CN107387031A - A kind of single-well injection-production pump group - Google Patents

Abstract

The invention discloses a kind of single-well injection-production pump group, including linear dynamo oil pump, linear electric motors water injecting pump and the oil water separator being arranged between the linear dynamo oil pump and the linear electric motors water injecting pump, the linear dynamo oil pump is arranged at the oil water separator top, and the linear electric motors water injecting pump is arranged at the oil water separator bottom；Single-well injection-production pump group provided by the invention, single-well injection-production system pump highly effective and safe can be made convenient and reliable, can realize and not stop well hot-washing wax remover automatically, to ensure the popularization of single-well injection-production technique, give full play to the economic benefit and social benefit of single-well injection-production technique.

Description

A same-well injection-production pump set

technical field

The invention relates to the technical field of oil field production equipment, in particular to a same-well injection-production pump set.

Background technique

As the oilfield enters the medium-high water cut period, a series of contradictions have been exposed in the production of the oilfield, mainly including that the oil well is close to the economic production limit due to the rise of water cut, which leads to premature production shutdown, resulting in a decline in recovery; the high water production of the oil well leads to an increase in the scale of water treatment. The investment in treatment equipment and operating costs are increasing; at the same time, the leakage and discharge in the process of produced water treatment have caused more and more environmental protection pressure; for inter-production and inter-injection wells with high oil and wax content, the conventional Frequency and cost of well cleaning. The effective way to solve the above problems is to transform the existing oil well lifting system and combine it with the downhole oil-water separation technology to form a downhole oil-water separation and injection-production system in the same well. The water injection pump re-injects the separated water. This technology can reduce the cost of oil recovery in high water-cut oilfields and improve the comprehensive benefits of oilfields.

For oil well pumps and water injection pumps in the same well injection and production system, the most basic requirements are:

(1) It can adapt to the dynamic changes of downhole parameters such as production layer pressure, water cut, oil-water separator efficiency, especially production (corresponding to pump flow), etc., and make timely and effective dynamic responses;

(2), can make full use of the pressure energy of the output layer;

(3), efficient, safe and reliable;

(4), convenient for underground installation and arrangement;

(5), no wax.

At present, there are basically three types of oil well pumps and water injection pumps used in the injection and production system of the same well. One is two series oil well pumps driven by a common pumping unit (kowtow machine) to complete water injection and oil production respectively; Downhole screw pumps are used to complete water injection and oil production respectively; the third is two downhole electric submersible pumps to complete water injection and oil production respectively. Of course, there are also combinations of oil well pump + downhole electric submersible pump or downhole screw pump + downhole electric submersible pump to complete water injection and oil production. The most basic thing for the oil pump and water injection pump used in the injection and production system of the same well is to adapt to the dynamic changes of downhole parameters such as the pressure of the production layer, water content, efficiency of the oil-water separator, especially the production (corresponding to the pump flow rate), etc., and Able to respond dynamically in a timely manner. For example, if the flow rate of the water injection pump cannot be adjusted dynamically, the oily water may be injected back into the ground, which will not only block the injection layer and cause the pump pressure to rise, but even worse, cause irreparable underground pollution. Either the water content in the crude oil produced by the oil well pump is too large, forming an ineffective circulation, causing great waste, and not fully achieving the ideal goal of the same well injection and production process.

At present, in the injection and production system of the same well, two series oil well pumps driven by pumping unit (kowtow machine) are used to complete water injection and oil production respectively. Not only is the system complex and inefficient, but the key is that it cannot meet the dynamic changes in output (corresponding to pump flow). Although Chinese Patent No. 201611167280.0 discloses "An Oil Well Pump with Adjustable Effective Stroke", the flow rate of the pump is changed by manually adjusting the relative position of the oil well pump plunger and the pump barrel on the ground, that is, by changing the effective volume, but this method is The lagged non-dynamic and untimely ones cannot meet the dynamic change requirements of downhole oil and water, and need to be shut down for adjustment. At the same time, when the pump is working, a part of useless work is required, which is not energy-saving. Two sets of downhole screw pumps in series are used to complete water injection and oil production respectively. Although the flow rate of the pump can be changed by speed regulation, the two pumps used for water injection and oil production are driven by the same motor, and the flow rate is increased or decreased at the same time. , and cannot meet the dynamic change requirements of downhole oil and water. When the downhole screw pump is injected with water, the reaction force of the production layer pressure to the axial force when the screw rotates is also very large, which may cause damage to the pump. Chinese patent 201420407147.8 "A Protection Device for Screw Pumps Used in the Same Well Injection-Production System" was developed to reduce the impact of the pressure of the production layer on the screw pump. It cannot use the pressure energy of the production layer but suffers from it. Two downhole electric submersible pumps are used to complete water injection and oil production respectively, and the flow rate can be adjusted by speed regulation. However, the downhole electric submersible pump is a multi-stage centrifugal pump. Not to mention the low efficiency of the high-pressure and small-flow centrifugal pump. The key is that the head (pump pressure) of the pump changes at the same time when the pump flow rate changes. If the requirements of water injection and oil production are met, the pump will adjust itself to operate at a lower pump efficiency, and the motor may overheat or even be damaged, making it difficult to guarantee reliability. At the same time, the production layer pressure also has a great influence on the downhole electric submersible pump. Chinese patent 201420361109.3 discloses "Inverted Multistage Centrifugal Pump Suitable for Injection and Production in the Same Well", which uses thrusters to overcome the influence of production layer pressure on the axial force of the pump. However, once the multistage centrifugal pump is designed and finalized, its corresponding The axial force is fixed, it is difficult to adapt to the influence of formation pressure changes, and it is also impossible to use the pressure energy of the production layer but suffer from it. Of course, the above-mentioned problems also exist when the three kinds of pumps are used in combination respectively.

