Methods, systems, computer equipment, and media for centering correction in wellbore logging of variable diameter wells

Abstract

This invention provides a method, system, computer equipment, and medium for centering correction of wellbore logging in variable-diameter wells. The method includes: pre-setting a vector representation of wellbore measurement data; obtaining the coordinates of each wellbore endpoint in Cartesian coordinates; gridding the search area using the endpoint coordinates as an outer rectangle to obtain grid points; constructing an inscribed circle with each grid point as the center and the minimum distance from the endpoint coordinates to the grid point as the radius, determining the maximum radius and corresponding center; constructing a new search area to obtain the new maximum radius and corresponding center; determining whether the error is satisfied; updating the center of the inscribed circle as the centering correction center of the variable-diameter wellbore, and updating the wellbore length and the coordinates of each wellbore endpoint. The system includes a data input unit, a data processing unit, a centering correction unit, and a drawing display unit connected in sequence. The advantage of this invention is that it provides a centering correction method that conforms to the characteristics of variable-diameter wells, laying the foundation for accurately establishing three-dimensional models of variable-diameter wells and calculating the throughput of commonly used toolchains.

Description

Technical Field

[0001] This invention relates to the field of geophysical logging technology for oil and gas, specifically to a wellbore centering correction method for variable wellbore diameter logging, a wellbore centering correction system for variable wellbore diameter logging, a computer device, and a computer-readable storage medium storing a computer program. Background Technology

[0002] Casing deformation is a significant issue in shale oil and gas development. Generally, after casing deformation, wellbore changes can be characterized using caliper logging to quantitatively evaluate the degree of deformation. Currently, caliper logging technology for characterizing casing deformation is relatively mature and has achieved good results. However, current engineering advancements have placed new demands on caliper logging evaluation techniques. A new technical challenge has emerged: how to employ a reasonable centering correction method to accurately establish a three-dimensional model of the casing-deformed wellbore and calculate the throughput capacity of commonly used tool strings.

[0003] Currently, the commonly used methods for centering correction in casing-modified wellbore are the geometric centroid method and the least squares method. Chinese patents and documents such as "An Elliptical Fitting and Eccentricity Time Image Correction for Multi-arm Diameter Wellbore in Production Logging" (application number CN201511001098.3), "Research on the Method for Correcting Diameter Eccentricity Images in Imaging Logging Based on Least Squares Method," and "Method for Correcting the Angle of Diameter Measurement Surface Based on Least Squares Elliptical Fitting" all employ the least squares method for centering correction in elliptical wellbore. However, in practical applications, this method has the following problems: ① The shape of the wellbore after casing modification is complex and not necessarily elliptical, therefore the elliptical fitting method based on the least squares method is not applicable; ② For approximately elliptical wellbore cross-sections, the diameter calculated using the least squares elliptical method is generally too large, while the diameter calculated using the geometric centroid method is too small, seriously affecting the calculation of tool throughput capacity. Therefore, providing a method, system, computer equipment, and medium for centering correction in casing-modified wellbore logging is of great significance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to solve one or more problems existing in the prior art. One objective of the present invention is to provide a wellbore logging centering correction method suitable for complex wellbore shapes after casing deformation. Another objective of the present invention is to provide a wellbore logging centering correction system for casing deformation wells that can accurately calculate the wellbore center.

[0005] To achieve the above objectives, the present invention provides a wellbore logging centering correction method for variable wellbore diameter, which may include the following steps: S1, pre-setting a wellbore diameter measurement data vector representation, wherein for a certain depth point k, the number of wellbores is n, and the wellbore diameter length vector is represented as r. kThe wellbore azimuth vector is represented by θ. k S2. Transform from polar coordinates to Cartesian coordinates; the coordinates of each wellhead endpoint are represented as P. k S3, with P k The circumscribed rectangle A of the enclosed polygonal region n To define the search region, the search region is gridded, and the grid points within the grid are represented as G. nij S4, Traverse each grid point G nij Using it as the center, calculate the coordinates of point P. k The distance to each circle's center is used, and the minimum distance is taken as the radius of the inscribed circle at each grid point. The minimum inscribed circle at each grid point is determined, and the maximum radius of the inscribed circle among all minimum inscribed circles is denoted as R. n Let the center of its inscribed circle be O. n S5, G nij Establish a new search region A as the apex of the new search region. n+1 The new search area is gridded, and new grid points G are established. (n+1),ij Determine the minimum incircle updated at the new grid point, and determine the maximum radius of its incircle as R. n+1 Determine the center of its inscribed circle as O. n+1 S6. Set the calculation accuracy error, and determine whether the error between the updated inscribed circle radius and the original inscribed circle radius meets the error condition. If not, proceed to step S5 to continue updating the inscribed circle. If it meets the condition, proceed to step S7. S7. The center of the updated inscribed circle is the center of the wellbore after centering correction. Update the wellbore length r′. k and the coordinates P′ of each well diameter endpoint k .

