Installation optimization method of three-dimensional well casing centralizer

Abstract

The invention relates to the field of petroleum drilling engineering, and discloses an installation optimization method for a three-dimensional well casing centralizer, which comprises the following steps of: setting the installation distance of an initial centralizer and presetting the centering degree of a casing; calculating the dog-leg angle change rate and the full-angle change rate of any casing segment in the three-dimensional borehole; the stress deformation of the casing sections is decomposed into dog leg angle plane stress deformation and well inclined plane stress deformation; the upper end axial force and the lower end axial force of the centralizer are calculated; calculating the total axial force and the total radial force of the casing segments; calculating the maximum deflection and the actual centering degree of the casing segments; judging whether the actual centering degree is equal to a preset centering degree or not; when it is judged that the actual centering degree is equal to the preset centering degree, it is determined that the initial installation distance is adopted, and otherwise, the initial installation distance is optimized. According to the installation optimization method for the three-dimensional borehole casing centralizer, the centralizer can be accurately and effectively installed on the casing, and it is guaranteed that the centering degree of the casing in a borehole meets the engineering quality requirement.

Description

Technical Field

[0001] This application belongs to the technical field of oil drilling engineering, and specifically relates to an installation optimization method for three-dimensional wellbore casing centralizers. Background Art

[0002] Casing centralizers are widely used in cementing operations to keep the casing away from the wellbore wall, improve the displacement efficiency, and obtain good cementing quality in the annulus. The cementing quality depends on the centralization of the casing in the wellbore, and the centralization of the casing in the wellbore is closely related to factors such as the performance, placement combination, and placement spacing of the centralizers. Correctly installing the centralizer spacing will reduce the length of contact between the casing and the wellbore wall, reduce the wear of the casing in the large hole section, and play a role in protecting the casing. However, in actual cementing operations, it is not that the more casing centralizers are used, the better the centralizing effect will be. Especially in highly deviated wells and horizontal wells, too many casing centralizers not only increase the production cost but also increase the casing rigidity, thus leading to a frequent risk of downhole complex situations. Since the actual contact state and force characteristics of the casing in the three-dimensional wellbore become extremely complex after installing the centralizers, the on-site centralizer installation plan mainly relies on empirical judgment and lacks theoretical basis and calculation methods. Therefore, aiming at the actual casing cementing operation conditions, considering actual wellbore conditions and formation and other factors and combining with the actual working experience of installing casing centralizers, it is urgent to establish a complete, effective, reasonable, and accurate installation method for casing centralizers in three-dimensional wellbores. Summary of the Invention

[0003] In view of the above at least one defect or deficiency of the prior art, this application provides an installation optimization method for three-dimensional wellbore casing centralizers, which realizes the precise and effective installation of centralizers on the casing and ensures that the centralization of the casing in the wellbore meets the engineering quality requirements.

[0004] To achieve the above object, this application provides an installation optimization method for three-dimensional wellbore casing centralizers, and the installation optimization method includes:

[0005] Obtain wellbore trajectory parameters, casing string structure parameters, and drilling fluid parameters, and set the installation spacing l of the initial centralizer i and preset the casing centralization ε 0 ;

[0006] According to the wellbore trajectory parameters and the installation spacing l of the initial centralizer i calculate the dogleg angle β and the total angle change rate K of any casing segment in the three-dimensional wellbore;

[0007] Decompose the three-dimensional force deformation of the casing segment into dogleg angle plane force deformation and well inclination plane force deformation according to the total angle change rate K;

[0008] According to the initial installation spacing li The axial force T' at the upper end of the centralizer is calculated based on the structural parameters of the casing string i and the axial force T" at the lower end i ;

[0009] Based on the axial force T' at the upper end i and the axial force T" at the lower end i the total axial force T of the casing section is calculated i ;

[0010] Based on the type of force and deformation, the structural parameters of the casing string, the initial installation spacing l i , the axial force T' at the upper end i and the axial force T" at the lower end i the total radial force N of the casing section is calculated i ;

[0011] Based on the type of force and deformation, the structural parameters of the casing string, the initial installation spacing l i , the total axial force T i and the total radial force N i the maximum deflection δ of the casing section is calculated max ;

[0012] Based on the allowable eccentricity [e] of the casing section and the maximum deflection δ max the actual centrality ε of the casing section is calculated i ;

[0013] It is judged whether the actual centrality ε i is equal to the preset centrality ε 0 ;

[0014] When it is judged that the actual centrality ε i is equal to the preset centrality ε 0 the initial installation spacing l i is determined to be adopted, otherwise, the initial installation spacing l i is optimized to satisfy that the actual centrality ε i is equal to the preset centrality ε 0 .

