Forced sand scraping pump and application method

Abstract

The present invention provides a forced sand scraping pump and an application method. The forced sand scraping pump includes a coupling, a sand blocking slide valve, a pump barrel, a pull rod, an outer barrel, an intermediate joint, a sand scraping ring and a liquid inlet valve. The coupling is connected to the outer barrel, the outer barrel is connected to the liquid inlet valve, the pump barrel is connected to the liquid inlet valve, the pull rod is connected to the intermediate joint, the pull rod passes through the sand blocking slide valve, and the sand scraping ring is located inside the pump barrel and has a sand scraping chamfer to scrape off the sand adhered to the inner wall of the pump barrel and carry it away by the produced liquid. The sand blocking slide valve blocks impurities from settling into the pump barrel and shields the pressure in the upper part of the pump barrel. The forced sand scraping pump and the application method solve the drawbacks brought by conventional parameter adjustment, reduce the probability of sand particles, scale and rust entering the plunger, solve the problems that gas affects the difficult opening and inability to open the plunger valve group, increase the plunger stroke, improve the pump efficiency, and extend the service life of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of oil equipment, and particularly to a forced sand scraping pump and an application method thereof. Background Art

[0002] During the application of a sand-producing oil well sucker rod pump, there are problems such as sand erosion, sand settlement causing damage to the pump valve of the sucker rod pump, and sand jamming of the plunger. When the pumping unit stroke is adjusted from high to low, the large sand grains originally carried at high speed gradually settle due to the change in flow velocity and the decrease in the liquid carrying capacity, and fall into the valve seat and the gap between the pump barrel / plunger. When the sand grains fall on the valve seat, during the downstroke, the valve ball and the valve seat do not close tightly, the pressure in the pump barrel increases, and the high-pressure fluid generates a high-pressure jet in the gap between the valve ball and the valve seat, resulting in cavitation of the valve group surface structure and causing the valve group to fail quickly. The sand grains between the pump barrel / plunger wear the pump barrel / plunger to form grooves, and the clearance seal fails, making it impossible to effectively lift the liquid.

[0003] In the Chinese patent application with the application number: CN201010011407.6, it relates to an equal-diameter sucker rod pump plunger assembly, which consists of an upper oil outlet joint, an equal-diameter plunger, a traveling valve ball, a traveling valve seat, and a valve seat joint. There is an oil outlet groove on the upper oil outlet joint, and the upper oil outlet joint, the equal-diameter plunger, and the valve seat joint are connected in sequence. The traveling valve ball is seated on the upper port of the traveling valve seat. A valve seat hole and a valve ball cavity are provided above the thread at the lower part of the equal-diameter plunger. The traveling valve seat is installed in the valve seat hole, and the traveling valve ball is in the valve ball cavity. A shield is installed above the valve ball cavity and fixed in the equal-diameter plunger. The structure of this application is that the upper end of the plunger body adopts a thin wall and is provided with a chamfer. Under the hydraulic action, the thin wall expands to cooperate with the pump barrel to realize sand scraping. However, in application, due to the influence of the downward resistance, material, etc. on the equal-diameter surface, it is easy to wear and lose the sand scraping function.

[0004] In the Chinese patent application with the application number: CN201220584313.2, it relates to a soft-sealing sand control pump. The lower part of the pump barrel is connected to the inlet valve. A sand swirling device is sleeved on the connecting rod. The lower part of the connecting rod is connected to the upper part of the oil outlet joint. The external thread on the upper part of the oil outlet joint is connected to the thread on the lower part of the upper plunger. The lower part of the connecting rod extends into the upper plunger, so that the sand swirling device is seated on the upper port of the upper plunger. The external thread on the lower part of the oil outlet joint 4 is connected to the upper part of the lower plunger. The lower part of the lower plunger is connected to the outlet valve. The upper plunger and the lower plunger are in clearance fit with the pump barrel. A sealing ring is installed on the lower plunger, and there is no clearance between the sealing ring and the pump barrel. The upper part of the upper plunger is an equal-diameter structure. A sand swirling device is installed above the upper plunger. The upper part of the upper plunger is an equal-diameter structure. A sealing ring is sleeved on the lower plunger so that there is no clearance between it and the pump barrel, and there is no leakage. Therefore, sand grains are easily discharged and will not enter the gap between the upper plunger and the pump barrel, and the problem of sand abrasion of the sucker rod pump caused by sand jamming can be avoided. This application adds a sand scraping ring made of a flexible material on the plunger body. The problem with it is that the hardness of the sand scraping ring is relatively soft, and sand grains are easily embedded in the sand scraping ring, resulting in the failure of sand scraping and accelerating the wear of the pump barrel.

