US2542259A - Unloader valve - Google Patents

Description

Feb. 20, 1951 c. M. oLr-:ARY

UNLOADER VALVE Original Filed July 10, 1944 atented Feb. 20, 1951 UNETED STATES PATENT OFFICE Original application July 10, 1944, Serial No. 544,209, now Patent No. 2,423,111, dated July 1,

1947, Serial No. 742,382

4 Claims. (Cl. 137-41153) The present invention relates to an apparatus for causing outflow ci well uid from wells of low productivity index, and is a division of applicants copending application, Serial No. 544,299, filed July 1G, 1944, now Patent No. 2,423,111, granted July 1, 1947.

It is the general object of the present inven-` tion to provide an improved form of blow-ofi valve for use in bottom hole gas-operated oil well pumps to aerate the column of oil when its density exceeds a desired maximum in value.

Another object of the invention is to provide an improved combination of bottom hole gas-- operated pump with a blow-off valve of the type mentioned associated with the operating gas supply of the pump.

Other objects, which will become apparent from the following specification and accompanying drawing, include the provision of an apparatus of the type mentioned which may be readily lowered into the outiiow tubing of a well on the gas tubing and which is simple and rugged in design and construction.

The invention is fully disclosed by way of example in the following description and in the accompanying drawing, in which:

Figure 1 is a vertical section of the device, at the beginning of the suction stroke;

Figure 2 is a similar section, showing the posi'.A tion of parts at the beginning of the pressure stroke; and

Figure 3 is a section on the line 3 3 of Figure 2.

In Figure l is shown the well outflow tubing 3, which extends substantially to the bottom of the well bore within the usual well Casing, not shown. n the bottom of the tubing 3 is iitted an endpiece 4 formed with a seat 4. Within the tubing 3, in turn, is mounted the power gas tubing or pressure flow tube 5', to the lower end of which is fixed an enlarged tube 5 carrying a pumping mechanism designated generally by the numeral l.

In the tube 5 is mounted a block 'I having mounted in its upper end a strainer or Scale trap il communicating with a central passage formed in the block. To the block 1 is secured a downwardly extending sleeve Iil formed with a series of ports I2 for a purpose that will pres ently be described. Beneath the ports, a crossover Iff is attached to the sleeve Ill and is ,formed with an axial passage It, for a purpose that will presently appear. Over the passage and within the sleeve le is mounted an unloader valve I3 having a head 2t adapted to seat ona seat 2l at the upper end of the passage I6. `The valve Divided and this application April 18,

I8 is formed with an axial passage 22,y and is suspended from the block 'I by a bellows 24 com-v municating with the passage 9. Another bellows 2E also joins the members l and I8 and forms an annular chamber 28 around the bellows 24, which chamber is sealed at substantially atmospheric pressure. When the unloader valve is seated, the body thereof forms a space 29 above the crossover I4 and in communication with the ports I2.

A jacket or extension tube 30 is suspended from the crossoverV I4 and is also spaced from the tubing 3 to form a continuation of the annular chamber 6 between tube 3 and the aligned tubes 5, I and 3B. The lower end oi the crossover is formed as a motor piston cylinder head 32, from which is suspended a motor piston cylinder 34 spaced annularly at St from the jacket 30. Between the crossover I4 and the head 32 is formed a number of radial ports 38 communicating with the axial passage I6.

In the cylinder 34 is slidably mounted a motor piston including a cylindrical sleeve 40 formed at its upper end with a skirt 42 of somewhat larger internal diameter. The juncture of the two diameters forms a valve seat 44. At the lower end of the motor piston is formed a head 46, and near the head are ports 48 forming a passage to the interior of the piston. The head 46 is formed with an axial bore 50 which has its upper end enlarged at 52 for a purpose that will presently be described. A pump plunger rod 54 passes through the bore Sil with slight clearance therein, and carries at its upper end a motor piston valve head 56 adapted to close on the seat 44.

A spring 58 is inserted between the valve head and the lower piston head 46 and holds the valve head 56 open under certain conditions that will presently be described. The rod 54 is formed with a collar 6D having a sliding rit in the enlarged bore 52.

