Plunger pump for oil pumping and rodless oil extraction system

Abstract

The plunger pump for oil pumping comprises a cylinder body, a plunger, a threaded driving rod, a liquid inlet one-way valve port, a liquid outlet one-way valve port and a rotary power output device, the plunger is arranged in the cylinder body in a sliding mode and can do reciprocating motion, and a sealed working containing cavity is formed by one end of the plunger and the top of the cylinder body; the other end of the plunger is connected with the rotating power output end of a threaded driving rod, and the rotating power input end of the threaded driving rod extends out of the cylinder body to be connected with the rotating power output end of a rotating power output device. The liquid inlet one-way valve port is circumferentially arranged on the upper portion of the cylinder body, an inlet of the liquid inlet one-way valve port is communicated with an oil layer, an outlet of the liquid inlet one-way valve port is communicated with the sealed working cavity, the liquid outlet one-way valve port is arranged on the top of the cylinder body, and an inlet of the liquid outlet one-way valve port is communicated with the sealed working cavity and an outlet of the liquid outlet one-way valve port is communicated with an overground oil outlet pipeline. The plunger pump for oil pumping is convenient to install and convenient to pump oil, and meanwhile the defect that an oil pumping unit does work on an oil pumping rod in the working process is overcome.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil production, and more particularly to a plunger pump for pumping oil and a rodless oil production system. Background Art

[0002] The process of underground oil extraction can be mainly divided into two stages. In the first extraction stage, the energy of the underground oil reservoir is used to extract oil, and the oil can gush to the ground by itself, which is called primary oil recovery. In the second extraction stage, the energy of machinery is used to extract oil. Under the action of mechanical energy, the oil is lifted from underground to the ground, which is called secondary oil recovery. There are various types of mechanical equipment commonly used in secondary oil recovery, which can be applied to different underground oil extraction environments. For example, the commonly used secondary oil recovery equipment is divided into rod pump oil production devices and rodless pump oil production devices. Among them, the commonly used rod pump oil production devices include pumping units and screw pumps.

[0003] The pumping unit converts the rotary motion of the motor into the reciprocating motion of the walking beam through a crank connecting rod mechanism. The sucker rod transmits the reciprocating motion of the walking beam to the oil pump, driving the piston of the oil pump to reciprocate in the pump barrel. The oil pump completes one suction of well fluid when the piston reciprocates once. When the formation fluid supply is sufficient and the working condition of the oil pump is good, the pumping efficiency of the pumping unit is relatively high. However, since it is a rod pumping method, the pumping unit that provides power is installed on the ground. The reciprocating motion of the pumping unit must be transmitted to the oil pump through the sucker rod. On the one hand, the pumping unit does work on the liquid column above the piston, and also does work on the sucker rod and the counterweight. At the same time, it also has to overcome the friction load and vibration load. Generally, about 80% of the electrical energy of the pumping unit motor is consumed in overcoming the mechanical itself and various friction and vibration loads, which belongs to useless work. Only about 20% of the electrical energy is used to lift the liquid column. This will result in a low electrical energy utilization rate. At the same time, due to material limitations, the oil pump cannot be placed too deep in the wellbore, and the surface pumping unit cannot be made too large, which limits the application of the pumping unit in oil fields that require deep pumping. The sucker rod often breaks and disconnects during use, causing accidents.

[0004] The screw pump is that the high-speed rotary motion of the motor is decelerated by a speed reduction mechanism, and then drives the downhole screw pump to rotate through the sucker rod to suck and lift the well fluid to the ground. Its disadvantages are that the screw pump cannot be placed too deep in the well, the sucker rod is easily twisted off, and the torque is transmitted through the slender sucker rod, resulting in large energy loss and low electrical energy utilization rate.

[0005] Among them, the commonly used rodless pump oil production devices include electric pumps, jet pumps and hydraulic piston pumps. The electric pump is an oil production equipment that transmits electrical energy to the downhole motor through a cable. The motor rotates to drive the centrifugal pump to rotate, thereby lifting the well fluid to the ground. Since the electric pump unit has no redundant auxiliary equipment, the motor directly transmits the kinetic energy to the centrifugal pump, and the centrifugal pump directly does work on the well fluid. However, due to the characteristics of the centrifugal pump's own characteristic curve, the pump efficiency is relatively low under high head and high discharge conditions, which is not conducive to the efficient utilization of electrical energy.

[0006] A jet pump is a device where surface equipment pressurizes power fluid on the surface and transports it through a dedicated power fluid pipeline to a downhole nozzle. The nozzle converts the pressure energy into kinetic energy, creating a low-pressure area behind the nozzle. The formation produced fluid flows in and mixes with the power fluid, and the kinetic energy is converted back into pressure energy through a diffuser tube, thereby lifting the mixed fluid to the surface. Its characteristics are few moving parts and a compact structure, but it is not suitable for deep well oil production and has low efficiency.

[0007] A hydraulic piston pump is a device where surface equipment pressurizes power fluid and transports it to a downhole hydraulic motor through a tubing or a dedicated power fluid pipeline. The power fluid drives the hydraulic motor to lift the crude oil to the surface. The characteristics of a hydraulic piston pump are a complex unit structure, high machining precision requirements, a large surface matching system, high investment, and low benefits. Summary of the Invention

[0008] In order to solve the problem of high oil production costs in existing oil production systems in the prior art, the present invention provides a plunger pump for oil extraction and a rodless oil production system, which are convenient to install and operate, and at the same time eliminate the disadvantage of doing work on the sucker rod during the operation of the pumping unit, improve the power utilization efficiency, and reduce the oil production cost.