[0005] In the Chinese patent application with the application number CN201810242446.3, it relates to a tubular sand scraping oil extraction pump, which includes an upper movable ball cover (1), an upper sealing ball (2), an upper sealing ball seat (3), an upper fixed valve joint (4), an upper movable valve joint (5), a plunger (6), a pump barrel (7), a middle movable valve cover (8), a middle sealing ball (9), a middle sealing ball seat (10), a sealing seat cover (11), a middle fixed valve joint (12), a lower fixed valve cover (13), a lower sealing ball (14), a lower sealing ball seat (15), and a lower fixed valve joint (16); it is characterized in that: it further includes an upper sand scraping device (17) that can scrape sand, so that the sand grains in the crude oil above the plunger cannot enter between the plunger (6) and the pump barrel (7). The upper sand scraping device (17) is composed of a sand hole straight-through joint (17-1) and a scraping knife ring (17-7). When the oil pump works to extract oil, the crude oil enters from the lower fixed valve joint (16) and goes up to the upper fixed valve joint (4); part of the sand grains in the crude oil above the oil extraction pump will precipitate under the influence of time and gravity; at this time, the scraping knife ring (17-7) of the upper sand scraping device (17) will scrape the sand grains into the knife groove (17-2) and flow back to the crude oil channel (17-4) through the sand return hole (17-3), so that the sand grains in the crude oil above the plunger cannot precipitate between the plunger (6) and the pump barrel (7), solving the problem of the oil extraction pump getting stuck and crashing due to the precipitation of sand grains in the crude oil at the upper opening of the plunger (6). This patented technology can maintain the sand scraping effect when the oil extraction pump is working properly, but when the machine is shut down for maintenance, the ground equipment fails, or the equipment parameters are adjusted, the deposited sand is likely to accumulate between the scraping knife ring and the pump barrel, resulting in pump jamming, so the problem of pump jamming during abnormal operation has not been solved.

[0006] In the Chinese patent application with the application number CN201610810910.5, it relates to an integrated device for scraping pipes and flushing sand in oil wells, which includes a flow splitting short joint, a flow splitting packer, a double-layer pipe body, a pipe scraper, and a sand flushing short joint that are interconnected and all have a double-layer pipe structure; its method for scraping pipes and flushing sand is as follows: First, the pipe scraper is opened and the flow splitting packer is retracted, and the device is lowered into the oil well casing, and washing fluid is injected into the casing annulus to complete pipe scraping and well washing; Second, after determining the sand surface position, the pipe scraper is retracted and the flow splitting packer is set; Then, sand flushing fluid is injected into the casing annulus, and positive pressure sand flushing or negative pressure sand flushing is used to flush the bottom of the well; Finally, the flow splitting packer is released and the drill pipe is pulled out. After determining the sand surface in this process method, the flow splitting packer is set. At this time, the pipe string cannot be lowered deeper, and sand flushing can only be carried out within the depth range of the pipe string. For deeper sand, effective sand flushing cannot be achieved, and the packer needs to be released and the sand surface needs to be probed again. However, limited by the packer, it cannot be set multiple times, so it is only applicable to oil wells with less accumulated sand.

[0007] The above prior arts are quite different from the present invention and cannot solve the technical problems we want to address. Therefore, we have invented a new forced sand scraping pump and its application method. Summary of the Invention

[0008] The objective of the present invention is to provide a forced sand scraping pump and its application method that adopt a sand blocking structure to reduce the probability of sand particles entering the plunger.

[0009] The objective of the present invention can be achieved through the following technical measures: a forced sand scraping pump, which includes a coupling, a sand blocking slide valve, a pump barrel, a pull rod, an outer barrel, an intermediate joint, a sand scraping ring, and a liquid inlet valve. The coupling is connected to the outer barrel, the outer barrel is connected to the liquid inlet valve, the pump barrel is connected to the liquid inlet valve, the pull rod is connected to the intermediate joint, the pull rod passes through the sand blocking slide valve, the sand scraping ring is located inside the pump barrel and has a sand scraping chamfer to scrape the sand adhered to the inner wall of the pump barrel and carry it away by the produced fluid. The sand blocking slide valve blocks the settlement of impurities into the pump barrel and shields the pressure in the upper part of the pump barrel.

[0010] The objective of the present invention can also be achieved through the following technical measures:

[0011] The forced sand scraping pump further includes a plunger body and a liquid discharge valve. The intermediate joint is connected to the liquid discharge valve, the sand scraping ring is connected to the plunger body, and the plunger body is connected to the intermediate joint.

[0012] The length of the plunger body is greater than 1.2 m, the length of the pump barrel is less than the stroke + the length of the plunger and greater than the stroke + 1.2 m.

[0013] The forced sand scraping pump further includes a plunger body and a liquid discharge valve. The intermediate joint is connected to the liquid discharge valve, the sand scraping ring is connected to the plunger body, and the plunger body is connected to the liquid discharge valve.

[0014] The length of the plunger body is greater than 1.2 m, the length of the pump barrel is less than the stroke + the length of the plunger and greater than the stroke + 1.2 m.

[0015] The forced sand scraping pump further includes a plunger body and a liquid discharge valve. The intermediate joint is connected to the sand scraping ring, the sand scraping ring is connected to the liquid discharge valve, the liquid discharge valve is connected to the plunger body, and the plunger body is connected to the liquid discharge valve.

[0016] The length of the plunger body is greater than 1.2 m, the length of the pump barrel is less than the stroke + the length of the plunger and greater than the stroke + 1.2 m.

[0017] The structure of the sand blocking slide valve is a rotating body structure with variable diameter.

