US2777398A - Gas lift valve and control system - Google Patents

Description

Jan 15, 1957 P. G; CARPENTER GAS LIFT VALVE AND CONTROL SYSTEM Filed Dec. 2, 1952 INVENTOR. AUL G. CARPENTER m MM A77' RNEVS United States Patent GAS LIFT VALVE AND CONTROL SYSTEM Paul G. Carpenter, Bartlesville, Okla., assiguior to Phillips Petroleum Company, a corporation of Delaware Application December 2, 1952, Serial N o. 323,570

Claims. (Cl. 10S-232) This invention relates to gas lift valves and to gas lift control systems'employing such valves. In one of its aspects, the invention is lof particular importance in the recovery of oil from wells and relates to a valve having a tloatable tubular member operated automatically responsive to the level of oil in the well. In another of its aspects, the invention relates to a telescopically engaged and slidable automatic shut-off valve having a oatable tubular member and system for producing oil from wells or for producing or lifting other liquids from Wells or similar places. l

Gas lift flow valves and systems are known. Generally, in operation, in the recovery of a liquid from a well, for example, oil from an oil well, employing a gas lift flow valve, an arrangement is employed whereby oil which has entered into the tubing string, as it is called, is caused to be aerated by gas which can be forced down in the annulus provided between the tubing string and the well casing. The gas in the aerated oil seeking the path of least resistance causes the oil to be lifted to the surface.

According to this invention, there is provided a gas lift flow valve comprising telescopically engaged tubing members having ports in each of saidpmembers, a portion of the lower tubing member being adapted to lloat in oil which rises within the well casing, the ports in said members being so positioned as to register to allow gas to flow into the tubing from the annulus between the tubing and the well casing, through a portion of the oil within the annulus and within the said tubing, when said lower tubing member is iloating in said oil.

In the drawing, Figure 1 is a vertical cross-sectional view of an embodiment of the invention in which there are employed three valves in series. The lower or lioatable tubular member of each valve receives and sealingly engages at its upper end the lower end of the upper tubular member of each valve, as later described more fully. The uppermost valve, not submerged in oil, is shown in closed position andthe two lower valves are shown submerged in oil and in open position. The piping of which the lower tubular members 4of each of the valves are constructed comprises sealed-in air or gas cells, bubbles or chambers providing said pipe portions with a density suiciently low to float in the liquid inthe well, as later described more fully.

Figure 2 is an enlarged View of the top valve of Figure l shown in open position.

Figure 4 is a vertical cross-sectional view of another valve according to the invention in which the upper tube receives the lower iloatable tubular member, instead of the lower tubular member receiving the upper tubular member as in the valves of Figure 1. Figure 3 shows a cross-sectional view of the valve of Figure 4 taken along the axis of the tubing string at line 3-3.

In order that the invention be more fully described and more readily understood, reference is now made to Figure 1 of the drawing which shows in open position operation within a well casing 1, perforated at its lower end 18, each of two lower valves in the tubing string which consists of a tubular portion 2 and three floatable tubular portions 3, 4 and 5. Tubular portions 3, 4 and 5 contain air bubbles to render them suliiciently low in density to float in the liquid within the well casing. It will be noted that as the liquid level rises in well casing 1, the lowest valve is opened, then the middle valve, because portion 5 is iloated before portion 4. Likewise, as the liquid would rise further portion 3 would be floated.

Referring now to Figure 2, the upper end of the lower tubular portion 3 is of enlarged internal diameter and is ported at 5A. An inwardly extending flange 7 is provided at the top of internally enlarged end of tubular portion 3. This flange coacts with outwardly extending flange 8, as later described. Tubular portion 2 at its lower end is of smaller outside diameter and is ported at 6 and anged with outwardly extending ange 8 just mentioned. Gas pumped into the annulus formed by the casing and tubing (see Figure l) will pass from the annulus through the ports 5A and 6 into the oil Within the tubing and aerate it causing it to rise to the surface owing to existing pressure differential between the bottorn and top of the well. Flanges 7 and 8 coact to prevent the tubular portion 3 from leaving the end of tubular portion 2. Also when the oil causes to iloat upwardly tubular portion 3, ange 7 will abut against the full diameter portion or shoulder 19 of tubular portion 2, thus preventing port 5 from over-shooting port 6.

lt is apparent that the valve in this system is telescopically slidable and for purposes of sealing and guiding the tubes one upon the other, sealing and guide rings 11 are provided. These guide rings can be integral with either one or both of the tubing portions. The guide rings can be constructed of any suitable material and may advantageously be made of the material of which the tubing is made. In one embodiment, so-called O rings, as shown in the figures of the drawing, are used.

Referring now to the uppermost valve in Figure 1, it will be noted that this valve is closed, there being no oil to cause its floating portion 3 to be pushed or floated upwardly into an operative position. In closed position the ports 5A and 6 are no longer in register and the sealing rings 11 prevent flow of gas from without the tubing string to within the same.

At the foot of the tubing string, it is provided with a perforated bull plug 16 attached by means of a collar 17.

Referring now to Figure 4, it will be noted that the upper tubular portion of the valve, which is machined at its lower end portion has an enlarged internal diameter whereas the upper end portion of the lower tubular portion possesses a smaller outside diameter. Thus the upper pipe portion receives the lower pipe portion. This it will be noted, as stated, is the opposite of the valves shown in Figures l and 2 in which lower pipe portion 3 receives upper pipe portion 2. The lower pipe portion of Figure 4 is hollowed, in lieu of air chambers, to render its apparent density sufciently low so that it will float.