It stands to reason that the linear motor oil well pump should have been applied in the same well injection and production system due to its unique advantages such as convenient downhole installation, simple flow adjustment, high efficiency and safety. But in fact, there are many defects in the application examples of linear motor oil well pumps, such as the influence of the gravity of the liquid column in the oil outlet pipe on the force of the linear motor mover. In addition, it is inconvenient to install and arrange the injection-production system in the same well, and so on.

Chinese patent 201410176744.9 "three-tube linear motor oil well pump" adopts the mover to unilaterally drive the plunger to reciprocate, which cannot make full use of the pressure energy of the production layer, and also has the force of the gravity of the liquid column in the oil outlet pipe on the mover of the linear motor. In order to solve the problem of impact, the unilateral drive of the motor is performed at the same time, and the installation of the same well injection and production downhole string is not used.

Chinese patent 201620132423.3 "A Linear Motor Oil Suction Pump and Pump Body" The special pump body structure is really effective in eliminating the influence of the gravity of the liquid column in the oil outlet pipe on the load of the linear motor by utilizing the pressure of the production layer. However, due to the unilateral driving of the mover and the reciprocating motion of the plunger, it is not easy to install and arrange underground, and the complex flow channel structure of the pump body affects the pump efficiency and reliability.

Chinese patent 201310482601.6 "A Downhole Oil Production Device Integrated with Magnetic Levitation Machine and Pump" is convenient for underground installation and layout, and fully utilizes the pressure energy of the production layer, but it does not eliminate the influence of the gravity of the liquid column in the oil flow pipe on the down load of the linear motor. The biggest problem is to use the inner sheath of the linear motor stator as the pump barrel and the linear motor mover to connect the plunger, but the inner sheath of the linear motor stator is actually a thin-walled slender tube with a thickness of about 1mm, which is very difficult to process and wear-resistant. The performance is not good, and its safety and reliability are difficult to guarantee. The most serious thing is that the gravity of the liquid column in the oil outlet pipe has a large inertia force on the motor mover during the downstroke, which may cause accidents such as motor damage and damage to downhole equipment.

At the same time, the above-mentioned three linear motor oil well pump patents all connect the motor mover to the plunger, which virtually increases the length of the pump and increases the difficulty of underground installation.

Downhole linear motor water injection pump has no application data at present.

Waxing of downhole wetted parts is inevitable, and wax removal is a must. It has nothing to do with what kind of downhole pump is used, but for the same well injection and production process, especially for the same well injection and production process after the third recovery, the problem of wax deposition will be more serious. Because after the crude oil is separated by the oil-water separator, the concentration of the oil lifted by the oil pump is greatly increased, and the concentration of wax and colloid in the oil is high. Road, etc.) is easy to wax. At the same time, due to the limited separation effect of the downhole oil-water separator, complex components in the reinjection water (such as poly-contained sewage) will also cause wax deposition on the flow parts of the water injection pump; in addition, in order to improve the reliability of the downhole pump, especially the volume Pumps are usually operated at low pump speeds. When the pumps are operated at low speeds, the liquid flow rate is low, and the suspended solids are easy to settle, which will also make the pump flow parts easier to deposit wax. The effects of wax deposition on downhole pumps are well known to those skilled in the art. At present, the effective way is to stop the well for hot washing, that is, to inject high-temperature and high-pressure water from the ground to the downhole for flushing. Hot washing takes a long time, costs high, and affects production.

How to make full use of the downhole linear motor oil well pump's advantages of easy installation, simple flow adjustment, full use of the pressure energy of the production layer, high efficiency, safety and reliability, to develop a pump for the same well injection and production system, and solve the problem of wax deposition in the flow-passing parts is the key Problems to be solved urgently by those skilled in the art.

Contents of the invention

The purpose of the present invention is to provide a same-well injection-production pump set to solve the above-mentioned problems in the prior art, to make the pumps used in the same-well injection-production system efficient, safe, convenient and reliable, to realize automatic non-stop thermal washing and wax removal, and to Guarantee the popularization of injection-production technology in the same well, and give full play to the economic and social benefits of the injection-production technology in the same well.