[0018] The inner surface of the sand blocking slide valve is finely ground. The inner diameter is slightly larger than the outer diameter of the pull rod for clearance fit, and its maximum outer diameter is greater than the inner diameter of the pump barrel.

[0019] The pull rod base body is made of iron-based material, and its outer surface is spray-welded. Its hardness is HRC57 - 62, and the surface roughness is higher than 3.2. The length of the pull rod is equal to the length of the pump barrel.

[0020] The annulus between the inner cavity of the pump barrel and the outer pipe of the pump barrel is not connected at the lower end.

[0021] The object of the present invention can also be achieved by the following technical measures: an application method of a forced sand scraping pump, which adopts a forced sand scraping pump and includes:

[0022] Step 1, during the normal working upstroke, the sand blocking slide valve seat is on the pump barrel, shielding the liquid column pressure on the upper part of the shielding plunger body. The valve ball and valve seat of the drain valve are affected by the impact of the liquid column and are reduced. The plunger body moves upward along with the pull rod. The sand scraping inclined plane at the upper end of the plunger body contacts the pump barrel and scrapes away the sand grains attached to the inner wall of the pump barrel, and is carried out of the pump barrel along with the fluid; the plunger and the drain valve move upward to create space, the pressure in the inner cavity of the pump barrel decreases, and the valve ball of the inlet valve opens under the action of the submergence pressure, and the produced liquid from the oil well enters the inner cavity of the pump barrel.

[0023] Step 2, during the normal working downstroke, when the produced liquid basically contains no gas, the plunger body compresses the liquid in the pump barrel, the pressure in the pump barrel increases. When the pressure in the pump barrel is higher than the pressure on the upper part of the plunger body, the valve ball of the drain valve opens, and the sand blocking slide valve also opens. The fluid passes through the drain valve, the inner cavity of the plunger body, the sand blocking slide valve and the annulus of the pump barrel, and enters the upper space of the plunger. At the same time, the fluid washes away the sand scraped by the sand scraping chamfer.

[0024] Step 3, when adjusting the parameters of the oil well surface equipment using the forced sand scraping pump, first analyze the flow field and the sand content in the surface produced liquid, and calculate the plunger speed υ A and the critical sand-carrying speed u x , compare these two speeds to adjust the stroke frequency.

[0025] The object of the present invention can also be achieved by the following technical measures:

[0026] In Step 2, when the produced liquid contains gas, the plunger body moves downward, the sand blocking slide valve falls freely, and shields the upper pressure. The pressure of the liquid in the upper part of the plunger body decreases due to the downward movement of the plunger body. The pull rod and the plunger body continue to move downward, compressing the fluid in the lower part of the plunger body, and the valve ball of the drain valve opens in time to solve the problem that the valve ball of the drain valve cannot open due to the influence of gas.

[0027] In Step 3, when the liquid column load is fully loaded on the plunger body, the plunger speed at this time is υ A ;

[0028]

[0029] u x ——Critical sand-carrying speed, m / s;

[0030] ρ s —— Density of sand grains, kg / m 3 ;

[0031] ρ1—— Density of fluid, kg / m 3 ;

[0032] d p —— Particle size, m;

[0033] μ—— Viscosity of fluid, Pa·s. When water content < 50%, the viscosity of the fluid is taken as the viscosity of crude oil. When the water cut > 70%, the viscosity of formation water is adopted. When the water cut is between 50% and 70%, if the viscosity ≥ 2000 mPa·s, the viscosity of formation water is adopted. If the viscosity < 2000 mPa·s, the mass-weighted mixed viscosity is calculated;

[0034] C s —— Volume concentration of sand grains, m 3 / m 3 ;

[0035] n—— Index, Re t Reynolds number of sand grain settlement, 0.2 < Re t < 1;

[0036] V—— Inertia index, W L = ρ L ·L P ·(A P - A r )·g,

[0037] a A Acceleration of the suspension point, Ap is the cross-sectional area of the plunger m 3 , Ar is the cross-sectional area of the rod m 3 A 管 is the cross-sectional area inside the tubing m 3 ρ L is the liquid density kg / m 3 , Lp is the distance of the plunger from the calculation point m; ξ is the area coefficient.

[0038] In step 3, when υ A ≥ u x , adjust from high stroke frequency to low stroke frequency, and the stroke frequency adjustment difference < 0.3 min -1 , and the interval time is not less than 48 h.

[0039] In step 3, when υ A ≤ u x , adjust from low stroke frequency to high stroke frequency, and the adjusted stroke frequency difference < 0.6 min -1, with an interval of not less than 48h, gradually adjust to reach the target pumping speed, and solve the problem that when the pumping speed is switched greatly between high and low, larger sand grains settle and seat, entering the gap between the pump barrel / plunger.

[0040] Compared with the prior art, the forced sand scraping pump and its application method in the present invention have the following beneficial effects:

[0041] 1) Studied the parameter adjustment method to solve the drawbacks brought by conventional parameter adjustment.

[0042] 2) Utilize structural innovation, adopt a sand blocking structure, and reduce the probability of sand grains, scale, and rust entering the plunger.

[0043] 3) When the oil well contains gas, during the downstroke, the sand blocking structure divides and shields the pressure of the upper pipe string of the pump, and solves the problem that it is difficult to open or impossible to open the plunger valve group affected by gas.

