CN208564927U - Hydraulic piston pump, downhole pump unit and downhole drainage test system - Google Patents

Abstract

The present application discloses a hydraulic piston pump, a downhole pump unit and a downhole drainage test system. The hydraulic piston pump includes a pump seat and a pump core seated in the pump seat; the pump core includes a lower piston cylinder, an upper piston cylinder, The reversing short joint, the reversing valve, the hollow connecting rod piston group and the lower joint fixed on the bottom end of the lower piston cylinder are located between the upper piston cylinder and the lower piston cylinder; the top end of the upper piston cylinder is provided with a conversion joint. The technical solution of the present application can separate the power fluid from the formation fluid, and can realize downhole shut-in and heavy oil heating.

Description

Hydraulic piston pump, downhole pump unit and downhole drainage test system

technical field

The present disclosure generally relates to the technical field of oil testing and testing of oil wells, and in particular relates to a hydraulic piston pump, a downhole pump unit and a downhole liquid discharge testing system adopting hydraulic drive and closed circulation.

Background technique

At present, in the field of oil and gas well testing and testing technology, hydraulic pump drainage or screw pump drainage is often used for formation drainage, among which hydraulic pumps mainly include hydraulic jet pumps and hydraulic piston pumps.

At present, the commonly used hydraulic pump, whether it is a jet pump or a piston pump, works by putting the pump core in the working string. The working string should at least consist of oil pipes, pump bases and packers from top to bottom. The pump core is sent to the downhole pump seat through the surface pump, and then the pump pressure is increased to drive the downhole pump to work, and the formation fluid and power fluid are returned from the annular space between the tubing and the casing (referred to as the oil-casing annulus) On the ground, after being separated and measured on the ground, a part of the mixed liquid is separated and used as a power fluid to be pumped into the well to drive the downhole pump to work. When starting the pump, the liquid is pumped from the oil-sleeve annulus, returned from the working oil pipe, and the pump core is flushed out of the wellhead. That is to say, the pump is discharged side by side in the positive circulation, and the pump is started in the reverse circulation. This working method is very simple and convenient, so it has been widely used. However, their common disadvantage is that the formation fluid and the power fluid are mixed together and discharged, which makes it difficult to judge the true fluidity of the formation fluid.

The screw pump can obtain pure formation fluid, but due to the torque limitation of the sucker rod and the leakage of the dynamic seal between the screw and the pump barrel, its lifting capacity is limited, and the pressure difference generally does not exceed 10MPa. In addition, the application of thermal recovery of heavy oil also has great limitations.

The hydraulic piston pump can separate the power fluid from the formation fluid, that is, the power fluid is closed in a closed cycle. In order to separate the power fluid from the formation fluid, another circulation channel must be provided for the power fluid. The usual practice is to place a layer of small oil pipes in the large oil pipe to form a concentric pipe string. When the liquid is drained, the piston pump core is put into the small oil pipe and pumped into the seat, and the piston group in the pump core is continuously boosted to drive the reciprocating motion of the piston group. After that, the spent motive fluid returns to the ground from the annular space between the small oil pipe and the large oil pipe, forming a closed cycle of motive fluid. The formation fluid is discharged to the surface from the annular space between the large tubing and the casing. When starting the pump, the pump core can be flushed out of the wellhead by pumping liquid from the annular space between the small oil pipe and the large oil pipe. For example, an article published in the 7th issue of "Petroleum Machinery" magazine in 2002 " Development and Application of Concentric String Closed Hydraulic Piston Pump".

The above-mentioned concentric tubular closed hydraulic piston pump is mainly used in the oil production process. To be used for oil test and test drainage, there are mainly the following problems:

One is to start the pump core from the center tube, which is bound to require a sufficient inner diameter of the center tube. If the inner diameter is too small, the pump core will be smaller, which not only increases the processing difficulty of the pump core, but also increases the fluid discharge volume. decrease. If working in a 5 ^1/2 ″ casing, the center pipe can only use a maximum of _{2 3/8} ^″ oil pipe (inner diameter 50.8mm), and the outer pipe can only use a maximum of ₃ ^1/2 ″ oil pipe (inner diameter 76mm). The maximum outer diameter cannot exceed 50mm. In this way, the most commonly used ₂ ^7/8 ″ tubing for ₅ ^1/2 ″ casing operations cannot be used, and all operating tubing needs to be replaced, which is costly and has poor versatility.

Second, there is a layer of depleted motive fluid channel between the motive fluid channel and the formation fluid channel. In case of heavy oil, the thermal energy of heating the motive fluid cannot directly act on the heavy oil to melt it. That is to say, the formation fluid channel and the power fluid channel are not in close proximity, which is not conducive to the realization of thermal recovery of heavy oil.

Third, the pump core itself cannot realize downhole shut-in and has no testing function.

SUMMARY OF THE INVENTION

In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a hydraulic piston pump, downhole pump capable of separating power fluid from formation fluid, large pump core displacement, low cost, convenient downhole shut-in and heavy oil heating. Pump unit and downhole drainage test system.