[0009] To achieve the above object, the present invention provides the following technical solution: A plunger pump for oil extraction, comprising a cylinder block, a plunger, a threaded drive rod, an inlet check valve port, an outlet check valve port, and a rotary power output device. The plunger is slidably arranged in the cylinder block and can reciprocate. One end of the plunger forms a sealed working cavity with the top of the cylinder block; the other end of the plunger is connected to the rotary power output end of the threaded drive rod, and the rotary power input end of the threaded drive rod extends out of the cylinder block for connection with the rotary power output end of the rotary power output device; the inlet check valve port is circumferentially arranged on the upper part of the cylinder block, the inlet of the inlet check valve port communicates with the oil layer, and the outlet communicates with the sealed working cavity. The outlet check valve port is arranged on the top of the cylinder block, the inlet of the outlet check valve port communicates with the sealed working cavity, and the outlet communicates with the above-ground oil outlet pipeline.

[0010] Further, the cylinder block includes a pump head and a pump barrel. The pump head seals the first end opening of the pump barrel. The plunger is slidably arranged in the pump barrel and can reciprocate. The inlet check valve port is circumferentially arranged between the pump head and the first end opening of the pump barrel. The outlet check valve port is arranged on the top of the pump head. The rotary power input end of the threaded drive rod extends out of the pump barrel for connection with the rotary power output end of the rotary power output device.

[0011] Further, the inlet check valve port includes a first mating valve groove provided on the outer wall of the pump head insertion section and a second mating valve groove provided on the inner wall of the barrel opening at the first end of the pump barrel. The pump head insertion section is inserted into the barrel opening at the first end of the pump barrel. The first mating valve groove and the second mating valve groove are mated to form a valve seat. The valve seat communicates the outside of the cylinder block with the sealed working cavity. A valve core and an elastic member are arranged in the valve seat. The valve core is abutted by the elastic member at the entrance where the valve seat communicates with the outside of the cylinder block.

[0012] Further, the exposed section of the pump head extends with an increased diameter from the insertion section away from the barrel opening at the first end of the pump barrel. An annular oil inlet groove is formed between the enlarged diameter surface of the exposed section of the pump head and the barrel opening at the first end of the pump barrel. The oil inlet groove is correspondingly communicated with the inlet check valve port.

[0013] Further, the outlet check valve port includes an outlet valve seat, an outlet valve core and an outlet elastic device. The outlet valve seat is arranged through the pump head. The outlet valve seat is a stepped drain hole with an increasing aperture in the outlet direction. Different-sized outlet valve cores are correspondingly arranged in the stepped drain hole. Valve covers are arranged in the stepped drain hole. The outlet valve core is abutted at the entrance of the outlet check valve port by the outlet elastic device and the valve cover.

[0014] Further, the pump barrel includes a first pump barrel and a second pump barrel. The pump head is covered on the barrel opening at the first end of the first pump barrel. The barrel opening at the second end of the first pump barrel is hermetically connected to the barrel opening at the first end of the second pump barrel. The top of the plunger reciprocates in the first pump barrel. The threaded drive rod passes through the shaft hole provided at the second end of the second pump barrel and is connected to the rotational power output end of the rotational power output device; a thrust bearing and a fixing nut are sleeved on the threaded drive rod. The thrust bearing and the fixing nut are respectively arranged at both ends of the shaft hole at the second end of the second pump barrel.

[0015] Further, an outer ring groove is formed on the outer side of the barrel opening at the second end of the first pump barrel, and an outer ring platform is formed on the outer side of the barrel opening at the first end of the second pump barrel. The outer ring groove and the outer ring platform are clamped; a sealed inner ring groove is formed on the inner side of the barrel opening at the second end of the first pump barrel. The bottom of the sealed inner ring groove is filled with a sealing filler. The side part of the sealed inner ring groove is slidably connected to the side wall of the plunger. The top of the sealed inner ring groove is buckled by a packing gland.

[0016] Further, a plurality of guiding mechanisms are arranged on the inner wall of the cylinder block. The arrangement direction of the guiding mechanisms is parallel to the linear track of the reciprocating movement of the plunger. The plunger is slidably connected to the guiding mechanisms.

[0017] The present invention further provides a rodless oil production system, which includes a rotational power output device and the plunger pump for oil extraction according to any one of claims 1 to 8. The rotational power output end of the rotational power output device is in transmission connection with the rotational power input end of the threaded drive rod of the plunger pump for oil extraction.

[0018] Further, it further includes a control device, which is electrically connected to the rotary power output device and is used to send an oil pumping instruction to the rotary power output device. The oil pumping instruction includes: 1) a first driving signal for controlling the rotary power output end of the rotary power output device to output rotary power in a first rotation direction; 2) a second driving signal for controlling the rotary power output end of the rotary power output device to output rotary power in a second rotation direction; 3) a revolution adjustment signal for adjusting the number of revolutions of the rotary power output end of the rotary power output device; 4) a rotation speed adjustment signal for adjusting the rotation speed of the rotary power output end of the rotary power output device.

