Title:
HYDRAULIC WELL PUMPING METHOD
United States Patent 3627048


Abstract:
Method for operating a downhole hydraulic well pumping system. One aspect of the invention is directed to a method for injecting spent power fluid into a lower or upper stratum of the ground while extracting energy from the power fluid in order to pump oil from another stratum to the surface of the ground. This expedient enables the spent power fluid to be advantageously used as a water flooding agent, and further enables chemical treatment of the upper or lower stratum to be carried out by utilizing the spent power fluid as the vehicle for transporting the chemical into the stratum. The associated apparatus comprehends a new combination of a production unit having a piston and control valve assembly which forms an engine for actuating a downhole pump. The piston and control valve assembly cooperates with the downhole pump motor in a manner to enable spent power fluid from the engine to be injected through a standing valve assembly into a stratum located below or above the producing formation.



Inventors:
ROEDER GEORGE K
Application Number:
05/041887
Publication Date:
12/14/1971
Filing Date:
06/01/1970
Assignee:
GEORGE K. ROEDER
Primary Class:
Other Classes:
166/268
International Classes:
E21B43/00; E21B43/14; E21B43/16; (IPC1-7): E21B43/16
Field of Search:
166/268,35R,35D,313,314,54.1,68,101,105,106 299
View Patent Images:



Primary Examiner:
Calvert, Ian A.
Parent Case Data:


REFERENCE TO RELATED APPLICATION

Ser. No. 733,954; filed June 3, 1968, and now U.S. Pat. No. 3,517,741, for "HYDRAULIC WELL PUMPING SYSTEM," of which this application is a "division" of.
Claims:
I claim

1. In a borehole which penetrates two different zones, at least one of which is fluid bearing, wherein the borehole has disposed therein a fluid actuated downhole pump assembly, said pump assembly including a motor and a production pump, said production pump lifts produced fluid from a fluid producing zone to the surface of the ground, the method of producing fluid from a first of said zones which is fluid bearing while simultaneously treating a second of said zones, comprising the steps of:

2. flow connecting the motor of said fluid actuated downhole pump assembly to a source of power fluid wherein the power fluid source is located uphole of the two zones;

3. flow connecting the spent power fluid from said motor to said second of said zones;

4. flow connecting the produced fluid from the first of said zones to the production pump of said pump assembly; and

5. isolating the first zone from the second zone to prevent production fluid from flowing from one to the other.

6. The method of claim 1 and further including the step of using water as the source of power fluid in order to water flood said second zone.

7. The method of claim 1, and further including the step of incorporating a treating chemical into the power fluid in order to subject said second zone to chemical treatment.

8. The method of claim 1 and further including carrying out step (4) by pacing a packer means between the first and second zone so as to isolate each zone from one another; and carrying out step (2) by flow connecting the spent power fluid from the downhole pump, through the packer means, and to the recited second zone.

9. The method of claim 4, and further including the step of including means by which each recited zone is isolated from one another upon removal of the pump.

10. A method of producing fluid from a first fluid-bearing stratum of a well simultaneously injecting fluid into a second stratum penetrated by the well wherein a downhole fluid actuated pump lifts the produced fluid from the first stratum to the surface of the earth; comprising the steps of:

11. isolating the first stratum from the second stratum by using a packer means;

12. flow connecting a power fluid source to the fluid actuated pump;

13. flow connecting the spent power fluid from the fluid actuated pump through the packer means and into the second stratum.

14. The method of claim 6, and further including the step of using water as the power fluid source in order to water flood said second stratum.

15. The method of claim 6 and further including the step of using a treating chemical as the power fluid source in order to subject said second stratum to chemical treatment.

16. The method of claim 6, and further including the step of including means by which each recited stratum is isolated from one another upon removal of the pump.

17. The method of claim 6, and further including the step of injecting a treating agent into the power fluid when it is desired to treat the second stratum with said treating agent.

Description:
BACKGROUND OF THE INVENTION

Various fluid operated deep well pumps, sometime called hydraulic oil well pumping or production units, are known to those skilled in the art. The production units generally include a valve system which receives power fluid from a pump located above the surface of the ground and which controllably supplies the power fluid to an engine. The engine reciprocates a piston rod which in turn actuates a fluid pump. The spent power fluid is generally comingled with the production fluid and forced to return to the surface of the ground by the action of the pump. Various prior art control valve and engine assemblies have proven successful for use in deep wells.