In a first aspect, the present application provides a hydraulic piston pump, comprising a pump seat and a pump core seated in the pump seat; the pump core of the hydraulic piston pump includes a lower piston cylinder, an upper piston cylinder, a The reversing short joint between the piston cylinders, the reversing valve, the hollow connecting rod piston group and the lower joint fixed at the bottom end of the lower piston cylinder; the top end of the upper piston cylinder is provided with a conversion joint;

The hollow connecting rod-piston group includes a hollow connecting rod passing through the short reversing joint, and an upper piston and a lower piston which are connected to both ends of the hollow connecting rod and are respectively matched with the upper piston cylinder and the lower piston cylinder in dynamic sealing; the Both the upper piston and the lower piston are hollow structures with up and down transparent; the inner lower end of the conversion joint is provided with a fixed valve; the lower joint is provided with a related well valve; the upper piston is provided with a traveling valve;

The reversing valve is slidably arranged between the short reversing joint and the hollow connecting rod.

According to the technical solutions provided in the embodiments of the present application, the reversing valve is located in the reversing cavity between the short reversing joint and the hollow connecting rod, and the reversing cavity is radially divided into a power fluid cavity and a depleted power liquid cavity The upper part of the reversing short joint is provided with a motive fluid inlet for introducing the motive fluid flowing between the pump seat and the pump core into the motive fluid chamber.

According to the technical solutions provided by the embodiments of the present application, the pump seat includes an outer cylinder, and the middle part of the outer cylinder is provided with an outer cylinder circulation hole; The inlet of the upper piston chamber in the cylinder, the exhaust port of the exhausted power fluid connected to the circulation hole of the outer cylinder, and the inlet of the lower piston chamber in the lower piston cylinder; the middle part of the reversing valve is radially provided with a reversing port; When the reversing valve is located at its lower limit point, the inlet of the upper piston chamber is directly connected to the motive fluid chamber, and the exhaust port of the depleted fluid and the inlet of the lower piston chamber are communicated with the depleted fluid chamber at the same time; When the reversing valve is at its upper limit point, the inlet of the lower piston chamber is communicated with the motive fluid chamber through the reversing port, and the exhaust port of the depleted motive fluid and the inlet of the upper piston chamber are communicated with the depleted fluid chamber at the same time. ;

The bottom of the reversing chamber is close to the hollow connecting rod and protrudes upward with a valve core; the lower part of the reversing valve is inserted between the valve core and the reversing short joint; the bottom of the valve core and the reversing short joint There is a pressure transmission hole between them; the middle part of the valve core facing the side of the hollow connecting rod is provided with a diversion groove; the reversing short joint is provided with a pressure relief hole below the valve core that communicates with the outer cylinder circulation hole ; The upper side wall of the hollow connecting rod is provided with an upper reversing groove, and the lower part is provided with a pair of adjacent lower reversing grooves;

When the hollow connecting rod is at its lower limit position, the upper reversing groove communicates with the pressure relief hole and the pressure transmission hole at the same time;

When the hollow connecting rod is at its upper limit position, the convex part between the two lower reversing grooves corresponds to the guide groove, so that the pressure transmission hole and the power fluid chamber are guided Pass.

According to the technical solutions provided in the embodiments of the present application, a sliding sleeve is provided inside the outer cylinder; a pawl is fixed at the top of the sliding sleeve; a pawl groove for clamping the pawl is provided outside the pump core; the Above and below the sliding sleeve, the inner wall of the outer cylinder is respectively provided with an upper clamping platform for clamping the opened pawl and a lower step for supporting the bottom end of the sliding sleeve, the sliding sleeve and the outer cylinder are respectively provided with sliding The sleeve circulation hole and the outer cylinder circulation hole, the sliding sleeve circulation hole and the outer cylinder circulation hole are aligned when the sliding sleeve is at its bottom dead center position, and staggered when it is at its top dead center position.

In a second aspect, the present application provides a downhole pump unit, comprising an oil pipe, a packer, a hollow sucker rod and any one of the above-mentioned hydraulic piston pumps, wherein the oil pipe, the pump base and the packer constitute a A working string, the pump core and the hollow sucker rod connected to the top of the pump core constitute a drain string running into the working string; the packer is located below the pump seat.

According to the technical solutions provided in the embodiments of the present application, a pressure gauge is installed at the bottom end of the pump core.

According to the technical solutions provided in the embodiments of the present application, a sand control pipe is arranged below the packer.

According to the technical solutions provided in the embodiments of the present application, the conversion joint is sealingly connected to the pump base, and the conversion joint is used to introduce the power fluid entering the pump core from the hollow sucker rod into the pump core and the pump base. The annular space located under the adapter, and the formation fluid drawn from the pump core is discharged into the annular space located above the adapter between the pump core and the pump seat.

