US3212406A

US3212406A - Pumping systems

Info

Publication number: US3212406A
Application number: US176219A
Authority: US
Inventors: Thomas F Mcduffie
Original assignee: Youngstown Sheet and Tube Co
Current assignee: Oil States Industries Inc
Priority date: 1962-02-28
Filing date: 1962-02-28
Publication date: 1965-10-19
Anticipated expiration: 1982-10-19

Description

Och 19, 1965 T. F. MCDUFFIE PUMPING SYSTEMS Filed Feb. 28, 1962 United States Patent IO 3,212,406 PUMPING SYSTEMS Thomas F. McDutle, Dallas, Tex., assignor to The Youngstown Sheet and Tube Company, Youngstown, Ohio, a corporation of hio Filed Feb. 2S, 1962, Ser. No. 176,219 4 Claims. (Cl. 91-165) This invention relates to systems for raising liquid from a well. In one important aspect it relates to a system for cleaning out a `gas well to permit maximum flow of gas from the well.

In some instances gas wells make suiiicient water and hydrocarbons that they are gradually choked off. When this happens, it is desirable to swab, pump, or otherwise remove the Water and hydrocarbon from the well. Pumps have been used for this purpose in the past. They have conventionally used an outside source of power.

It is an object of this invention to provide a system which will maintain the well clean without the use of extraneous power.

Another object of this invention is to provide a system for lifting liquid from a well in which gas from the Well is utilized to provide the lifting power in an economical manner.

Another object is to provide apparatus for lifting liquids from a well which uses gas pressure as a power source in such a manner as to be economically comparable with electric driven pumping units.

Another object is to provide a system for removing liquid from wells including a pumping apparatus which is automatically placed in operation when a head of liquid in the well obstructs gas flow and is automatically placed on standby when this head of liquid has been removed.

Another object is to provide a system as in the preceding object in which the well pumping apparatus can be placed on idle cycle when the well is not producing to keep the parts free and in good working order.

Another object is to provide an economical gas operated motor for reciprocating a well pump.

Other objects, features and advantages of the invention will be apparent from the drawing, the specication and the claims.

In the drawing, wherein like reference numerals indicate like parts, and wherein an illustrative embodiment of this invention is shown;

FIGURE 1 is a schematic illustration of the system of this invention; and

FIGURE 2 is a view in vertical section on an enlarged scale through the shutoff valve and motor operator therefor.

The well illustrated is provided with a casing having a screen 11 on `the lower section thereof through which the liquids and gas ow into the well casing. A pump indicated generally at 12 is positioned in the well adjacent the producing formation. This pump is schematically illustrated as its particular construction forms no part of the invention, and any desired liquid pump may be used.

A well head indicated generally at 13 is provided on the surface at the upper end of casing 19. This well head has a main gas outlet 14 which is connectable to a gathering system not shown, and an auxiliary gas outlet 15. In the illustrated embodiment gas is produced through the casing to the

outlets

14 and 15.

` The well head 13 has a liquid outlet 16 which receives liquid from the tubing 17 in which the pump 12 is mounted.

The pump 12 is operated by a reciprocating pump rod 18 attached to a polish rod 19 extending through the Well head 13.

lCe

A pumping apparatus is provided for reciprocating the polish rod 19 and preferably is attached directly thereto. In the illustrated form of the invention a mounting ange 21 is provided on the well head and a cross bar support 22 is supported on the mounting ange by studs 23.

A main gas chamber is preferably provided by a pair of gas chambers 24 supported on cross bar support 22. These chambers may be provided lby sections of pipe closed at each end as shown. Specically, the cross bar support 22 is a plate-like member which is welded to the lower end of the chambers 24 to provide a closure therefor. A cross head plate 25 extends across the upper end of the chambers 24 and is welded thereto to provide a closure for the chambers and a support.

A closed cylinder 26 is supported on the cross head 25. A piston 27 reciprocates in cylinder 26. A connecting rod 28 extends outside of the cylinder 26 and connects the piston 27 to the polish rod 19.