In the production of oil and other fluids from deep wells having multiple producing formations, it may be desirable to dispose of either fresh or salt water which is sometime produced along with oil. The disposal of this salt water is often costly. On the other hand, in water flooding programs and the like, it may be necessary to provide a source of water in order to flood various oil producing stratum with a low cost disposable fluid. Under these circumstances it may be necessary to purchase the water since its use in a controlled program results in an economic gain in the form of increased production. An advantageous expedient recognized by the oil industry is the injection of gases, steam, salt or fresh water, as well as other treating chemicals in order to produce various oil strata.

SUMMARY OF THE INVENTION

The present invention comprehends a method for transferring spent power fluid from a downhole pump associated with a production formation into a water flood zone. The spent power fluid includes oil or water which is eliminated from a downhole pump in producing oil from an oil production stratum. The water flood zone or stratum may be located either above or below the production formation. In exemplifying the present invention, a standing valve assembly is used in conjunction with other apparatus as an illustration. The valve is placed in communication with a production formation with the valve assembly being separated from the water flood zone and the production formation by means of a packer. The valve cooperates with a hydraulic oil well production unit and includes telescopingly arranged parts having passageways therein which normally permit the flow of produced oil through the valve and into the pump of the production unit where the pump lifts the produced oil to the surface of the earth. Simultaneously, the valve permits the spent power fluid from the engine to flow into a water flood zone, thereby precluding comingling of the spent power fluid with the produced oil as well as preventing commingling of the water flood zone with the production zone. The valve is selectively shifted to a shut off nonproducing position in order to enable removal of the bottom hole production unit while precluding commingling of the two formations. In this latter position, the telescoping coacting parts of the standing valve assembly precludes the flow of fluid between the production formation and the water flood zone to thereby enable replacement of the bottom hole pump as well as to make possible the chemical treatment of either zone and to permit bottom hole pressure testing of either zone to be carried out separately from one another.

Alternatively, the pumping system could include the before mentioned standing valve in combination with a production unit having a piston and control valve which unitizes the valve assembly and motor into a single reciprocating piston and control valve arrangement. The piston and control valve which forms the engine and valve assembly includes a hollow connecting rod reciprocatingly attached to the piston of a conventional double acting oil production pump. The hollow rod continues from the engine, through the pump, and into fluid communication with the standing valve by means of an isolation tube and stinger pipe. Production fluid from the standing valve flows about an annulus formed between the stinger tube and the standing valve and into the pump unit, while the spent power fluid flows through the stinger tube and through a series of passageways provided within the standing valve to where it is ultimately dissipated into a water flood zone, or the like.

It is therefore an object of the present invention to provide a method of utilizing the spent power fluid from a bottom hole production unit for water flood control.

Another object of the present invention is to provide a method of exhausting spent power fluid from a bottom hole production unit without using a closed power fluid system to prevent commingling the production fluid and the spent power fluid.

A further object of the present invention is to provide a method of utilizing water which is produced along with oil from one formation as the power fluid for actuating a bottom hole pump as well as using the spent power fluid for a water flood agent in another stratum.

A still further object of the present invention is the provision of a method for utilizing spent power fluid from a down hole production unit in order to treat another production zone.

Another object of the present invention is the provision of an improved method for a bottomhole pumping system which includes a production unit comprised of the combination which includes a piston and control valve integrated into a single moving unit, and which provides an engine which reciprocates a pump, with the spent power fluid from the engine being controllably flowed into a disposal zone of the well by means of an improved standing valve assembly.

These and other objects of the present invention will become readily apparent to those skilled in the art upon reading the following detailed description and by referring to the accompanying drawings.

The above objects are attained in accordance with the present invention by the provision of a method which is carried out essentially as set forth in the above abstract.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are fragmentary vertical cross-sectional views illustrating the hydraulic well pumping system of the present invention;

FIG. 2 is an enlarged vertical cross-sectional view showing a portion of the device seen in FIGS. 1A and 1B;

FIG. 3 is a fragmentary vertical cross-sectional view of part of the device seen in FIG. 2, but shown in a different operating position;

FIG. 4 is an enlarged fragmentary cross-sectional view of part of the device seen in the foregoing figures;

FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 2; and

FIG. 6 is a cross-sectional view taken along line 6--6 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Looking now to the details of the drawing, and in particular to FIGS. 1A and 1B, in conjunction with the remaining figures, there is seen an oil producing stratum 6, a water flood zone 7, a vertical borehole having a casing 8 coextensive herewith, and with a packer 9 separating the two strata from one another. The packer is attached to a foot 10 having power tubing 11 upwardly depending therefrom and with the hydraulic well pumping system being operatively connected to the piping and to the foot. Slidably located within the power tubing there is seen a portion of the hydraulic well pumping system which includes a production unit having an apertured nose 12 about which there is sealingly positioned spaced apart packers 14 located on the power fluid inlet 16. The inlet diverges into a circumferentially extending packer seal assembly 18 which is provided with a circumferentially extending groove having an O-ring 20 sealingly located therein. The O-ring is slidably received in close tolerance fitting relationship within an O-ring collar 22. The packer seal assembly is connected to a stroke chamber sub 24 which in turn is threadedly attached to a barrel, generally indicated by the numeral at 25. The stroke chamber sub forms a chamber 26 within which the terminal end of an input rod 28 reciprocates. The stroke chamber reduces in diameter into an input rod passageway 30 which includes a packing gland received within a counterbore 32 at the lower extremity thereof. The input rod is provided with a longitudinally extending hollow passageway 34 therethrough and is connected by inlet boss 36 to a novel piston and control valve arrangement generally illustrated by the arrow at numeral 40. The piston and control valve reciprocates within a cylinder formed internally of the barrel. The piston includes expansible metal sealing rings 38, 38' disposed at the upper and lower extremities thereof. The details of the piston and control valve will be discussed more fully later on.

From the piston a connecting rod extends downwardly from an outlet boss 41 in a manner as best seen at 42. The connecting rod interconnects the piston with a double acting pump 44. The details of the double acting pump are not set forth in detail, but generally the pump includes upstroke exhaust ports 45 and downstroke exhaust ports 46. Further details of the pump are not deemed necessary for a full comprehension of the invention since the design and construction of several such pumps are well known to those skilled in the art.

A hollow discharge rod extends from the lower extremity of the pump at 47 where it is slidably received in a reciprocative manner within an isolation tube 48 with the free end of the rod terminating therein. The pump inlet is in communication with the chamber formed between the outer peripheral wall surface of the isolation tube and the inside peripheral wall surface of the barrel.

A bottom plug 50 is threadedly attached to the lower end of the barrel and includes a multiplicity of longitudinally extending radially spaced apart drilled passageways 51. An isolation tube counterbore 54 sealingly receives the lower depending free end of the isolation tube in close fitting relationship therewith. About the isolation tube there is circumferentially disposed a groove having O-ring 52 fitted therein. The bottom plug includes a shoulder 56 which sealingly cooperates with the pump seat 56'. The isolation tube counterbore reduces in diameter and continues as the lowermost portion of the hydraulic pump unit, also called a stinger, as seen at numeral 60. The outside peripheral wall surface of the depending marginal end portion of the stinger is provided with O-ring seals 61 which are slidably received within the illustrated shoulder of the counterbore.

A standing valve assembly, generally indicated by the numeral 62 is slidably received within counterbore 64 of the foot and includes the before mentioned pump seat. The standing valve further includes a telescoped member 83 which is made integrally with and downwardly depending from the before mentioned pump seat, and which is telescopingly received within a main body member 70 thereby leaving an annular area 66 between the main body member and the foot. The main body member is comprised of a lower portion 68 which is screw threaded onto an upper portion 74 by means of threads 72. The two spaced apart enlargements are seen to be formed by members 74, 76 which cooperate to provide an annulus 78 therebetween. Enlargement 74 seats against the foot as seen at 80 while enlargement 76 is provided with seal means in the form of a circumferentially extending groove having an O-ring 82 therein. Pump seat 57 is provided with a lower hollow terminal end which is screw threaded at 84 into engagement with a similarly threaded plug 86. The lower extremity of the plug includes biasing means 88 which biases the telescoped pump seat member in an upward direction. Cavity flow passageway 90 communicates with ports 92, 93 and with chamber 94; while port 96 located within the foot communicates with annulus 78, ports 97, 98, 51, and annulus 100 when the valve is in the operative position. Port 99 is flow connected to port 99' which flow communicates the stinger with the lower formation by means of counterbore 64.

Cavity flow passageway 90 also communicates with passageway 101 which is flow connected to the production tubing 102 and which carries production fluid from formation 6 to the surface of the ground.

Looking more particularly to the details of the integrated or unitized piston and control valve 40 (which is shown in greater detail in FIGS. 2 and 3) there is seen the before mentioned hollow input rod 28 and upper boss 36 at the uppermost portion of the figures. The boss has a shoulder near numeral 104 which abuts the uppermost face of the piston 40. O-rings 106 seal the downwardly projecting portion of the boss which is received within counterbore 108 of the uppermost portion 110 of the piston. The threaded connection 112 rigidly affixes the boss of the cylinder. The lowermost end of the boss forms a valve seat 114 at the lower extremity of the passageway 116. Radially extending passageways 118 provide fluid flow ingo drilled passageway 120.