In a third aspect, the present application provides a downhole fluid drainage testing system, including any one of the above-mentioned downhole pump units, a power fluid circulation system and a formation fluid metering system; the power fluid circulation system includes providing the hollow sucker rod with A motive fluid injection pump, a motive fluid storage tank communicated with the annular cavity between the casing and the tubing; the formation fluid metering system includes a formation fluid storage tank communicated with the annular cavity between the hollow sucker rod and the tubing; The injection pump draws motive fluid from the motive fluid storage tank.

According to the technical solutions provided in the embodiments of the present application, a heating device is provided between the power fluid storage tank and the water injection pump.

In the present application, by setting the pump core as a double-acting pump, the hydraulic piston pump has high working efficiency and stable liquid discharge;

At the same time, in this application, the pump seat is connected with the oil pipe, packer, etc. to form a working pipe string, and the power fluid input channel is formed by only running one layer of oil pipe into the casing by directly connecting the hollow sucker rod with the pump core. , the closed circulation channel of the power fluid discharge channel and the formation fluid discharge channel; compared with the method of running the double-layer oil pipe in the casing in the prior art, the outer diameter of the pump core can be made larger, so that the discharge of the pump core can be made larger. Larger volume and less processing difficulty, thereby reducing the production cost of the pump core.

According to the technical solutions provided in the embodiments of the present application, the pump seat adopts a pawl-type sliding sleeve design to realize linkage with the pump core. The pawl of the pump shrinks and gets stuck in the pawl groove outside the pump core, so that the sliding sleeve is linked with the pump core until the bottom dead center; at this time, the circulation channel on the pump seat is opened, and the drainage function can be realized; That is, when the pump core is not in the pump seat, the pawl on the sliding sleeve is in an open state and the sliding sleeve is kept at the top dead center position through the upper clamping structure. At this time, the circulation channel on the pump seat is closed, and the pump seat has With full permeability and pressure bearing capacity, it can perform various operations on the formation, such as perforation, testing, acidizing, fracturing and other operations.

The liquid discharge test system of the present application also has a test function. After a period of liquid discharge, it is necessary to close the liquid production channel to measure the pressure recovery. The power fluid circulation channel can be closed, and then pressurized from the formation fluid channel to make the pump core The shut-in valve inside is in a reverse pressurized state and maintained. At this time, the shut-in valve acts as a plug to block the formation fluid channel to realize downhole shut-in, and the pressure gauge will record the pressure and temperature changes during the entire drainage test process. .

The liquid discharge test system of the present application is applied to heavy oil production by surrounding the formation fluid channel with the dynamic fluid channel and the depleted dynamic fluid channel, and the heavy oil can be heated by heating the dynamic fluid.

Description of drawings

Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

Fig. 1 is the structural representation of the hydraulic piston pump when the hollow connecting rod is at its bottom dead center position;

Fig. 2 is the structural representation of the hydraulic piston pump when the hollow connecting rod is at its top dead center position;

Fig. 3 is the structural schematic diagram of the reversing short joint when the hollow connecting rod is at its bottom dead center position;

Fig. 4 is the structural representation of the reversing short joint when the hollow connecting rod is at its top dead center position;

Fig. 5 is the structural representation of the hollow connecting rod-piston group in the present application;

Fig. 6 is the structural schematic diagram of the pump seat before the pump core is seated;

Fig. 7 is the structural schematic diagram of the pump seat after the pump core is seated;

Fig. 8 is the structural representation of the downhole pump unit of the present application;

Fig. 9 is the structural representation of the conversion joint at the top of the pump core;

FIG. 10 is a schematic structural diagram of the downhole fluid drainage testing system in the present application.

Labels in the figure:

10. Casing; 20. Operation string; 30. Drainage string; 40. Power fluid circulation system; 70. Tubing tee; 60. Tubing hanger;

21, pump seat; 22, oil pipe; 23, packer; 24, sliding sleeve; 25, pawl; 26, outer cylinder circulation hole; 27, sliding sleeve circulation hole; 28, outer cylinder; 31, pump core; 32 , hollow sucker rod; 33, pawl groove; 34, adapter; 35, pressure gauge; 41, water injection pump; 42, power fluid storage tank; 51, formation fluid storage tank;

31-2, upper piston cylinder; 31-3, lower piston cylinder; 31-4, hollow connecting rod; 31-5, reversing short joint; 31-6, reversing valve; 31-7, fixed valve; 31- 8. Shut-in valve; 31-9, traveling valve; 31-10, lower joint

34-1, upper cylindrical section; 34-2, lower cylindrical section; 34-3, connecting part; 34-4, first inclined port; 34-5, second inclined port;

31-4-1, upper reversing groove; 31-4-2, lower reversing groove; 31-4-3, upper piston; 31-4-4, lower piston;

31-5-1, Power fluid chamber; 31-5-2, Powerless liquid chamber; 31-5-3, Power fluid inlet; 31-5-4, Upper piston chamber inlet; 31-5-5, No power Liquid discharge port; 31-5-6, lower piston chamber inlet;

31-5-7, valve core; 31-5-8, pressure transmission hole; 31-5-9, pressure relief hole; 31-5-7-1, diversion groove;

31-6-1, reversing port.