[0044] 4) Straighten the pull rod connecting the plunger to prevent the pull rod from bending, increase the plunger stroke, and improve the pump efficiency.

[0045] 5) Straighten the plunger to slow down the mechanical wear between the plunger / pump barrel, thereby reducing the clearance leakage and extending the service life.

[0046] 6) The benefits brought by the sand blocking structure at the same time are that during the upstroke, it can reduce the impact of the liquid column on the closing of the pump valve ball / valve seat, and delay the service life of the valve ball / valve seat. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a structural diagram of a specific embodiment 1 of the forced sand scraping pump of the present invention;

[0048] Figure 2 It is a structural diagram of a specific embodiment 2 of the forced sand scraping pump of the present invention

[0049] Figure 3 It is a structural diagram of a specific embodiment 3 of the forced sand scraping pump of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0050] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0051] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, and / or combinations thereof.

[0052] The following are several specific embodiments of applying the present invention.

[0053] Embodiment 1

[0054] As Figure 1 shown, Figure 1 is a structural diagram of the forced sand scraping pump of the present invention. The forced sand scraping pump has an oil pumping pump valve with anti-impact performance. It mainly includes: 1 coupling, 2 sand blocking slide valve, 3 pump barrel, 4 pull rod, 5 outer barrel, 6 sand scraping ring, 7 plunger body, 8 intermediate joint, 9 drain valve, 10 inlet valve.

[0055] The 1 coupling is connected to the 5 outer barrel, the 5 outer barrel is connected to the 10 inlet valve, the 3 pump barrel is connected to the 10 inlet valve, the 4 pull rod is connected to the 8 intermediate joint, the 8 intermediate joint is connected to the 9 drain valve, the 6 sand scraping ring is connected to the 7 plunger body, the 7 plunger body is connected to the 8 intermediate joint, and the 4 pull rod passes through the 2 sand blocking slide valve.

[0056] The described 6 sand scraping ring has a sand scraping chamfer, which can scrape off the sand adhered to the inner wall of the 3 pump barrel and be carried away by the produced fluid.

[0057] The described 2 sand blocking slide valve (1) functions to prevent rust, scale and impurities from settling into the pump barrel above the slide valve, (2) functions to shield the pressure above the pump barrel, (3) functions to straighten the plunger and reduce the wear of the plunger, solve the problem that it is difficult to open or impossible to open the plunger valve group affected by gas, (4) prevents the pull rod from bending, increases the plunger stroke, and improves the pump efficiency, (5) during the upward stroke, it can reduce the impact of the liquid column on the closing of the oil pumping pump valve ball / valve seat and delay the service life of the valve ball / valve seat.

[0058] The described 2 sand blocking slide valve has an inner surface that is finely ground, and the inner diameter is slightly larger than the outer diameter of the 4 pull rod for clearance fit, and its maximum outer diameter is larger than the inner diameter of the pump barrel. The structure of the sand blocking slide valve is a variable-diameter rotating body structure.

[0059] The described 4 pull rod has an iron-based material matrix and is spray-welded on the outer surface. Its hardness is HRC57 - 62, and the surface roughness is higher than 3.2. The length of the pull rod is equal to the length of the 2 pump barrel.

[0060] The length of the described 3 pump barrel is less than the stroke + plunger length and greater than the stroke + 1.2 m, and the inner wall treatment method conforms to the conventional treatment method of the oil pumping pump barrel.

[0061] The length of the 7 plunger bodies is greater than 1.2 m.

[0062] The described 10 inlet valves are connected to the pump barrel and the outer pipe.

[0063] The annulus between the inner cavity of the pump barrel and the outer pipe of the pump barrel is not connected at the lower end.

[0064] The working characteristic of the forced sand scraping pump is that during the upstroke, the 2 sand scraping slide valve seat is on the pump barrel, shielding the liquid column pressure on the upper part of the shielding plunger. The valve ball and valve seat of the 9 discharge valves are reduced by the impact of the liquid column. The 7 plunger moves upward with the pull rod. The sand scraping inclined plane at the upper end of the plunger contacts the pump barrel to scrape off the sand grains attached to the inner wall of the pump barrel and carry them out of the pump barrel with the fluid.

[0065] The plunger and the discharge valve move upward to create space, the internal pressure of the 3 pump barrel decreases, the valve ball of the 10 inlet valve opens under the action of the submerged pressure, and the produced liquid from the oil well enters the inner cavity of the 3 pump barrel.

[0066] During the downstroke, (1) when the produced liquid is basically gas-free, the plunger compresses the liquid in the pump barrel, the pressure in the pump barrel increases. When the pressure in the pump barrel is higher than the pressure above the plunger, the valve ball of the discharge valve opens, and the sand scraping slide valve also opens. The fluid passes through the discharge valve, the inner cavity of the plunger, the sand scraping slide valve and the annulus of the pump barrel, and enters the upper space of the plunger. At the same time, the fluid washes away the sand scraped by the sand scraping chamfer. (2) When the produced liquid contains gas, the plunger moves downward, the sand scraping slide valve falls freely and shields the upper pressure. The liquid above the plunger decreases in pressure due to the downward movement of the plunger. The pull rod and the plunger continue to move downward, compressing the fluid below the plunger. The valve ball of the discharge valve can open in time to solve the problem that the valve ball of the discharge valve cannot open due to the influence of gas.