[0019] The first driving signal controls the forward rotation of the rotary power output end of the rotary power output device, and the second driving signal controls the reverse rotation of the rotary power output end of the rotary power output device.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] The present invention provides a plunger pump for oil pumping. The liquid outlet check valve port is arranged at the top of the cylinder block, and the liquid inlet check valve port is arranged on the side wall of the cylinder block, which is convenient for the liquid inlet check valve port to communicate with the oil layer under the oil well, and the liquid outlet check valve port to communicate with the above-ground oil outlet pipeline of the oil well. The installation is convenient. When in use, the cylinder block can be placed at the height of the oil layer.

[0022] Further, the plunger pump has the characteristic of high efficiency, can abandon the disadvantage of doing work on the sucker rod in the working process of the existing pumping unit, and can efficiently convert electrical energy into mechanical energy in combination with the rotary power output device, and efficiently convert mechanical energy into formation fluid pressure and lift the oil to the ground with low energy consumption, achieving the purpose of improving the utilization rate of electrical energy and reducing the oil production cost.

[0023] Further, the present invention forms an annular oil inlet groove between the pump head and the pump barrel. Larger particles in the oil liquid will be clamped at the notch of the oil inlet groove, which can avoid larger particles of impurities from blocking the liquid inlet check valve port and improve the stable working time of the plunger pump for oil pumping of the present invention.

[0024] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the embodiments of the present invention more clearly and implement them according to the content of the description, the following takes the preferred embodiments of the present invention and describes them in detail with reference to the accompanying drawings as follows. Description of the Drawings

[0025] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to limit the present invention. And throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0026] Figure 1It is a schematic structural diagram of a rodless oil production system provided by an embodiment of the present invention;

[0027] Figure 2 is Figure 1 an enlarged view of the structure of A in

[0028] In the accompanying drawings: 100 plunger pump, 1011 pump head, 1012 first pump barrel, 1013 second pump barrel; 102 plunger; 103 threaded drive rod; 104 inlet check valve port, 104a first mating valve groove, 104b second mating valve groove, 104c valve core, 104d elastic member, 104e oil groove; 105 outlet check valve port; 106 guiding mechanism; 107 sealing packing; 108 packing gland; 109 thrust bearing; 110 fixing nut;

[0029] 200 rotary power output device; 210 lubricating oil tank; 220 reducer; 221 upper gear set, 222 upper support plate, 223 lower gear set, lower support plate 224, 225 large cover gear, 226 planetary gear set, 227 planetary gear bracket, 228 output shaft of the reducer, 229 input shaft of the reducer; 230 drive motor, 231 motor bearing end cover, 232 motor stator, 233 motor rotor, 234 motor output shaft. Specific Embodiments

[0030] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended purpose of the invention embodiment, the following combines the accompanying drawings and preferred embodiments to detail the specific embodiments, structures, features and effects of the rodless oil production system and its plunger pump proposed according to the embodiments of the present invention. In the following description, different "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0031] Figures 1 to 2 For an embodiment of the rodless oil production system provided by the present invention, please refer to Figures 1 to 2 , a rodless oil production system proposed by an embodiment of the present invention includes:

[0032] The plunger pump 100 includes a cylinder block 101, a plunger 102, a threaded drive rod 103, a liquid inlet check valve port 104, and a liquid outlet check valve port 105. The plunger 102 can reciprocate within the cylinder block 101. One end of the plunger 102 in the first direction of reciprocating movement forms a sealed working cavity with the inner wall of the cylinder block 101. A guiding mechanism 106 parallel to the linear trajectory of the reciprocating movement of the plunger 102 is formed within the cylinder block 101. The plunger 102 is slidably connected to the guiding mechanism 106. The rotational power output end of the threaded drive rod 103 is in threaded driving connection with one end of the plunger 102 in the second direction of reciprocating movement. The liquid inlet check valve port 104 and the liquid outlet check valve port 105 are respectively communicated with the sealed working cavity;

[0033] The rotational power output device 200, whose rotational power output end is in driving connection with the rotational power input end of the threaded drive rod 103;

[0034] Place the plunger pump 100 of the rodless oil production system and the rotational power output device 200 vertically down in the oil well, which is convenient for the liquid inlet check valve port 104 to communicate with the oil layer under the oil well, and the liquid outlet check valve port 105 to communicate with the above-ground oil outlet pipeline of the oil well.

[0035] Preferably, it further includes a control device. The control device is electrically connected to the drive motor 230 of the rotational power output device 200, and is used to send an oil pumping instruction to the drive motor 230, so that the drive motor 230 cyclically outputs rotational power in the first rotational direction and rotational power in the second rotational direction according to the oil pumping instruction. The first rotational direction is opposite to the second rotational direction. The control device can be arranged on the ground to send an oil pumping instruction to the drive motor 230 underground.

[0036] The whole of the rodless oil production system can be cylindrical, and its outer diameter is smaller than the inner diameter of the oil well.

[0037] Preferably, the guiding mechanism 106 and the cylinder block 101 can be an integral structure or a split structure.

[0038] Preferably, the cylinder block 101 itself can be an integral structure or a split structure;

[0039] In some integral structures, for the convenience of production, the cylinder block 101 includes a pump head 1011 and a pump barrel. The pump head 1011 seals the first end opening of the pump barrel;

[0040] In some split embodiments, the cylinder block 101 includes a pump head 1011, a first pump barrel 1012, and a second pump barrel 1013. The pump head 1011 covers the first end opening of the first pump barrel 1012, and the opening at the second end of the first pump barrel 1012 is sealingly connected to the first end opening of the second pump barrel 1013. The guiding mechanism 106 is a slide rail provided on the inner wall of the second pump barrel 1013, and the top of the plunger 102 can reciprocate within the first pump barrel 1011. The slider at the bottom of the plunger 102 is slidably connected to the slide rail.