Detailed ways

The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the related invention, but not to limit the invention. In addition, it should be noted that, for the convenience of description, only the parts related to the invention are shown in the drawings.

It should be noted that the embodiments in the present application and the features of the embodiments may be combined with each other in the case of no conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

1 and 2 are schematic structural diagrams of an embodiment of a hydraulic piston pump provided by the application, including a pump base 21 and a pump core 31 seated in the pump base 21; the pump core of the hydraulic piston pump 31 includes a lower piston cylinder 31-3, an upper piston cylinder 31-2, a reversing short joint 31-5 between the upper piston cylinder 31-2 and the lower piston cylinder 31-3, a reversing valve 31-6, a hollow connection a rod-piston group and a lower joint 31-10 fixed on the bottom end of the lower piston cylinder 31-3; a conversion joint 34 is installed on the top of the upper piston cylinder 31-2;

The hollow connecting rod-piston group includes a hollow connecting rod 31-4 passing through the short reversing joint 31-5, and a hollow connecting rod 31-4 connected to both ends of the hollow connecting rod 31-4 and connected to the upper piston cylinder 31-2 and the lower piston cylinder respectively. 31-3 The upper piston 31-4-3 and the lower piston 31-4-4 which are matched with the dynamic seal; the upper piston 31-4-3 and the lower piston 31-4-4 are both the upper and lower transparent hollow structures; A fixed valve 31-7 is arranged at the inner lower end of the conversion joint 34; a related well valve 31-8 is arranged in the lower joint 31-10; and a traveling valve 31-9 is arranged in the upper piston 31-4-3;

The reversing valve 31-6 is slidably disposed between the short reversing joint 31-5 and the hollow connecting rod 31-4.

Preferably, as shown in FIG. 3 and FIG. 4 , the reversing valve 31-6 is located in the reversing cavity between the short reversing joint 31-5 and the hollow connecting rod 31-4 and will change the diameter of the reversing cavity The direction is divided into a motive fluid chamber 31-5-1 and a depleted motive fluid chamber 31-5-2; the upper part of the reversing short joint 31-5 is provided with the motive fluid flowing between the pump base 21 and the pump core 31 Introduced into the motive fluid inlet 31-5-3 of the motive fluid chamber 31-5-1.

Preferably, the pump seat 21 includes an outer cylinder 28, and an outer cylinder circulation hole 26 is provided in the middle of the outer cylinder; the side walls of the reversing chamber are respectively provided with a connection to the upper piston cylinder 31-2 from top to bottom. The inner upper piston chamber inlet 31-5-4, the depleted power fluid discharge port 31-5-5 connected to the outer cylinder circulation hole 26, and the lower piston chamber inlet 31-5-6 connected to the lower piston cylinder 31-3 ; The middle of the reversing valve 31-6 is radially provided with a reversing port 31-6-1; when the reversing valve 31-6 is at its lower limit point, the upper piston chamber inlet 31-5- 4. It is directly connected to the motive fluid chamber 31-5-1, and the depleted motive fluid outlet 31-5-5 and the lower piston chamber inlet 31-5-6 are connected to the depleted fluid chamber 31-5-2 at the same time. When the reversing valve 31-6 is at its upper limit point, the lower piston chamber inlet 31-5-6 leads to the power fluid chamber 31-5-1 through the reversing port 31-6-1 the exhaust port 31-5-5 and the upper piston chamber inlet 31-5-4 are connected to the exhaust port 31-5-2 at the same time;

The bottom of the reversing chamber is close to the hollow connecting rod 31-4 and a valve core 31-5-7 protrudes upward; the lower part of the reversing valve 31-6 is inserted into the valve core 31-5-7 and the reversing short joint 31-5; a pressure transmission hole 31-5-8 is provided between the bottom of the valve core 31-5-7 and the reversing short joint 31-5; the valve core 31-5-7 faces A guide groove 31-5-7-1 is arranged in the middle of the side surface of the hollow connecting rod 31-4; the short reversing joint 31-5 is provided with a circulation hole with the outer cylinder below the valve core 31-5-7 26 connected pressure relief holes 31-5-9; as shown in Figure 5, the upper side wall of the hollow connecting rod 31-4 is provided with an upper reversing groove 31-4-1, and the lower part is provided with a pair of adjacent lower Reversing slot 31-4-2;

When the hollow connecting rod 31-4 is at its lower limit position, the upper reversing groove 31-4-1 communicates with the pressure relief hole 31-5-9 and the pressure transmission hole 31-5-8 at the same time;

When the hollow connecting rod 31-4 is at its upper limit position, the protruding part between the two lower reversing grooves 31-4-2 corresponds to the guide groove 31-5-7-1 , so that the pressure transmission hole 31-5-8 is connected to the power fluid chamber 31-5-1.

