Oil well pump

Abstract

The invention discloses an oil well pump which comprises a pump cylinder, a plunger and an outer pipe, the plunger is arranged in the pump cylinder, and the lower end of the pump cylinder is connected with the outer pipe through a standing valve sand setting device. The standing valve sand setting device comprises a liquid inlet valve, a short pipe and a two-way joint; the lower end of the liquid inlet valve is connected with a short pipe, the short pipe is connected with a two-way connector, the two-way connector penetrates through the pump cylinder to be connected with the outer pipe, and the liquid inlet valve is communicated with the outside. Sand in crude oil is settled twice, so that the standing valve is protected, the time for blocking the standing valve by sand grains is prolonged, the maintenance and repair time of the oil pumping unit is prolonged, and the production benefit of an oil field is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil well pumps, in particular to an oil well pump. Background Art

[0002] With the deepening of oil field development, low permeability reservoirs and fault block reservoirs begin to produce sand. When the oil pump works in such sand-containing oil wells, it often fails due to sand stuck in the plunger or valve group. The commonly used anti-sticking method is to use a long plunger to prevent sand from sticking in the pump. However, the conventional long plunger anti-sand sticking pump is mainly suitable for larger sand particles and is not suitable for low permeability and fault block reservoirs. The main reason is that the sand particles in these reservoirs are small and easy to enter the gap. Secondly, the pump depth of this type of oil well is generally deep. When the fixed valve settles the sand particles, the pump is opened again. The pressure difference between the fixed valve ball and the valve seat is large, and the gap jet occurs, causing the valve group to fail quickly.

[0003] Publication (Announcement) No.: CN218293825U, discloses a DFC type long plunger sand settling oil pump. The device includes a plunger assembly and a pump barrel assembly, the plunger assembly is installed inside the pump barrel assembly, and also includes an outer barrel assembly and a sand prevention assembly, the plunger assembly includes an upper movable valve on the plunger, a plunger body and a lower movable valve on the plunger, the upper end of the upper movable valve on the plunger is connected to the plunger suspension rod, the lower end of the upper movable valve on the plunger is connected to the plunger body, and the lower end of the plunger body is connected to the lower movable valve on the plunger. The utility model has the functions of sand and gas prevention, can prevent fine sand in the oil well from entering the long plunger sand settling oil pump, prevent the outer surface of the plunger and the inner surface of the pump barrel from wearing, increase pump efficiency, and prevent sand jam.

[0004] The sand-blocking prevention method of the prior art is a sand-filtering method, which filters sand before the fluid enters the oil pump. However, due to its structure, its pores are small in order to effectively filter sand particles. For colloids and waxes with larger particle sizes, when such impurities adhere to the filter screen, it will lead to ineffective liquid inflow, and measures are needed to unblock or lift the pipe column. In addition, the sand-filtering method cannot completely filter fine particles. When the surface oil pump is maintained, the power is cut off, etc., the floating valve and the fixed valve are prone to sand stuck in the valve group due to the sedimentation of sand in the liquid, or the gap sand jet occurs after the pumping is started, causing the oil pump to fail.

[0005] Publication (announcement) number: CN113217362B, discloses a sand and gas prevention oil pump, including a pump barrel assembly, a sliding plunger assembly is arranged in the pump barrel assembly, a gas-liquid separation assembly is arranged at the end of the pump barrel assembly, a liquid inlet channel is arranged on one side of the gas-liquid separation assembly, and the oil containing sand and gas is passed into the pump barrel assembly from the liquid inlet channel, and the short plunger in the plunger assembly slides against the seal in the pump barrel assembly to form a multi-stage compression chamber for sand settling and exhaust. A three-stage sand prevention and two-stage gas prevention structure is adopted, which can not only adapt to the crude oil exploitation in the well conditions with severe sand production, but also has a good gas prevention effect. It belongs to a special oil pump that can adapt to the crude oil exploitation in the well conditions with severe sand production and high gas content, has good sand and gas prevention effect, strong bearing capacity, and long service life.

[0006] The sand blocking method of the prior art is a sand blocking and sand settling method. However, due to its structural reasons, in order to effectively settle the sand particles, the sand prevention measures of the plunger and the floating valve have a small annular sand settling cavity volume, and the pipe column above the pump barrel is long, which cannot meet the long-term sand settling requirements.