The longitudinally extending drilled passageways 122 connect the chamber formed within the barrel above the piston to radial passageways 124. Second radial passageways 126 flow connect to the longitudinally extending passageways 128 by means of the chamber formed within the small cylinder 130. Piston 132 has a lower portion in the form of a Maltese Cross having radiating guides or fins 134 thereon which are slidably received in close fitting relationship within the small cylinder 130. The head 136 of the small piston seats against valve seat member 114. The lower extremity of the Maltese Cross at 138 freely abuts against the uppermost face of intermediate piston 140. Piston 140 includes an upper portion 142, lower portion 144, connected together by a reduced diameter portion which leaves an annulus 146 therebetween. Piston 132 and 140 could be made into a single member, however this particular construction is preferred since many alignment problems are eliminated by the illustrated construction.

Intermediate piston 140 reciprocates within intermediate cylinder 148 while the upper or small piston 132 reciprocates within the small cylinder 130, with each piston coacting together in a reciprocating manner as a single unit. Radial passageway 150 is fluid connected to outlet 151 by means of longitudinal passageway 152. Lower boss 154 is threadedly attached at 154' to the main body of the piston. Radial ports 158 and 160 are provided in the boss. A counterbore receives the lower boss in a manner similar to the upper boss 36. A drilled passageway 162 extends longitudinally through the piston and reciprocatingly receives pilot valve 164 therein. The pilot valve includes upper reduced terminal end 166, enlarged upper portion 168, spiral undercut 170, reduced diameter portion 172, lower enlarged portion 173, reduced diameter portion 174, and lower terminal end 167. As seen at 166, one terminal end of the pilot valve always protrudes from the piston and alternately engages or impacts against the packing gland 32 (FIG. 1), or the packing gland of the motor (not shown).

OPERATION

In operation the engine (i.e., the combination piston and valve means) and pump are assembled into the illustrated production unit which is used in a system of the parallel free type. The production unit can also be used in a multiplicity of other systems. The entire production unit can be circulated into and out of the piping 11 by controlling the direction of flow through the piping and the production return line 102. With the flow of power fluid being in a downward direction through the piping 11, and the production unit assembled into a unitary apparatus with the unit being placed within the piping in the illustrated manner of FIGS. 1A and 1B, the bottom plug seats within the pump seat 57 of the standing valve, with mutual contact being attained therebetween at 56. Power fluid flows down through the piping and into the apertured nose, through the packer seal assembly, and into the stroke chamber. The O-ring collar prevents power fluid from flowing externally between the unit and the piping. The flow must therefore continue through the uppermost portion of the reciprocating hollow input rod 28 and into the piston and control valve assembly, where the power fluid reciprocatingly actuates piston 40 within the polished portion of the barrel.

In operation of the combination piston and control valve, and as particularly seen in FIG. 2, the power fluid enters upper boss 36 where the main flow continues through radial passageway 118, longitudinal passageway 120, into the annulus 146, and through outlet 151 where the power fluid exerts a force upon the bottom of the piston to thereby force the piston in an upward direction within the barrel 25. Upper and lower rings 38 and 38' prevent escape of fluid between the piston and barrel. Flow of fluid through passageway 178, about the annulus formed by the reduced diameter portion of the pilot valve at 172, and into the area below piston portion 144 exerts an upward pressure upon the piston 140. Noting the difference in area of intermediate piston at 144 and small piston at 136, it is seen that the area of piston 144 with respect to piston 136 is unequal and accordingly the small piston 132 is maintained forceably seated against valve seat 114. The contoured valve portion 136 of the small piston together with the cooperative action between small cylinder 130 and the upper cylindrical portion of the piston prevents escape of fluid therethrough. This cooperative action between the recited elements provides a double seal.

As the piston 40 travels in an upward direction in order to assume the illustrated position of FIG. 2, the fluid within chamber 33 must escape to allow movement of the piston into the upper portion of the cylinder as the piston travels toward packing gland 32. This is accomplished by the provision of passageways 122 which are interconnected to passageways 128 by means of radial passageways 124, 126, and to the free portion of cylinder 130 (i.e., between the elements or fins of the Maltese Cross) in order to permit the flow of fluid through radial passageway 160 and through the hollow connecting rod 42. As the piston travels in this manner in an upward direction, it reaches its limit of travel (FIG. 2) whereupon the upper terminal end of the pilot valve at 166 contacts the packing gland 32 to thereby drive the pilot valve in a downward direction to the position illustrated in FIG. 3.

