US2252047A - Well pumping system and apparatus - Google Patents

Description

g W431; A. W. STEENBERGH 252M WELL PUMPING SYSTEM AND APPARATUS Filed Sept. 15, 1959 2 Sheets-Sheet 1 Fig.6 lnven'l'or: Alexander wllhelmus Sfzenbz h W y A. W. STEENBERGH 225M?" WELL P UM PIPIG SYSTEM AND APPARATUS Filed Sept. 15, 1939 2 Sheets-Sheet 2 Fig. 9

lnvenio'r: Aiexander Wilhalm us Sreenberqh his w-fffifw PatentedlAug. 12, 194i WELL PUMPING srs'rrmr rum arram'rus Alexander Wilhelmus Steenbergh, The Hague, Netherlands, assignor to Shell Development Company, San Franc! of Delaware sco,-. Calif., a-corporatlo1n V Application September 15, 1939, Serial No. 295,044

In the Netherlands September 16, 1938 4 1 Claims. (Cl.103-- -52) The present invention relates to gas pressure operated pumps and systems for raising liquids from oil wells and pertains particularly, to gas-lift pumps having, and to systems using, a'plunger which is raised to the surface by means of gas pressure and which carries upwards a load of well In gas-lift pumps the well liquid is allowed to accumulate in a tubing or eduction tube, then gas is introduced at the bottom of the'tube and the liquid is forced to the surface by the gas.

By then releasing the gas pressure and repeating the cycle well liquids may be raised to the surface. However, with this system the consumption of gas, that is the gas-oil ratio, is uneconomicaily high for many wellsand, consequently, freely moving plungers have been used between the load of well fluid and the driving gas to prevent part of the rising liquid from adhering to the wall of the tubing or eduction tube and flowing back or even, in the event of the velocity of the gas being raised with each stroke, but so that gas consumption be low, a large load of liquid should be raised per cycle. Therefore, according to the known systems, the liquid level in, and consequently also outside the tubing is allowed to rise considerably in order to compensate for the limited diameter of the tubing. Although decreased gas consumption is therebyobtained, these systems have the disadvantage of a high liquid level, which naturally means a highback pressure on the producing layer and which adversely affects the producing capacity of that layer.

It is, therefore, an object of the present invention to provide an improved well pumping system, whereby large loads of well liquid can be raised with both low gas consumption and low liquid level in the well. t

It is another object of the present invention to provide an improved well pump of the gas-powered type.

It isa further object of the-present invention to provide an improved well pump having a displacement chamber and an arrangement whereby cumulated well fluid in each cycle.'

Further objects and advantages will be ap- Figure 3 is a schematic sectional view of another modiflcation of ;the llquld accumulating portion of the improved well pump.

Figure 4 is a schematic'sectional view of still another modification of the liquid-accumulating portion I Figure 5 is a schematic sectional view of another modification of the liquid-accumulating portion.

Figure 6 is a schematic sectional view of a further modification of the liquid-accumulating portion.

Figure 7 is a schematic sectional view of another modification of the liquid-accumulating portion.

Figure 8 is a schematic sectional view of still another modification of the liquid-accumulating portion.

Figure 9 is a schematicsectional view of a further modification of the liquid-accumulating portion.

According to the system of the present invention fluids from the producing formation penetrated by a well are allowed to pass into an accumulating space having a relatively large diameter and provided with means to prevent fluid flow in the reverse direction and with an eduction tube having a relatively small diameter and most position in the eduction tube, a load of liquid is introduced into the space above the said parent from the following description taken in reference to the drawings, wherein:

Figure 1 is a vertical sectional view of a well showing schematically a preferred embodiment of the present well pump,

Figure 2 is a schematic sectional view-of a modthe present device.

plunger; with the aid of gas pressure. Pressure is then allowed to build up in the space below the plunger in the eduction tube, the plunger thus being lifted, together with its load of liquid, to the well head, where the liquid load is discharged.