[0007] Publication (Announcement) No.: CN217950639U discloses a non-fixed valve type sand control oil pump, comprising an outer tube, an upper thin pump barrel and a lower thick pump barrel are installed in the outer tube, a mechanical seat seal is connected between the upper thin pump barrel and the lower thick pump barrel, and the mechanical seat seal is detachably mounted on the outer tube, an upper piston with a hollow interior is installed in the upper thin pump barrel, a lower piston with a hollow interior is installed in the lower thick pump barrel, a floating valve assembly is installed on the top of the upper piston, and the bottom of the upper piston extends to It extends into the lower thick pump barrel and a sealing ring cavity is formed between the two. The sealing ring cavity is connected to the interior of the upper piston. A downstream movable valve assembly 1 is connected between the upper piston and the lower piston, and a downstream movable valve assembly 2 is connected to the bottom end of the lower piston. This patent adopts a non-fixed valve structure and relies on the change in the volume of the sealing ring cavity to realize the valve ball opening and closing process, which solves the problems of sand burial and pump jamming, air lock, etc., extends the service life and improves the pump efficiency. Moreover, it is no longer necessary to lift the oil pipe when inspecting the pump, saving the pump inspection cost.

[0008] The prior art method for preventing sand from getting stuck adopts a replacement method to remove the fixed valve, which can avoid problems with the fixed valve, but there is a problem of the locking mechanism swinging and wearing out.

[0009] In summary, the technical solutions of the above-disclosed technologies, the technical problems to be solved, and the beneficial effects produced are all different from the present invention. Regarding more technical features, technical problems to be solved, and beneficial effects of the present invention, the above-disclosed technical documents do not provide any technical inspiration. Summary of the invention

[0010] In view of the above-mentioned defects in the prior art, an object of the present invention is to provide an oil pump which can settle the sand particles in the fluid in the pump barrel and can also settle the sand particles contained in the fluid in the oil pipe above the plunger.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] A pump comprises a pump barrel, a plunger and an outer tube. The plunger is arranged in the pump barrel, and the lower end of the pump barrel is connected to the outer tube through a fixed valve sand settling device.

[0013] The plunger is hollow inside, the upper end of the upper plunger is connected to the upper liquid outlet valve, and the lower end is connected to the lower liquid outlet valve;

[0014] The outer diameter of the upper liquid outlet valve is larger than the inner diameter of the pump barrel.

[0015] The upper end of the outer tube is connected to the upper joint, and the lower end is connected to the lower joint.

[0016] The upper end of the pump barrel is connected with a pump barrel straightening joint; the bottom of the pump barrel is sealed.

[0017] The plunger, the upper liquid outlet valve and the lower liquid outlet valve form a plunger string; the length of the plunger string is greater than the sum of the lengths of the pump barrel straightening joint and the pump barrel.

[0018] The fixed valve sand settling device comprises a liquid inlet valve, a short pipe and a two-way joint;

[0019] The lower end of the liquid inlet valve is connected to a short tube, the short tube is connected to a two-way joint, the two-way joint passes through the pump barrel and is connected to an outer tube, so that the liquid inlet valve is connected to the outside world.

[0020] The annulus formed by the short tube and the pump barrel is called the first sand settling chamber;

[0021] The annulus formed by the outer tube and the pump barrel is called the second sand settling chamber.

[0022] The pump barrel straightening joint is provided with a spiral guide groove.

[0023] In order to achieve the above object, the present invention adopts the following technical solutions:

[0024] A method for using an oil pump,

[0025] S1: Preparation;

[0026] Connect the sucker rod to the pull rod, connect the pull rod to the plunger string, connect the upper joint to the oil pipe, and connect the lower joint to the tail pipe screen and the screw plug.

[0027] S2: Pumping work;

[0028] The plunger moves upward, the inlet valve opens due to the pressure difference, and the crude oil enters the pump barrel through the two-way joint;

[0029] The plunger moves downward, the liquid inlet valve closes, the crude oil enters the plunger through the lower liquid outlet valve, and then enters the oil pipe above through the upper liquid outlet valve, realizing normal oil pumping production.

[0030] The length calculation method of the tail pipe connected to the lower joint is:

[0031]

[0032] Where:

[0033] L, length of tail pipe, m / s; ρ s , density of sand particles, kg / m 3 ; ρ1, density of the fluid, kg / m 3 ; A. Sand settling cross-sectional area of ​​tail pipe, m 2 ;dp , particle size, m; C S , sand volume concentration, m 3 / m 3 ;

[0034] μ: fluid viscosity, Pa.s. When the water content is less than 50%, the fluid viscosity adopts the crude oil viscosity; when the water content is greater than 70%, the formation water viscosity is adopted; when the water content is between 50% and 70%, if the viscosity is ≥2000mPa.s, the formation water viscosity is adopted; if the viscosity is less than 2000mPa.s, the mass-weighted mixed viscosity is adopted for calculation;

[0035] n: sedimentation index, Re t Reynolds number for sand sedimentation, 0.2<Re t <1;