On the lower end of the extension 3u is secured a downwardly extending `barrel 62 of smaller diameter and joined to the extension by an annular disk connector 64. The lower end or barrel 62 carries a tting 63 inserted in. the seat 4.

The lower end of the pump plunger rod 54 carries a pump plunger 66 working in barrel t2. The area of the plunger 66 is smaller than the area of the seat 44. Pump rod 54 is provided with stop collar 61, which limits the separation of the valve 5S and piston 4t in the open position of the valve.

The power gas flows through the space 6B be- Y valve 56 comes to rest on seat 45.

tween the connector 65. and the lower end of the motor piston cylinder 34. While the disk connector acts as a lower stop for piston 45, contact between the piston and disk 54 does not block communication between space 69 and the pump barrel 62.

In the lower surface of the cylinder head 52 is mounted an upwardly opening check valve, including a ball 1E) adapted to close on a seat s. The valve communicates through a restricted lateralpassage l2 in the crossover is with the space 6. The passageway l2 does not communicate with the ports 38.

In the lower end of the pump barrel 62 is mounted a discharge valve housing lprovided in its lower end with a seat 18. rihe housing i6 contains a ball valve S adapted to close downwardly in the seat i8, and is formed with a suitable number or" laterally extending ports 82 registering wtih ports 85m the barrel through connecting nipples 84, thereby bringing the valve housing into communication with the lower end 5 of the well uid space. The pump chamber S5 between the housingl and pump plunger 56 is in communication with the space within barrel 62 and below housing l5 through the passages between the nipples 64, as best shown in Figure 3.

A iluid intake pipe 96 from the well is inserted with the tting, constitutes the standing valvev or intakevalve assembly.

In Figure 2, the parts are illustrated in the position they assume at the beginning of the pumping or downward stroke of plunger S6. The power gas iiows down tubing 5 through the, trap 8, bellows 24, passages 22 and i5, ports spaces and 69, ports 48 and the open valve seat t4 into the chamber 94 above the valve head 56. chamber 94 communicates through the, restricted passage 'i2 with the space which. is at a pressure determined by the head of well fluid standing therein and less than the power gas pressure. However, due to the restricted passageway l2, the pressure in chamber 54 may be substantially equal to the pressure of the power gas supply. This same pressure acts on both sides oi valve 56, both sides of piston 4i), and also on the top of plunger 66. sures on the piston lill, itself, are balanced, and

the power gas moves the plunger 55 downwardly through its pumping stroke by reason of the fact that it is acting on an excess upwardly-facing area on the plunger and valve unit 55 and 5S equal to the cross-sectional area of plunger 66. During the pumping stroke, that portion of the power gas which ows through passage 'i2 enters the column of oil in tube t and provides a gas lift effect. During the pumping stroke, Spring 53 holds the valve 55 open by moving the then balanced piston 45 downwardly in advance of the valve. However, near the end of the pumping stroke, piston 45 engages disk 5ft and is brought to a stop. Thereupon continued downward movement of plunger 56 compresses spring 5S and The valve 55 is now held on its seat by the pressure above the motor piston 45 and the power gas pressure acting on plunger 65. When the valve 56 is seated, the pressure effective area of the upper side of the valve is greater than the pressure effective area of its lower side by the cross-sectional area The,

During this condition, therefore, the pres-4 CII of the plunger 65. which is attached to valve rod 66. y

The downward pressure in chamber 94 is now diminishing through the restricted exhaust pas sage l2, while the upward gas pressure at the space 59 remains constant against the lower end of motorpiston 45. The pressure effective area of the lower side of motor piston lid, which is subject to power gas pressure, is its area minus the area ofpump plunger 66. When the pressure in chamber 9s above the motor piston 45 drops to a point where the pressure gas on the lower side of piston 46 exerts a force greater than the force on its upper side, the piston valve 53, rod 6) and plunger 6i? move upward. The suction stroke of the plunger is thus initiated, raising the valve Si.' and seating the valve 8s by suction in the chamber S5, as shown in Figure l, drawing which it is exhausting. The size of the opening' 'i2 and the relative diameters of pistonifii, valve 56 and plunger 56 are so chosen for any given power gas pressure and well iluid pressure that valve 5S remains closed during the suction stroke until the skirt 4Z of piston 40 strikes the cylinder head 32.