[0041] Preferably, the slide rail is a chute of a straight rod, and the slider at the bottom of the plunger 102 is a slider slidably connected to the chute. Alternatively, the slide rail is a slide rod of a straight rod, and the slider at the bottom of the plunger 102 is a chute slidably connected to the slide rod.

[0042] Preferably, the number of slide rails is not limited to one, and may be multiple slide rail groups arranged oppositely on the inner wall of the second pump barrel 1013.

[0043] Preferably, in the realization of the sealing connection between the opening at the second end of the first pump barrel 1012 and the opening at the first end of the second pump barrel 1013, an outer ring groove opened on the outer side of the opening at the second end of the first pump barrel 1012 is clamped with an outer ring platform opened on the outer side of the opening at the first end of the second pump barrel 1013. A sealing inner ring groove is opened on the inner side of the opening at the second end of the first pump barrel 1012. The bottom of the sealing inner ring groove is filled with a sealing packing 107. The side of the sealing inner ring groove is slidably connected to the side wall of the plunger 102, and the top of the sealing inner ring groove is buckled by a packing gland 108.

[0044] Preferably, the threaded drive rod 103 passes through a shaft hole provided at the second end of the second pump barrel 1013. At both ends of the shaft hole at the second end of the second pump barrel 1013, a thrust bearing 109 and a fixing nut 110 are respectively provided. The thrust bearing 109 and the fixing nut 110 are sleeved on the threaded drive rod 103.

[0045] Preferably, the rotational power output end of the threaded drive rod 103 and the thread on one side in the second direction of the reciprocating movement of the plunger 102 can be connected by spline transmission. Driven by the rotational power of the rotational power output end of the threaded drive rod 103, due to the guiding of the plunger 102 by the guiding mechanism 106, the plunger 102 can move on a straight line trajectory reciprocating within the cylinder block 101.

[0046] In implementation, in the first implementation mode, the rotational power output end of the threaded drive rod 103 is an external threaded rod, and one side in the second direction of the reciprocating movement of the plunger 102 has an internal threaded hole. The external threaded rod is threadedly connected to the internal threaded hole. The axis of the internal threaded hole and the axis of the external threaded rod are respectively coaxial with the axis of the cylinder block 101.

[0047] In the second embodiment, the rotational power output end of the threaded drive rod 103 is an internal threaded hole, and an external threaded rod is provided on one side in the second direction of the reciprocating motion of the plunger. The internal threaded hole is in threaded transmission connection with the external threaded rod. The axis of the internal threaded hole and the axis of the external threaded rod are respectively coaxial with the axis of the cylinder block 101.

[0048] Preferably, the opening positions of the liquid inlet one-way valve port 104 and the liquid outlet one-way valve port 105 are selected according to requirements. Optionally, the liquid inlet one-way valve port 104 is opened on the side of the cylinder block 101; the liquid outlet one-way valve port 105 is opened on the top of the cylinder block 101, or the liquid inlet one-way valve port 104 is opened on the top of the cylinder block 101 and the liquid outlet one-way valve port 105 is opened on the side wall of the cylinder block 101.

[0049] Preferably, the number of the liquid inlet one-way valve ports 104 is not limited to one, and its opening position and quantity are determined according to the oil layer. Generally, the oil layer is located around the cylinder block 101, and there can be multiple liquid inlet one-way valve ports 104. The multiple liquid inlet one-way valve ports 104 are circumferentially arranged on the side of the cylinder block 101 to simultaneously suck oil from the oil layers around the cylinder block 101.

[0050] Preferably, the liquid inlet one-way valve port 104 includes: a liquid inlet valve seat, a liquid inlet valve core, and a liquid inlet elastic device. The liquid inlet one-way valve port can be a separate valve component installed on the cylinder block, or the liquid inlet valve seat is opened on the cylinder block.

[0051] Preferably, the liquid outlet one-way valve port 105 includes: a liquid outlet valve seat, a liquid outlet valve core, and a liquid outlet elastic device. The liquid outlet one-way valve port 105 can be a separate valve component installed on the cylinder block 101, or the liquid outlet valve seat is opened on the cylinder block 101. The number of the liquid outlet valve cores is not limited to one. For example, the liquid outlet valve seat is a stepped drain hole with an increasing aperture in the liquid outlet direction. The liquid outlet valve core includes a larger spherical valve core and a smaller spherical valve core. The smaller spherical valve core is installed in the small-diameter installation hole of the stepped drain hole, and the larger spherical valve core is installed in the large-diameter installation hole of the stepped drain hole. The shape of the liquid outlet valve core is not limited to spherical, and it can also be a valve core of other shapes, and its function is to ensure the one-way flow of liquid. Valve covers of different sizes are installed in the large-diameter installation hole and the small-diameter installation hole.