To achieve the above object, the present invention provides the following scheme:

The invention provides an injection-production pump set for the same well, which includes a linear motor oil well pump, a linear motor water injection pump, and an oil-water separator arranged between the linear motor oil well pump and the linear motor water injection pump. The oil pump is arranged on the upper part of the oil-water separator, and the linear motor water injection pump is arranged on the lower part of the oil-water separator;

The linear motor oil well pump includes a first linear motor stator, a first linear motor mover, a first cylinder liner, a first fixed valve and a first floating valve, and the two ends of the first linear motor stator are sequentially connected There are the first cylinder liner and the first fixed valve, the two ends of the first cylinder liner are respectively connected to the first linear motor stator and the inner hole at one end of the first fixed valve, and the first The inner hole of the cylinder liner communicates with the inner hole of the first linear motor stator and the first fixed valve, and the first linear motor mover is a circular tube structure with a first oil-water passage inside, so The first floating valve is arranged at the bottom of the first linear motor mover, and the first linear motor mover is arranged at the first linear motor stator and the two ends of the first linear motor stator In the through hole of the first cylinder liner, a first sealing assembly is provided between the two ends of the outer wall of the first linear motor mover and the first cylinder liner, and the valve seat of the first floating valve is located at The bottom of the valve ball, the valve seat of the first fixed valve is located at the bottom of the valve ball;

The linear motor water injection pump includes a second linear motor stator, a second linear motor mover, a second cylinder liner, a second fixed valve and a second floating valve, and the two ends of the second linear motor stator are sequentially connected with the The second cylinder liner and the second fixed valve, the two ends of the second cylinder liner are respectively connected to the inner holes of the second linear motor stator and the second fixed valve end, the inner hole of the second cylinder liner The hole communicates with the inner hole of the second linear motor stator and the second fixed valve, the second linear motor mover is a circular tube structure with a second oil-water passage inside, and the second floating valve It is arranged at the bottom of the second linear motor mover, and the second linear motor mover is arranged in the through holes of the second linear motor stator and the second cylinder liner at both ends of the second linear motor stator, A second sealing assembly is provided between the two ends of the outer wall of the second linear motor mover and the second cylinder liner, the valve seat of the second floating valve is located on the top of the valve ball, and the valve seat of the second fixed valve is The seat sits on top of the ball.

Preferably, a first electric heating element is provided in the middle of the outer wall of the first cylinder liner, a first sheath is arranged outside the first electric heating element, and one end of the first sheath is connected to the outer wall of the first fixed valve, The other end of the first sheath is connected to the outer wall of the stator of the first linear motor.

Preferably, sealing rings are provided at the connection between the first sheath and the first fixed valve and the connection between the first sheath and the first linear motor stator.

Preferably, the first electric heating element is an adjustable temperature electric heating element.

Preferably, a second electric heating element is provided in the middle of the outer wall of the second cylinder liner, and a second sheath is arranged outside the second electric heating element, and one end of the second sheath is connected to the outer wall of the second fixed valve, The other end of the second sheath is connected to the outer wall of the second linear motor stator.

Preferably, sealing rings are provided at the connection between the second sheath and the second fixed valve and the connection between the second sheath and the second linear motor stator.

Preferably, the second electric heating element is an adjustable temperature electric heating element.

Preferably, the first cylinder sleeves at both ends of the linear motor oil well pump are arranged symmetrically.

Preferably, the second cylinder sleeves at both ends of the linear motor water injection pump are arranged symmetrically.

Preferably, it also includes a displacement sensor and a speed sensor respectively arranged on the linear motor oil well pump and the linear motor water injection pump, and the displacement sensor and the speed sensor are connected to a control system.

Compared with the prior art, the present invention has achieved the following beneficial technical effects:

The same well injection-production pump set provided by the present invention, the linear motor oil well pump and the linear motor water injection pump have a simple structure, convenient installation in the well, and simple flow adjustment. Efficient, safe, reliable, and versatile, electric heating elements are installed on the linear motor oil well pump and linear motor water injection pump, which can realize automatic non-stop thermal washing and wax removal, which ensures the promotion of the same well injection and production technology, fully embodies the same Economic and social benefits of well injection-production technology.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without paying creative labor.

Fig. 1 is a schematic diagram of the overall assembly structure of the same well injection-production pump group in the present invention;

Fig. 2 is the structural representation of the linear motor oil well pump in the same well injection-production pump group in the present invention;

Fig. 3 is the enlarged structural representation of the top of the linear motor oil well pump in the same well injection-production pump group in the present invention;

Fig. 4 is the enlarged structural representation of the bottom end of the linear motor oil well pump in the same well injection-production pump group in the present invention;

Fig. 5 is the structural representation of the linear motor water injection pump in the same well injection-production pump group in the present invention;

Fig. 6 is the enlarged schematic structural view of the top of the linear motor water injection pump in the same well injection-production pump group in the present invention;

Fig. 7 is the enlarged structure schematic diagram of the bottom end of the linear motor water injection pump in the same well injection-production pump group in the present invention;

