Gas lift manifold

Application filed September

This invention relates to devices for lowering tubing in oil wells and especially in wells which are being flowed by the well known gas-lift method.

The principal object of the invention is to provide a method and a structure whereby the tubing may be lowered in a gas-lift well to ^a lower level during and simultaneously with introduction of the high pressure gas which is being employed to flow the well. Th us no opportunity can be afforded for “losing the well, i. e. total or material loss of natural flow of the oil from the formation into the well hole, as.sometimes happens when the circulation of gas is interrupted for a period of time sufficient to lower the tubing.

It is common practice to recover oil from deep wells by the introduction of high pressure gas into the well either through the cas^2,1 torough ^a central flow tubing in such fashion that the gas in its passage around the lower end of the tubing picks up the oil, atomizes it and carries it to the surface. When first placing a well on gas lift, the oil 2 > initially stands much higher in the well than is desired for subsequent flow. ~

UNITED STATES PATENT OFFICE °^{F L}°^S ™^ELES> CALIFORNIA, ASSIGNOR TO UNION OIL COM ΜΥΟΓ CALIFORNIA, OF LOS ANGELES, CALIFORNIA, _A CoJorSn oS

GAS LIFT MANIFOLD

8, 1930. Serial No. 480,327.

flow of the well was necessarily interrupted, i he very common result of this method was that the well sanded up, caved in, or for some ^®^af^{on bad} Physical condition so affected that upon restoring gas circulation _esafter lowering the tubing it was found that the well had been substantially lost or its impaired^{11 Veryseriously and} permanently

In view of these facts it has been a desider- _eoatum ever since the gas-lift method of flowing wells became popularity devise some safe, practical and adequate means for lowering the tubing in the well to greater depths while maintaining the flow by gas-lift, in order that 65 the oil head could be discharged substantial· ly as fast as the tubing was lowered. So far as is known, the present invention constitutes tne first successful accomplishment of this ^;character and is the first to meet the need. :

The invention resides in a method and in a means whereby the circulation of high pressure gas may be positively maintained in a gas-lift well simultaneously with and dur_r ., - mg the entire procedure of lowering the tub- Tk to® resultant head. Many times, however, additinnal -Lnntiu. +,,1,4__. ·> .&

this head is so great that it cannot be over30 come and the oil body wholly discharged with the available gas pressure if the tubing be initially lowered to the required depth. In some such instances it has been possible first . to flow out as much of the head standing in the ' ‘ ^a® to® available gas pressure would discharge, then remove the gas connection to gam access to the tubing thereby resulting in upper end “of the string of tubing^nofmiilv tbTtnW^ff^PreSSUre+^ln Λ ^he n^·’'^{then lo}u^er suspended in the well, and also in combination 40 ctor» a. secondconnection whereby gas mav store _h as circulation before the formation be supplied to the tubin & string hvwnv Λ «« ?aS^re btoWing. up the head Additional lengthsi to such a yalue that it could not be overcome, lengths are connected with the string and ' However inmost cases topnaturakflow of oil· being lowered therewith. — ^St™-^and + .>1^·,^1S ίθΤ rapid for such procedure bly and the two .-/ ^to be followed. ..Ailqther practice has been to thus Constitute· employ suitable, valves for holding: jmessuiC introduction of on the.well while lowering:the'Tubiiig, but' since,lip means had ever been devised where- si ., Of the gas could be con- ‘ ’ tiriued during the lowering Aperation, the additional lengths of tubing into the well· According to a preferred method and construction the step of maintaining gas circu- eo lation is accomplished by lowering the tubing through an assembly of valves having in combination a permanent connection for supplying gas under pressure directly to the lower portion of the valve assembly in order that 85 . the gas may be normally applied to the open „_____are

--------- This valve assein^J S^as connections mentioned a manifold for the selective 95 ... . . gas. ’-. :- ^T,^h® upper and lower Val ves of said As-^; sembly are conveniently ih the form of pack- ’ mg rams which are adapted to permit passage therethrough of the tubing lengths to loo

1,052,716 which is adapted to be passed through the . valves of said assembly, which is also adapted to have additional tubing lengths attached thereto, and which is further adapted to introduce said lengths into said assembly, to ₇₀attach them to the tubing which normally hangs in the well, and to lower the entire tubing string. The invention may be also stated as comprising the combination of a valve assembly adapted to ’ be secured to a ₇₅well casing and including a plurality of valves adapted to pass tubing and to retain gas pressure under various tubing lowering conditions, a hollow lowering stem adapted to be passed through said valves for intro- ₈o ducing additional tubing and for removing and restoring equipment employed to suspend the tubing string during normal operation of the well, a connection to supply gas to a lower portion of the head during certain ₈₅operations, and a second gas connection for supplying gas to said lowering stem.