As shown in Figures 1 to 4, the power fluid pumped from the top of the pump core 31 enters the annular cavity between the pump core 31 and the pump base 21 through the adapter 34. Then enter into the motive fluid chamber 31-5-1 through the motive fluid inlet 31-5-3 of the reversing short joint 31-5 on the pump core 31;

As shown in FIG. 1 and FIG. 4 , when the reversing valve 31-6 is at the lower limit point, the upper piston chamber inlet 31-5-4 is directly communicated with the power fluid chamber 31-5-1, and the power The liquid enters the upper piston cylinder 31-2 through the upper piston chamber inlet 31-5-4, pushes the hollow connecting rod piston group to move upward, the pressure in the lower piston cylinder 31-3 decreases, and the downhole pressure pushes the shut-in valve 31- 8 is opened, and the formation fluid is sucked into the lower piston cylinder. At this time, due to the increase in the pressure in the formation fluid cavity of the upper piston cylinder 31-2, the floating valve 31-9 is closed, and the fixed valve 31-7 is opened. The formation fluid in the formation fluid cavity of the upper piston cylinder 31-2 is discharged from the fixed valve 31-7; at the same time, the depleted fluid outlet 31-5-5 and the lower piston chamber inlet 31-5-6 are simultaneously discharged with the depleted fluid. The cavity 31-5-2 is connected; the depleted motive fluid located in the lower piston cylinder 31-3 is discharged through the lower piston chamber inlet 31-5-6, the depleted fluid outlet 31-5-5 and the outer cylinder circulation hole 26 in sequence , into the annular space between the pump seat 21 and the casing 10 .

As shown in Fig. 2 and Fig. 3, when the hollow connecting rod piston group moves to the top dead center position, the convex part between the two lower reversing grooves 31-4-2 and the guide groove 31-4-2 5-7-1, so that the pressure transmission hole 31-5-8 is connected to the power fluid chamber 31-5-1, and the high-pressure power fluid simultaneously acts on the bottom of the reversing valve 31-6, pushing the Move the valve up to the upper limit position. At this time, the lower piston chamber inlet 31-5-6 is connected to the power fluid chamber 31-5-1 through the reversing port 31-6-1, and the power fluid enters through the lower piston chamber inlet 31-5-6 into the power fluid chamber of the lower piston cylinder 31-3, and push the hollow connecting rod piston group to move downward; at this time, the fixed valve 31-7 is closed, the floating valve 31-9 is opened, and the formation fluid passes through the center of the hollow connecting rod piston group The hole is drawn into the formation fluid chamber of the upper piston cylinder 31-2. At the same time, the depletion fluid outlet 31-5-5 and the upper piston chamber inlet 31-5-4 are connected to the depletion fluid chamber 31-5-2, and are located in the motive fluid chamber of the upper piston cylinder 31-2. The depleted fluid is discharged through the upper piston chamber inlet 31-5-4, the exhausted fluid outlet 31-5-5 and the outer cylinder circulation hole 26 in sequence, and enters the annular space between the pump base 21 and the casing 10.

Preferably, as shown in FIGS. 6 and 7 , the outer cylinder 28 of the pump seat 21 is provided with a sliding sleeve 24 ; the top end of the sliding sleeve 24 is fixed with a pawl 25 ; The pawl groove 33 for clamping the pawl 25; the inner wall of the outer cylinder 28 is provided with an upper clamping platform for clamping the opened pawl and a bottom for supporting the sliding sleeve 24 above and below the sliding sleeve 24 respectively. The sliding sleeve 24 and the outer cylinder 28 are respectively provided with a sliding sleeve circulation hole 27 and an outer cylinder circulation hole 26, and the sliding sleeve circulation hole 27 and the outer cylinder circulation hole 26 are located in the sliding sleeve 24 Aligned at the bottom dead center position and staggered at the top dead center position.

As shown in FIG. 6 , when the pump core 31 is not seated, the sliding sleeve 24 is at its top dead center position. At this time, the outer cylinder circulation hole 26 of the outer cylinder 28 and the sliding sleeve circulation hole 27 on the sliding sleeve 24 are staggered. 28 is closed, while the pawl 25 on the sliding sleeve 24 is in an open state to keep the sliding sleeve 24 in its top dead center position. As shown in FIG. 7 , when the pump core 31 is seated into the pump seat 21 along with the drain string 30 , the pawl 25 on the sliding sleeve 24 is aligned with the pawl groove 33 of the pump core 31 , and the sliding sleeve 24 is pushed by pressing When moving downward, the pawl 25 contracts, so that the sliding sleeve 24 is linked with the pump core 31 until the bottom end of the sliding sleeve 24 reaches its bottom dead center position. At this time, the outer cylinder circulation hole 26 on the outer cylinder 28 is aligned with the sliding sleeve circulation hole 27 on the sliding sleeve 24, and the circulation channel of the pump base 21 is opened.