In the figure: 1-linear motor oil pump, 2-linear motor water injection pump, 3-oil-water separator, 11-the first linear motor stator, 12-the first linear motor mover, 13-the first cylinder liner, 14 - the first fixed valve, 15 - the first floating valve, 16 - the first oil-water passage, 17 - the first sealing assembly, 18 - the first electric heating element, 19 - the first sheath, 21 - the second linear motor stator, 22-Second linear motor mover, 23-Second cylinder liner, 24-Second fixed valve, 25-Second floating valve, 26-Second oil-water passage, 27-Second sealing assembly, 28-Second electric heater Component, 29-second sheath, A-wellhead, B-water injection layer, C-oil-water boundary, D-production layer, Q11-lower volume chamber of oil well pump, Q12-upper volume chamber of oil well pump, Q21-water injection pump Lower volume chamber, Q22- water injection pump upper volume chamber.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The purpose of the present invention is to provide a same-well injection-production pump set to solve the problems in the prior art.

In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

The present invention provides a same-well injection-production pump set, as shown in Figures 1-7, comprising a linear motor oil well pump 1, a linear motor water injection pump 2, and an oil-water pump set between the linear motor oil well pump 1 and the linear motor water injection pump 2 The separator 3, specifically, the linear motor oil pump 1 is arranged on the upper part of the oil-water separator 3, and the linear motor water injection pump 2 is arranged on the lower part of the oil-water separator 3;

Wherein the specific structure of the linear motor oil well pump 1 is: comprising the first linear motor stator 11, the first linear motor mover 12, the first cylinder liner 13, the first fixed valve 14 and the first traveling valve 15, the first The two ends of the linear motor stator 11 are connected with the first cylinder liner 13 and the first fixed valve 14 in turn, the first cylinder liner 13 at the two ends of the first linear motor stator 11 is symmetrically arranged, and the two ends of the first cylinder liner 13 are respectively connected to the first The linear motor stator 11 is connected to the inner hole of one end of the first fixed valve 14, the inner hole of the first cylinder liner 13 communicates with the inner hole of the first linear motor stator 11 and the first fixed valve 14, and the first linear motor The sub 12 is a circular tube structure with a first oil-water passage 16 inside, the first floating valve 15 is set at the bottom of the first linear motor mover 12, and the first linear motor mover 12 is set at the first linear motor In the through holes of the stator 11 and the first cylinder liner 13 at both ends of the first linear motor stator 11, a first sealing assembly 17 is arranged between the two ends of the outer wall of the first linear motor mover 12 and the first cylinder liner 13, To ensure the sealing performance of the connection between the first linear motor mover 12 and the first cylinder liner 13, the valve seat of the first floating valve 15 is located at the bottom of the valve ball, and the valve seat of the first fixed valve 14 is located at the bottom of the valve ball;

The middle part of the outer wall of the first cylinder liner 13 of the linear motor oil pump 1 is provided with a temperature-adjustable first electric heating element 18, and the outside of the first electric heating element 18 is provided with a first sheath 19, and one end of the first sheath 19 is connected to the first fixed valve. 14, the other end of the first sheath 19 is connected to the outer wall of the first linear motor stator 11, and the connection between the first sheath 19 and the first fixed valve 14 and the connection between the first sheath 19 and the first linear motor The joints of the wire motor stator 11 are all provided with sealing rings.

The specific structure of the linear motor water injection pump 2 is basically the same as that of the linear motor oil well pump 1, except for the installation method of the fixed valve and the floating valve. The specific linear motor water injection pump 2 includes the second linear motor stator 21, the first Two linear motor movers 22, the second cylinder liner 23, the second fixed valve 24 and the second floating valve 25, the two ends of the second linear motor stator 21 are connected with the second cylinder liner 23 and the second fixed valve 24 in sequence, The cylinder sleeves at the two ends of the two linear motor stators 21 are symmetrically arranged, and the two ends of the second cylinder sleeve 23 are connected with the inner holes of the second linear motor stator 21 and the second fixed valve 24 respectively, and the inner holes of the second cylinder sleeves 23 are connected with the second The inner hole of the linear motor stator 21 and the second fixed valve 24 communicates, the second linear motor mover 22 is a circular tube structure with a second oil-water passage 26 inside, and the second floating valve 25 is arranged on the second linear motor motor. At the bottom of the sub 22, the second linear motor mover 22 is arranged in the through hole of the second linear motor stator 21 and the second cylinder liner 23 at both ends of the second linear motor stator 21, and the two ends of the outer wall of the second linear motor mover 22 are connected to the A second sealing assembly 27 is provided between the second cylinder liners 23 to ensure the sealing performance of the connection between the second linear motor mover 22 and the second cylinder liner 23, which is different from the linear motor oil well pump 1 and the linear motor water injection pump 2. The valve seat of the second floating valve 25 is located on the top of the valve ball, and the valve seat of the second fixed valve 24 is located on the top of the valve ball.