More specifically the invention comprises a manifold which includes an assembly of aligned valves and two gas connections for ₃₀supplying gas to the assembly, wherein upper and lower valves, in the form of rams for example, are adapted to seal off tubing projected therethrough and at the same time to permit slippage of the tubing, and where- as in an intermediate valve is adapted to be opened to pass tubing and to be closed to completely cut off passage of gas through the valve when the tubing has been removed from its path, one of the gas connections in- ioo eluding a hollow lowering stem adapted to be slipped through said upper and lower valves and to be packed thereby against gas passage during various operations. The invention also resides in the method of controlling the various valves and the passage of gas during the removal of the normal tub. ing-suspending equipment and during the introduction of additional tubing.

The invention resides further in the meth- no od of lowering tubing into a well or removing it therefrom while maintaining gas introduction to continue the flow of the well. It resides also in moving the tubing with intermittent introduction of gas, such introduc- 115 tion being made during a sufficient number of various operations incident to tubing lowering or raising so that an excessive head of oil will not be allowed to accumulate in the well. . -²⁰

In the accompanying drawings wherein one embodiment of the invention is disclosed for the purpose of illustration,

Fig. 1 is a sectional elevation indicating the complete apparatus required both for flow- 125 ing the well normally and for lowering tubing during flow, the break above the intermediate valve indicating the dividing line between the permanent and temporary equipment; ¹³⁰ be added and of a hollow “lowering stem” or “slip joint” which forms a part of the second gas connection above mentioned. This stem, which is conveniently merely a length of tub5 ing, preferably has the same diameter as the well tubing and serves as a tool to which the additional lengths of tubing are to be connected and by which they are to be lowered. Usually hereinafter it will be known as the 10 “lowering stem”. The ram-type valves contain two heavy packing jaws adapted to be closed about the stem and tubing lengths to make gas-tight joints therewith and at the same time permit the stem and tubing to be

IS slipped therethrough. Usually said valves will be referred to merely as “rams”. These rams are further adapted to be opened sufficiently wide to pass the tubing couplings and also to pass a landing or suspending man20 drel and its packer, which mandrel and packer normally function to support the tubing in the casinghead and thereby suspend said tubing in the well. An intermediate valve, such as a gate valve, serves to com25 pletely cut off gas thereabove so as to prevent escape of gas through the upper packing ram during the interval when it is necessary, to open the said upper ram for the introduction or removal of the lowering stem and/or any parts attached thereto. Such parts are the landing mandrel and the additional lengths of tubing being introduced, and are selectively attached to said stem at various stages of the procedure. The lower ram serves not 35 only as a packing device but also as an agent for temporarily suspending the whole string of tubing within the well by catching the uppermost coupling of the tubing string upon the upper edges of the jaws of the ram 40 during those intervals when the lowering stem is being withdrawn and wh?n a new length of tubing is being connected to the string. Both the gas connection to the valve, assembly and the gas connection to the low45 ering stem are provided with valves in order that the gas flow may be controlled as desired. By selective manipulation of these gas valves and of the two packing rams and the intermediate valve, tubing lengths may 50 be successively added and the tubing lowered with maintenance of gas introduction throughout the entire procedure.