Thus, by applying gas pressure, the contents of a relatively short vertical interval of the borehole or, for instance, of a liquid-accumulating or gas pressure on the producing layer is avoided.

In well pumps capable of carrying out the above mode of operation it is preferable to provide automatic means for controlling thepressure difference between top and bottom side of the plunger in order to prevent the plunger from"- being lifted until almost all the liquid from the accumulating space has passed into the space in the lift tube above the plunger. Consequently in the improved well pumps of the present invention automatic means are-provided for alternately directing the flow of fluid into the space in the lift tube either above or below the plunger ports II. t'ilfei eby lowered, the float l6 descends downward in responseto a drop in liquid level or to cessation of the flow of liquid into the space above the plunger. I

Referring to Figure 1 of the drawings, a borehole I contains a well casing 2 having the lower section thereof perforated or slotted with holes a valve cage 1a.

Within the casing 4 and depending into the chamber 5 is a tubing or lift tube 8, the annular space 9 between the casing 4 and the tubing 8 forming a conduit for pressure gas. Freely movable withinth'e tubing 8 is a plunger or lift piston III, which rests near the bottom of the tubing when in the stationary phase of its operation. At a point above the stationary position of the plunger Ill the tubing 8 is provided with lateral inlets or inlet ports H which permit accumulated liquid in the chamber 5 to enter the eduction tube 8. Carried in the lowermost portion of the tubing 8 and opening underneath the plunger ID in its rested position is a gas inlet and valve seat l2, which is normally closed by a valve I3, which is carried by a horizontal member l4 projecting beyondthe width of the tubing 8. A coil spring I5 or other resilient means,

' spaced between the member l4 and the bottom of the chamber 5, or other-suitable support, normally holds the valve, l3 against the valve seat l2.

Surrounding the tubing 8 is a float l8, prefvalve i3 is forced away from its seat i2 by the weight of the float it against the pressure of the spring l5. The gas pressure thus being automatically applied through the valve opening to this space underneath the plunger III in the lift tube 8, the plunger or lift piston travels upwards towards the surface, carrying the load of well liquid above it. At the well head the plunger l0 discharges by suitable means its load of liquid into a discharge pipe I8.

After the load of liquid is discharged, the gas pressure to the chamber 5 and thence to the tubing 8 is released and the plunger l8 falls to the bottom of the tube 8 as liquid accumulation within the chamber starts again. The cycle is then repeated'at a rate dependingon the size of the borehole, the apparatus, flow of liquid from the formations, etc.

To make the plunger I fall gradually on its return to the bottom, the diameter thereof may be slightly smaller than the inside diameter of the lift tube 8 or a small hole may be provided in the plunger bottom, or any other suitable der 23 is a relatively weak coil spring 24, supporterably comprising a tubular section having an axial bore I1 and constructed so as to have a specific gravity less. than oil well liquids. For example, the float It may be of a material such as wood (as shown) or may be of a hollow metal or other suitable construction. The diameter of the bore H is preferably somewhat larger than the outside diameter of the tubing 8. so that, when the float I8 is in a position about the tubing 8 at the level oi?v the inlets II, the bore I! of the float [8 does not fit closely enough to seal the inlets II, but forms a passage to allow restricted flow of liquid into the inlet ports H.

In operation of the well pump of the present invention the liquid entering the borehole i from producing formations penetrated thereby passes through the holes 3 of the casing 2 and accumulates in the chamber 5, the ball valve 1 rising from its seat 8 to allow liquid flow. As the liquid rises in the chamber 5 and carries the float l8 upward, the inlet ports II are exposed, allowing liquid to enter the tubing 8 above the lift piston ill in stationary position at the bottom of 'the tube 8. Gas pressure is then applied to the surface of the liquid in chamber 5 through the gas supply line I9 and the annular space 8 between the casing 4 and tubing 8. The pressure within ing above it a horizontal plate member 25 to which a valve 28 is attached by means of rod 21, said spring 24 normally holding the valve 26 away from its seat 22. Vertical rods 28, acting as guides for plate 25 in its vertical movement, are aflixed to the shoulder 23. The parts are arranged so that the plate 25 is always higher than the inlet ports II and is so spaced near to the tubing 8 that the liquid flowing into the inlets Ii must first pass around the plate 25.