When the pump core 31 is pulled out after the liquid discharge is completed, the top end of the liquid supply and discharge pipe string 30 is given upward lifting force. When the pump core 31 is seated, the pawl 25 on the sliding sleeve 24 in the pump seat 21 has contracted and is stuck in the pump core 31. The ratchet groove 33 outside the pump core 31 forms a linkage with the pump core, so when the pump core 31 is pulled out, the sliding sleeve 24 in the pump base 21 will also return to the upper clamping table position with the pump core 31, and then the pump core is released. 31, the pump core 31 is taken out, so that the circulation channels on the pump base 21 are synchronously closed. When the above-mentioned hydraulic piston pump is used in the downhole drainage, the full continuity and pressure bearing capacity of the working string 20 can be restored after the pump base 21 is opened, and any other operations can also be performed.

As shown in the schematic structural diagram of the underwater pump unit provided by the present application in FIG. 8 , the underwater pump unit includes an oil pipe 22, a packer 23, a hollow sucker rod 32 and any one of the above-mentioned hydraulic piston pumps. The oil pipe 22, the pump The seat 21 and the packer 23 form the operation string 20 run into the downhole casing 10 , and the pump core 31 and the hollow sucker rod 32 connected to the top of the pump core 31 form the exhaust rod 32 run into the work pipe string 20 . The liquid pipe string 30 ; the packer 23 is located below the pump base 21 . The upper and lower ends of the above-mentioned pump base 21 are respectively provided with female buckles and male buckles, so as to be connected with oil pipes or other downhole tools.

During field operations, first run the designed operation string 20 into the casing 10 of the construction wellbore in sequence, and set the packer 23 at a predetermined position downhole; Run down into the operation string 20 so that the pump core 31 sits in the pump seat 21; when the liquid is drained, the power fluid enters from the hollow sucker rod 32 to provide the pump core 31 with power for reciprocating motion, and the pump core 31 is pumped from the downhole The up-coming formation fluid is discharged from the annular space between the hollow sucker rod 32 and the oil pipe 22, and the depleted fluid of the pump core 31 is discharged from the annular space between the oil pipe 22 and the casing 10; A pressure gauge 35 is connected to the bottom end, and the pressure gauge 35 goes downhole along with the drainage string 30 to monitor pressure and temperature changes downhole at any time.

In the above embodiment, for example, the casing 10 is a ₅ ^1/2 " casing, and the oil pipe 32 is a commonly used ₂ ^7/8 " oil pipe with an inner diameter of 62 mm, then the outer diameter of the pump core in this embodiment can be 58-60 mm, The single-stroke displacement can be increased by about 50% compared with the 50mm concentric tubular column hydraulic piston pump.

In order to prevent the formation sand from entering the liquid production channel and adversely affect the drainage, a sand control pipe can be arranged below the packer 23 in the operation string 20 to prevent mechanical impurities such as formation sand from entering the operation string.

The above-mentioned power fluid can be made of clear water or by adding some lubricants to the clear water, and the preparation is very convenient and the cost is low.

Preferably, the conversion joint 34 is sealingly connected with the pump base 21 , and the conversion joint 34 is used to introduce the power fluid entering the pump core 31 from the hollow sucker rod 32 into the pump core 31 and the pump base 21 . The annular space located below the adapter 34 and the formation fluid drawn from the pump core 31 is discharged into the annular space located above the adapter 34 between the pump core 31 and the pump base 21 . As shown in FIG. 9 , the conversion joint 34 includes an upper cylindrical section 34-1, a lower cylindrical section 34-2, and a connecting portion 34-3 connecting the upper cylindrical section 34-1 and the lower cylindrical section 34-2; The connecting portion 34-3 protrudes outward and is sealingly connected to the pump seat 21, so that the annular space between the pump core 31 and the pump seat 21 is divided into two parts, upper and lower; the connecting portion 34-3 is provided with a first inclined port 34-4 and the second inclined port 34-5; the power fluid entering from the hollow sucker rod 32 is converted into the pump core 31 and the pump seat 21 through the first inclined port 34-4 and is located below the connecting part 34-3 The formation fluid extracted from the pump core 31 is discharged into the annular space above the connecting portion 34-3 between the pump core 31 and the pump base 21 through the second inclined port 34-5.

The fixed valve 31-7, the traveling valve 31-9 and the shut-in valve 31-8 are all one-way valves, and the formation fluid can only pass upward through the above one-way valve, but cannot pass downward; When moving upward, the floating valve 31-9 is closed, the fixed valve 31-7 is opened, and the formation fluid above the upper piston 31-4-3 is lifted above the fixed valve 31-7, thereby entering the hollow sucker rod 32 The annular space between the oil pipe and the oil pipe 22; when the hollow connecting rod piston group moves downward, the fixed valve 31-7 is closed, the traveling valve 31-9 is opened, and the formation fluid enters the upper piston through the traveling valve 31-9, so Repeatedly, the formation liquid can be continuously lifted to the surface, and the shut-in valve 31-8 is always open during the liquid discharge process.