[0015] In some embodiments, the wellbore trajectory parameters include the difference in well depth ΔL, the well inclination angle α i and the azimuth angle

[0016] Based on the wellbore trajectory parameters, the dogleg angle β and the full angle change rate K of any casing section in the three-dimensional wellbore are calculated, satisfying:

[0017]

[0018] Wherein, the subscript i represents the i-th centralizer or the i-th span of the casing segments.

[0019] In some embodiments, the casing string structure parameters include casing parameters and centralizer parameters. The casing parameters include the equivalent effective floating weight w e of the casing, the internal bending moment M Ri of the casing in the dogleg angle plane, and the radius R i of the casing bending arc segment. The centralizer parameters include the friction μN i between the centralizer and the casing segment;

[0020] Calculate the upper axial force T i ' and the lower axial force T i " of the centralizer according to the initial installation spacing l i ", satisfying:

[0021]

[0022] Wherein, is the average well inclination angle.

[0023] In some embodiments, calculate the total axial force T i ' of the casing segment according to the upper axial force T i " and the lower axial force T i ", satisfying:

[0024]

[0025] In some embodiments, calculate the total radial force N i of the casing segment according to the force and deformation type, the casing string structure parameters, the initial installation spacing l i ', the dogleg angle β, the upper axial force T i " and the lower axial force T i , including:

[0026] Calculate the radial force N Ri received by the centralizer in the dogleg angle plane R and the radial force N Pi received by the centralizer in the well inclination plane P respectively, satisfying:

[0027] N Ri = N' Ri + N' R ', i N Pi = N' Pi + N' P '; i ;

[0028] Among them, N' Ri is the radial force received by the upper end of the centralizer in the dog-leg angle plane R, and satisfies:

[0029]

[0030] N R ” i is the radial force received by the lower end of the centralizer in the dog-leg angle plane R, and satisfies:

[0031]

[0032] N' Pi is the radial force received by the upper end of the centralizer in the well deviation plane P, and satisfies:

[0033]

[0034] N P ” i is the radial force received by the lower end of the centralizer in the well deviation plane P, and satisfies:

[0035]

[0036] According to the radial force N Ri received by the centralizer in the dog-leg angle plane R Pi and the radial force N i received by the centralizer in the well deviation plane P, calculate the total radial force N

[0037]

[0038] In some embodiments, W RX(i) is the uniformly distributed load component of the casing gravity along the casing axis in the dog-leg angle plane R, and satisfies:

[0039]

[0040] W RY(i) is the uniformly distributed load component of the casing gravity along the direction perpendicular to the casing axis in the dog-leg angle plane R, and satisfies:

[0041]

[0042] W PY(i) is the uniformly distributed load component of the casing gravity along the direction perpendicular to the casing axis in the well deviation plane P, and satisfies:

[0043] W PY(i) =-W i m 3 .

[0044] In some embodiments, the casing parameters include the casing elastic modulus E and the moment of inertia I of the casing cross-section. According to the type of force and deformation, the casing string structure parameters, the initial installation spacing l i , the total axial force T i and the total radial force N i calculate the maximum deflection δ of the casing segment max , satisfying:

[0045]

[0046] where u is the stability coefficient of the beam under combined axial and bending loads, satisfying:

[0047]

[0048] In some embodiments, the centralizer parameters include the deformation amount s of the casing centralizer. According to the centralizer parameters, the allowable eccentricity [e] of the casing segment, the maximum deflection δ max and the maximum eccentricity e max calculate the actual alignment degree ε of the casing segment i , satisfying:

[0049]

[0050] The allowable eccentricity [e] of the casing is taken as one-third of the annular clearance between the casing and the wellbore, satisfying:

[0051]

[0052] where d h is the wellbore diameter, and d co is the outer diameter of the casing;

[0053] The maximum eccentricity e of the casing max is equal to the sum of the maximum deflection δ of the casing and the deformation amount s of the casing centralizer, satisfying: max e

[0054] e max = δ max + s.

[0055] In some embodiments, when the centralizer is a rigid centralizer, the deformation amount s of the centralizer satisfies:

[0056]

[0057] where d h is the wellbore diameter, and d rc is the outer diameter of the centralizer;

[0058] When the centralizer is an elastic centralizer, the deformation amount s of the centralizer satisfies:

[0059]

[0060] where k is the stiffness coefficient of the centralizer;

[0061] When one of the two-end centralizers is a rigid centralizer and the other is an elastic centralizer, the deformation amount s of the centralizer satisfies:

[0062]

[0063] In some embodiments, when the actual centralization degree ε of the casing i is less than the preset centralization degree ε 0 then the initial centralizer spacing l is reduced i ; when the actual centralization degree ε of the casing i is greater than the preset centralization degree ε 0 then the initial centralizer spacing l is increased i ; recalculate until it is equal to the preset centralization degree.