Each of the main gas chambers 24 is connected to one end of cylinder 26 through suitable conduits 29 which are arranged to convey uid pressure from the main gas chambers to the cylinder. For lubrication purposes, it is preferred that a small amount of oil be placed in the lower end of the main gas chambers below the inlets of the conduits 29 so that this oil will be delivered to the cylinder 26 and lubricate the piston and connecting rod.

From the description upto this point it is apparent that the pump 12 is operated by reciprocation of piston 27. In order to provide fluid pressure for raising piston 2'7, the main gas chambers 24 have their inlet connected to a source of uid under pressure. Preferably, this source is gas pressure of the well being pumped. Each main gas chamber 24 has an inlet provided by identical standpipes 29 extending into the main gas chambers. The two standpipes 29 are connected to a main conduit 31-31a which receives gas from a gas dryer 32 which in turn receives gas from the auxiliary gas outlet 15 of the well head through line 33.

Control of flow of pressure iuid to the main gas chambers 24 is provided by a system of valves which can be set to place the pump on idle or normal operation. The system of valves controls the speed of the upstroke of piston 27 and provides for operation of the system when a head of Huid in the well is placing a back pressure on the well, and stops operation of the system when this back pressure is removed.

Upstroke speed of piston 27 is provided by the setting of re-gulator valve 34 which controls flow of fluid through conduit 31. Hesistance to upward movement of piston 27 is provided by the weight of the sucker rod 18 and by the head of iiuid on the pump. Thus, if regulator valve 34 is set at a pressure which will result in an upward force on the lower face of piston 27 which is just slightly more than enough to raise the string, the upward speed of piston 27 will be rather slow. On the other hand, if the regulator valve is set to provide a pressure resulting in substantially greater force than needed, upward movement of piston 27 will be rather fast. Thus, the setting of regulator 34 will control the upstroke speed of piston 27.

In lorder to provide for downward movement of piston 27, the main gas chambers 24 are connected to the upper or other end of cylinder 26 through the connecting conduit 35. This conduit has a regulator valve 36 therein which functions to control the downward speed of piston 27 and to conserve the amount of gas used by the system. The regulator valve 36 will always be set to provide for a lesser pressure in the upper end of cylinder 26 than in the lower end thereof. The amount of pressure downstream of regulator valve 36 will determine the speed of the downstroke, as an excess pressure in the upper end of cylinder 26 over that needed to provide the necessary downward force on piston 27 will result in faster downward movement of piston 27. It is also noted that regulator valve 36 is placed in parallel with a small needle valve. The purpose of this needle valve 62 is to provide a method of bypassing a small amount of gas past regulator valve 36 to prevent the piston 27 from stalling on the downstroke should this tend to occur for one reason or another. Needle valve 62 may also be used to cause a very slow downstroke speed when regulator valve 36 is shut off.

At this point it might be noted that the inlet regulator 34 for the main gas reservoirs 24 also functions as a check valve and prevents reverse ilow of pressure fluid from the main gas reservoir. Thus, as pressure from line 35 is applied to the upper end of cylinder 26 to force piston 27 downwardly, the pressure in the main gas reservoir increases. This is true even though some gas is being withdrawn through conduit 35 because the gas in conduit 35 is at a lesser pressure than gas in the main gas chamber. Thus, on the next cycle of operation this increased pressure is available to assist in raising piston 27, utilizing as small an amount of gas as possible.

Alternate pressurizing and venting of the upper end of cylinder 26 is provided for in response to reciprocation of said piston by a spool valve indicated generally at 37 and

control valves

38 and 39 which are operated by a cam 41 on connecting rod 28.

The spool valve in one position connects line 35 to the upper end of cylinder 26. In the other position it closes off line 35 and connects the upper end of cylinder 26 to a vent line 42. Vent line 42 may vent pressure fluid to atmosphere, to the gathering system if pressure conditions permit, or to a separate line for conducting the gas to any desired point for further use.