As shown in FIG. 10 , as shown in the structural schematic diagram of the downhole liquid discharge test system provided by the present application, the downhole liquid discharge test system includes any one of the above-mentioned downhole pump units, a power fluid circulation system 40 and a formation fluid metering system; The fluid circulation system 40 includes a water injection pump 41 that provides motive fluid into the hollow sucker rod 32, and a motive fluid storage tank 42 that communicates with the annular cavity between the casing 10 and the oil pipe 22; the formation fluid metering system includes and The formation fluid storage tank 51 is connected to the annular cavity between the hollow sucker rod 32 and the oil pipe 22 ; the injection pump 41 extracts the motive fluid from the motive fluid storage tank 42 . Those skilled in the art know according to common sense that the above-mentioned downhole liquid drainage testing system is further provided with pipelines connecting various systems and components and valves installed on the pipelines.

During field operation, firstly run the designed operation string 20 into the construction wellbore in sequence, set the packer 23 at the predetermined position downhole, set the tubing hanger 60 and connect the tubing tee 70 . At this time, various operations can be performed on the target layer, such as perforating, acidizing, fracturing, etc.

When the liquid needs to be drained, the drain string 30 is lowered into the operation string 20 in sequence, and the pump core 21 is seated in the pump base 31, and the circulation channel on the pump base 31 is opened by pressing down the drain string 30. , and then connect the power fluid circulation system 40 and the formation fluid metering system. Then start the water injection pump 41, the power fluid is transported to the pump core 21 through the hollow sucker rod, and drives the hollow rod piston group in the pump core 21 to reciprocate, and the formation fluid passes through the annular space between the hollow sucker rod 32 and the oil pipe 22. Lift to the ground for separation and measurement. The spent motive fluid is returned to the motive fluid storage tank 42 through the annular space between the oil pipe 22 and the casing 10, and then enters the injection pump to be pressurized after being filtered to form a closed cycle of motive fluid, which drives the downhole pump piston group to keep reciprocating. , so that the formation fluid is continuously lifted to the ground.

When the well needs to be shut in, the shut-in valve 31-8 can be pressed from the liquid production channel to make the shut-in valve 31-8 in the reverse pressure state, so that the production liquid channel can be closed, thereby realizing the downhole shut-in, and the operation is very convenient.

Preferably, a heating device is provided between the motive fluid storage tank 42 and the injection pump 41; if it is a heavy oil well, a heating device is provided between the motive fluid storage tank 42 and the injection pump 41 in the motive fluid circulation system 40, for example The heating furnace heats the power fluid to a certain temperature and then pumps it into the well from the hollow sucker rod 32, so that the heat emitted by the hollow sucker rod 32 will directly melt the heavy oil, so that the liquid can be drained smoothly. The heating temperature of the power fluid should be able to melt the heavy oil.

The above description is only a preferred embodiment of the present application and an illustration of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solution formed by the specific combination of the above-mentioned technical features, and should also cover the above-mentioned technical features without departing from the inventive concept. Other technical solutions formed by any combination of its equivalent features. For example, a technical solution is formed by replacing the above features with the technical features disclosed in this application (but not limited to) with similar functions.

Claims (10)

1. a kind of hydraulic piston pump, which is characterized in that enter the pump core (31) in pump seat (21) including pump seat (21) and seat；It is described Pump core (31) includes lower piston cylinder (31-3), upper piston cylinder (31-2), is located at upper piston cylinder (31-2) and lower piston cylinder (31-3) Between commutation pipe nipple (31-5), reversal valve (31-6), hollow connecting rod piston group and be fixed on lower piston cylinder (31-3) bottom The lower contact (31-10) at end；The top of the upper piston cylinder (31-2) is equipped with crossover sub (34)；

The hollow connecting rod piston group include across it is described commutation pipe nipple (31-5) hollow connecting rod (31-4) and be connected to hollow The connecting rod both ends (31-4) and the upper piston (31-4- cooperated respectively with upper piston cylinder (31-2) and lower piston cylinder (31-3) dynamic sealing And lower piston (31-4-4) 3)；The upper piston (31-4-3) and lower piston (31-4-4) are transparent hollow structure； The interior lower end of the crossover sub (34) is provided with fixed valve (31-7)；Shut-in valve is equipped in the lower contact (31-10) (31-8)；Travelling valve (31-9) is equipped in the upper piston (31-4-3)；

The reversal valve (31-6), which can slide up and down to, to be arranged between the commutation pipe nipple (31-5) and hollow connecting rod (31-4).

2. hydraulic piston pump according to claim 1, it is characterised in that:

Commutation of the reversal valve (31-6) between commutation pipe nipple (31-5) and hollow connecting rod (31-4) is intracavitary and will The chamber radial separations that commutate are power sap cavity (31-5-1) and weary power sap cavity (31-5-2)；The top of commutation pipe nipple (31-5) It is provided with and enters the power fluid that the power fluid flowed between pump seat (21) and pump core (31) imported into power sap cavity (31-5-1) Mouth (31-5-3).