The middle part of the outer wall of the second cylinder liner 23 of the linear motor water injection pump 2 is the same as that of the linear motor oil well pump 1, and is also provided with a temperature-adjustable electric heating element, specifically named as the second electric heating element 28, and the second electric heating element 28 is provided with a second electric heating element outside. Sheath 29, one end of the second sheath 29 is connected to the outer wall of the second fixed valve 24, the other end of the second sheath 29 is connected to the outer wall of the second linear motor stator 21, and the second sheath 29 is connected to the second fixed valve 24 and the connection between the second sheath 29 and the second linear motor stator 21 are provided with sealing rings.

The present invention provides an injection-production pump set in the same well. In the specific application process, in order to meet the requirements of convenient and reliable underground layout and installation, the bottom end of the linear motor oil well pump 1 is installed on the upper part of the oil-water separator 3, and the top end of the linear motor oil well pump 1 is connected to the top of the oil-water separator 3. The oil outlet pipe leading to the wellhead A is connected, the top of the linear motor water injection pump 2 is installed on the lower part of the oil-water separator 3, and the bottom end of the linear motor water injection pump 2 is connected to the water injection pipe leading to the water injection layer B (the oil-water separator 3 is the existing technology, its structure and working principle will not be repeated). After the crude oil is separated by the oil-water separator 3, the oil flows to the top of the oil-water separator 3, above the oil-water boundary C, that is, the bottom of the linear motor oil well pump 1, and the water flows to the bottom of the oil-water separator 3, between the oil-water boundary C Down, that is, the top of the linear motor water injection pump 2. When the linear motor oil well pump 1 is working, the oil is lifted from the bottom to the top (low pressure to high pressure) of the linear motor oil well pump 1 through the oil outlet pipe to the ground wellhead A; when the linear motor water injection pump 2 is working, the water is pumped from the linear motor water injection pump 2 From the top to the bottom (from low pressure to high pressure), it is reinjected into the downhole injection layer through the outlet pipe; after the above working method, the injection and production group of the same well uses the linear motor oil well pump 1 and the linear motor water injection pump 2 to complete the water injection and oil production respectively.

Combined with the specific structure of the linear motor oil well pump 1, the specific working principle of the linear motor oil well pump 1 is as follows:

When the linear motor oil well pump 1 is working, the first linear motor mover 12 moves upward (upstroke), the volume of the lower volume chamber Q11 of the oil well pump increases, the pressure decreases, and the first fixed valve 14 below the linear motor oil well pump 1 opens; The volume of the upper volume chamber Q12 of the oil well pump becomes smaller and the pressure rises, the first floating valve 15 is closed, and the first fixed valve 14 above the linear motor oil well pump 1 is opened; during this stroke, the separated oil from the production layer D enters the lower part of the oil well pump Volume chamber Q11, the oil in volume chamber Q12 on the well pump is lifted to the wellhead A. The first linear motor mover 12 moves downward (downstroke), the volume of the lower volume chamber Q11 of the oil well pump becomes smaller and the pressure rises, and the first fixed valve 14 below the linear motor oil well pump 1 closes; the upper volume chamber Q12 of the oil well pump The volume increases and the pressure decreases, the first floating valve 15 is opened, and the first fixed valve 14 above the linear motor oil well pump 1 is closed. The oil in the lower volume chamber Q11 of the oil well pump enters into the upper volume chamber Q12 of the oil well pump through the first oil-water passage 16 of the first linear motor mover 12; Oil pumping function of oil pump 1.

When the linear motor oil well pump 1 is in motion, the output of the motor is as follows:

Downstroke: F _ys +π/4D ² P _C ＝G _D +G _Y +f ₁ +π/4D ² P _y

Up stroke: F _yx +G _D +G _YQ +π/4(D ² -d ² )P _Q ＝π/4(D ² -d ² )P _Q +f ₂

F _yx +(G _D +G _YQ )＝f ₂

F _ys --- The force that the motor gives to the first linear motor mover 12 when the linear motor oil well pump 1 is upstroke

F _yx --- The force exerted by the motor on the first linear motor mover 12 when the linear motor oil well pump 1 is in the downstroke

P _C --- downhole production layer D pressure G _D --- first linear motor mover 12 gravity

G _Y --- The gravity of the liquid column in the oil outlet pipe from the upper part of the first fixed valve 14 below the linear motor oil well pump 1 to the wellhead A