In the operation of this modification gas pressure is likewise applied to the accumulated liquid the chamber rises quickly above the pressure outin the chamber 5 is forced by the gas pressure into andv upwards in the eduction tube 8 through As the liquid level in the chamber is in the chamber 5, forcing the liquid to pass into the lift tube 8 through inlets II. The flow of liquid into the inlets ll passing around the plate 25 drags the plate downwards, which brings the valve 28 into contact with the valve seat 22. The passage through the upwardly directed pipe 2| is thereby closed until substantially all the liquid above the plate 25 has been forced up into the tube 8 through the openings ll. As the liquid level falls below the plate 25, the dragging force of the flowing liquid on the plate 25 is removed and the valve 28 is forced open by the action of the spring 24. Gas then rushing into the pipe 2| forces the lift piston ill with its load of liquid to the well head, where the liquid is discharged, and the cycle is repeated.

According to another embodiment, as shown in Figure 3, the valve l3, which engages the open-v ing and valve seat I2 in the bottom of the tubing 8, is carried by a float 38, so that the valve I3 .is in closed position when the liquid level in the chamber 5 is high and is in open position when the level is low. The lateral openings or inlets II are provided with tubular conduits 3|, which extend downward and open near the bottom of the chamber 5 or open at a point at or below the level of the bottom of the float 38 when in' its uppermost position. Guides 32 are provided to insure that the float is axially aligned, so that the valve l3 correctly. engages its seat I2; or the tubular conduits 8|, when three or more are used, may be arranged to provide a sliding flt about the float stand thereby guide the valve it into its proper position.

It can readily be seen thatin this modification the valve It is kept closed by the buoyant force oi float 30 during the period when liquid is being forced into thetubing 8 through conduits t i, and opens when the liquid level falls to such an extent as no longer to force the float 30 and valve it up against the valve seat H. The rest of the operation is similar to that of the first-described embodiment. B

A slight variation of the last-described mouth cation is shown in Figured, wherein the tubular conduits 3| from the lateral openings or inlets M are replaced by a tube or tubular apron or jacket 40, which surrounds the lower part of the tubing 8 and the float 30 and which'is narrowed at the top and fastened by the narrowed portion I which, in fact. is the same as that according to.

Figure 3, after removal of valve It with seat it circumferentially to the tubing 8 at a point above the inlets In thisconstruction the float holds the valve I3 in closed position by not only its buoyancy, but also due to the driving force of This may beexplained, for example'with reference to the embodiment according to Figure 7,

and float M with guides 32.

It is clear-that the plunger will beliited only when the diflerence between the pressures against the bottom of the plunger and at the top thereof respectively becomes'larger than that equal tolarger than that ,equal to the weight of' the plunger less its liquid displacement. This re,-

sistance may be kept low by keeping the rate the upwardly moving liquid imparting a dragging action on the float 30. v

This last-described embodiment may be still further varied to obtain some other special advantages. As shown in Figure 5, the tubeor tubular apron or jacket 40 is narrowed'in the lower portion-below the float and extended downwards as a tubing 50. In this modification the apron or jacket 40 with the working parts therein may be located in the upper part of the accumulating or displacement chamber 5. The lower part of the chamber thus remains available for accumulation of liquid and the bottom of this chamber, together with the standing valve 1, is cleaned, or at least more nearly emptied completely, during each cycle, by the liquid which under gas pressure is passing along on its way upward.

In still another variation, as shown in Figure 6, the jacket or apron extension tubing extending upwards opens into the Jacket 40 at a higher level, so that the jacket 40 thus becomes a secondary bailer chamber and may be provided with any modification of the automatic and liquidoperated valve means, .such as for example the float 30 and downwardly extending tubular con du'its 3| of the modification shown in Figure 3.

