam, or the like, as a heating mediui'n, into the auxiliary string, the check valve 29 in'the arrangement shown in Figures 6 and 7 prevents the well fluid in the producing string la from flowing into the auxiliary string 2a but allows the condensed steam to accumulate and build up a columnof liquid in theauxiliary string 2a. When the condensation water column has created a back pressure sufllcient to overcome the pressure within the producing string, the ball 30 of the check valve rises and the condensate discharges into the producing string and is carlied to the surface alongf'with the well fluid. Further, in another advantageous arrangement shown in Figure 8; obtained by reversing theattached to the lower end of the auxiliary tubing string as shown in Figure 1, or maybe connected between lengths of the auxiliary string in the Referri to Figures 5, 6, and '1, the special bottom coupling consists of a cylindrical member 20 having three longitudinal channels 2|, 22,

' I and 23 connected to each other by cross channels 24- andir25: Longitudinal channel 2| .is threaded illustrated in- Figure '7, V a 10 arrangement, as shown in'Figur'e 9 which diiiers tubing coupling 20, and exchanging the positions of the check valve 29 and the plug 21 and replacing the plug 28 with a string of tubing 2c which forms a return line, steam as a heating fluid may be circulated down the auxiliary string 2a, through the tubing joint 20 byway of vertical channel 22, cross-channel 24, and vertical channel 23 through the therein contained check valve 29 and nozzle 3 I which serve, respectively, to prevent reversal of flow and to impart a back pressure to the descending fluid in the flow line 2a and thence up the return string 20. the walls of the producing string may be heated and the deposition thereon of paraffin prevented, but without discharging the steam or condensate into the oil stream which may cause the formationof undesirable emulsions. Also,'in still another from that shown in Figure 8 in that the auxiliary tubing string 2a is attached to channel 23 instead of channel 22", plug 28 closes the upper end of channel 22, the lower end of which is now open, and the check valve 29 removed from channel 22,

a heating fluid such as steam may be passed down the auxiliary string 2a into vertical channel 23,where a back pressure is built up by means of the nozzle 3|, and passes on through crosschannel 24 and vertical channel 22 and discharges therefrom to inside the well casing."

It may be readily seen that the bottom coupling 5 is advantageously flexible in its uses. Thus, for example, the rearrangeable coupling is particularly effective throughout the life of a well having paraffin trouble by facilitating several phases of treatment to maintain efficient production. In the early life of the 'well, little paraffln generally accumulates and small amounts of steam may be passed down the auxiliary or heating string and discharged into the oil stream, as shown in Figs. 6 and 7, the amount of steam being so'small as not to form emulsions with the oil. In.the later life of the well, greater amounts of steam are necessary to maintain efficient production by preventing increased paraflln deposition in the oil flow string. Since the greater amounts of steam increas the emulsion problem often to such an extent that steam and condensate can no longer be discharged in the oil stream, the coupling 5 is rearrangedto allow discharging into some other return passage, such as, a return line string. as shown in Fig; 8, or into the space between the tubing strings and the borehole, as shown in Fig. 9. V y

We claim as our invention: I

1. In a systemfor conveying fluids to and from a borehole by means of a main tubing string and an auxiliary tubing string exterior and substantially parallel to the main string, the combination of saidstrings of tubing with coupling means for said tubing strings comprising a substantially cylindrical coupling body, a central longitudinal tance less-than one-half of the axial length of the coupling body, said .bores being oilset with regard to the central bore and to each other, connecti'ng means'on the upper and lower portions bore therethrough, connecting means on the upper and the lower portion or said bore adapted to hold in engagement the ends of the first tubing string adjacent said coupling,longitudinal bores extending into the coupling body respectively from the upper and lower faces thereof to a distance less than one-half of the axial length of the coupling body, said bores being offset with regard to the central bore and to each other, con,-

necting means on the upper and lowergportions of said bores respectively to hold in engagement the ends of the second tubing string adjacent said coupling. and transverse channel means within 1 the coupling body in communication between said bores, a e for returning to the surfac fluid flowing down through the auxiliary string and means associated with the lowest. length of the 2. In a system for conveying fluids to and from a borehole by means of a main tubing string and an auxiliary tubing string exterior and substantially' parallel to the main strinm'the combination of said strings of tubing with coupling means for said tubing strings comprising two substantially cylindrical members, screw-threaded pin and box means on said members for engagement with second tubing string adapted to direct fluid flow therefrom into' said return passage. a

an auxiliary tubing string exterior and substantially parallel to the main string, the combination of said strings of tubing with coupling means for said tubing formed of two substantially cylindrical'members having screw-threaded pin and box means for engagement with each other, each of said members having a transverse'face adapted to abut a corresponding face of the other memher when said members are engaged, arcuate grooves on said faces at least partially in register when said members are engaged, a central bore passing longitudinally through the coupling formed by the engagement of said members, connecting means on th upper and lower portion of said bore adapted to hold in engagement the ends of the first tubing string adjacent said coupling,

longitudinal bores extending into the coupling members from the non-abutting transverse faces of said members and opening into the grooves of their abutting. faces, said bores being oifset with regard to the centralbore and to each other when" the members are engaged, and means on the upper portion of the offset bore through the upper member and on the lower portion of the lower member to hold in engagement the ends of the second string adjacent said coupling means a passage for returning to the surface fluid flowing down through the auxiliary string. and means associated with the lowest length of the second tubing string to direct fluid flow therefrom into said return passage.

4. In combination, at least two tubing strings xterior and substantially parallel to each other,

and coupling means for simultaneously Joining sections of said tubing strings, said means being;

formed of two substantially cylindrical members having screw means for engagement with each other, each of said members having a transverse face adapted to abut a corresponding face of the other member when said members are engaged, arcuate grooves on said faces at least partially in register when said members are engaged, an axial bore through each of said members, means at the end of said bores adjacent the non-abutting faces each other, a central longitudinal bore through the coupling body formed by the engagement of said members, connecting means on the upper and the lower portion or said bore adapted to hold in engagement the ends of the flrst tubing string adjacent said coupling,'longitudinal bores extending into the coupling body respectively from the upperand lower faces thereof to a disof said members for connecting sections of one of said tubing. strings thereto, longitudinal bores r offset with regard to said axial bores and extend ing into the coupling members from'the nonabutting transverse faces of said members and opening into the grooves of their abutting faces,- and means at the ends of said offset bores a'd-- jacent theFnon-abuttingiaces of said members: for connectingsections of the other tubing strings thereto. I

JO'SEPHUS ononarus an'romos MARIA BIERMANN.

nicnsanscmrm. K

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