[0052] The rotary power output device 200 includes: a lubricating oil tank 210, a speed reducer 220, and a driving motor 230 arranged in sequence from top to bottom; the output shaft of the speed reducer 220 passes through the bottom shaft hole opened at the bottom of the lubricating oil tank 210 and the top shaft hole opened at the top of the lubricating oil 210 tank and is in transmission connection with the rotary power input end of the threaded drive rod 103, and the shaft hole at the top of the speed reducer 220 communicates with the lubricating oil storage chamber of the lubricating oil tank 210; the motor output shaft of the driving motor 230 is in transmission connection with the input shaft of the speed reducer 220. The lubricating oil in the lubricating oil tank 210 flows into the speed reducer 220 under the action of gravity to lubricate the reduction gears in the speed reducer 220. Specifically, the shaft hole at the bottom of the speed reducer 220 communicates with the shaft hole of the driving motor 230, so that the lubricating oil tank 210 lubricates the output shaft of the driving motor 230 at the same time.

[0053] In some sealing solutions, the cylinder body at the bottom of the cylinder block 101 is flange-sealed to the cylinder body at the top of the lubricating oil tank 210, the cylinder body at the bottom of the lubricating oil tank 210 is flange-sealed to the cylinder body at the top of the speed reducer 220, and the cylinder body at the bottom of the speed reducer 220 is flange-sealed to the cylinder body at the top of the driving motor 230. The axis of the cylinder body of the cylinder block 101, the axis of the cylinder body of the lubricating oil tank 210, and the axis of the cylinder body of the speed reducer 220 are respectively coaxial with the axis of the output shaft of the speed reducer 230.

[0054] Preferably, the motor output shaft of the driving motor 230 and the input shaft of the speed reducer 220 can be in spline transmission connection. For example, the driving motor 230 includes a motor bearing end cover 231, a motor stator 232, a motor rotor 233, and a motor output shaft 234. The first end of the motor rotor 233 is rotatably connected to the shaft hole at the bottom end of the motor stator 232, the second end of the motor rotor 233 is rotatably connected to the shaft hole at the top end of the motor stator 233, the motor bearing end cover 231 is hermetically sealed to the shaft hole at the bottom end of the motor stator 233, and the motor output shaft 234 is arranged at the second end of the motor rotor 233. A spline sleeve is provided on the input shaft of the speed reducer 220, and a spline is provided on the motor output shaft 234, and the spline of the motor output shaft 234 is inserted into the spline sleeve of the input shaft of the speed reducer 22.

[0055] Preferably, the driving motor 230 can be an ordinary high-torque motor.

[0056] Preferably, the speed reducer 220 can adopt a planetary gear structure. For example, the speed reducer is a speed increasing and torque reducing device, which includes: a speed increasing and torque reducing housing, an upper gear set 221, an upper support plate 222, a lower gear set 223, a lower support plate 224, a large cover gear 225, a planetary gear set 226, a planetary gear bracket 227, an output shaft 228 of the speed reducer, and an input shaft 229 of the speed reducer. The upper support plate 222, the lower support plate 224, and the planetary gear bracket 227 are stacked from top to bottom in the speed increasing and torque reducing housing. The upper gear set 221 is arranged between the top plate of the speed increasing and torque reducing housing and the upper support plate 222. The lower gear set 223 is placed between the upper support plate 222 and the lower support plate 224. The large cover gear 225 and the planetary gear set 226 are arranged between the lower support plate 224 and the planetary gear bracket 227.

[0057] The input shaft 229 of the speed reducer is arranged in the shaft hole of the bottom plate of the speed increasing and torque reducing housing and is in transmission connection with the first transmission end of the planetary gear set 226. The second transmission end of the planetary gear set 226 is in transmission connection with the first transmission end of the large cover gear 225. The second transmission end of the large cover gear 225 is in transmission connection with the first transmission end of the lower gear set 223. The second transmission end of the lower gear set 223 is in transmission connection with the first transmission end of the upper gear set 221. The second transmission end of the upper gear set 221 is in transmission connection with the output shaft 228 of the speed reducer 220. The output shaft 228 of the speed reducer 220 is arranged in the shaft hole of the top plate of the speed increasing and torque reducing housing.

[0058] In the technical solution provided by the embodiment of the present invention, the rodless oil production system is placed under the oil production well, so that the liquid inlet check valve port 104 communicates with the oil layer under the oil production well, and the liquid outlet check valve port 105 communicates with the above-ground oil outlet pipeline of the oil production well. The ground control device transmits electric energy to the downhole rotary power output device 200. The rotary power output by the rotary power output device 200 drives the threaded drive rod 103 to rotate forward and backward. Under the threaded transmission of the rotary power output end of the threaded drive rod 103 and the plunger 102, the plunger 102 reciprocates in the cylinder block 101, so that the volume of the sealed working cavity changes to realize oil suction and oil pressure. Compared with the prior art, the high efficiency characteristics of the plunger pump are fully utilized, and the disadvantage of doing work on the sucker rod during the working process of the pumping unit is abandoned. Among them, in the technical solution provided by the embodiment of the present invention, the rotary power output device 200 efficiently converts electric energy into mechanical energy, and the mechanical energy is efficiently converted into formation fluid pressure and the oil is lifted to the ground with lower energy consumption.