The spool valve 37 is of conventional construction with oppositely-facing pressure-responsive surfaces to which fluid pressure is fed through

lines

43 and 44. Line 43 is connected to control valve 39 and line 44 is connected to control valve 38. These Valves receive pressure iluid from the main gas chambers 24 through a manifold system 45.

Valves

38 and 39 are conventional in construction and are so arranged that either spring or pilot gas pressure is used to hold cam rollers 65 and 66 in an extended position. They are depressed by passage of cam 41. In their normal or extended position gas from the manifold 45 is blocked.

Lines

43 and 44 from spool valve 37 are vented to atmosphere through lines 63 and 64. In the depressed position the vent line is closed and gas pressure from line 45 is connected to the line (either 43 or 44, as the case may be) leading to spool valve 37. With the apparatus in the position shown, further downward movement of connecting rod 28 will cause cam 41 to depress cam roller 66 on valve 39 closing off vent line 63. Gas pressure from line 45 is connected to line 43. The combination of gas pressure on side 43 of the inner spool of valve 37 and atmospheric pressure on the other side 44 will cause the spool to shift and thus the spool valve 37 will be shifted to a position at which the upper end .of cylinder 26 is connected to vent 42 and conduit 35 is closed olf. When the piston 27 approaches the top of its stroke, as shown in dashed outline at 27a, the cam roller 65 of the other control valve 38 is operated by cam 41 to reverse the pressure condition on spool valve 37 and provide for pressurizing of the upper end of cylinder 26.

Preferably means are provided for operating the system only when a head of liquid is maintaining a back pressure on the well. This means includes a shut-off spool valve 46 which is shiftable between positions permitting flow of tluid through line 31 and preventing flow of fluid through line 31. Reference is made to FIGURE 2 Wheren a preferred form of shut-off valve is shown. The inlet 47 of the shut-off valve is connected through line 31a to the gas dryer 32. The outlet 48 is connected to line 31 and leads to regulator valve 34. The valve is conventional in construction and employs a plurality of seals 49,

S0 and 51 which cooperate with valve member 52 to control flow of fluid through the valve. The spool valve may be operated by a diaphrgam 67 secured to one end of valve member 52 and responsive to well pressure on one side through inlet 54 to which line 57 is connected. The other end of the valve member 52 is operated by a diaphragm 53 responsive to reduced Well pressure coming from regulator valve 58 through volume tank 59 thus to line 55 connected to port 56. Regulator valve 58 draws its pressure from line 57. By reference to FIGURE l it will be noted that conduit 57 extends from line 31a through a regulator valve 58 and an accumulator chamber 59. The valve 58 is set to provide at inlet 56 a lesser pressure than present at inlet 54. In practice the regulator 58 will be set to provide a constant pressure at inlet 56 and fluctuation of well pressure at inlet 54 of diaphragm 53 will cause the diaphragm to ex and shift valve 46. A suitable spread in operation of valve 46 is provided by the friction of the seals, and if desired by a detent indicated generally at 61.

When it is desired to place the system on standby, the needle valve 60 is adjusted to permit a very slight flow of fluid to the pumping apparatus, thus regulating its operation to such speed as needed to keep the parts free and the well ready for resumption of normal flow conditions.

When on stream, gas from the casing annulus passes to the ydryer 32 where the gas is dried. The needle valve 60 will be open and well pressure will be effective in

lines

55 and 57. Regulator 58 will be set to provide a pressure drop thereacross and maintain in accumulator chamber 59 a selected pressure less than well pressure when there is no back pressure on the well. With this condition a buildup of uid head in the well will reduce the gas pressure available in the dryer 32 and hence to the inlet 54 -of the diaphragm motor operator. When the force exerted on the diaphragm through port 56 exceeds the force exerted through port 54 by an amount sufcient to overcome the friction of the valve and the detent 61, the spool valve will be shifted to open position. It will be noted that the areas of