[0064] Through the above technical solutions, the installation optimization method of the three-dimensional wellbore casing centralizer of the present application is based on the longitudinal and transverse bending continuous beam structure model. Aiming at the force and deformation of the casing segment between two centralizers in the three-dimensional wellbore, factors such as wellbore trajectory parameters, casing string structure parameters, and drilling fluid parameters are comprehensively considered. A mechanical model of the maximum deflection of the casing segment is established. Combining with the multi-eccentricity models of different centralizer types, the theoretical model of casing centralization is corrected, and the actual centralization degree of the casing is calculated. By comparing and analyzing the actual centralization degree with the preset centralization degree, the accurate and effective installation of the centralizer on the casing can be realized, ensuring that the centralization degree of the casing in the wellbore meets the engineering quality requirements. Overall, the present application can provide a theoretical basis and guiding significance for the installation design of the centralizer.

[0065] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent specific embodiment part. Brief Description of the Drawings

[0066] The drawings are used to provide a further understanding of the embodiments of the present application, and constitute a part of the specification. They are used together with the following specific embodiments to explain the embodiments of the present application, but do not constitute a limitation to the embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without creative efforts. In the drawings:

[0067] Figure 1 is a schematic diagram of the steps of an installation optimization method for a three-dimensional wellbore casing centralizer in a specific embodiment of the present application;

[0068] Figure 2 Schematic diagram of the force analysis model for the casing section between two centralizers in a three-dimensional wellbore;

[0069] Figure 3 Schematic diagram of the force analysis model for the centralizer in a three-dimensional wellbore;

[0070] Figure 4 Schematic diagram of the program calculation flow for an installation optimization method of a three-dimensional wellbore casing centralizer in a specific embodiment of the present application.

[0071] Description of the reference numerals

[0072] 1 Casing section 2 Centralizer Specific embodiments

[0073] The following further describes in detail the specific embodiments of the present application with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining and understanding the present application, and are not used to limit the present application.

[0074] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with exemplary embodiments.

[0075] In oil drilling engineering, the centralizer used is a tool responsible for stabilizing the downhole drill string and preventing deviation. During casing drilling operations, multiple centralizers are successively and spacedly sleeved on the outer peripheral wall of the casing. By adjusting the distance between two adjacent centralizers to an appropriate value, the casing section between the two centralizers is subjected to appropriate forces, and at this time, the casing section can be in the central position of the wellbore, thereby improving the stability of the wellbore.

[0076] In view of this, as Figures 1 to 4 shown, the first exemplary embodiment of the present application provides an installation optimization method for a three-dimensional wellbore casing centralizer, and the installation optimization method includes the following steps:

[0077] S10: Obtain the wellbore trajectory parameters, casing string structure parameters, and drilling fluid parameters, and set the installation spacing l of the initial centralizer i and preset the casing centralization degree ε 0 ;

[0078] S20: Calculate the dogleg angle β and the total angle change rate K of any casing section 1 in the three-dimensional wellbore according to the wellbore trajectory parameters and the installation spacing l of the initial centralizer i ;

[0079] S30: Decompose the three-dimensional force deformation of the casing section 1 into the dogleg angle plane force deformation and the well inclination plane force deformation according to the total angle change rate K;

[0080] S40: According to the initial installation spacing li 、Calculate the axial force T' at the upper end and the axial force T'' at the lower end of the centralizer 2 for the casing string structure parameters i ’ and the axial force T i ”

[0081] S50: Calculate the total axial force T of the first casing segment according to the axial force T' at the upper end and the axial force T'' at the lower end i ’ and the axial force T i ” i ;

[0082] S60: Calculate the total radial force N of the first casing segment according to the force and deformation type, casing string structure parameters, initial installation spacing l i 、dog-leg angle β, axial force T' at the upper end and axial force T'' at the lower end i ’ and the axial force T i ” i ;

[0083] S70: Calculate the maximum deflection δ of the first casing segment according to the force and deformation type, casing string structure parameters, initial installation spacing l i 、total axial force T i and the total radial force N i max ;

[0084] S80: Calculate the actual centrality ε of the first casing segment according to the centralizer parameters, allowable eccentricity [e] and maximum deflection δ of the first casing segment max i ;

[0085] S90: Determine whether the actual centrality ε i is equal to the preset centrality ε 0 ;

[0086] S100: When it is determined that the actual centrality ε i is equal to the preset centrality ε 0 , determine to adopt the initial installation spacing l i , otherwise, correct the initial installation spacing l i until the actual centrality ε i is equal to the preset centrality ε 0 。

[0087] It should be noted that in step S10, the initial installation spacing l of the centralizer 2 i can be determined by considering wellbore conditions, formation and other factors and combining with actual working experience. In actual implementation, the initial installation spacing l i can be selected as a relatively large value to facilitate subsequent adjustment to an appropriate value. Thus, the initial installation spacing l i is used between every two of the multiple centralizers 2.​They are installed on the casing at intervals, thereby separating the casing into multiple casing segments 1 of equal length. Among the multiple casing segments 1, if the well deviation angle of the upper measuring point of any one casing segment 1 is less than that of the lower measuring point, this casing segment 1 is an inclination-increasing section; otherwise, it is an inclination-decreasing section.