[0059] Figures 1 to 2 For an embodiment of the plunger pump of the rodless oil production system provided by the above embodiment of the present invention, please refer to Figures 1 to 2 An embodiment of the present invention provides a plunger pump 100 of a rodless oil production system, including:

[0060] Cylinder block 101, plunger 102, threaded drive rod 103, inlet check valve port 104, outlet check valve port 105. The plunger 102 can reciprocate within the cylinder block 101. One end of the plunger 102 in the first direction of reciprocating motion forms a sealed working cavity with the inner wall of the cylinder block 101. A guiding mechanism 106 parallel to the linear trajectory of the reciprocating motion of the plunger 102 is arranged within the cylinder block 101. The plunger 102 is slidably connected to the guiding mechanism 106. The rotational power output end of the threaded drive rod 103 is in threaded transmission connection with one end of the plunger 102 in the second direction of reciprocating motion. The inlet check valve port 104 and the outlet check valve port 105 are respectively communicated with the sealed working cavity;

[0061] In the technical solution provided by the embodiment of the present invention, since a plurality of inlet check valve ports 104 are circumferentially arranged around the side wall of the cylinder block 101, and the outlet check valve port 105 is arranged at the top of the cylinder block 101. During the downhole installation of the plunger pump 100, the cylinder block 101 is placed at the oil layer height, which is convenient for the inlet check valve port 104 to communicate with the oil layer under the pumping well, and the outlet check valve port 105 to communicate with the above-ground oil outlet pipeline of the pumping well, and the installation is convenient.

[0062] Further, for the convenience of production, the cylinder block 101 includes a pump head 1011 and a pump barrel. The pump head 1011 seals the first end opening of the pump barrel; the inlet check valve port 104 is arranged between the pump head 1011 and the first end opening of the pump barrel. The inlet check valve port 104 can be a separate valve component. After assembly, oil leakage is likely to occur on the outer periphery of the separate valve component. To improve its reliability, the inserted section of the pump head 1011 is inserted into the first end opening of the pump barrel; the inlet check valve port 104 includes a first mating valve groove 104a arranged on the outer wall of the inserted section of the pump head, a second mating valve groove 104b arranged on the inner wall of the first end opening of the pump barrel, a valve core 104c, and an elastic member 104d. The first mating valve groove 104a and the second mating valve groove 104b are mated to form a valve seat. The valve seat is respectively communicated with the outside of the cylinder block and the sealed working cavity. The valve core 104c is abutted by the elastic member 104d against the inlet communicating the valve seat with the outside of the cylinder block.

[0063] Preferably, the valve core 104c can adopt a spherical valve, and the elastic member 104d can adopt a stainless steel spring, etc., but is not limited thereto. Specifically, the exposed section of the pump head 1011 extends with an increased diameter from the inserted section away from the first end opening of the pump barrel. An annular oil inlet groove 104e is formed between the increased diameter surface of the exposed section of the pump head 1011 and the first end opening of the pump barrel. During operation, the oil on the outer periphery first enters the oil groove 104e and then enters the inlet check valve port 104, which can avoid blocking the inlet check valve port 104 by relatively large particles of impurities. The relatively large particles of impurities will be clamped at the notch of the oil inlet groove 104e.

[0064] In implementation, there are multiple liquid inlet check valve ports 104, and the multiple liquid inlet check valve ports 104 are circumferentially arranged around the side wall of the pump barrel. Axial simultaneous oil production can be achieved. In practice, the arrangement of the liquid inlet check valve ports 104 is not limited to one circle, and the opening positions and quantities are determined according to the oil layer. The liquid inlet check valve ports 104 are single-spool or multi-spool.

[0065] In some embodiments, a first flange is provided on the outer wall of the pump head 1011, a second flange is provided on the pump barrel, and the first flange and the second flange are fixedly connected by bolts. During assembly, first insert the insertion section of the pump head 1011 into the barrel opening at the first end of the pump barrel, and then fixedly connect the first flange and the second flange by bolts.

[0066] In other embodiments, an external thread is provided on the outer wall of the insertion section of the pump head 1011, an internal thread is provided on the inner wall of the barrel opening at the first end of the pump barrel, and the outer wall of the insertion section of the pump head 1011 is threadedly connected to the inner wall of the barrel opening at the first end of the pump barrel. During assembly, screw the insertion section of the pump head 1011 into the barrel opening at the first end of the pump barrel, and align the first mating valve groove 104a with the second mating valve groove 104b to form a valve seat.

[0067] Preferably, the liquid outlet check valve port 105 can be arranged in the middle of the top of the pump head 1011. When the rodless oil production system is vertically installed underground in an oil well, the cylinder body is placed at the height of the oil layer, and the liquid outlet check valve port 105 can facilitate the connection with the above-ground oil outlet pipeline of the oil well. The liquid outlet check valve port 105 is single-spool or multi-spool.

[0068] The oil pumping method of the rodless oil production system proposed in an embodiment of the present invention is as follows:

[0069] Place the rodless oil production system underground in the oil well, connect the liquid inlet check valve port 104 to the oil layer underground in the oil well, connect the liquid outlet check valve port 105 to the above-ground oil outlet pipeline of the oil well, and send an oil pumping instruction to the rotary power output device 200;

[0070] The rotary power output device 200 cyclically outputs rotary power in the first rotary direction and rotary power in the second rotary direction according to the oil pumping instruction. The first rotary direction is opposite to the second rotary direction, so that the oil in the oil layer is sucked into the sealed working cavity by the plunger moving in the second direction through the liquid inlet check valve port 104, and the oil in the sealed working cavity is pushed into the above-ground oil outlet pipeline by the plunger 102 moving in the first direction through the liquid outlet check valve port 105.