diaphragms

53 and 67 are not the same. Diaphragm 53 is larger than diaphragm 67. This is so the forces exerted by the diaphragms will be balanced with a difference in pressure of 20 to 30 lbs/sq. in. This is so the -unit will start pumping when the well pressure is still higher than the line pressure. This will permit Well pressure to pass through regulator 34 and maintain an operating pressure in the main gas chambers 24. If we assume the piston 27 to be in the position illustrated in the drawing and the slide valve 37 to be positioned to vent the upper end of cylinder 26, the pressure in gas chambers l24 will move the piston 27 to the dotted line position shown at 27a. At this time the slide valve 37 will be shifted by engagement of cam 41 with the cam roller 65 on control valve 38. The vent 42 will be closed and conduit 35 will be connected to the upper end of cylinder 26. As the regulator valve 36 will be set to provide a.,lesser pressure in the upper end of cylinder 26 than present in main gas chambers 24, the full main gas chamber pressure Will not be exerted on the top of piston 27.r The regulator 36 will be set for a sutiicient amount of pressure to move the piston 27 downwardly at the desired rate of speed. As the piston moves down, the pressure inl gas chambers 24 will increase, thus storing up additional energy for raising the piston 27 on the next -upstroke thereof. As the piston 27 reaches its lowermost position, control valve 39 is operated to pressure one side of spool valve 37 and shift the valve to a position at which line 35 is closed off, and the top of the cylinder is vented to permit a repetition of the cycle just described.

As the Well is unloaded, the gas pressure in the well will increase. When this increases to a selected value, the force exerted by this pressure ou diaphragm 67 will be suciently greater than that exerted through port 56 to overcome the friction of the valve and detent 61 and shift the valve 46 to closed position. This permits the system to go on standby until such time as the liquid level in the well has increased to a point where it again needs unloading, at which time the above described cycle will be repeated.

If it is desired to close in the well for any purpose, the system may be placed on idle to prevent accumulations of sand, etc. from freezing the pump. This may be accomplished by closing the throttle valve 60 to a point at which only sufcient gas is metered through the valve to provide for very low frequency operation of the pump. During this time the regulator valve 34 will normally be full open due to the reduced pressure conditions in the main gas chambers 24.

It will be still further appreciated that when the flow of gas is restricted by throttle valve 60 the pressure -beyond that point will be reduced. This reduction will be lower than the setting of regulator valve 58. This will cause the pressure on both ends of sensing valve 46 to be equal. Since each end of sensing valve 46 contains a diaphragm and they are of unequal area, the larger size diaphragm will override the smaller size and cause the .sensing valve 46 to remain in an open position. This in effect bypasses the sensing valve.

It will be appreciated that while the pump piston 27 is directly connected to the polish rod 19, that this construction is not necessary. The conventional walking beam might be interspersed between the pump and polish rod and the pump utilized to rock the walking beam.

It will further be appreciated that the use of pressure on both sides of the diaphragm `53 is not absolutely necessary, as the force provided -by gas at inlet 56 could be provided by any desired resilient means.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and materials, as Well as in the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

What -is claimed is:

1. Pumping apparatus comprising,

a closed cylinder,

a piston reciprocal in said cylinder,

a connecting rod attached to the piston and extending outside of said cylinder,

a main gas chamber having a gas inlet,

firsty regulator valve means controlling said inlet and connectable to a source of duid under pressure and providing for selection of a desired pressure downstream thereof and preventing backllow of uid therethrough, I

means establishing fluid communication between said chamber and -one end of said cylinder, means connecting the main gas chamber to the other end of said cylinder, said connecting means including a second regulator valve means providing a pressure differential thereacross to control the pressure available to the other end of said cylinder, and

means responsive to reciprocation of said piston for alternately interrupting and providing for ow of fluid through said connecting means and alternately releasing fluid from and preventing release of fluid from said other end of said cylinder.