In practice the various parts, particularly the inlets II and the passage between the float l6 and the tubing 8 or between the float 30 and the jacket or apron 40, should be so dimensioned thatin each cycle after the liquid-has passed by the float, the float: will descend, opening the valved means communicating to beneath the that the force required for overcoming the resistance against flow of gas through the inlets II plunger ID in the lift tube 8. It is also preferable plunger ID.

of pressure gas supply within moderate limits. so that the plunger will stay at rest.

The total resistance to flow. through the conduit 3| is equal to friction resistance plus-the hydrostatic head, the latter having a zero value when the conduit 3| is totally submerged in the fluid in chamber 5. As the fluid level in chamber 5 recedes, however, the hydrostatic head in conduit 3| increases in valve, the fluid column within said conduit being no more completely balanced by the fluid outside of said conduit. The resistance to fluid flow from point 33 to point |l through conduit 3| increases in value, therefore.

while the fluid level in chamber 5 recedes from point It to point as. The increasing resistance to flow through conduit 3| builds up, therefore, when the fluid in chamber 5 has receded to a predetermined level below point 20, to a value greater than the resistance to flow'of the alter nate path 83-2|I--l|, thereby causing the plunger In to be lifted.

In the modification shown in Figure 2 the me-' chanical. means 22-28 may be dispensed with as well, the only conditions for satisfactory operation then being that the upwardly directed pipe 2| is extended to a predetermined height above the inlet ports H, as shown in Figure 8, and that the resistance to flow of liquid through inlet ports H is kept within certain limits.

The liquid level in the accumulating space once being depressed below opening 34, the liquid head inside pipe 2|, which remains constant, will no longer be balanced by that outside said pipe and a hydrostatic head of a value which continuously increases as the level in chamber 5 is depressed will be applied upwards to the lower. face of The plunger III will therefore be lifted as soonas the following inequality of forces obtains in the apparatus of Fig. 8.

F11+H21F21 W1o+Fm wherein F11 is the force of friction opposing fluid flow through ports ml is the hydrostatic head of the fluid column in conduit 2| F21 is the force of friction opposing fluid flow in conduit 2| I liquid level and said compartment. tained, for instance, by so dimensioning the pasn will be understood'that it is also possible to combine the modifications of Figures 7 and 8, the device then showing a conduit extending downwards from inlet ports II and another conduit extending upwards from inlet port 20, the opening 34 of the latter conduit then lying at a predetermined distance above the opening 33 o the former conduit. As mentioned above, the modifications accord. ing-to Figures '1 and 8 are rather sensitive as regards the rate at which the pressure gas isto be admitted into the accumulating space, the resistanceto flow of liquid into the space in the lift tube above the plunger being an important factor.

This difliculty may be overcome if in the way of both the passages to the spaces in the lift tube above and below the plunger respectively choke means are inserted for neutralizing the effect of too fast a pressure gasadmittance on the liquid flow, which is illustrated in Figure 9, showing a compartment 35, an inlet port or passage 20 to the space below the plunger, a conduit or passage means 3| from said compartment to the inlet ports ll above the plunger and a passage 38 between the accumulating chamber Choking may be atsage 36 and passage means 3| that the resistance to flow of liquid of the former is larger than that of the latter or by providing said passage 36 with a downwardly extending pipe in the mannor of tubing 50 in Figure 6.

It is to be understood that many other variations may be made without departing from the spirit of the present invention. For example, there may be provided one or more passages between the accumulating space and the spaces in the lift tu'be above and below the plunger. Or, for instance, suitable shock absorbers may be provided at each end of the stroke of the plunger. Or the inner casing 4 may be omitted entirely by providing the holes 3 in the well casing 2 with inwardly opening one-way valves, whereby the lower portion of the casing becomes the bailer chamber and the annular space between the tubing 8 and the casing 2 becomes the conduit for high pressure gas. Or various types of guiding means may be used with the moving parts to ensure proper alignment.