[0088] The key to determining whether the casing segment 1 is deformed under force in a two-dimensional wellbore or a three-dimensional wellbore lies in determining the changes in the well deviation angle and azimuth angle of the two measuring points at both ends of the casing segment 1. Specifically, when the well deviation angle of the two measuring points at both ends of the casing segment 1 changes and the azimuth angle remains unchanged, this casing segment 1 is deformed under force in a two-dimensional wellbore. At this time, the force deformation type of the casing segment 1 can be determined as force deformation in the well deviation plane, that is, only the force problem of the casing segment 1 in the well deviation plane P needs to be considered; when the well deviation angle and azimuth angle of the two measuring points at both ends of the casing segment 1 both change, this casing segment 1 is deformed under force in a three-dimensional wellbore. At this time, the force deformation type of the casing segment 1 can be determined as force deformation in the dogleg angle plane and force deformation in the well deviation plane, that is, the force problems of the casing segment 1 in the dogleg angle plane R and the well deviation plane P need to be analyzed separately. Since the full angle change rate of the casing segment 1 is determined by the well deviation angle and azimuth angle, and the installation optimization method of this exemplary embodiment mainly aims at the case where the casing is deformed under force in a three-dimensional wellbore, therefore, in step S30, the force deformation type of the casing segment can be divided into force deformation in the dogleg angle plane and force deformation in the well deviation plane according to the full angle change rate K.

[0089] It can be seen that the installation optimization method of the three-dimensional wellbore casing centralizer of this exemplary embodiment is based on the longitudinal and transverse bending continuous beam structure model. Aiming at the force deformation of the casing segment between two centralizers in a three-dimensional wellbore or a two-dimensional wellbore, factors such as wellbore trajectory parameters, casing string structure parameters, centralizer parameters, and drilling fluid parameters are comprehensively considered. A maximum deflection mechanical model of the casing segment is established, and the actual centralization degree of the casing segment is calculated. By comparing and analyzing the actual centralization degree with the preset centralization degree, the installation spacing between two centralizers is corrected, so as to realize the accurate and effective installation of the centralizer on the casing, ensure that the centralization degree of the casing in the wellbore meets the engineering quality requirements. Generally speaking, this application can provide a theoretical basis and guiding significance for the installation design of the centralizer.

[0090] It should be noted that as Figure 2 shown, the dogleg angle plane R is composed of the defined plane A, B, and O, and the well deviation plane P is defined by the chord AB and the H axis. The force on the casing segment 1 in the three-dimensional wellbore needs to be decomposed onto the dogleg angle plane R and the well deviation plane P for analysis. In some other embodiments, the force on the casing segment 1 in the two-dimensional wellbore only needs to be analyzed on the well deviation plane P. The installation optimization method described below mainly aims at the force problem of the casing segment 1 in the three-dimensional wellbore, and the force problem of the casing segment 1 in the two-dimensional wellbore will be supplemented and explained in subsequent embodiments.

[0091] When analyzing the forces on casing section 1 in a three-dimensional wellbore, it is first necessary to determine the direction of the forces on casing section 1. As Figure 2 shown, the normal vector of the dogleg angle plane R satisfies:

[0092]

[0093] The normal vector of the well inclination plane P satisfies:

[0094]

[0095] Wherein, is a unit vector, α i is the well inclination angle, is the azimuth angle, and are the average well inclination angle and the average azimuth angle respectively.

[0096] Thus, the angle γ between the dogleg angle plane R and the well inclination plane P satisfies:

[0097]

[0098] The unit binormal vector m of casing section 1 in the three-dimensional wellbore satisfies:

[0099]

[0100] Wherein, τ is the unit tangent vector of the casing, and m 1 , m 2 , m 3 are the components in the direction and satisfy:

[0101]

[0102] The unit normal vector m of casing section 1 in the three-dimensional wellbore satisfies: n = m × τ.

[0103] In an alternative or preferred embodiment, for step S20, the wellbore trajectory parameters include the difference in well depth ΔL of casing section 1, the well inclination angle α i and the azimuth angle

[0104] Calculate the dogleg angle β and the full angle change rate K of any casing section 1 in the three-dimensional wellbore according to the wellbore trajectory parameters, and satisfy:

[0105]

[0106] Wherein, the subscript i is the i-th centralizer or the i-th casing section.