G _YQ --- Liquid gravity in the upper volume chamber Q12 of the oil well pump

P _y --- linear motor oil well pump 1 discharge pressure f ₁ f ₂ --- friction D --- inner diameter of the first cylinder liner 13

d---The diameter of the first oil-water passage 16

From the force analysis of the linear motor oil well pump 1 in motion, it can be seen that during the upstroke, the force direction of the production layer D pressure P _C is consistent with the direction of the motor output force, that is to say, the pump fully utilizes the output force when it works. Layer D pressure energy. During the downstroke, the output of the motor only needs to overcome the frictional force, and the gravity G _D of the first linear motor mover 12 and the gravity G _YQ of the liquid in the upper volume chamber Q12 of the oil well pump return one piece to the first linear motor mover 12 Downward force, so the motor output is very small, energy-saving and high-efficiency, more importantly, the first fixed valve 14 above the linear motor oil well pump 1 is closed during the down stroke, which avoids the upper part of the first fixed valve 14 above the linear motor oil well pump 1 The gravity G _Y of the liquid column in the oil outlet pipe to the wellhead A gives the first linear motor mover 12 greater inertial force. In fact, the general pump hanging height is about 1000m. The oil outlet pipe from the upper part of the first fixed valve 14 above the linear motor oil well pump 1 to the wellhead A is very long, and the gravity G _Y of the liquid column in the pipe is also very large. The motor mover 12 does not need a lot of force. If the gravity of the liquid column G _Y is not isolated, then the first linear motor mover 12 will accelerate under the action of the gravity G _Y of the liquid column when it travels down. A back electromotive force of the linear motor constrains the downward speed of the first linear motor mover 12, otherwise the stall of the first linear motor mover 12 will cause damage to downhole equipment, and the back electromotive force is very harmful to the motor. Simultaneously, when the pump is stopped due to a power failure or the pump is stopped for some reason, the rapid drop of the first linear motor mover 12 caused by the gravity G _Y of the liquid column is also avoided. The first fixed valve 14 installed on the upper part of the volume cavity Q12 of the oil well pump in the present invention effectively solves the influence of liquid column gravity G _Y on the downward movement of the first linear motor mover 12, and greatly improves the safety of the pump.

Combined with the specific structure of the linear motor water injection pump 2, the specific working principle of the linear motor water injection pump 2 is as follows:

When the linear motor water injection pump 2 is working, the second linear motor mover 22 moves upward (upstroke), the volume of the lower volume cavity Q21 of the water injection pump increases, the pressure decreases, and the second fixed valve 24 below the linear motor water injection pump 2 is closed, and the injection The volume of the upper volume chamber Q22 of the water pump becomes smaller and the pressure rises, the second floating valve 25 is opened, the second fixed valve 24 above the linear motor water injection pump 2 is closed, and the water in the upper volume chamber Q22 of the water injection pump passes through the second oil-water passage 26 Enter the lower volume chamber Q21 of the water injection pump. The second linear motor mover 22 moves downward (downstroke), the volume of the lower volume chamber Q21 of the water injection pump becomes smaller and the pressure rises, and the second fixed valve 24 below the linear motor water injection pump 2 opens; the volume of the upper volume chamber Q22 of the water injection pump becomes larger and the pressure decreases, the second floating valve 25 is closed, and the second fixed valve 24 above the linear motor water injection pump 2 is opened. The separated water in the production layer D enters the upper volume chamber Q22 of the water injection pump, and the water in the lower volume chamber Q21 of the water injection pump is reinjected into the water injection layer B; the second linear motor mover 22 reciprocates in this way, realizing the water injection function of the water injection pump.

When the linear motor water injection pump 2 is in motion, the output of the motor is as follows:

Upstroke: F _ss +π/4(D ² -d ² )P _Q ＝G _D +G _Q +f ₁ +π/4(D ² -d ² )P _Q

F _ss =G _D +G _Q +f ₁

Down stroke: F _sx +G _D +G _YS +π/4D ² P _C ＝π/4D ² P _z +f ₂

F _ss --- The force that the motor gives to the second linear motor mover 22 when the linear motor water injection pump 2 is upstroke

F _sx --- The force that the motor gives to the second linear motor mover 22 when the linear motor water injection pump 2 is down stroke

P _C --- downhole production layer D pressure G _D --- second linear motor mover 22 gravity

G _YS --- Liquid column gravity of the upper water inlet pipe of the second fixed valve 24 above the linear motor water injection pump 2

G _YQ --- Liquid gravity in the upper volume chamber Q22 of the water injection pump

P _z --- linear motor water injection pump 2 discharge pressure f ₁ f ₂ --- friction D --- inner diameter of the second cylinder liner 23

d---the diameter of the second oil-water passage 26

From the force analysis of the linear motor water injection pump 2 in motion, it can be seen that during the downstroke, the force direction of the production layer D pressure P _C is consistent with the direction of the motor output force, that is to say, the pump fully utilizes the output force when it works. Layer D pressure energy. Moreover, the gravity G _D of the second linear motor mover 22 and the gravity G _YS of the liquid in the tube give the second linear motor mover 22 a downward force, thereby greatly reducing the output of the motor and saving energy. During the upstroke, the output of the motor only needs to overcome the frictional force, the gravity of the second linear motor mover 22, and the gravity of the liquid in the upper volume chamber Q22 of the water injection pump. What is more critical is that the second fixed valve 24 above the linear motor water injection pump 2 is closed during the upstroke, which prevents the second linear motor from the upper part of the second fixed valve 24 above the linear motor water injection pump 2 to the gravity G _YS of the water inlet pipe liquid column. Sub 22 greater reaction force, energy saving and high efficiency. At the same time, when the pump is stopped due to a power failure or for some reason, the rapid drop of the second linear motor mover 22 caused by the gravity of the liquid column G _Y is also avoided, which greatly improves the safety of the pump.