[0036] V: inertia index, W L =ρ L ·L P ·(A P -A r )·g, where a A Suspension acceleration, A p is the cross-sectional area of ​​the plunger m 3 , A r is the cross-sectional area of ​​the rod m 3 , A 管 is the cross-sectional area of ​​the oil pipe m3, ρ L is the liquid density kg / m 3 , L p is the distance m from the plunger to the calculation point.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The invention settles the sand in the crude oil twice, thereby protecting the fixed valve, prolonging the time that the fixed valve is blocked by sand particles, prolonging the maintenance and repair time of the oil pump, and improving the production efficiency of the oil field. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of an oil well pump of the present invention;

[0040] In the figure: 1. upper joint; 2. upper liquid outlet valve; 3. pump barrel straightening joint; 4. pump barrel; 5. plunger; 6. outer tube; 7. lower liquid outlet valve; 9. liquid inlet valve; 10. short tube; 11. two-way joint; 12. lower joint. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] See also Figure 1 The present invention provides an oil pump, comprising a pump barrel 4, a plunger 5, and an outer tube, wherein the plunger 5 is arranged in the pump barrel 4, and the lower end of the pump barrel 4 is connected to the outer tube through a fixed valve sand settling device;

[0043] The plunger 5 is hollow inside, the upper end of the upper plunger 5 is connected to the upper liquid outlet valve 2, and the lower end is connected to the lower liquid outlet valve 7. The two liquid outlet valves allow liquid to enter from the lower end of the plunger 5 and flow out from the upper end. The plunger 5, the upper liquid outlet valve 2, and the lower liquid outlet valve 7 form a plunger string; the outer diameter of the upper liquid outlet valve 2 is larger than the inner diameter of the pump barrel 4, so that the plunger 5 will not fall into the pump barrel 4;

[0044] The upper end of the outer tube 6 is connected to the upper joint 1, and the lower end is connected to the lower joint 12;

[0045] The upper end of the pump barrel 4 is connected to a pump barrel straightening joint 3 to straighten the pump barrel 4 in the outer tube 6; another method to prevent the plunger 5 from falling into the pump barrel 4 is that the length of the plunger string is greater than the sum of the lengths of the pump barrel straightening joint 3 and the pump barrel 4; the bottom of the pump barrel 4 is sealed and a fixed valve sand settling device is provided at the lower end of the pump barrel 4;

[0046] The fixed valve sand settling device comprises a liquid inlet valve 9, a short tube 10, and a two-way joint 11; the lower end of the liquid inlet valve 9 is connected to the short tube 10, the short tube 10 is connected to the two-way joint 11, the two-way joint 11 passes through the pump barrel 4 and is connected to the outer tube 6, so as to connect the liquid inlet valve 9 with the outside world;

[0047] The annulus formed by the short tube 10 and the pump barrel 44 is called the first sand settling chamber;

[0048] The annulus formed by the outer tube 6 and the pump barrel 4 is called the second sand settling chamber;

[0049] The pump barrel straightening joint 3 is provided with a spiral guide groove, which can guide the sand in the oil pipe into the second sand settling chamber.

[0050] Method of use of the present invention:

[0051] S1: Preparation;

[0052] The sucker rod is connected to the pull rod, the pull rod is connected to the plunger string, the upper joint 1 is connected to the oil pipe, and the lower joint 12 is connected to the tail pipe screen and the thread plug.

[0053] S2: Pumping work;

[0054] The plunger 5 moves upward, the inlet valve 9 is opened by the pressure difference, the outlet valve is closed under the pressure difference, and the crude oil enters the pump barrel through the two-way joint 11;

[0055] The plunger 5 moves downward, and the liquid inlet valve 9 is a one-way valve, which is in a closed state. The crude oil enters the plunger 5 through the lower liquid outlet valve 7, and then enters the oil pipe above through the upper liquid outlet valve 2, achieving normal oil pumping production;

[0056] The crude oil in the plunger 4 has a relatively high flow rate, but some gravel will still be deposited. This part of gravel will automatically fall into the first sand settling chamber, so that the liquid inlet valve 9 will not be stuck, the maintenance time of the pumping unit will be extended, and the production efficiency of the oil field will be improved;

[0057] After the crude oil enters the oil pipe, the sand in the crude oil will fall downward, pass through the spiral guide groove of the pump barrel straightening joint 3, enter the second sand settling chamber, and continue to fall into the tail pipe.