[0107] In an alternative or preferred embodiment, for step S40, the casing string structure parameters include casing parameters and centralizer parameters. The casing parameters include the equivalent effective floating weight w of the casing e , the internal bending moment M of the casing in the dogleg angle plane Ri , the radius R of the bent arc section of the casing i , and the centralizer parameters include the friction μN between the centralizer and the first section of the casing i , where μ is the friction coefficient between the inner wall of the second centralizer and the first section of the casing, and is dimensionless according to the type of the second centralizer

[0108] According to the initial installation spacing l i , the casing parameters and the centralizer parameters, calculate the upper axial force T i ' and the lower axial force T i " of the second centralizer, satisfying:

[0109]

[0110] where is the average well inclination angle

[0111] In this embodiment, considering the influence of the additional tension caused by the density difference between the inner and outer fluids of the casing on the floating weight of the casing, the equivalent effective floating weight w of the casing can be corrected based on the principle of effective buoyancy, satisfying: e

[0112]

[0113] where w a is the effective unit gravity of the first section of the casing in air, ρ s and ρ m are the densities of the inner and outer fluids of the first section of the casing respectively, d co and d ci are the outer diameter and inner diameter of the first section of the casing respectively

[0114] In an alternative or preferred embodiment, for step S50, calculate the total axial force T i ' and the lower axial force T i " of the first section of the casing, satisfying: i

[0115]

[0116] In an alternative or preferred embodiment, decompose the radial force of the second centralizer into the dogleg angle plane R and the well inclination plane P for analysis. Therefore, step S60 includes steps S61 and S62. Specifically:

[0117] ​​S61: Calculate the radial force N exerted on the centralizer within the dogleg angle plane R Ri and the radial force N exerted on the centralizer within the well inclination plane P Pi , satisfying:

[0118] N Ri = N' Ri + N' R ' i (Equation 10), N Pi = N' Pi + N' P ' i (Equation 11);

[0119] where N’ Ri is the radial force exerted on the upper end of the centralizer 2 within the dogleg angle plane R, satisfying:

[0120]

[0121] N R ” i is the radial force exerted on the lower end of the centralizer 2 within the dogleg angle plane R, satisfying:

[0122]

[0123] N’ Pi is the radial force exerted on the upper end of the centralizer 2 within the well inclination plane P, satisfying:

[0124]

[0125] N P ” i is the radial force exerted on the lower end of the centralizer 2 within the well inclination plane P, satisfying:

[0126]

[0127] S62: Calculate the total radial force N of the casing section 1 based on the radial force N Ri exerted on the centralizer within the dogleg angle plane R Pi and the radial force N i exerted on the centralizer within the well inclination plane P, satisfying:

[0128]

[0129] In the above equation, W RX(i) is the uniform load component of the casing gravity along the casing axis within the dogleg angle plane R, satisfying:

[0130]

[0131] W RY(i)is the uniformly distributed load component of the casing gravity in the direction perpendicular to the casing axis within the dogleg angle plane R, satisfying:

[0132]

[0133] W PY(i) is the uniformly distributed load component of the casing gravity in the direction perpendicular to the casing axis within the well deviation plane P, satisfying:

[0134] W PY(i) =-W i m 3 (Equation 19).

[0135] M P(i) is the bending moment of the centralizer 2 within the well deviation plane P, M Ri is the bending moment of the centralizer 2 within the dogleg angle plane R, M P(i) and M Ri can be solved by the three-moment equations established for the continuous beam with combined flexure and axial load, which will not be elaborated here.

[0136] In an alternative or preferred embodiment, for step S70, the casing parameters include the casing elastic modulus E and the casing cross-sectional moment of inertia I. According to the stress and deformation type, casing parameters, initial installation spacing l i , total axial force T i and total radial force N i calculate the maximum deflection δ of the casing segment 1 max , satisfying:

[0137]

[0138] where u is the stability coefficient of the beam with combined flexure and axial load, dimensionless, satisfying:

[0139]

[0140] Specifically, by analyzing the deflections of the casing segment 1 in the dogleg angle plane R and the well deviation plane P respectively, we can obtain:

[0141] The maximum deflection δ of the casing segment 1 in the dogleg angle plane R R , satisfying:

[0142]

[0143] The maximum deflection δ of the casing segment 1 in the well deviation plane P P , satisfying:

[0144]

[0145] Taking δ R and δ PSubstituting the above formula can calculate the maximum deflection δ of the casing section 1 in the three-dimensional wellbore. max .

