CN-122020937-A - Method for calculating throughput of electric submersible screw pump unit

CN122020937ACN 122020937 ACN122020937 ACN 122020937ACN-122020937-A

Abstract

A method for calculating the throughput of an electric submersible screw pump unit. The electric submersible screw pump unit comprises a guide cover, a screw pump, a flexible shaft, a motor and a protector which are sequentially arranged, and the calculation method comprises the steps of S1 simplifying the structure of the electric submersible screw pump unit, S2 analyzing the trafficability condition of the electric submersible screw pump unit, considering that the electric submersible screw pump unit can be slowly and continuously put in under the premise of not damaging the structure of the electric submersible screw pump unit, S3 establishing a continuous beam analysis model, and S4 analyzing and calculating the trafficability of the electric submersible screw pump unit. The method has the beneficial effects that a calculation model based on a continuous beam structure is established by analyzing the trafficability condition of the electric submersible screw pump unit, and the technical support is provided for the construction operation of the electric submersible screw pump unit in the L-shaped horizontal well by adopting the trafficability capability of the strength condition and deformation condition computer unit.

Inventors

GE LIJUN
LAN ZHEN
LI XIAOHU
LIU XUEWEN
FAN BIN
QIN MENGFU
LIU YINHUA

Assignees

中国石油集团渤海石油装备制造有限公司
中国石油天然气集团有限公司
渤海石油装备（天津）新世纪机械制造有限公司

Dates

Publication Date: 20260512
Application Date: 20241112

Claims (10)