[0067] For the method of adjusting parameters of the forced sand scraping pump, aiming at the problem of adjusting from high stroke frequency to low stroke frequency, analyzing the flow field, the method of gradually reducing the stroke frequency step by step can be adopted.

[0068] When the liquid column load is fully loaded on the plunger, the velocity υ of the plunger at this time A

[0069]

[0070] u x —— Critical sand-carrying velocity, m / s;

[0071] ρ s —— Density of sand grains, kg / m 3 ;

[0072] ρ1 —— Density of fluid, kg / m 3 ;

[0073] d p —— Particle size, m;

[0074] μ —— Viscosity of the fluid, Pa·s. When the water content is less than 50%, the viscosity of the crude oil is used. When the water cut is greater than 70%, the viscosity of the formation water is used. When the water cut is between 50% and 70%, if the viscosity is ≥ 2000 mPa·s, the viscosity of the formation water is used. If the viscosity is < 2000 mPa·s, the mass-weighted mixed viscosity is calculated.

[0075] C s —— Volume concentration of sand grains, m 3 / m 3 ;

[0076] n —— Index, Re t Reynolds number of sand grain settlement, 0.2 < Re t < 1.

[0077] V —— Inertia index, W L = ρ L ·L P ·(A P -A r )·g, a A Acceleration of the polished rod, Ap is the cross-sectional area of the plunger m 3 , Ar is the cross-sectional area of the rod m 3 , A 管 is the cross-sectional area of the tubing inner m 3 , ρ L is the liquid density kg / m 3 , Lp is the distance from the plunger to the calculation point m; ξ is the area coefficient.

[0078] When υ A ≥ u x , adjust from high stroke rate to low stroke rate, the stroke rate adjustment difference < 0.3 min -1 , the interval time is not less than 48 h. When υ A ≤ u x , adjust from low stroke rate to high stroke rate, the adjusted stroke rate difference < 0.6 min -1 , the interval time is not less than 48 h, and gradually adjust to reach the target stroke rate to solve the problem that when there is a large conversion between high and low stroke rates, larger sand grains settle and seat in the clearance between the pump barrel / plunger.

[0079] Example 2:

[0080] In the specific Example 2 of applying the present invention, as Figure 2As shown in the figure, a forced sand scraping pump, where the 1 coupling is connected to the 5 outer cylinder, the 5 outer cylinder is connected to the 10 inlet valve, the 3 pump barrel is connected to the 10 inlet valve, the 4 pull rod is connected to the 8 intermediate joint, the 8 intermediate joint is connected to the 6 sand scraping ring, the 6 sand scraping ring is connected to the 7 plunger body, the 7 plunger body is connected to the 9 drain valve, and the 4 pull rod passes through the 2 sand blocking slide valve.

[0081] The described 6 sand scraping ring has a sand scraping chamfer, which can scrape off the sand adhered to the inner wall of the 3 pump barrel and be carried away by the produced fluid.

[0082] The described 2 sand blocking slide valve (1) functions to prevent rust, scale and impurities from settling into the pump barrel above the slide valve, (2) shields the pressure above the pump barrel, (3) straightens the plunger to reduce plunger wear, solves the problem that it is difficult to open or impossible to open the plunger valve group affected by gas, (4) prevents the pull rod from bending, increases the plunger stroke, and improves the pump efficiency, (5) during the upstroke, it can reduce the impact of the liquid column on the closing of the pump valve ball / valve seat and delay the service life of the valve ball / valve seat.

[0083] The described 2 sand blocking slide valve has an inner surface that is finely ground. The inner diameter is slightly larger than the outer diameter of the 4 pull rod for clearance fit, and its maximum outer diameter is larger than the inner diameter of the pump barrel. The structure of the sand blocking slide valve is a rotating body structure with variable diameter.

[0084] The described 4 pull rod has an iron-based material matrix and is spray-welded on the outer surface. Its hardness is HRC57 - 62, and the surface roughness is higher than 3.2. The length of the pull rod is equal to the length of the 2 pump barrel.

[0085] The length of the described 3 pump barrel is less than the stroke + plunger length and greater than the stroke + 1.2m. The treatment method of its inner wall conforms to the conventional treatment method of the pump barrel of a sucker rod pump.

[0086] The length of the described 7 plunger body is greater than 1.2m.

[0087] The described 10 inlet valve is connected to the pump barrel and the outer pipe.

[0088] The annulus between the inner cavity of the pump barrel and the outer pipe of the pump barrel is not connected at the lower end.

[0089] The working characteristic of the forced sand scraping pump is that during the upstroke, the 2 sand blocking slide valve seats on the pump barrel, shielding the liquid column pressure above the plunger. The impact of the liquid column on the valve ball and valve seat of the 9 drain valve is reduced. The 7 plunger moves upward with the pull rod, and the sand scraping inclined surface at the upper end of the plunger contacts the pump barrel to scrape off the sand grains adhering to the inner wall of the pump barrel and carry them out of the pump barrel with the fluid.