[0146] In an alternative or preferred embodiment, when the azimuth angle remains unchanged and the well deviation angle changes continuously with the well depth, the wellbore can be defined as a two-dimensional wellbore, and the force analysis of the casing can be defined as a force problem in the two-dimensional wellbore. At this time, only the maximum deflection of the casing section 1 in the well deviation plane P needs to be calculated, satisfying:

[0147]

[0148] In an alternative or preferred embodiment, for step S80, the centralizer parameters include the deformation amount s of the casing centralizer. According to the centralizer parameters, the allowable eccentricity [e] of the casing section 1 and the maximum deflection δ max Calculate the actual centrality ε of the casing section 1 i , satisfying:

[0149]

[0150] The allowable eccentricity [e] of the casing is taken as one-third of the annular space gap between the casing and the wellbore, satisfying:

[0151]

[0152] The maximum eccentricity e of the casing max is equal to the sum of the maximum deflection δ of the casing max and the deformation amount s of the casing centralizer, satisfying:

[0153] e max = δ max + s (Equation 27).

[0154] Thus, by comparing the consistency between the actual centrality ε i and the preset centrality ε 0 , the centrality of the casing section 1 can be judged accordingly and the installation spacing of the centralizer 2 can be corrected.

[0155] Since the deformation amount s of the casing centralizer needs to be considered when calculating the actual centrality ε i of the casing section 1, and the deformation amounts of different types of centralizers 2 are different, therefore, different deformation amounts s of the centralizer need to be substituted for calculation.

[0156] Specifically, in this embodiment, when the centralizers at both ends are rigid centralizers, the deformation amount s of the centralizer satisfies:

[0157]

[0158] Wherein, d h is the wellbore diameter, d rcis the outer diameter of the centralizer;

[0159] When the centralizers at both ends are elastic centralizers, the deformation amount s of the centralizer satisfies:

[0160]

[0161] where k is the stiffness coefficient of the centralizer 2.

[0162] When one of the centralizers at both ends is a rigid centralizer and the other is an elastic centralizer, the deformation amount s of the centralizer satisfies:

[0163]

[0164] Thus, the installation optimization method of this exemplary embodiment combines the multi-eccentricity models of different types of centralizers 2 to improve the judgment accuracy of the centralization degree of the casing section 1, making the adjustment of the spacing of the centralizer 2 more accurate.

[0165] The second exemplary embodiment of the present invention provides a machine-readable storage medium, on which instructions are stored, and the instructions are used to cause the machine to execute the above-mentioned installation optimization method of the three-dimensional wellbore casing centralizer.

[0166] The third exemplary embodiment of the present invention provides a processor for running a program, and when the program runs, it executes the above-mentioned installation optimization method of the three-dimensional wellbore casing centralizer.

[0167] The processor includes a kernel, and the kernel retrieves the corresponding program unit from the memory. One or more kernels can be set, and by adjusting the kernel parameters, the execution of the installation optimization method of the three-dimensional wellbore casing centralizer can be achieved.

[0168] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of, for example, read-only memory (ROM) or flash memory (flash RAM), and the memory includes at least one storage chip.

[0169] The fourth exemplary embodiment of the present invention further provides a computer program product, including a computer program, and when the computer program is executed by a processor, it implements the above-mentioned installation optimization method of the three-dimensional wellbore casing centralizer.

[0170] Next, refer to Figure 4 A specific embodiment is provided to illustrate how to execute the installation optimization method of the three-dimensional wellbore casing centralizer of the present application in practical applications.

[0171] Step 1: Input wellbore trajectory parameters, casing string structure parameters, and drilling fluid parameters.

[0172] Among them, the wellbore trajectory parameters are shown in Table 1, including the well depth, vertical depth, well deviation angle, azimuth angle, etc. of the wellbore; the casing string structure parameters are shown in Table 2, including dimensions, thread types, lengths, steel grades, etc. The casing used in this embodiment is: Φ127mm float shoe + Φ127mm casing (BG125V×11.1mm BGT2) + Φ127mm casing (BG125V×11.1mm BGT2) + Φ127m float collar + Φ127mm casing (BG125V×11.1mm BGT2) + Φ127mm casing string (Q125-II×11.1mmTSH W563) + Φ127mm landing joint; the centralizer parameters are shown in Table 3, including the structural form, nominal casing size, nominal bit size, maximum outer diameter, etc. The drilling fluid parameters include density and rheological parameters, etc. In this embodiment, white oil-based drilling fluid is used, and the density is 1.24g / cm 3 , the dynamic yield stress of the drilling fluid is 8Pa, and the density of the cement slurry is 1.51g / cm 3 , and the dynamic yield stress of the cement slurry is 11Pa.

[0173] Step 2: Data processing and calculation.