A particularly important feature of this invention, as noted, is the provision of a valve which is actuated by a lloating tubular portion and to this end, the entire tubing or a part thereof and preferably the iloating member thereof, can be made of thermosetting or thermoplastic resins including such materials as phenol, urea or melamine formaldehydes, polyvinyl formal, polyvinyl chloride, polyvinyl chloride-acetate copolymers, polyester type resins, thermoplastic resins such as cellulose acetate, cellulose acetate butyrate, cellulose butyrate, cellulose propionate, and ethyl cellulose, and any other suitable resin or modifications of the above resins.

As noted, in the case of oil, or other liquids, some of which have a specific gravity usually of less than 1, the plastic material can be provided with air-lilled, gas-filled ayer/,39e

or other `cells forming compartments moulded into the pipe. Holesmay .be drilled lengthwise inthe pipeto reduce its overall specific gravity. Suitable aerating or blowing agents may be used to form the air cells within the pipe. Evacuated or partially evacuated sections can be provided in the pipe. The plastic pipe may be constructed having a filler for the purpose of adding strength and reducing weight. Filler such as Fiberglas, glass cloth, or cotton fabric, can be used. Any woven, knitted, or matted fabric or fibrous material can be used for the purpose of adding strength to the pipe. The pipe can be of a laminated construction.

It will be readily apparent to one skilled in the art that the valve and system here described are entirely automatic in operation, the tubing being in tension when the level of liquid in the well is too low for gas lifting the same and being in compression due to the buoyancy effect of said liquid when its level is sufficiently high to allow gas lifting of the same by gas flowing through the ports in register.

As a variant of the invention, the tubing member 5 can be lifted upwardly by the use of a wire line attached to it and extending through the tubing to the surface of the well. At the surface the said wire can be operated manually or can extend over a weighted pulley system to render the tubing member more buoyant. To this end, a wire 9 suitably attached at points 10 around the inner surface of tubing member 3 is provided and extends through stuffing box 12 over pulley 13 to winch, or other operating mechanism, 14. The operating mechanism 14.- can be arranged to coact with the valves in the tubing string to render their lower sections more readily buoyant.

According to the invention, any gas suitable for gaslifting and any liquid which can be gas-lifted, can be passed to the surface of a well by means of the valve and system shown.

Further according to the invention, the use of plastic tubing suitably reinforced can be accomplished by joining said tubing to the end of a conventional tubing string.

In Figure 3, splines 15 are shown to provide guides which prevent twisting of the valve portions thus to maintain the ports in full register.

Reasonable variation and modification are possible within the scope of the foregoing disclosure, drawing and claims to the invention, the essence of which is that there have been provided a valve and system for gas-lifting a fluid from wells, especially oil from oil wells, substantially as shown and described and that the said valve or at least a portion thereof can be made of plastic, suitably rein forced, and, when desirable, aerated to provide hollows or enclosed spaces therein, for which purpose an aerating agent, for example, sodium bicarbonate or ammonium bicarbonate, can be used.

I claim:

1. A tubular valve structure, adapted for gas-lifting of liquid from a well, comprising in combination an upper tubular member and a lower tubular member, the lower end portion of the upper tubular member and the upper end portion of the lower tubular member having ports and being telescopically engaged over a length of each of said end portions of said members such that the ports of each can be brought into register with the ports of the other, the said lower tubular member having at least one sealed space in the tube wall thereof to provide it with a densitysuch that rise of a fluid into `which itis `placed to a level above said ports in said upper end portion of said lower tubular member will float said lower tubular member upwardly to bring said ports into register.

2. A structure as described in claim l in which a portion of said lower tubular member, below the ports therein, has a longitudinally extending hollow sealed space in the tube wall thereof to adapt it to float in a fluid in which it is immersed.

3. A structure according to claim l in which the Wall of said lower tubular member is made of plastic having a plurality of chambers sealed therein, said chambers being of size sufficient to provide said member with said density.

4. A structure according to claim l, located in a well, in which structure a wire is connected to and extends from a point on said lower tubular memberupwardly through the upper tubular member and out through the top portion of said upper tubular member and is adapted to be connected to a tension-producing suspension which when the structure is in use is ata point on the surface at the location of said well and aids in the floating of said lower tubular member.

5. In a gas pressure lift system, adapted for raising oil from an oil well in which the gas pressure is so low that it will no longer cause oil to flow, a well casing, a tubing string within said casing forming an annulus between said casing and said tubing string, the lower end portion of said tubing string being of smaller outside diameter than the upper end portion of said tubing string, forming a shoulder at the place at which the outside diameter of the tube decreases, said portion of smaller outside diameter having a port therein and a sealing ring above and a sealing ring below said port surrounding said portion of smaller diameter, an outwardly extending Harige above said sealing ring above said port upon said portion of smaller diameter, a iloatable tubular member at its upper end having a portion of increased internal diameter, adapted to receive and to telescopically engage sealingly said lower endportion, sealingly receiving and engaging said lower end portion of smaller diameter by means of said sealing rings, said portion of increased internal diameter at its upper end having an inwardly extending flange adapted to abut alternately the top of said outwardly extending flange and said shoulder, said iloatable tubular member having a port therein so placed as to be in register with the port in said lower end portion of said tubing string when said iloatable'tubular member is fully floated and said inwardly extending flange is abutting against said shoulder,`the distance between said last-mentioned flange and shoulder allowing motion of the floatable tubular member sufficient to cause registering of the ports in said lower end portion `and said floatable member.

References Cited in the le of this patent UNITED STATES PATENTS 1,735,025 Watts Nov. 12, 1929 1,825,094 Scheuber Sept. 29, 1931 2,106,340 Conover ,Jan. 25, 1938 2,191,370 Chenault Feb. 20, 1940 2,255,648 Bryan Sept. 9, 1941

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