[0090] The plunger and the drain valve move upward to create space, the internal pressure of the 3 pump barrel decreases, and the valve ball of the 10 inlet valve opens under the action of the submerged pressure, and the produced fluid from the oil well enters the inner cavity of the 3 pump barrel.

[0091] During the downstroke, (1) when the produced fluid is basically gas-free, the plunger compresses the fluid in the pump barrel, the pressure in the pump barrel rises. When the pressure in the pump barrel is higher than the pressure above the plunger, the valve ball of the drain valve opens, and the sand control sliding valve also opens. The fluid passes through the drain valve, the inner cavity of the plunger, the sand control sliding valve and the annulus between the pump barrel, and enters the space above the plunger. At the same time, the fluid washes away the sand scraped off by the sand scraping chamfer. (2) When the produced fluid contains gas, the plunger descends, the sand control sliding valve falls freely and shields the upper pressure. The pressure of the fluid above the plunger decreases due to the downward movement of the plunger. The pull rod and the plunger continue to descend, compressing the fluid below the plunger. The valve ball of the drain valve can be opened in time to solve the problem that the valve ball of the drain valve cannot be opened due to the influence of gas.

[0092] For the parameter adjustment method of the forced sand scraping pump, aiming at the problem of adjusting from high stroke frequency to low stroke frequency, the flow field is analyzed, and the method of gradually reducing the stroke frequency step by step can be adopted.

[0093] When the liquid column load is fully loaded on the plunger, the velocity υ of the plunger at this time A

[0094]

[0095] u x ——Critical sand-carrying velocity, m / s;

[0096] ρ s ——Density of sand grains, kg / m 3 ;

[0097] ρ1——Density of fluid, kg / m 3 ;

[0098] d p ——Particle size, m;

[0099] μ——Viscosity of fluid, Pa.s. When the water cut is <50%, the viscosity of the fluid is the viscosity of crude oil. When the water cut is >70%, the viscosity of formation water is adopted; when the water cut is between 50% and 70%, if the viscosity ≥ 2000 mPa.s, the viscosity of formation water is adopted. If the viscosity <2000 mPa.s, the mass-weighted mixed viscosity is calculated.

[0100] C s ——Volume concentration of sand grains, m 3 / m 3 ;

[0101] n——Index, Re t Reynolds number of sand grain settlement, 0.2 < Re t < 1.

[0102] V——Inertia index, W L = ρL ·L P ·(A P -A r )·g, a A The acceleration of the polished rod, Ap is the cross-sectional area of the plunger in m 3 , Ar is the cross-sectional area of the rod in m 3 , A 管 is the cross-sectional area of the tubing in m 3 , ρ L is the liquid density in kg / m 3 , Lp is the distance of the plunger from the calculation point in m; ξ is the area coefficient.

[0103] When υ A ≥u x , adjust from high stroke frequency to low stroke frequency, the difference in stroke frequency adjustment < 0.3 min -1 , the interval time is not less than 48 h. When υ A ≤u x , adjust from low stroke frequency to high stroke frequency, the adjusted stroke frequency difference < 0.6 min -1 , the interval time is not less than 48 h. Gradually adjust to reach the target stroke frequency to solve the problem that when there is a large-scale conversion between high and low stroke frequencies, larger sand grains settle and seat, entering the gap between the pump barrel / plunger.

[0104] Example 3:

[0105] In the specific Example 3 of applying the present invention, as Figure 3 shown, a forced sand scraping pump, the coupling 1 is connected to the outer cylinder 5, the outer cylinder 5 is connected to the inlet valve 10, the pump barrel 3 is connected to the inlet valve 10, the pull rod 4 is connected to the intermediate joint 8, the intermediate joint 8 is connected to the sand scraping ring 6, the sand scraping ring 6 is connected to the drain valve 9, the drain valve 9 is connected to the plunger body 7, the plunger body 7 is connected to the drain valve 9, and the pull rod 4 passes through the sand blocking slide valve 2.

[0106] The described sand ring 6 has a sand scraping chamfer, which can scrape off the sand adhered to the inner wall of the pump barrel 3 and is carried away by the produced liquid.

[0107] The described sand blocking slide valve 2 (1) functions to prevent rust, scale and impurities from settling into the pump barrel above the slide valve, (2) functions to shield the pressure above the pump barrel, (3) functions to straighten the plunger and reduce the wear of the plunger, solve the problem that it is difficult to open or impossible to open the plunger valve group affected by gas, (4) prevent the pull rod from bending, increase the plunger stroke and improve the pump efficiency, (5) during the upstroke, it can reduce the impact of the liquid column on the closing of the pump valve ball / valve seat and delay the service life of the valve ball / valve seat.

[0108] The described sand blocking slide valve has an inner surface that is finely ground. The inner diameter is slightly larger than the outer diameter of the pull rod 4 for clearance fit, and its maximum outer diameter is larger than the inner diameter of the pump barrel. The structure of the sand blocking slide valve is a variable-diameter rotating body structure.

[0109] For the described 4 pull rods, the matrix is made of iron-based material, the outer surface is spray-welded, with a hardness of HRC57 - 62 and a surface roughness higher than 3.2. The length of the pull rod is equal to the length of the 2 pump barrels.