[0174] 1) Preset a suitable centralization value according to the basic data input on site and select the centralizer type;

[0175] 2) Try to take an initial centralizer installation spacing to divide the entire casing into micro-elements, and obtain the full angle change rate of a certain i-span casing segment;

[0176] 3) Judge the force and deformation of the i-span casing segment in the two-dimensional and / or three-dimensional wellbore, and decompose the force in the three-dimensional wellbore into the force in the well deviation plane P and the force in the dogleg angle plane R;

[0177] 4) Calculate the axial force and radial force of the centralizer;

[0178] 5) Calculate the axial load and total radial force of the casing segment;

[0179] 6) Calculate the total deflection of the casing segment in the well deviation plane P and the dogleg angle plane R. If the azimuth angle remains unchanged and the well deviation angle changes continuously with the well depth, it is defined as the casing deflection deformation problem in the two-dimensional well deviation plane, and the simplified formula is used to calculate the total deflection of the casing segment in the well deviation plane;

[0180] 7) Calculate the theoretical centralization of the casing, compare this centralization with the preset centralization value in step 1). If the calculated theoretical centralization is greater than the preset centralization, increase the centralizer spacing, otherwise decrease the centralizer spacing, and repeat the above calculations until the on-site preset centralization is satisfied.

[0181] 8) And so on until all the casing segments are adjusted.

[0182] This optimized design method takes into account the actual wellbore conditions and the performance characteristics of centralizers, combines the on-site working experience of installing casing centralizers, and obtains a complete and effective method for optimizing the installation of casing centralizers for the mechanical model of casing deformation between centralizers under actual working conditions.

[0183] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a machine-readable storage medium, a processor, or a computer program product. Therefore, the present invention can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) containing computer-usable program code.

[0184] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0185] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means that implement the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0186] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are performed on the computer or other programmable device to generate a computer-implemented process, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0187] In a typical configuration, a computing device includes one or more processors (CPUs), an input / output interface, a network interface, and memory.

[0188] The memory may include non - permanent memory in the form of computer - readable media, random access memory (RAM) and / or non - volatile memory such as read - only memory (ROM) or flash RAM. The memory is an example of computer - readable media.

[0189] Computer - readable media includes permanent and non - permanent, removable and non - removable media and can store information by any method or technology. The information can be computer - readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase - change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read - only memory (ROM), electrically erasable programmable read - only memory (EEPROM), flash memory or other memory technologies, compact disc read - only memory (CD - ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette tapes, magnetic disk storage or other magnetic storage devices, or any other non - transitory medium that can be used to store information that can be accessed by a computing device.

[0190] It should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non - exclusive inclusion, such that a process, method, article or apparatus comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or apparatus. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising the element.

[0191] The above are only embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. The installation optimization method of the three-dimensional wellbore casing centralizer includes: Obtain the wellbore trajectory parameters, casing string structure parameters and drilling fluid parameters, and set the initial installation spacing l of the centralizer i And the casing centering degree ε0 is preset; According to the wellbore trajectory parameters and the initial installation spacing l of the centralizer i Calculating the dogleg angle β and the full angle change rate K of any casing segment in the three-dimensional wellbore; Decomposing the three-dimensional stress deformation of the casing segment into the stress deformation of the dogleg angle plane and the stress deformation of the well inclination plane according to the full angle change rate K; According to the initial installation spacing l i , the casing string structural parameters calculate the upper end axial force T of the centralizer i ' and the lower end axial force T i ”; According to the upper end axial force T i ' and the lower end axial force T i Calculate the total axial force T of the casing segment i ; According to the stress deformation type, the casing string structural parameters, the initial installation spacing l i , the upper end axial force T i ' and the lower end axial force T i Calculate the total radial force N of the casing segment i ; According to the stress deformation type, the casing string structural parameters, the initial installation spacing l i , the total axial force T i and the total radial force N i Calculate the maximum deflection δ of the casing segment max ; According to the allowable eccentricity [e] of the casing segment and the maximum deflection δ max Calculate the actual centering degree ε of the casing segment i ; Determine the actual centering degree ε i Is it equal to the preset centering degree ε0? When the actual centering degree ε is determined i When the preset centering degree ε0 is equal to the preset centering degree ε0, the initial installation spacing l is determined to be adopted. i Otherwise, the initial installation spacing l i Correction is performed until the actual centering degree ε i Equal to the preset centering degree ε0.

2. The installation optimization method of a three-dimensional wellbore casing centralizer according to claim 1, wherein: The wellbore trajectory parameters include the difference in well depth ΔL between the casing segments, the well inclination angle α i and azimuth The dogleg angle β and the full angle change rate K of any casing segment in the three-dimensional wellbore are calculated according to the wellbore trajectory parameters to satisfy: Wherein, the subscript i refers to the i-th said centralizer or the i-th said casing segment.