Broadly stated, the invention, as considered in the light of the above disclosures, 55 comprises the combination of an assembly of aligned valves adapted to pass tubing, with a plurality of gas connections for said assembly adapted for selectively introducing gas to the assembly at different points during 60 various operations in order to maintain circulation of high pressure gas to the well throughout said operations.. The invention also comprises the combination of said valve assembly and gas connections, wherein one 65 connection includes a tubing-lowering stem

1,869,718 , ^g.2 is a cross section taken approximately on theilme 2—2 of Fig. 1;

Fig. 3 is a vertical sectional elevation showmg more or less diagrammatically one of the ⁰ steps m removing the . landing packer and landing mandrel while maintaining gas circulation and preparatory to introduction of tubing, the upper packing ram being closed and the suspended string of tubing being landed on the lower packing ram;

Fig. 4 is. a similar view showing the landing mandrel and its packing disconnected from the string of tubing and in an elevated position above the intermediate valve which has been closed to retain the gas pressure being applied to the tubing and to permit the removal of the landing mandrel and its packer through the upper ram;

Fig. 5 is a similar view showing a new section of tubing attached.to the lowering stem fnd in position about to be threaded into the tubing suspended on the lower ram, the upper ram being closed; the upper gas control valve has been opened to insure intro duction of gas through the lowering stem following the attachment of the latter to the suspended tubing; the lower gas control valve will be closed before opening the lower .. F^am in order to prevent introduction of «as into the annular oil chamber below the ram·

Fig. 6 illustrates the position of the valves while lowering a collar or coupling through the lower ram and slipping the new tubin°· section through the upper ram, the lower gas control valve being closed to prevent the passage of gas into the annular oil chamber below the ram.

Fig. 7 illustrates a succeeding position;

Fig. 8 disclosed a modified form of gas connection to the manifold for intermittent gas introduction; and

Fig. 9 illustrates a modified structure for normal support of the tubing.

i Referring particulary to Fig. 1 the entire physical structure required for operation according to the present invention is there shown. That portion which is required on the well as a permanent fixture to be em- ₆₀ ployed for normal gas lift is shown mounted upon the well casing 14, and that portion which is required to be attached for the lowering of the tubing 16 is shown as elevated somewhat there above and aligned for low65 «ring into operative position. The tubing lowering assembly includes massive valves A and B of the ram type and a gate valve C disposed therebetween. For convenient distinction the valves A and B will hereinafter βο usually be referred to as rams rather than as valves. The ram A is threaded upon a special head 15 mounted upon casing 14 and a short section of pipe 17 serves to mount the gate valve C upon said ram A. The ram B is carried upon a pipe section 18 which is adapted to be threaded into the upper end of the housing of gate valve C when the apparatus is being prepared for lowering tubing, lhe ram A is provided with a gas supply connection 20 controlled by valve 21 for nor- _9Λnjally supplying to the well high pressure gas obtained from a gas main 22. A connection 23 also leading from the main 22 is provided with a valve 24 which is closed normally but permits temporary introduction or gas to the tubing by a different route during those intervals when the tubing is connected up for the actual lowering (or raising) thereof. Such temporary gas introduction is made by way of a hose 25 leading go to a swivel 26 adapted to be supported in the well ng or derrick by means of a bail 27. The swivel 26 carries the lowering stem or slip joint 28. This stem is conveniently in the rorm of a short length of tubing which has 86 the same diameter as the tubing 16 and is adapted to extend through the rams A and B and gate valve C and to be connected with the upper end of a landing mandrel or tubing support M which is normally carried upon a 90 suspending packer P normally resting in the casing head 15 and supporting the tubing 16 through the medium of a coupling 30.

During normal operation of the well, ram A is in open position as shown in Fig. 1, the 95 gate valve C is in closed position to prevent escape of gas, the valve 24 is closed, and gas under pressure is supplied from the main 22 past the open valve 21 and by way of the connection 20 to the upper side of the ram A ioo above the jaws thereof and thence thfbugh the ram into mandrel M and tubing 16 which is suspended on the packer P. The oil and gas are discharged from the head 15 by way of a conduit 32. 106

The valves A and B, which as above indicated are of the ram type, are each provided with two jaws 35 reciprocating in suitable guideways and provided with suitable packing as at 36. Said jaws are adapted to be 110 actuated either by hand screws 37 as shown, or hydraulically or otherwise as well understood or desired. When in wide open position as indicated in Fig. 1, the spread of the jaws 35 is sufficient to pass the landing packer P as well as the mandrel M and couplings 30 and 30'. The opposing faces of these jaws have semi-circular passages wherebv the jaws are adapted to receive and be closed about the lowering stem 28 or the tubing 16, ¹²⁰or an additional tubing length 16'. The packing 36 assures a gas-and-oil-tight engagement which is necessary during tubinglowering operations because the packer P will 125 have been removed, as presently to be described.