1. The method for calculating the throughput capacity of the electric submersible screw pump unit comprises a guide cover, a screw pump, a flexible shaft, a motor and a protector which are sequentially arranged, and is characterized in that in order to calculate whether the electric submersible screw pump unit can smoothly pass through a target well section of an L-shaped horizontal well, the method for calculating the throughput capacity of the electric submersible screw pump unit comprises the following steps: S1, simplifying structure of electric submersible screw pump unit Decomposing the electric submersible screw pump unit into simplified models with similar structures, wherein the whole unit is formed by connecting a plurality of simplified models; S2, analyzing passing conditions of electric submersible screw pump unit When the deflection deformation of the unit cannot enable the unit to smoothly pass through the target well section under the action of self gravity, the pressure of the inner wall of the sleeve on one side of the outer wall of the unit, which is close to the curvature center, is increased, and the deflection deformation of the unit is increased, so that the unit can be considered to slowly and continuously enter under the premise of not damaging the structure of the unit; S3, establishing a continuous beam analysis model Taking the joint of the simplified model decomposed in the step S1 as a fulcrum, setting each fulcrum as a middle support, setting a deformation rule similar to a continuous Liang Moxing, and establishing a continuous beam analysis model; s4, analyzing and calculating the passing capacity of the electric submersible screw pump unit S4-1, acquiring a spatial position parameter of any point of a well track; s4-2, calculating the deformation required by the unit when the unit passes through a certain well section; s4-3, establishing a stress analysis model; S4-4, establishing a three-bending moment equation of the fulcrum; s4-5, establishing a relation between the counter force, the concentrated force and the bending moment at the support; S4-6, establishing a deformation amount relation of each part of the unit; s4-7, establishing constraint conditions; S4-8, circularly calculating until the condition that the unit can pass through the target well section is met.
2. The method for calculating the throughput of the electric submersible screw pump unit according to claim 1, wherein: in the step S4-1, the spatial position parameter of any point of the well track is obtained, the spatial position parameter is set as a function which changes along with the well depth x, a three-bending moment interpolation algorithm is adopted, a three-time well spline function S (x) is constructed, the first derivative values of two adjacent measuring points are brought into an S (x) expression, an N+I order linear equation set is obtained in parallel, required variables are obtained through element elimination and back substitution, and the corresponding dog leg degree (°/30 m) and curvature radius R are calculated according to the well bevel angle and the azimuth angle at any well depth x: μ k ＝1-λ k (7) The radius of curvature R is such that, Wherein: k = number of segments, 1,2,3, &..; L k , the distance between two adjacent measuring points, m; x k ,x k-1 -the well depth of two adjacent measuring points, m; Epsilon k ,ε k-1 -spatial position parameters of two adjacent measuring points; x-well depth, m; n is the number of measuring points; second derivatives of M k ,M k-1 -S (k) and S (k-1); alpha k ,α k-1 -the well inclination angle of two adjacent measuring points; Beta k ,β k-1 , azimuth angles of two adjacent measuring points; Lambda-dogleg degree, °/30m.
3. The method for calculating the throughput of the electric submersible screw pump unit according to claim 2, characterized in that: s4-2, calculating deformation required by the unit when the unit passes through a certain well section, and establishing a geometric analysis model; under rigid conditions, the maximum length L max of each component of the computer set when passing through the well section; When the length L of a certain part of the unit is less than or equal to L max , the unit can directly pass through; when the length L of a certain part of the unit is larger than L max , the unit passes through after bending deformation, and the minimum deformation is as follows: wherein: R-radius of curvature, m; L max -the maximum length of the rigid body can pass R, m; d-diameter of rigid body, m; D, the inner diameter of the oil pipe, m; Tau-maximum distance between the rigid body and the bottom of the sleeve, m; ω min -the minimum deformation required by R, mm.
4. A method of calculating throughput of an electric submersible screw pump unit according to claim 3, characterized by: In the step S4-3, a stress analysis model is built, and stress analysis is carried out on the unit, wherein the stress analysis model comprises a well oblique angle, the gravity of the unit in liquid, the component force of the supporting reaction force of the inner wall of the sleeve to the supporting point of the unit in the Y direction, and the concentration force N of the inner wall of the sleeve to the outer wall of the unit, which is close to the center of curvature circle.
5. The method for calculating the throughput of the electric submersible screw pump unit according to claim 4, wherein: in the step S4-4, a three-bending moment equation of the middle support is established: wherein: M i -bending moment at the middle support, dividing the machine component into 3 sections, i= {1,2}, N/M; L i -the length of each segment in the reduced model, m; s i -bending moment diagram area, i= {1,2}, N/m 2 ; z i -centroid position of bending moment diagram area, i= {1,2}, m.
6. The method for calculating the throughput of the electric submersible screw pump unit according to claim 5, wherein the method comprises the following steps: the step S4-5 establishes a relation between the counter force, the concentrated force and the bending moment at the middle support, According to the bending moment obtained in the step S4-4, a relation formula among a component force F of the support reaction force of the inner wall of the sleeve on the unit in the Y direction, a concentrated force N of the inner wall of the sleeve on the outer wall of the unit, which is close to the center of curvature, and the bending moment at the support is obtained by a statics equation, wherein the relation formula is as follows: wherein: F R0 , namely, component force of a supporting counterforce at the left end of the guide cover simplified model in the Y direction, and N; N—the middle of each segment bears the concentrated force from the upper wall of the casing, i= {1,2,3}, N; m—bending moment at middle pivot, i= {1,2}, N/M; alpha-well inclination angle, °; L 1 , the length of the guide sleeve simplified model, m; l 2 , screw pump and flexible shaft, simplifying the length of the model, m; L 3 -motor+protector shaft reduced length of model, m; F R1 1 , namely, component force of a supporting counterforce at the right end of the guide cover simplified model in the Y direction, and N; f R1 2 , namely a screw pump and a flexible shaft to simplify component force of the left end support reaction force of the model in the Y direction, and N; F R2 1 , namely a screw pump and a flexible shaft to simplify component force of the right-end support reaction force of the model in the Y direction, and N; F R2 2 -a component force of a motor and protector simplification model left end support reaction force in the Y direction, and N; f R3 , namely a motor and protector simplifying component force of the counter force at the right end of the model in the Y direction, and N; q f1 -the gravity of the guide cover simplified model in the liquid is converted into uniform distribution force, N/m; q f2 -screw pump and flexible shaft simplify the gravity of the model in the liquid, and convert the gravity into uniform distribution force, N/m; q f3 -motor+protector simplified model gravity in liquid, converted into uniform distribution force, N/m.
7. The method for calculating the throughput of the electric submersible screw pump unit according to claim 6, wherein: in the step S4-6, the deformation amount relation formula of each part of the unit is established, The bending deformation is generated under the combined action of gravity q in the liquid, concentrated force N born by the middle part of each section of model from the upper wall of the sleeve and any cross section bending moment M (v), and deflection superposition is carried out on each simply supported beam to solve the following steps: ω imax ＝ω qimax +ω Nimax +ω Mimax (19) wherein: Omega imax -maximum deformation per section of model, mm; omega qimax -deformation of each section of model due to uniform distribution force, mm; omega Nimax -deformation of each section of model due to concentrated force, mm; omega Mimax -deformation of each section of model due to bending moment, mm; E-elastic modulus, 10 3 MPa; i 1 ,I 2 ,I 3 moment of inertia, m 4 .
8. The method for calculating the throughput of the electric submersible screw pump unit according to claim 7, wherein: said step S4-7 establishes a constraint that, When the deformation omega imax of the step S4-6 is equal to the minimum deformation omega min of the step S4-2, and the bending stress of the bending moment M (v) of any cross section of the unit is smaller than the allowable bending stress [ sigma w ]: wherein: M (v) -bending moment of cross section of unit, v is epsilon [0,33.74], N/M; W i -bending section coefficients, i= {1,2,3}, m 3 ; s is a safety coefficient which is more than or equal to 1.0; [ sigma w ] -flexural allowable stress of material, MPa.
9. The method for calculating the throughput of the electric submersible screw pump unit according to claim 8, wherein: in the step S4-8 of the above-mentioned, According to the formula 12 in the step S4-4, calculating the bending moment M at each support by using the concentrated force N; According to the formula 13-formula 18 in the step S4-5, calculating a counter force F, and further calculating a bending moment M (v) of any cross section of the electric submersible screw pump unit; Calculating the deformation omega imax according to the formulas 19-22 in the step S4-6; According to the constraints described in step S4-7, When the formula 23 has a solution, the unit can pass smoothly; when equation 23 is not solved, it indicates that the unit cannot pass, and the pump depth needs to be adjusted or the unit external dimension needs to be reselected.
10. The method for calculating the throughput of the electric submersible screw pump unit according to claim 9, wherein: The value range of the safety coefficient s is 1.0-2.0.