3. The installation optimization method of a three-dimensional wellbore casing centralizer according to claim 2, wherein: The casing string structural parameters include casing parameters and centralizer parameters, and the casing parameters include casing equivalent effective buoyancy weight w e , the internal bending moment M of the casing in the dogleg angle plane Ri , casing bending arc radius R i The centralizer parameters include the friction between the centralizer and the casing segment μN i ; According to the initial installation spacing l i , the casing parameters and the centralizer parameters to calculate the upper end axial force T of the centralizer i ' and the lower end axial force T i ",satisfy: in, is the average well inclination angle.

4. The installation optimization method of a three-dimensional wellbore casing centralizer according to claim 3, wherein: According to the upper end axial force T i ' and the lower end axial force T i Calculate the total axial force T of the casing segment i ,satisfy:

5. The installation optimization method of a three-dimensional wellbore casing centralizer according to claim 3, wherein: According to the stress deformation type, the casing parameters, the initial installation spacing l i , the dogleg angle β, the upper end axial force T i ' and the lower end axial force T i Calculate the total radial force N of the casing segment i include: Calculate the radial force N of the centralizer in the dogleg angle plane R respectively Ri And the radial force N in the well inclination plane P Pi ,satisfy: N Ri =N′ Ri +N″ Ri ,N Pi =N′ Pi +N″ Pi ; Among them, N' Ri is the radial force on the upper end of the centralizer in the dogleg angle plane R, satisfying: N″ Ri is the radial force on the lower end of the centralizer in the dogleg angle plane R, satisfying: N' Pi is the radial force on the upper end of the centralizer in the well inclination plane P, satisfying: N″ Pi is the radial force on the lower end of the centralizer in the well inclination plane P, satisfying: According to the radial force N received by the centralizer in the dogleg angle plane R Ri And the radial force N in the well inclination plane P Pi , calculate the total radial force N of the casing segment i ,satisfy:

6. The installation optimization method of a three-dimensional wellbore casing centralizer according to claim 5, wherein: W RX(i) is the uniformly distributed load component of the casing gravity along the casing axial direction in the dogleg angle plane R, satisfying: W RY(i) is the uniformly distributed load component of the casing gravity in the dogleg angle plane R along the direction perpendicular to the casing axis, satisfying: W PY(i) is the uniformly distributed load component of the casing gravity in the well inclination plane P along the direction perpendicular to the casing axis, satisfying: <h2 style=";text-align:left;direction:ltr">W<h2 style=";text-align:left;direction:ltr"> PY(i) <h2 style=";text-align:left;direction:ltr"> 2-W<h2 style=";text-align:left;direction:ltr"> i <h2 style=";text-align:left;direction:ltr"> m3.

7. The installation optimization method of a three-dimensional wellbore casing centralizer according to claim 5, wherein: The casing parameters include casing elastic modulus E, casing section inertia moment I, according to the stress deformation type, the casing parameters, the initial installation spacing l i , the total axial force T i and the total radial force N i Calculate the maximum deflection δ of the casing segment max ,satisfy: Among them, u is the stability coefficient of the longitudinal and transverse bending beam, which satisfies:

8. The installation optimization method of a three-dimensional wellbore casing centralizer according to claim 7, wherein: The centralizer parameters include the deformation s of the casing centralizer, which is calculated based on the centralizer parameters, the allowable eccentricity [e] of the casing segment, and the maximum deflection δ max and the maximum eccentricity e max Calculate the actual centering degree ε of the casing segment i ,satisfy: The permissible eccentricity of the casing [e] is one third of the annular gap between the casing and the wellbore, satisfying: Among them, d h is the borehole diameter, d co is the outer diameter of the casing; The maximum eccentricity of the casing is e max Equal to the maximum casing deflection δ max The sum of the deformation s of the casing centralizer satisfies: e max =d max +s.

9. The installation optimization method of a three-dimensional wellbore casing centralizer according to claim 8, wherein: When the two-end centralizers are rigid centralizers, the deformation s of the centralizers satisfies: Among them, d rc is the outer diameter of the centralizer; When the two-end centralizers are elastic centralizers, the deformation s of the centralizers satisfies: Wherein, k is the stiffness coefficient of the centralizer; When one of the two end centralizers is a rigid centralizer and the other is an elastic centralizer, the deformation s of the centralizer satisfies:

10. The installation optimization method of a three-dimensional wellbore casing centralizer according to claim 9, wherein: The actual centering degree ε of the sleeve i When it is less than the preset centering degree ε0, the initial centralizer spacing l is reduced. i ; The actual centering degree of the sleeve ε i When it is greater than the preset centering degree ε0, the initial centralizer spacing l is increased. i ; Recalculate until it is equal to the preset centering.

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