[0110] The length of the described 3 pump barrels is less than the stroke + the length of the plunger and greater than the stroke + 1.2 m, and the inner wall treatment method conforms to the conventional treatment method of the pump barrel of the sucker rod pump.

[0111] The length of the described 7 plunger body is greater than 1.2 m.

[0112] The described 10 intake valve is connected to the pump barrel and the outer pipe.

[0113] The annulus between the inner cavity of the pump barrel and the outer pipe of the pump barrel is not connected at the lower end.

[0114] The working characteristic of the forced sand scraping pump is that during the upstroke, the 2 sand shielding slide valve seat is on the pump barrel, shielding the liquid column pressure above the shielding plunger. The valve ball and valve seat of the 9 discharge valve are affected by the impact of the liquid column and decrease. The 7 plunger moves upward with the pull rod, and the sand scraping inclined plane at the upper end of the plunger contacts the pump barrel to scrape off the sand grains attached to the inner wall of the pump barrel and carry them out of the pump barrel with the fluid.

[0115] The plunger and the discharge valve move upward to create space, the internal pressure of the 3 pump barrel decreases, and the valve ball of the 10 intake valve opens under the action of the submerged pressure, and the produced liquid from the oil well enters the inner cavity of the 3 pump barrel.

[0116] During the downstroke, (1) when the produced liquid contains basically no gas, the plunger compresses the liquid in the pump barrel, the pressure in the pump barrel increases. When the pressure in the pump barrel is higher than the pressure above the plunger, the valve ball of the discharge valve opens, and the sand shielding slide valve also opens. The fluid passes through the discharge valve, the inner cavity of the plunger, the sand shielding slide valve and the annulus of the pump barrel and enters the upper space of the plunger. At the same time, the fluid washes away the sand scraped by the sand scraping chamfer. (2) When the produced liquid contains gas, the plunger moves downward, the sand shielding slide valve falls freely and shields the upper pressure. The liquid above the plunger decreases in pressure due to the downward movement of the plunger. The pull rod and the plunger continue to move downward, compressing the fluid below the plunger, and the valve ball of the discharge valve can be opened in time to solve the problem that the valve ball of the discharge valve cannot be opened due to the influence of gas.

[0117] For the parameter adjustment method of the forced sand scraping pump, aiming at the problem of adjusting from high stroke frequency to low stroke frequency, by analyzing the flow field, the method of gradually reducing the stroke frequency step by step can be adopted.

[0118] When the liquid column load is fully loaded on the plunger, the velocity υ of the plunger at this time A

[0119]

[0120] u x ——Critical sand-carrying velocity, m / s;

[0121] ρ s —— Density of sand grains, kg / m 3 ;

[0122] ρ1—— Density of fluid, kg / m 3 ;

[0123] d p —— Particle size, m;

[0124] μ—— Viscosity of fluid, Pa·s. When water content < 50%, the viscosity of crude oil is adopted; when water cut > 70%, the viscosity of formation water is adopted; when water content is between 50% and 70%, if viscosity ≥ 2000 mPa·s, the viscosity of formation water is adopted, if viscosity < 2000 mPa·s, the mass weighted mixing viscosity is calculated.

[0125] C s —— Volume concentration of sand grains, m 3 / m 3 ;

[0126] n—— Index, Re t Reynolds number of sand grain settlement, 0.2 < Re t < 1.

[0127] V—— Inertia index, W L =ρ L ·L P ·(A P -A r )·g, a A Acceleration of the suspension point, Ap is the cross-sectional area of the plunger m 3 Ar is the cross-sectional area of the rod m 3 A 管 is the cross-sectional area of the tubing inner m 3 ρ L is the liquid density kg / m 3 Lp is the distance from the plunger to the calculation point m; ξ is the area coefficient.

[0128] When υ A ≥ u x , adjust from high stroke frequency to low stroke frequency, the stroke frequency adjustment difference < 0.3 min -1 , the interval time is not less than 48 h. When υ A ≤ u x , adjust from low stroke frequency to high stroke frequency, the adjusted stroke frequency difference < 0.6 min -1 , the interval time is not less than 48 h, and gradually adjust to reach the target stroke frequency to solve the problem that larger sand grains settle and seat into the pump barrel / plunger clearance during large-scale conversion between high and low stroke frequencies.

[0129] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0130] Except for the technical features described in the specification, the rest are well-known technologies to those skilled in the art.