For the first electric heating element 18 and the second electric heating element 28 installed on the outside of the first cylinder liner 13 and the second cylinder liner 23, since the first electric heating element 18 and the second electric heating element 28 are the same, for the sake of simplicity and clarity, they are collectively referred to as electric heat The electric heating element, the electric heating element composed of the first sheath 19 and the second sheath 29 is relatively independent, and the electric heating element is placed on the first cylinder liner 13 and the first sheath 19 as well as the second cylinder liner 23 and the second liner. In the sealed space formed by the two sheaths 29, the temperature of the electric heating element is adjustable, and its power supply circuit is also separated from the power supply circuit of the linear motor part. The heat of the electric heating element is transferred to the lower volume chamber Q11 of the oil well pump, the upper volume chamber Q12 of the oil well pump, the lower volume chamber Q21 of the water injection pump and the upper volume chamber Q22 of the water injection pump through the first cylinder liner 13 and the second cylinder liner 23, and the liquid passes through each The volume chamber is heated, and when the heated liquid is lifted to the wellhead A or reinjected into the water injection layer B, the wax deposits on the surface of all flow-through parts that the high-temperature liquid flows through will be melted and washed away until it is cleared.

When the flow rate, discharge pressure, and motor current of the linear motor oil well pump 1 or linear motor water injection pump 2 fluctuate abnormally due to wax deposition and scaling, the corresponding sensors in the well will transmit the data to the ground control system. The ground control system has a built-in The program automatically judges the power supply to the electric heating element, and automatically judges and adjusts the temperature of the electric heating element through the feedback signals of multiple temperature sensors in the well, so that the pumped liquid can be heated to the set temperature range, and the heated liquid flows through the linear motor pumping The oil pump 1 or the linear motor water injection pump 2 washes the wax deposits on the surface of the flow-passing parts to achieve the purpose of thermal washing and wax removal. Taking the linear motor oil well pump 1 as an example, the liquid is heated once when it enters the lower volume chamber Q11 of the oil well pump during the upstroke, and is heated twice when it enters the upper volume chamber Q12 of the oil well pump during the downstroke, and then lifted to Wellhead A. The wax and scale on the surface of each valve group where the liquid flows, the oil outlet pipe to the wellhead A, etc. are melted little by little, washed away until cleared.

Stop heating after the linear motor oil pump 1 or the linear motor water injection pump 2 have normal working parameters. Of course, the electric heating elements on the linear motor oil well pump 1 and the linear motor water injection pump 2 can work at the same time or not at the same time, which is automatically controlled by the ground control part corresponding to the linear motor oil well pump 1 or the linear motor water injection pump 2 . For the linear motor oil well pump 1, the viscosity of crude oil can be reduced by heating, and its fluidity can be improved, which is more suitable for lifting heavy oil and high waxy oil. For the linear motor water injection pump 2, the high temperature also cracks some macromolecular components (such as polymers and chemicals) in the reinjected sewage, and also kills the microorganisms in the reinjected sewage, effectively avoiding the return Pollution of formation by injection of sewage.

In fact, because the downhole liquid itself has a certain temperature (generally around 50°C), taking the linear motor oil well pump 1 as an example, the purpose of heating is to ensure the temperature required for melting wax when the liquid flows to the wellhead A ( Generally around 60°C), the heat capacity does not need to be too large, so the power of the heating element is not very large.

The oil-water separator 3 of the injection-production pump group of the same well is usually separated by gravity. The granular impurities in the crude oil, such as sand grains, will settle in the sand collection pipe at the lower part of the oil-water separator 3 due to their large mass. After separation, the oil (water) There is almost no granular impurities in the pump, which will not cause mechanical wear to the flow-passing parts in the pump. The first sealing assembly 17 and the second sealing assembly 27 adopted in the present invention can effectively prevent high-pressure leakage and improve pump efficiency, and the first sealing The component 17, the second sealing component 27, the first cylinder liner 13, the second cylinder liner 23, the first floating valve 15, the second floating valve 25, the first fixed valve 14 and the second fixed valve 24 all have a single function The wearing parts can be improved economically and conveniently through materials, heat treatment, processing and other technological means, thus ensuring the high efficiency, safety and reliability of the pump. The first sealing assembly 17, the second sealing assembly 27, the first cylinder liner 13 and the second cylinder liner 23 of the pump are all arranged in the same structure up and down, which can improve the versatility of pump parts and facilitate installation, use and maintenance.

The first floating valve 15 and the second floating valve 25 can be installed on the bottom of the linear motor mover, can also be installed on the top of the linear motor mover, and can also be installed in the oil-water passage of the linear motor mover. Even the mover of the linear motor can be disconnected and installed at any position in the middle of the mover of the linear motor, and the function of the floating valve can be realized.