[0071] Further, in the technical solution provided by the embodiment of the present invention, the rodless oil production system is placed under the pumping well, the liquid inlet check valve port 104 communicates with the oil layer under the pumping well, and the liquid outlet check valve port 105 communicates with the above-ground oil outlet pipeline of the pumping well. The ground control device transmits electric energy to the downhole rotary power output device 200, and the rotary power output by the rotary power output device 200 drives the threaded drive rod 103 to rotate forward and backward. Under the threaded drive of the rotary power output end of the threaded drive rod 103 and the plunger 102, the plunger 102 reciprocates in the cylinder block, causing the volume of the sealed working cavity to change to achieve oil suction and oil pressure. Compared with the prior art, the high-efficiency characteristics of the plunger pump are fully utilized, and the disadvantage of doing work on the sucker rod during the working process of the pumping unit is abandoned. Among them, in the technical solution provided by the embodiment of the present invention, the rotary power output device efficiently converts electric energy into mechanical energy, and the mechanical energy is efficiently converted into the formation fluid pressure and the oil is lifted to the ground with lower energy consumption.

[0072] Among them, the pumping instructions include:

[0073] 1) The first drive signal and the second drive signal that the rotary power output device 200 executes cyclically. The first drive signal controls the rotary power output end of the rotary power output device 200 to output rotary power in the first rotation direction, and the second drive signal controls the rotary power output end of the rotary power output device 200 to output rotary power in the second rotation direction. The first drive signal and the second drive signal cause the rotary power output by the rotary power output device 200 to drive the threaded drive rod 103 to rotate forward and backward.

[0074] 2) The number-of-turns adjustment signal for adjusting the number of rotation turns of the power output end of the rotary power output device 200.

[0075] 3) The rotational speed adjustment signal for adjusting the rotational speed of the power output end of the rotary power output device 200.

[0076] By setting parameters to control the rotational speed, forward and reverse rotation, and number of revolutions of the drive motor 230 of the rotary power output device 200, the reciprocating linear motion of the plunger 102 in the cylinder block, as well as the stroke and motion frequency of the plunger 102, are realized. The stroke adjustment of the plunger 102 is realized by controlling the rotational speed.

[0077] Placing the rodless oil production system under the pumping well, so that the liquid inlet check valve port 104 communicates with the oil layer under the pumping well, and the liquid outlet check valve port 105 communicates with the above-ground oil outlet pipeline of the pumping well, specifically includes:

[0078] The plunger pump 100 and the rotary power output device 200 are arranged from top to bottom under the pumping well, so that the liquid inlet check valve port 104 on the side wall of the cylinder block 101 communicates with the oil layer under the pumping well, and the liquid outlet check valve port 105 at the top of the cylinder block communicates with the above-ground oil outlet pipeline of the pumping well.

[0079] In the above embodiments, the descriptions of the various embodiments have their own emphases. For parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0080] It can be understood that the relevant features in the above devices can be referred to each other. In addition, the "first", "second", etc. in the above embodiments are used to distinguish the various embodiments, and do not represent the advantages or disadvantages of the various embodiments.

[0081] In the specification provided herein, a large number of specific details are set forth. However, it can be understood that the embodiments of the present invention may be practiced without these specific details. In some instances, well-known structures and techniques are not shown in detail so as not to obscure the understanding of this specification.

[0082] Similarly, it should be understood that, in order to streamline this disclosure and assist in understanding one or more of the various inventive aspects, in the foregoing description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, the disclosed devices should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, the inventive aspects lie in less than all of the features of the single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of the present invention.

[0083] Those skilled in the art can understand that the components in the devices of the embodiments can be adaptively changed and arranged in one or more devices different from this embodiment. The components in the embodiments can be combined into one component, and in addition, they can be divided into multiple sub-components. Except that at least some of such features are mutually exclusive, any combination can be used to combine all the features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all the components of any device so disclosed. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) can be replaced by an alternative feature that provides the same, equivalent, or similar purpose.

[0084] In addition, those skilled in the art can understand that, although some of the embodiments herein include certain features included in other embodiments rather than other features, the combination of the features of different embodiments means that it is within the scope of the present invention and forms different embodiments. For example, in the following claims, any one of the claimed embodiments can be used in any combination. The various component embodiments of the present invention can be implemented in hardware or in combination thereof.

[0085] It should be noted that the above embodiments are illustrative of the present invention rather than restrictive thereof, and those skilled in the art can design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or components not listed in the claim. The word "a" or "an" preceding an element or component does not exclude the presence of a plurality of such elements or components. The present invention can be implemented by means of a device including several different elements. In a claim listing several elements, several of these elements may be embodied by the same item of element. The use of the words first, second, and third, etc. does not denote any order. These words may be interpreted as names.

[0086] The above are only the preferred embodiments of the present invention, and are not any form of limitation to the present invention. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A plunger pump for oil pumping, characterized in that, It includes a cylinder block (101), a plunger (102), a threaded drive rod (103), an inlet check valve port (104), an outlet check valve port (105) and a rotary power output device (200). The plunger (102) is slidably arranged in the cylinder block (101) and can reciprocate. One end of the plunger (102) forms a sealed working cavity with the top of the cylinder block (101). The other end of the plunger (102) is connected to the rotary power output end of the threaded drive rod (103), and the rotary power input end of the threaded drive rod (103) extends out of the cylinder block (101) for connection with the rotary power output end of the rotary power output device (200). The inlet check valve port (104) is circumferentially arranged on the upper part of the cylinder block (101). The inlet of the inlet check valve port (104) is communicated with the oil layer, and the outlet is communicated with the sealed working cavity. The outlet check valve port (105) is arranged on the top of the cylinder block (101). The inlet of the outlet check valve port (105) is communicated with the sealed working cavity, and the outlet is communicated with the above-ground oil outlet pipeline.