2. Pumping apparatus comprising,

a closed cylinder,

a piston reciprocal in said cylinder,

a connecting rod attached -to the piston and extending outside of said cylinder,

a main gas chamber having a gas inlet,

a shut-off valve controlling flow through Said inlet,

a pressure operated motor means for said shut-oit valve opening said shut-olf valve when pressure at the inlet of said shut-off valve is less than a selected value and closing said shut-off valve when said pressure is more than a selected value,

first regulator valve means also controlling flow through said inlet and providing for selection of a desired pressure downstream thereof and preventing backow of fluid therethrough,

means establishing uid communication between said chamber and one end of said cylinder,

means connecting the main gas chamber to the other end of said chamber, said connecting means including a second regulator valve means providing a pressure differential thereacross to control the pressure available to the other end of said cylinder, and

means responsive to reciprocation of said piston for alternately interrupting and providing for ow of fluid through said connecting means and alternately releasing -uid from and preventing release of fluid from said other end of said cylinder.

3. Pumping apparatus comprising,

a closed cylinder,

a piston reciprocal in said cylinder,

a connecting rod attached to the piston and extending outside of said cylinder,

a main gas chamber having a gas inlet,

rst regulator valve means controlling said inlet and connectable to a source of fluid under pressure and providing for selection of a desired pressure downstream thereof and preventing backow of uid therethrough,

means establishing fluid communication between said chamber and one end of said cylinder,

means connecting the main gas chamber to the other end of said cylinder, said connecting means including a second regulator valve means providing a pressure differential thereacross to control the pressure available to the other end of said cylinder,

means responsive to reciprocation of said piston for alternately interrupting and providing for flow of fluid through said connecting means and alternately releasing fluid from and preventing release of fluid from said other end of said cylinder, and

a needle valve controlling flow through said inlet and controlling speed of operation of the pumping apparatus by controlling lthe volume of gas passing therethrough.

4. Pumping apparatus comprising,

a closed cylinder,

a piston reciprocal in said cylinder,

a connecting rod attached to the piston and extending outside of said cylinder,

a main gas chamber having a gas inlet,

a shut-olf valve controlling ow through said inlet,

a pressure operated motor means for said shut-off valve opening said shut-oit valve when pressure at the inlet of said shut-off valve is less than a selected value and closing said shut-olf valve when said pressure is more than a selected value,

first regulator valve means also controlling ow through said inlet and providing for selection of a desired pressure downstream thereof and preventing backow of tluid therethrough,

means connecting the main gas chamber to -the other end of said cylinder, said connecting means including a second regulator valve means providing a pressure differential thereacross to control the pressure available to the other end of said cylinder,

means responsive to reciprocation of said piston for alternately interrupting and providing for flow of uid through said connecting means and alternately releasing fluid from and preventing release of fluid from said other end of said cylinder, and

a needle valve also controlling flow through said inlet and controlling speed of operation of the pumping 7 apparatus by controlling the volume of gas passing therethrough.

References Cited by the Examiner UNITED STATES PATENTS Lang 91-279 856,709 6/07 2,045,945 6/36 Carr 103-45 2,366,777 1/45 Farley 91-321 2,466,375 4/49 Carbon 91-446 2,490,323 12/49 Pounds 60 52 2,612,142 9/52 Smith 60-52 3,032,065 5/62 Jolley 91-446 References Cited by the Applicant UNITED STATES PATENTS Hubbard. Lower. Habenicht. Kowalski et al. White. Vincent.

Exam z'ners.

Claims

1. PUMPING APPARATUS COMPRISING, A CLOSED CYLINDER, A PISTON RECIPROCAL IN SAID CYLINDRICAL, A CONNECTING ROD ATTACHED TO THE PISTON AND EXTENDING OUTSIDE OF SAID CYLINDER, A MAIN GAS CHAMBER HAVING A GAS INLET, FIRST REGULATOR VALVE MEANS CONTROLLING SAID INLET AND CONNECTABLE TO A SOURCE OF FLUID UNDER PRESSURE AND PROVIDING FOR SELECTION OF A DESIRED PRESSURE DOWNSTREAM THEREOF AND PREVENTING BACKFLOW OF FLUID THERETHROUGH, MEANS ESTABLISHING FLUID COMMUNICATION BETWEEN SAID CHAMBER AND ONE END OF SAID CYLINDER,