When the injection-production linear motor oil well pump 1 and the linear motor water injection pump 2 are working downhole, they transmit signals through pressure, flow, oil-water level sensors, oil-water interface instruments, and displacement and speed sensors installed at appropriate positions downhole. For the surface control system, the parameters such as the flow rate of the linear motor oil well pump 1 and the linear motor water injection pump 2 are adjusted dynamically and accurately by changing the stroke length and pump speed of the pump to meet the requirements of dynamic changes in downhole parameters. The cylindrical shape of the pump and the central oil-water passage in the present invention are convenient for installation and arrangement in the well.

The present invention uses specific examples to illustrate the principle and implementation of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; meanwhile, for those of ordinary skill in the art, according to the present invention Thoughts, there will be changes in specific implementation methods and application ranges. In summary, the content of this specification should not be construed as limiting the present invention.

Claims (10)

1. A kind of 1. single-well injection-production pump group, it is characterised in that：Including linear dynamo oil pump, linear electric motors water injecting pump and it is arranged at institute The oil water separator between linear dynamo oil pump and the linear electric motors water injecting pump is stated, the linear dynamo oil pump is arranged at The oil water separator top, the linear electric motors water injecting pump are arranged at the oil water separator bottom；

   The linear dynamo oil pump includes first straight line motor stator, first straight line electric mover, the first cylinder sleeve, the first fixation Valve and the first travelling valve, the first straight line motor stator both ends are connected with first cylinder sleeve and described first in turn and fixed Valve, one end endoporus of the first cylinder sleeve both ends respectively with the first straight line motor stator and first standing valve are connected, The endoporus of first cylinder sleeve communicates with the endoporus of the first straight line motor stator and first standing valve, and described first is straight Line electric mover is the circular tube structure that an inside carries the first profit path, and first travelling valve is arranged at the first straight line Electric mover bottom, the first straight line electric mover are arranged at the first straight line motor stator and the first straight line motor In the through hole of first cylinder sleeve at stator both ends, the outer wall both ends of the first straight line electric mover and first cylinder sleeve it Between be provided with the first seal assembly, the valve seat of first travelling valve is located at valve ball bottom, the valve seat position of first standing valve In valve ball bottom；

   The linear electric motors water injecting pump includes second straight line motor stator, second straight line electric mover, the second cylinder sleeve, the second fixation Valve and the second travelling valve, the second straight line motor stator both ends are connected with second cylinder sleeve and described second in turn and fixed Valve, one end endoporus of the second cylinder sleeve both ends respectively with the second straight line motor stator and second standing valve are connected, The endoporus of second cylinder sleeve communicates with the endoporus of the second straight line motor stator and second standing valve, and described second is straight Line electric mover is the circular tube structure that an inside carries the second profit path, and second travelling valve is arranged at the second straight line Electric mover bottom, the second straight line electric mover are arranged at the second straight line motor stator and the second straight line motor In the through hole of second cylinder sleeve at stator both ends, the outer wall both ends of the second straight line electric mover and second cylinder sleeve it Between be provided with the second seal assembly, the valve seat of second travelling valve is located at the top of valve ball, the valve seat position of second standing valve At the top of valve ball.
2. 2. single-well injection-production pump group according to claim 1, it is characterised in that：The is provided with the middle part of first outer wall of cylinder jachet One electric heating element, the first sheath is provided with outside first electric heating element, and described first sheath one end is fixed with described first The outer wall connection of valve, the first sheath other end are connected with the outer wall of the first straight line motor stator.
3. 3. single-well injection-production pump group according to claim 2, it is characterised in that：First sheath and first standing valve Junction and the junction of first sheath and the first straight line motor stator be provided with sealing ring.
4. 4. single-well injection-production pump group according to claim 3, it is characterised in that：First electric heating element is temperature controllable electric heating Element.
5. 5. single-well injection-production pump group according to claim 1, it is characterised in that：The is provided with the middle part of second outer wall of cylinder jachet Two electric heating elements, the second sheath is provided with outside second electric heating element, and described second sheath one end is fixed with described second The outer wall connection of valve, the second sheath other end are connected with the outer wall of the second straight line motor stator.
6. 6. single-well injection-production pump group according to claim 5, it is characterised in that：Second sheath and second standing valve Junction and the junction of second sheath and the second straight line motor stator be provided with sealing ring.
7. 7. single-well injection-production pump group according to claim 6, it is characterised in that：Second electric heating element is temperature controllable electric heating Element.
8. 8. single-well injection-production pump group according to claim 1, it is characterised in that：The linear dynamo oil pump both ends it is described First cylinder sleeve is symmetrical arranged.
9. 9. single-well injection-production pump group according to claim 1, it is characterised in that：The linear electric motors water injecting pump both ends it is described Second cylinder sleeve is symmetrical arranged.
10. 10. single-well injection-production pump group according to claim 1, it is characterised in that：Also include being separately positioned on the straight-line electric Displacement transducer and velocity sensor on machine oil well pump and the linear electric motors water injecting pump, institute's displacement sensors and the speed Degree sensor is connected with a control system.