Description

Method for calculating throughput of electric submersible screw pump unit Technical Field The invention relates to an electric submersible screw pump unit, in particular to a calculation method of the throughput capacity of the electric submersible screw pump unit, and belongs to the technical field of oil gas development. Background In recent years, L-shaped horizontal wells have become the dominant well for coal bed gas development due to their high yield benefits. In the L-shaped horizontal well of the coal bed gas, the closer the pumping position is to the perforation depth, the more favorable the bottom hole pressure is released, so that the pumping position of the L-shaped horizontal well of the coal bed gas is mostly arranged near the horizontal section, and the L-shaped horizontal well can only adopt a rodless lifting exploitation mode. As a rodless lifting process with strong applicability, the electric submersible screw pump is applied to the L-shaped horizontal well of coal bed gas, and is limited by the length of the electric submersible screw pump unit and the inner diameter size of a sleeve, especially when the dogleg degree (degree/30 m) of the L-shaped horizontal well is large, the unit can be damaged when the unit passes through the dogleg, and even the unit pipe column is blocked in the well when serious. At present, the main means for researching the trafficability of underground equipment or tools in the exploitation of coal bed gas L-shaped horizontal wells are a geometric method, a mechanical method, an analog method and the like, for example, a geometric analysis method for judging trafficability by using a curvature radius is only suitable for rigid conditions, a simply supported beam model is used for judging trafficability of an electric submersible screw pump unit, the proposed trafficability judging condition and a theoretical calculation model of the electric submersible screw pump in a highly-inclined well are not considered in analysis, the influence of external force is not considered, the model applicability is low when the length of an analysis object is long, and a large deformation analysis method of ANSYS is used for simulating the trafficability of the electric submersible pump unit, but the modeling process is complex, and the calculation accuracy depends on the setting of boundary conditions. At present, few cases of the passing capability of the electric submersible screw pump unit are calculated, no mature and feasible passing capability analysis theory or calculation method exists, the lower construction operation is performed according to experience, and the lower construction operation is performed according to experience, so that necessary theoretical support is lacked, and the problems of high equipment failure rate, short service life, frequent underground accidents and the like are caused. Disclosure of Invention In order to overcome the defects of the traditional electric submersible screw pump unit in exploitation application of a coalbed methane L-shaped horizontal well, the invention provides a calculation method of the throughput capacity of the electric submersible screw pump unit. The technical scheme adopted for solving the technical problems is that the method for calculating the throughput capacity of the electric submersible screw pump unit comprises a guide cover, a screw pump, a flexible shaft, a motor and a protector which are sequentially arranged, and in order to calculate whether the electric submersible screw pump unit can smoothly pass through a target well section of an L-shaped horizontal well, the method for calculating the throughput capacity of the electric submersible screw pump unit comprises the following steps: S1, simplifying structure of electric submersible screw pump unit The electric submersible screw pump unit is decomposed into simplified models with similar structures, and the whole unit is formed by connecting a plurality of simplified models. S2, analyzing passing conditions of electric submersible screw pump unit When the deflection deformation of the unit cannot enable the unit to smoothly pass through the target well section under the action of self gravity, the pressure of the inner wall of the sleeve on one side of the outer wall of the unit, which is close to the center of curvature, is increased, and the deflection deformation of the unit is increased, so that the unit can be considered to slowly and continuously enter under the premise of not damaging the structure of the unit. S3, establishing a continuous beam analysis model And (3) taking the joint of the simplified model decomposed in the step (S1) as a fulcrum, setting each fulcrum as a middle support, setting the deformation rule to be similar to a continuous Liang Moxing, and establishing a continuous beam analysis model. S4, analyzing and calculating the passing capacity of the electric submersible screw pump unit S4-1, acquiring a spatial position paramet