Figs. 3 to 6, inclusive,^ are diagrammatic representations of successive steps employed in removing the landing mandrel M with its

1,852,716 and its packer P are withdrawn therefrom and then removed from the stem 28.

The structure has now been prepared tor actually running in additional lengths. of tubing. A new length (or lengths) of tubing 16' having a coupling 30' secured on its upper end, is next mounted on the lower end of the lowering stem 28 (see Fig., 5) through the medium of said coupling 30'. The suecceding operations are largely reversals ot the operations previously described. They consist in lowering the new tubing length 16 through the open ram B while the various valves are in the position of Fig. 4. The ram B is then closed about the tubing length 16 as in Fig. 5, the gate valve C is opened, the gas control valve 24 is opened, and the tubing length 16' is forced downward through the gate C in alignment with the coupling 30 which is supported upon the jaws 35 of ram A. Said tubing 16' is then threaded into said coupling 30 and valve 21 is closed. In general, this is the same position as that of Fi<>·. 3, except that section 16' replaces the landing mandrel M. Also it is the position ⁹⁰of Fig. 6 except, for ram A and coupling 30. It will be particularly noted, however, that as indicated in Fig. 5 the valve 24 should be opened before the new tubing length 16' is threaded into the collar 30, in order to insure ⁹⁵against any interruption of gas circulation. It will also be noted that for the same reason there is a stage when both valves 21 and 24 will, in practice be open. Said tubing 16' having been threaded into coupling 30, valve ^luu21 will be closed. The stem 28 with the attached tubing 16 is next elevated slightly through the medium of bail 27 to remove the weight of the tubing string 16 from the jaws of ram A. Said jaws are then opened, as indicated in Fig. 6, and the weight of the string is allowed to pull the new tubing section 16' slowly down through the closed packing jaws of the ram B until the coupling 30' of section 16' is just above ram B, and cou- ¹¹⁰pling 30 is well below ram A. Ram A will be closed tightly about the tubing length 16',. as indicated in Fig. 7, and ram B opened for passage of coupling 30' which is then allowed to descend by slippage , of section ^11J16' through jaws of ram A until said coupling 30' is adjacent these jaws. Ram B is then closed. If a second tubing length 16' has been connected below stem 28 the operations will be repeated to pass the couplings through the rams and lower said second length. In order to introduce another length (or lengths) of tubing, the coupling 30' is rested upon ram A, and (ram B having been closed) the stem 28 is untilreaded from coupling 30', ¹⁴⁰gas is turned in through valve 21 and cut off through valve 24, stem 28 is lifted above gate C which is then closed, and ram B is opened for removal of stem 28, whereby the parts again assume the relation shown in Fig. 4 ¹³⁰ packer P and running in new lengths of tubing.

Operation

The operations required for lowering the ⁵ tubing will now be described. With the normal operating equipment A, C, Μ, P, 20, 22, and valves 21 and 24 in the positions indicated in Fig. 1, the pipe section 18 carrying the upper ram B is threaded into the gate valve housing C. The hose 25, which is attached to the swivel 26 suspended in the derrick. is connected with the gas valve 24, and the slip joint or lowering stem 28 is passed ₁₅ through the open j aws of the ram B into a position approximately as'indicated in Fig.

1. The jaws 35 of ram B are then moved into packing position against the stem 28, the gate valve C is opened, and the gas-control ₂₀ valve 24 is also opened; see Fig. 3. Low enng stem 28 is now forced downward through the gate valve C and into engagement with the landing mandrel M whereupon said stem is threaded into firm engagement with the or threads in the upper end of said mandrel.

Since the well is now being flowed by passage of the gas through valve 24, hose 25, stem -8 and thence to the tubing 16, the valve 21 may be closed as indicated in F.'g/3. This closing „„ of valve 21 is necessary to insure against subsequent introduction of high pressure ga.-> into the space between the casing 14 and tubing 16. The next step is the elevation of the stern 28 and tubing 16, together with the land05 ing mandrel M and packer P, into the position of Fig. 3 so that the coupling 30 on the tubing 16 is just above the jaws 35 of the ram A. Said jaws 35 of ram A are then moved into the closed position of Fig. 3, and 40 the coupling 30 .is allowed to settle upon the jaws so that the latter support the entire weight of the suspended tubing. Wrenches are next applied to the stem 28 to unscrew the landmg mandrel M from coupling 30. To 45 insure that the joint between the mandrel M and coupling 30 is broken rather than the joint between stem 28 and mandrel M, a special tapered thread or mutilated thread, or the like, may be employed in the upper end of the landing mandrel M, or a left hand thread connection may be used requiring tae temporary use of a special left hand threaded stem in p^ace of stem 28 for the removal ot mandrel M. Having freed the landing man55 drel M from the coupling 30 sa^:d mandrel M and its packer P are lifted into a position above the gate valve C.