Claims

1. Application method of a forced sand scraping pump, characterized in that, The forced sand scraping pump used in this method includes a coupling, a sand retaining sliding valve, a pump barrel, a pull rod, an outer barrel, an intermediate joint, a sand scraping ring and a liquid inlet valve. The coupling is connected to the outer barrel, the outer barrel is connected to the liquid inlet valve, the pump barrel is connected to the liquid inlet valve, the pull rod is connected to the intermediate joint, the pull rod passes through the sand retaining sliding valve, and the sand scraping ring is located inside the pump barrel and has a sand scraping chamfer to scrape off the sand adhered to the inner wall of the pump barrel and is carried away by the produced fluid. The sand retaining sliding valve blocks impurities from settling into the pump barrel and shields the pressure in the upper part of the pump barrel; The forced sand scraping pump further includes a plunger body and a liquid discharge valve. One end of the plunger body is connected to the sand scraping ring, and the other end is connected to the liquid discharge valve through the intermediate joint, or one end of the plunger body is connected to the liquid discharge valve, and the other end is connected to the intermediate joint through the sand scraping ring; The length of the plunger body is greater than 1.2 m, the length of the pump barrel is less than the stroke + the length of the plunger, and the length of the pump barrel is greater than the stroke + 1.2 m; The structure of the sand retaining sliding valve is a rotating body structure with variable diameter; the inner surface of the sand retaining sliding valve is finely ground, the inner diameter is slightly larger than the outer diameter of the pull rod for clearance fit, and its maximum outer diameter is larger than the inner diameter of the pump barrel; The base body of the pull rod is made of iron-based material, and the outer surface is spray-welded. Its hardness is HRC57 - 62, the surface roughness is higher than 3.2, and the length of the pull rod is equal to the length of the pump barrel; The annulus between the inner cavity of the pump barrel and the outer pipe of the pump barrel is not connected at the lower end; The application method includes the following steps: Step 1, during the upward stroke of normal operation, the sand retaining sliding valve seats on the pump barrel to shield the liquid column pressure above the plunger body. The valve ball and valve seat of the liquid discharge valve are less affected by the impact of the liquid column. The plunger body moves upward with the pull rod. The upper sand scraping inclined surface of the plunger body contacts the pump barrel to scrape off the sand grains adhering to the inner wall of the pump barrel and is carried out of the pump barrel with the fluid; the plunger and the liquid discharge valve move upward to create space, the pressure in the inner cavity of the pump barrel decreases, and the valve ball of the liquid inlet valve opens under the action of the submergence pressure, and the produced fluid of the oil well enters the inner cavity of the pump barrel; Step 2, during the downward stroke of normal operation, when the produced fluid is basically gas-free, the plunger body compresses the liquid in the pump barrel, and the pressure in the pump barrel increases. When the pressure in the pump barrel is higher than the pressure above the plunger body, the valve ball of the liquid discharge valve opens, and the sand retaining sliding valve also opens. The fluid passes through the liquid discharge valve, the inner cavity of the plunger body, the annulus between the sand retaining sliding valve and the pump barrel, and enters the space above the plunger. At the same time, the fluid flushes away the sand scraped off by the sand scraping chamfer; Step 3, when adjusting the parameters of the oil well surface equipment with a forced sand pumping pump, first analyze the flow field and the sand content in the surface liquid, and calculate the plunger speed υ A , the critical sand-carrying speed u x , compare these two speeds to adjust the stroke frequency.

2. The application method of the forced sand scraping pump according to claim 1, characterized in that In Step 2, when the produced fluid contains gas, the plunger body moves downward, the sand retaining sliding valve falls freely and shields the upper pressure. The pressure of the liquid above the plunger body decreases due to the downward movement of the plunger body. The pull rod and the plunger body continue to move downward, compressing the fluid below the plunger body, and the valve ball of the liquid discharge valve opens in time to solve the problem that the valve ball of the liquid discharge valve cannot open due to the influence of gas; 3. The application method of the forced sand scraping pump according to claim 1, characterized in that, In step 3, when the liquid column load is fully applied to the plunger body, the plunger velocity is υ at this time A ; u x —— Critical velocity of sand carrying, m / s; ρ s —— Density of sand grains, kg / m 3 ; ρ1——Density of the fluid, kg / m 3 ; d p —— Particle size, m; μ——viscosity of the fluid, Pa·s. When the water cut is <50%, the viscosity of the fluid is the viscosity of crude oil. When the water cut is >70%, the viscosity of formation water is adopted; when the water cut is between 50% and 70%, if the viscosity ≥2000 mPa·s, the viscosity of formation water is adopted. If the viscosity <2000 mPa·s, the mass weighted mixed viscosity is calculated; C s —— Volume concentration of sand grains, m 3 / m 3 ; n——exponent, Re t Reynolds number of sand particle settlement, 0.2 < Re t < 1; V——Inertia index, W L = ρ L ·L P ·(A P - A r )·g, a A Suspended point acceleration, Ap is the cross-sectional area of the plunger m 3 , Ar is the cross-sectional area of the rod m 3 , A 管 is the cross-sectional area inside the tubing m 3 , ρ L is the liquid density kg / m 3 , Lp is the distance of the plunger from the calculation point m; ξ is the area coefficient.

4. The application method of the forced sand scraping pump according to claim 1, characterized in that, In step 3, when υ A ≥u x , adjust from a high pumping speed to a low pumping speed, and the difference in pumping speed adjustment < 0.3 min -1 , and the interval time is not less than 48 h.

5. The application method of the forced sand scraping pump according to claim 4, characterized in that In step 3, when υ A ≤ u x , adjust from a low pumping speed to a high pumping speed, with the adjustment difference of pumping speed < 0.6 min -1 , the interval time is not less than 48 h, and gradually adjust to reach the target pumping speed to solve the problem that when there is a large conversion between high and low pumping speeds, sand grains settle and seat, and the clearance between the pump barrel / plunger.

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