[0058] Calculation method for the length of the lower joint 12 connected to the tail pipe:

[0059]

[0060] Where:

[0061] L: length of tail pipe, m / s;

[0062] ρ s : Density of sand particles, kg / m 3 ;

[0063] ρ1: density of the fluid, kg / m 3 ;

[0064] A: sand settling cross-sectional area of ​​tail pipe, m 2 ;

[0065] d p : particle size, m;

[0066] μ: fluid viscosity, Pa.s. When the water content is less than 50%, the fluid viscosity adopts the crude oil viscosity; when the water content is greater than 70%, the formation water viscosity is adopted; when the water content is between 50% and 70%, if the viscosity is ≥2000mPa.s, the formation water viscosity is adopted; if the viscosity is less than 2000mPa.s, the mass-weighted mixed viscosity is adopted for calculation;

[0067] C S : Sand volume concentration, m 3 / m 3 ;

[0068] n: sedimentation index, Re t Reynolds number for sand sedimentation, 0.2<Ret <1;

[0069] V: inertia index, W L =ρ L ·L P ·(A P -A r )·g, where a A Suspension acceleration, A p is the cross-sectional area of ​​the plunger m 3 , A r is the cross-sectional area of ​​the rod m 3 , A 管 is the cross-sectional area of ​​the oil pipe m3, ρ L is the liquid density kg / m 3 , L p is the distance m from the plunger to the calculation point.

[0070] All components and connection methods of components not discussed in this application belong to the known technologies in this technical field and can be directly applied without further explanation.

[0071] In the present invention, the term "plurality" refers to two or more than two, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0072] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “front” and “back” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0073] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A well pump, comprising a pump barrel, a plunger, and an outer tube, wherein the plunger is arranged in the pump barrel, characterized in that: The lower end of the pump barrel is connected to the outer pipe through a fixed valve sand settling device.

2. The oil well pump according to claim 1, characterized in that: The plunger is hollow inside, the upper end of the upper plunger is connected to the upper liquid outlet valve, and the lower end is connected to the lower liquid outlet valve; The outer diameter of the upper liquid outlet valve is larger than the inner diameter of the pump barrel.

3. The oil well pump according to claim 2, characterized in that: The upper end of the outer tube is connected to the upper joint, and the lower end is connected to the lower joint.

4. The oil well pump according to claim 3, characterized in that: The upper end of the pump barrel is connected with a pump barrel straightening joint; the bottom of the pump barrel is sealed.

5. The oil well pump according to claim 4, characterized in that: The plunger, the upper liquid outlet valve and the lower liquid outlet valve form a plunger string; the length of the plunger string is greater than the sum of the lengths of the pump barrel straightening joint and the pump barrel.

6. The oil well pump according to claim 5, characterized in that: The fixed valve sand settling device comprises a liquid inlet valve, a short pipe and a two-way joint; The lower end of the liquid inlet valve is connected to a short tube, the short tube is connected to a two-way joint, the two-way joint passes through the pump barrel and is connected to an outer tube, so that the liquid inlet valve is connected to the outside world.

7. The oil well pump according to claim 6, characterized in that: The annulus formed by the short tube and the pump barrel is called the first sand settling chamber; The annulus formed by the outer tube and the pump barrel is called the second sand settling chamber.

8. The oil well pump according to claim 7, characterized in that: The pump barrel straightening joint is provided with a spiral guide groove.

9. A method for using a wellbore pump, characterized in that: S1: Preparation; Connect the sucker rod to the pull rod, connect the pull rod to the plunger string, connect the upper joint to the oil pipe, and connect the lower joint to the tail pipe screen and the screw plug; S2: Pumping work; The plunger moves upward, the inlet valve opens due to the pressure difference, and the crude oil enters the pump barrel through the two-way joint; The plunger moves downward, the liquid inlet valve closes, the crude oil enters the plunger through the lower liquid outlet valve, and then enters the oil pipe above through the upper liquid outlet valve, realizing normal oil pumping production.

10. A method for using a well pump according to claim 9, characterized in that: The length calculation method of the tail pipe connected to the lower joint is: Where: L, length of tail pipe, m / s; ρ s , density of sand particles, kg / m 3 ; ρ1, density of the fluid, kg / m 3 ; A. Sand settling cross-sectional area of ​​tail pipe, m 2 ; d p , particle size, m; C S , sand volume concentration, m 3 / m 3 ; μ: fluid viscosity, Pa.s. When the water content is less than 50%, the fluid viscosity adopts the crude oil viscosity; when the water content is greater than 70%, the formation water viscosity is adopted; when the water content is between 50% and 70%, if the viscosity is ≥2000mPa.s, the formation water viscosity is adopted; if the viscosity is less than 2000mPa.s, the mass-weighted mixed viscosity is adopted for calculation; n: sedimentation index, Re t Reynolds number for sand sedimentation, 0.2<Re t <1; V: inertia index, W L =ρ L ·L P ·(A P -A r )·g, where a A Suspension acceleration, A p is the cross-sectional area of ​​the plunger m 3 , A r is the cross-sectional area of ​​the rod m 3 , A 管 is the cross-sectional area of ​​the oil pipe m3, ρ L is the liquid density kg / m 3 , L p is the distance m between the plunger and the calculation point.

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