During the operations just described, the ' travel of the gas has been through the hose 60 25 and stem 28. Since.it is now desired to remove the stem 28, it is necessary first to open the valve 21 to supply gas below the gate valve C and then to close the valves 24 and C as indicated in Fig. 4. The upper ram B 65 is next opened and the landing mandrel M

1,852,716 S (except that mandrel M is missing). Addisections 16' are next attached, ^andd;he tubing-lowering operations repeated.

Thus, any required amount of tubing may ⁰ be lowered into a gas-lift well without the slightest interruption in the application of the high pressure gas required to maintain normal flow of the well. As rapidly as the _ lower end of the tubing is passed into the oil body m the well the gas flow will , discharge the. corresponding head, and there will be no interference whatever with production. At the end of the tubing lowering operations the landing mandrel M and its packer P are restored and lowered into their seat in the casing head 15 by a similar operation.

Also, tubing can be as readily raised in a well, to remove tubing lengths while con20 S^as circulation and maintaining gaslift flow. The only difference in operation will be that the tubing will be elevated through the .rams instead of lowered and the rams will be manipulated to pass the cou₂₅ plmgs 30 upward instead of downward.

It is obvious that the flow of the well may be reversed, from that thereinbefore indicated, that is, gas may normally be introduced through the casing and the oil flowed out through the tubing.

Instead of supplying gas continuously during the various operations, the hose 25 may be eliminated as illustrated in Fig. 8, so that gas introduction can take place only 35 intermittently by way of the connection 20 and valve 21. Under these conditions the valve 21 will be open at all times that the ram A is closed in order that gas introduction may take place during maximum periods 40 ^oi.^time· With this arrangement the stem 28 will be sealed either by means of e plug or by employment of a solid stem in order to prevent loss of gas therethrough. Another arrangement for intermittent operation, which is perhaps preferable for most wells, is to keep the valve 21 closed and to use the hose 25 and stem 28 as the sole means of introducing gas. When operating in this manner the gate valve C and the valve 24 will 50 always be closed as late as possible and opened . . as soon as possible. Thus gas cam be applied to the tubing as soon as the stem 28 or tubing length 16' is packed in the ram B, and will be continued until the moment stem 28 is to be 55 /moved from ram B. One great advantage ^m. using the hose 25 where gas is to be supplied intermittently by a single route, is that gas will always be passing info' the well during those intervals in which the tubing is 60 actually being lowered into the oil body. °If . ... required to cut off oil flow at intervals during gas interruption the oil line 32 mav have a valve 132.

A modified arrangement for mounting the ₆₅ apparatus is'illustrated in Fig. 9. Here the . .. special midway head 15 is omitted and the lower ram A serves as the normal casing head, tubing packer and tubing suspending means, the mandrel M being mounted directly upon ' the jaws of the ram and the packer P being eliminated. It necessary a reducing nipple 70 115. may be employed between ram A and the casing 14.

It should be understood that, while the packing rams A, B and the gate valve C are employed as possible means for accomplish- 75 mg the corresponding functions, it would nevertheless be sufficient for the purposes of the invention to employ any serviceable type of valve as a substitute for the gate valve C, and to use other types of packers in place of 80 the rams. Such packers could for example be rubber bags or other inflatable or compressible devices, which would serve to seal or pack the tubing. In the latter instance any substitute for the jaws of the lower ram 85 as supporting means for the suspended tubing, could be employed. Further, the rams could be operated otherwise than manually; for instance they could be power operated by steam or gas pressure or by hydraulical pres-' »0 sure or electric motors.

It is also to be understood that the specific disclosures made herein are for the purpose of illustrating the invention and are not to be considered.as limiting since variations within 85 the scope of the invention may be made readily by those skilled in the art.