I claim as my invention:

1. In a gas-lift system, the combination of a tubular string extending into a well, the lower portion of said string forming a liquid-accumulating chamber, said chamber having a nonreturn inlet valve,.means for delivering pressure gas to said chamber, a lift tube depending into said chamber, a plunger freely movable in said tube, means to support'said plunger at. rest adjacent to the lower end of said tube within 'said chamber, upper inlet ports above the plunger at rest in said tube to permit liquid accumulation in said tube above said plunger, a lower inlet port connecting said tube below the plunger at rest therein with said chamber and level-responsive means for controlling flow through said upper and lower inlet ports.

2. In a gas-lift system, the combination of a tubular string extending into a well, the lower portion of said string forming a liquid-accumulating chamber, said chamber having a non-rea plunger freely movable in saidtube, means to support said plunger at rest below said ports to permit liquid accumulation in said tube above said plunger, a valve between said chamber and said tube below the plunger at rest in said tube, and level-responsive means within said chamber adapted to open said valve when the pressure gas admitted into said chamber depresses the liquid therein to a predetermined level.

3. In a gas-lift system, the combination of a tubular string extending into a well, the lower portion of said string forming a liquid-accumulating chamber, said chamber having a nonreturn inlet valve, means for delivering pressure gas to said chamber, a lift tube depending into said chamber, inlet ports in said tube adjacent to the lower end thereof within said chamber, a plunger freely movable in said tube, means to support said plunger at rest below said ports to permit liquid accumulation in said tube above said plunger, a valve between said chamber and said tube below the plunger at rest in said tube, said valve comprising a stationary valve seat member and a movable valve member normally held in closed position against said seat member by resilient means, and floatable means adapted to act against said resilient means and to force said movable valve member away from said stationary seat member when the pressure gas admitted into said chamber depresses the liquid therein to a predetermined level.

4. In a gas-lift system, the combination of a tubular string extending into a well, the lower portion of said string forming a liquid-accumulating chamber, said chamber having a nonreturn inlet valve, means for delivering pressure gas to said chamber, a lift tube depending into said chamber, inlet ports in said tube adjacent to the lower end thereof within said chamber, a plunger freely movable in said tube, means to support, said plunger at rest below said ports to permit liquid accumulation in said tube above said plunger, a valve between said chamber and said tube below the plunger at rest in said tube, said valve comprising a stationary valve seat member and a movable valve member carried by fioatable means adapted to open said valve when the pressure gas admitted into said chamber depresses the liquid therein to a predetermined level.

5. In a gas-lift system, the combination of a tubular string extending into a well, the lower portion of said string forming a liquid-accumulating chamber, said chamber having a nonturn inlet valve, means for delivering pressure gas to said chamber, a lift tube depending into said chamber, inlet ports in said tube adjacent to the lower end thereof within said chamber,

return inlet valve, means for delivering pressure gas to said chamber, a lift tube depending into said chamber, inletports in said tube adjacent to the lower end thereof Within said chamber,

conduits attached to said tube about said inlet tubular string extending into a well, the lowerportion of said string forming a liquid-accumulating chamber, said chamber having a nonreturn inlet valve, means for delivering pressure gas to said chamber, a lift tube depending into said chamber, a plunger freely movable in said 7 tube, means to support said plunger at rest ad jacent to the lower end of said tube within said chamber, upper inlet ports abovethe plunger at rest in said tube to permit liquid accumulation in said tube above said plunger, a lower inlet port connecting said tube below the plunger at rest therein with said chamber and level-responsive means for controlling flow through said upper and lower inlet ports, said flow control means consisting of conduits attached to said tube about said upper inlet ports and extending downwards within said chamber for opening below said lower inlet port.

7. In a gas-lift system, the combination of a, tubular string extending into a well, the lower portion oi said string forming a liquid-accumulating chamber, said chamber having a nonreturn inlet valve, means for delivering pressure gas to said chamber, a lift tube depending into said chamber, a plunger freely movable in said tube, means to support said plunger at rest adjacent to the lower end of said tube within said chamber, upper inlet ports above the plunger

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