2. The plunger pump for oil extraction according to claim 1, characterized in that, The cylinder block (101) includes a pump head (1011) and a pump barrel. The pump head (1011) covers the first end opening of the pump barrel. The plunger (102) is slidably arranged in the pump barrel and can reciprocate. The inlet check valve port (104) is circumferentially arranged between the pump head (1011) and the first end opening of the pump barrel. The outlet check valve port (105) is arranged on the top of the pump head (1011). The rotary power input end of the threaded drive rod (103) extends out of the pump barrel and is connected to the rotary power output end of the rotary power output device (200).

3. The plunger pump for oil extraction according to claim 2, characterized in that, The inlet check valve port (104) includes a first mating valve groove (104a) arranged on the outer wall of the inserted section of the pump head (1011) and a second mating valve groove (104b) arranged on the inner wall of the first end opening of the pump barrel. The inserted section of the pump head (1011) is inserted into the first end opening of the pump barrel. The first mating valve groove (104a) and the second mating valve groove (104b) are mated to form a valve seat. The valve seat communicates the outside of the cylinder block with the sealed working cavity. A valve core (104c) and an elastic member (104d) are arranged in the valve seat. The valve core (104c) is abutted by the elastic member (104d) at the entrance where the valve seat communicates with the outside of the cylinder block.

4. The plunger pump for oil extraction according to claim 3, characterized in that, The exposed section of the pump head (1011) extends with an enlarged diameter from the inserted section away from the first end opening of the pump barrel. An annular oil inlet groove (104e) is formed between the enlarged diameter surface of the exposed section of the pump head (1011) and the first end opening of the pump barrel. The oil inlet groove (104e) is correspondingly communicated with the inlet check valve port (104).

5. A plunger pump for oil pumping according to claim 1, characterized in that, The outlet check valve port (105) includes an outlet valve seat, an outlet valve core and an outlet elastic device. The outlet valve seat penetrates through the pump head (1011). The outlet valve seat is a stepped drain hole with an increasing diameter in the outlet direction. Different-sized outlet valve cores are correspondingly arranged in the stepped drain hole. Valve covers are arranged in the stepped drain hole. The outlet valve core is abutted against the inlet of the outlet check valve port (105) by the outlet elastic device and the valve cover.

6. A plunger pump for oil extraction according to claim 2, characterized in that, The pump barrel includes a first pump barrel (1012) and a second pump barrel (1013). The pump head (1011) is covered on the first end opening of the first pump barrel (1012). The opening of the second end of the first pump barrel (1012) is hermetically connected to the opening of the first end of the second pump barrel (1013). The top of the plunger (102) reciprocates within the first pump barrel (1011). The threaded drive rod (103) passes through the shaft hole provided at the second end of the second pump barrel (1013) and is connected to the rotational power output end of the rotational power output device (200). A thrust bearing (109) and a fixing nut (110) are sleeved on the threaded drive rod (103), and the thrust bearing (109) and the fixing nut (110) are respectively arranged at both ends of the shaft hole at the second end of the second pump barrel (1013).

7. A plunger pump for oil extraction according to claim 2, characterized in that, An outer ring groove is formed on the outer side of the opening of the second end of the first pump barrel (1012), and an outer ring platform is formed on the outer side of the opening of the first end of the second pump barrel (1013). The outer ring groove and the outer ring platform are clamped. A sealing inner ring groove is formed on the inner side of the opening of the second end of the first pump barrel (1012). The bottom of the sealing inner ring groove is filled with a sealing packing (107). The side of the sealing inner ring groove is slidably connected to the side wall of the plunger (102), and the top of the sealing inner ring groove is buckled by a packing gland (108).

8. A plunger pump for oil extraction according to claim 1, characterized in that, A plurality of guiding mechanisms (106) are arranged on the inner wall of the cylinder block (101). The arrangement direction of the guiding mechanisms (106) is parallel to the linear trajectory of the reciprocating motion of the plunger (102), and the plunger (102) is slidably connected to the guiding mechanisms (106).

9. A rodless oil production system, characterized in that, It includes a rotational power output device (200) and the plunger pump for oil extraction according to any one of claims 1 to 8. The rotational power output end of the rotational power output device (200) is in transmission connection with the rotational power input end of the threaded drive rod (103) of the plunger pump for oil extraction.

10. The rodless oil production system according to claim 9, characterized in that, It further includes a control device. The control device is electrically connected to the rotational power output device (200) and is used to send an oil extraction instruction to the rotational power output device (200). The oil extraction instruction includes: 1) a first drive signal for controlling the rotational power output end of the rotational power output device (200) to output rotational power in the first rotational direction; 2) a second drive signal for controlling the rotational power output end of the rotational power output device (200) to output rotational power in the second rotational direction; 3) a revolution number adjustment signal for adjusting the number of revolutions of the rotational power output end of the rotational power output device (200); 4) a rotational speed adjustment signal for adjusting the rotational speed of the rotational power output end of the rotational power output device (200). Wherein the first drive signal controls the forward rotation of the rotational power output end of the rotational power output device (200), and the second drive signal controls the reverse rotation of the rotational power output end of the rotational power output device (200).

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