When the extended skirt 42 strikes the head 32 at the end of its suction stroke, the pressure in chamber 94 further reduces until the tension of spring 58 and the pressure responsive area on the underside of seated Valve 56 are suilcient to open the valve against its` upper pressure area, as shown in Figure 2. There is now equal unit pressure on both sides of the motor piston 46 and the pressure gas now exerts a resultant downward force against the area of plunger 66 to I initiate the downstroke, as previously described. The opening of valve 55 in relation to seat 44 is limited by stop collar 6l.

Once the valve 56 is seated, it cannot come oli"V valve 92 is seated and valve 86 is unseatedbypressure in the chamber 86, as shown in Figure 2. The wellv fluid that was previously drawnV into barrel 62 is now discharged into the f space 6', 6.

It is obvious that there is exhaust of power gas on the power stroke, so that the flow of gas into the head of well fluid is continuous. This flow of gas is ordinarily sufficient to .produce a constantly flowing discharge of aerated well uid to the surface of the ground.

Back ow of well fluid into the chamber 94 is prevented by the inwardly closing check valve 16 on its seat 'I0'.

In the event that the head of well fluid becomes,

too dense for continuous aerated discharge, the unloader valve I8 provides means for a blow-oli. This' is brought about by well fluid pressure being built up in the outflow tubing and reacting against the area of the unloader valve I8 eX- posed to well iuid at the space 29. The unloader valve I8 is normally held seated by pres'- sure'gas acting on4 that portion of valve I8 confined by bellows 24, this area being substantially larger than the seated area of valve I8 on its seat 2l. The passage 22 through valve I8 is smaller in cross-sectional area than the area of valve seat 2|. This provides a continuous pressure on the valve I8, tending to hold it upon its seat 2|.

When the unloader valve I8 is raised and the gas pressure is communicated to the head of well iiuid at the ports I2, the friction of the flowing fluid in chamber ii imposes a greater pressure in space 29 and on the valve I8 than at the time the valve was rst unseated. This additional force insures that the valve I8 will remain open until such time as the well fluid starts to discharge at the surface. The back pressure of the discharging fluid eventually drops to a point where the pressure in bellows 24 is suiiicient to seat the valve. The fluid remaining in tubing 3 continues to discharge by the expansion of the power gas trapped inthe tubing by the seating of valve I8. The quick action of the valve thus saves pressure gas and permits the pumping mechanism to commence operation without waiting for a complete blow-down of the well. A balanced pressure condition, holding the pump inoperative, would be of only momentary duration.

Thus, it is not necessary with this unloader valve to blow the tubing dry in order to close the valve. The result of this characteristic is a very positive and economical operation.

It is preferable that the well fluid pressure responsive parts of valve i8 be of a larger area than the power gas pressure responsive parts tending to hold the valve upon its seat 2l,

whereby to permit the opening of Valve I8 by low well fluid heads.

It will be noted that the cross-sectional area of passage 22 is smaller than the area of bellows 24. When the valve I8 is away from its seat 2I, the pressure in the area coniined by bellows 24 and flowing through the restricted passage 22 urges the valve on its seat, It is this force that moves the valve toward its seat when a portion of the well fluid has been ejected at the surface and permits operation of the `pumping mechanism, as previously set forth.

The higher the pressure in the system, the greater the slug or head of well iiuid must be to overcome the greater force exerted on the gas pressure responsive parts. If the pressure be lowered, a correspondingly smaller head will be required to open the unloader valve. A denite diierential can be established between all the parts or the pumping mechanism and the unloader valve to be applicable over a wide range of varying well conditions by control of the power gas pressure.

The parts of the unloading valve are so proportioned that when the column of fluid loads up to a predetermined pressure where the performance of the pumping mechanism is retarded, the valve opens and the power gas ejects the fluid from the tubing. Such loading up of the tubing is sometimes brought about by a slug of Water or by a drop in gas pressure at its source 6. or by the cutting in of other wells on. the saine line, which will also reduce the gas pressure.