3. hydraulic piston pump according to claim 2, it is characterised in that:

The pump seat (21) includes outer cylinder (28), and the middle part of the outer cylinder (28) is equipped with outer cylinder circulation port (26)；The commutation chamber Side wall be respectively arranged with from top to bottom the upper piston chamber inlet (31-5-4) being communicated in upper piston cylinder (31-2), be communicated to it is outer The weary power fluid outlet (31-5-5) of cylinder circulation port (26), the lower piston chamber inlet (31- being communicated in lower piston cylinder (31-3) 5-6)；The middle part of the reversal valve (31-6) radially offers commutation mouth (31-6-1)；When the reversal valve (31-6) is located at it When lower limit site, the upper piston chamber inlet (31-5-4) is directly connected with the power sap cavity (31-5-1), the weary power Liquid outlet (31-5-5) and lower piston chamber inlet (31-5-6) are connected with weary power sap cavity (31-5-2) simultaneously；It is changed when described When to valve (31-6) limit point disposed thereon, the lower piston chamber inlet (31-5-6) passes through commutation mouth (31-6-1) and described dynamic Power sap cavity (31-5-1) conducting, the weary power fluid outlet (31-5-5) and upper piston chamber inlet (31-5-4) are moved with weary simultaneously Power sap cavity (31-5-2) conducting；

It is close to hollow connecting rod (31-4) and is extended with spool (31-5-7) upwards in the bottom of the commutation chamber；The reversal valve (31-6) Lower part insertion spool (31-5-7) with commutate pipe nipple (31-5) between；The bottom of the spool (31-5-7) and the commutation are short Pressure transmission hole (31-5-8) is provided between section (31-5)；The middle part of the spool (31-5-7) towards the side hollow connecting rod (31-4) It is provided with diversion trench (31-5-7-1)；The commutation pipe nipple (31-5) is provided with below the spool (31-5-7) and outer cylinder The relief hole (31-5-9) of circulation port (26) connection；The upper portion side wall of the hollow connecting rod (31-4) is provided with reversing groove (31-4- 1), lower part is provided with a pair of adjacent lower reversing groove (31-4-2)；

When the hollow connecting rod (31-4) is located at its lower limit site location, the upper reversing groove (31-4-1) is simultaneously described in connection Relief hole (31-5-9) and pressure transmission hole (31-5-8)；

It is convex between two lower reversing grooves (31-4-2) when the hollow connecting rod (31-4) limit point position disposed thereon It is corresponding with the diversion trench (31-5-7-1) to play position, so that the pressure transmission hole (31-5-8) and the power sap cavity (31- 5-1) be connected.

4. hydraulic piston pump according to claim 3, it is characterised in that: be equipped with sliding sleeve (24) in the outer cylinder (28)；Institute The top for stating sliding sleeve (24) is fixed with pawl (25)；The pump core (31) is externally provided with the pawl slot for blocking pawl (25) (33)；Outer cylinder (28) inner wall is separately provided for blocking the pawl of opening above and below the sliding sleeve (24) Top fastening station and it is used to support getting out of a predicament or an embarrassing situation for sliding sleeve (24) bottom end, offers sliding sleeve respectively on the sliding sleeve (24) and outer cylinder (28) and follow Annular distance (27) and outer cylinder circulation port (26), the sliding sleeve circulation port (27) and outer cylinder circulation port (26) are located in the sliding sleeve (24) It is staggered when alignment, dead-centre position disposed thereon when its lower dead point position.

5. a kind of underground pump assembly, it is characterised in that: including oil pipe (22), packer (23), hollow rod (32) and right It is required that hydraulic piston pump described in 1 to 4 any one, the oil pipe (22), pump seat (21) and packer (23) form lower going-into-well Working string (20) in setting of casing (10), the pump core (31) and hollow rod (32) group for being connected to pump core (31) top At the drain tubing string (30) being lowered into working string (20)；The packer (23) is located at the lower section of the pump seat (21).

6. underground pump assembly according to claim 5, it is characterised in that: the bottom end of the pump core (31) is equipped with pressure gauge (35)。

7. underground pump assembly according to claim 5 or 6, it is characterised in that: be provided with below the packer (23) Sand-proof pipe.

8. underground pump assembly according to claim 5 or 6, it is characterised in that: the crossover sub (34) and pump seat (21) It is tightly connected, the crossover sub (34) is for the power fluid for entering pump core (31) from hollow rod (32) to be imported into The annular space being located at below crossover sub (34) between pump core (31) and pump seat (21) will simultaneously be extracted out out of pump core (31) Formation fluid is drained into the annular space being located above crossover sub (34) between pump core (31) and pump seat (21).

9. a kind of underground drain test macro, which is characterized in that including the described in any item underground pump assemblys of claim 5 to 8, Power fluid circulation (40) and formation fluid metering system；The power fluid circulation (40) includes toward the hollow rod (32) the power fluid storage that water injecting pump (41), the annular chamber between casing (10) and oil pipe (22) of power fluid are connected to is provided in Tank (42)；The formation fluid metering system includes the ground that the annular housing between hollow rod (32) and oil pipe (22) is connected to Layer liquid holding vessel (51)；The water injecting pump (41) extracts power fluid out of described power fluid holding vessel (42).

10. drain test macro in underground according to claim 9, which is characterized in that the power fluid holding vessel (42) with Water injecting pump is provided with heating device between (41).