Looking now to the details of FIG. 3 in conjunction with FIGS. 1 and 2, and in order to explain the action of the engine valve system on the downstroke, those skilled in the art will now realize that power fluid from the hollow passageway 34 flows against small piston 132 thereby driving it in a downward direction along with the intermediate piston 140 within the cylinder 148 until the lowermost portion 144 of the piston abuts member 154. This action brings the device into the configuration of FIG. 3 and permits the flow of fluid to occur through passageway 124, 122, whereupon the fluid pressure is exerted against the upper face of the piston thereby driving the main piston 40 in a downward direction where the piston assumes the position of FIG. 3. Fluid located below the main piston and above the seal pack-off liner (not shown but located in the area generally indicated by numeral 142) must exhause therefrom in order to enable the piston to travel downwardly within the barrel. This is accomplished by the provision of passageway 152 which permits fluid flow into the cylinder 130, through radial passageway 126, longitudinal passageway 128, radial passageway 160, and through the hollow connecting rod 42, where the fluid ultimately reaches the isolation tube. The combination piston and control valve, or engine, continues to reciprocate in this manner so long as a power source is supplied to the engine and valve assembly, and so long as the outlet 42 is at a sufficiently reduced pressure with respect to the fluid in passageway 34.

Connecting rod 42 reciprocatingly actuates the double acting pump 44 with the pump inlet being in communication with the annulus provided between the isolation tube 48 and the barrel. Pump outlets 45 and 46 deliver fluid in a downward direction into annulus 90, up through passageway 101, and into the production tubing 102 where the fluid is forced to ground level. The spent power fluid from hollow connecting rod 42 flows through central passageways located in the pump where it exits at the depending terminal end of the hollow discharge rod as seen at 47 in FIG. 1B. Since the isolation tube 48 is sealed within counterbore 54 of the bottom plug 50 the fluid must continue to flow through the lower hollow depending end of the plug and through the stinger as seen at 58, whereupon the fluid then flows through radial passageways 99 and 99', into the annulus between the main body member and the foot at 66, to where the spent power fluid then flows through the perforations 7' below the packer 9 and into the water flood zone 7.

Still looking to the details of FIGS. 1A and 1B it will now be realized that production fluid from formation 6 flows into the perforations 6' to provide a production fluid level 141 within the casing 8. The production fluid enters the foot through radial passageway 96 where the fluid flows through annulus 78, through radial ports 97, 98 and into the annulus about the lower depending end of the stinger where the fluid is then free to flow upwardly through the spaced apart radial production fluid inlet passageways 51 and into the barrel of the pump.

When it is desired to retrieve the production unit, the power fluid flow is discontinued and circulation is reversed by applying a positive pressure upon the production return line. This action simultaneously forces the production unit and the pump seat of the free standing valve in an upward direction whereupon the unit is then forced from the pump seat and to the ground level as fluid is pumped through the production return line. It will be noted that the pump seat follows the pump for a limited distance when fluid pressure is exerted through radial passageway 92, longitudinal passageway 93, and into the chamber 94. This action is due to the difference in area of the pump which is exposed to the fluid pressure from production line 102, which forces telescoping member 57 to move upward with respect to the main body member 74 thereby misaligning ports 97 with respect to ports 98 and misaligning ports 99 with respect to ports 99'. Spring 88 assures the continued misalignment of the ports to thereby preclude comingling of liquid from the water flood zone 7 with fluid from the production zone 6. When the production unit is pumped back into operative position, the lowermost depending end portion, or stinger, of the plug again enters the pump seat thereby forcing the standing valve back into the open position of FIG. 1B.

The free standing valve of the present invention also permits either or both zones 6 and/or 7 to be simultaneously treated with various chemicals while using an isolation tool and while the production unit is removed from the piping. This operation is best carried out by positioning an isolation tool onto the standing valve in order to expose the zone to be treated while blocking off the remaining zone. When the treatment has been accomplished, the isolation tool is pumped out of the hole. As the tool is pumped from the hole, the standing valve will shift to the closed position prior to the tool leaving the valve seat, in accordance with the previously described operation of the valve in conjunction with the pump.

It is contemplated to use the present invention in combination with various operations other than oil production. In sulfur production, for example, superheated water can be used as the power fluid with the spent power fluid being injected below the molten sulfur in order to place additional sulfur into solution. Accordingly, the use of water as the power fluid in order to produce oil from an oil bearing formation should be considered as one of many exemplifications of the present invention.

The foregoing is considered as illustrative only of the principles of the invention.