By regulation of input gas pressure, the head of well uid necessary to open the blow-olf` valve I8 can be controlled. The relation of the respective pressure responsive areas to each other can be so designed to operate under varied well conditions, and, by regulation of the gas pressure, can be made to pump deep or shallow wells with a minimum of gas.

It is understood that various areas of motor pistons, valves, pump plungers and various spring tensions and sizes of Vents may be used to meet various well conditions.

The disclosed pumping mechanism can be of the insert type removable with the power gas string, as illustrated, or of the tubing type requiring removal of both strings to service the pump. The pump can be so arranged to produce the well fluid through the smaller string of pipe, in which case the outer string of pipe would be used to conduct power gas to the pumping mechanism.

Although a specific embodiment of the invention has been illustrated and described, it will be understood that various alterations in the details of construction may be made without departing from the scope of the invention as indicated by the appended claims.

What is claimed is:

l. An unloader valve comprising a supporting member having an inlet port therein, an expansible elastic bellows, which is generally circular incross section, secured in sealed relation at one end to said supporting member in position to receive and conduct fluid entering said port, a Valve member secured in sealed relation to the opposite end of said bellows and having an opening therethrough of smaller diameter than the diameter of said bellws and communicating with the interior of the bellows, a third member mounted in fixed position with respect to the supporting member and having an outlet port in alignment with the opening in said valve member, cri-operating valve seating areas on the valve member and third member surrounding the opening and outlet port respectively and adapted to be forced into seating engagement by pressure within the bellows acting on the valve member, and a second bellows of larger diameter and surrounding the first bellows and secured in sealed relation at its opposite ends to the supporting member and valve member respectively, said second bellows and said supporting member being of larger diameter than said valve seating areas whereby for any given fluid pressure eX isting within the inner bellows said valve member will be unseated by a predetermined pressure existing in the space surrounding the second bellows.

2. A valve for automatically aerating a column of liquid in a well outflow tubing, comprising a housing having a gas supply passageway, an outlet port in said housing, a movable valve element having a restricted opening therethrough in constant communication with said passageway, a stationary valve seat adapted when engaged with said valve to prevent flow through said opening to said port, and means responsive to the pressure at said port tending to lift said valve from said seat.

3. A valve for automatically aerating a column of liquid in a well outflow tubing, comprising a housing having a gas supply port, an outlet port in sad'housing, a gas ow passage adapted to connect said ports, a valve for controlling flow through said passage, a movable pressure responsive means Subject to the pressure at said outlet port for opening said Yvalve when the pressure at said outlet port reaches a predetermined value, Yand means responsive to the pressure differential across said valve due to the gas flow through said passage for exerting an opy posing force tending to close the valve.

4. A gas supply and unloader valve mechanism for a gas-operated bottom holewell pump having an operating gas supply conduit and a liquid discharge conduit, said valve comprising a chamber having three ports, one of said ports being a discharge port, the second being a gas supply port and the third being a pump supply outlet port, a-movable valve element in said chamber and adapted to engage the third port,

said element having a restricted opening therethrough adapted to deliver gas from the second port through said third port when the valve element is in engagement with the third port, and means to prevent flow of gas from the second port to the third port except through -said restricted opening, said last means being movable and subject to the pressure at the rst port Vacting in a direction to lift the Vvalve element off the third port and thereby place said restricted opening in communication with the rst -port and also subject when the valve engages said third port to a force incident to the pressure drop through said restricted opening tending to hold the valve in engagement with said third port.

Y CHARLES M. OLEARY.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,543,488 Todd June 23, 1925 2,029,457 Beardmore Feb. 4, 1936 2,254,631 Temple Sept. 2, 1941 2,269,189 Downs Jan. 6, 1942 2,312,201 Thompson et al. Feb. 23, 1943 2,328,841 OLeary Sept. '7, 1943 2,342,855 Green Feb. 29, 1944 2,356,423 OLeary Aug. 22, 1944 2,368,999 OLeary Feb. 6, 1945 2,423,111 OLeary July 11, 1947

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