[0006] According to one or more exemplary embodiments of one aspect of the present invention, the meshing of the search region may include: meshing the search region A n Discretized into a two-dimensional grid, search region A n Composed of M rows and N columns, A n Internal grid point G nij The two-dimensional coordinates are represented as {g n,i,j ,g n,i,j}, (1≤i≤N-1, 1≤j≤M-1), where n represents the number of iterations, and i and j represent two-dimensional grid points.

[0007] According to one or more exemplary embodiments of one aspect of the present invention, the radius of the smallest inscribed circle at the grid point can be expressed as: Let {inner_r nij The center of the incircle corresponding to the largest radius in the circle is O. n And let the maximum radius be R. n .

[0008] According to one or more exemplary embodiments of one aspect of the present invention, the error condition may include |R n+1 -R n |≤error.

[0009] According to one or more exemplary embodiments of one aspect of the present invention, the wellbore length vector r k It can be represented as r k =[r0,r1,…,r n-1 Let the high-end azimuth angle of the first electrode plate be... Wellbore azimuth vector θ k It can be represented as

[0010] According to one or more exemplary embodiments of one aspect of the present invention, the transformation from polar coordinates to Cartesian coordinates may include: assuming the coordinates of each wellbore endpoint at the k-th depth point are P. k Coordinates P of each wellbore endpoint k Represented as P k = [x, y]; Let the x-axis coordinates of all wellbore endpoints be x = [x0, x1, ..., xy]. n-1 Let the y-axis coordinates of all wellbore endpoints be y = [y0, y1, ..., y]. n-1 According to the trigonometric formula, the x-axis coordinate of the wellbore endpoint is x = sin(θ). k )·r k The y-axis coordinate of the wellbore endpoint is y = cos(θ) k )·r k .

[0011] According to one or more exemplary embodiments of one aspect of the present invention, the center O of the circle after the (n+1)th iteration that satisfies the error condition is determined. n+1 The center O of the wellbore after centering correction at the k-th depth point can be used. k Simultaneously update the wellbore endpoint coordinates, and denote the updated wellbore endpoint coordinates as P′. k For the wellbore endpoint coordinate P at the k-th depth point k Calculate coordinates P k With center O k The distance is used as the updated wellbore length r′. k r′ in the xy plane of the Cartesian coordinate system k for:

[0012] According to one or more exemplary embodiments of one aspect of the present invention, the updated wellbore endpoint coordinate P′ k It can be represented as: P′ k = [x′, y′]; its x-axis coordinate is: x′ = sin(θ′) k)*r′ k The y-axis coordinate is: y′=cos(θ′) k )*r′ k The updated wellbore azimuth vector θ′ k It can be represented as: Coordinates to When x0 > 0, then When x0 < 0, then Where (x0, y0) are the Cartesian coordinates of the current endpoint of the first electrode plate.

[0013] Another aspect of the present invention provides a wellbore logging centering correction system for casing-modified wells. The system may include a data input unit, a data processing unit, a centering correction unit, and a plotting display unit connected in sequence. The data input unit is configured to input two-dimensional coordinates of the well trajectory and two-dimensional spatial coordinates of the wellbore after casing modification. The data processing unit is configured to integrate and correlate well trajectory data and wellbore logging data after casing modification. The centering correction unit is configured to execute the wellbore logging centering correction method for casing-modified wells described in any one of the above-mentioned methods to obtain the center of the casing-modified wellbore at a specific depth after centering correction. The plotting display unit is configured to display the calculation results of the centering correction unit.

[0014] Another aspect of the present invention provides a computer device, the device comprising: a processor; and a memory storing a computer program, wherein when the computer program is executed by the processor, the well logging centering correction method for casing variable well diameter described in any one of the above claims can be implemented.

[0015] Another aspect of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, can implement the wellbore logging centering correction method for variable well diameter as described in any of the above claims.

[0016] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0017] (1) The well logging centering correction method for variable well diameter proposed in this invention can be applied to non-elliptical wellbore sections and has high calculation accuracy.

[0018] (2) The well logging centering correction method for casing-variable well diameter proposed in this invention is a centering correction method that conforms to the characteristics of casing-variable wellbore, and provides basic data for three-dimensional wellbore modeling and tool throughput calculation after casing-variable well diameter. Attached Figure Description

[0019] The above and other objects and features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0020] Figure 1A flowchart illustrating a wellbore logging centering correction method for a casing variable wellbore according to an exemplary embodiment of the present invention is shown.

[0021] Figure 2 A schematic diagram of the original wellbore and the wellbore after casing modification is shown;

[0022] Figure 3 This diagram illustrates a polygonal region gridded by the coordinates of each wellbore endpoint, representing an exemplary embodiment of the present invention.

[0023] Figure 4 A schematic diagram of the minimum inscribed circle at a grid point is shown as an exemplary embodiment of the present invention;

[0024] Figure 5 A schematic diagram illustrating the determination of the maximum value of the inscribed circle radius and the center coordinates in an exemplary embodiment of the present invention is shown.

[0025] Figure 6 A schematic diagram of a new search region gridding is shown as an exemplary embodiment of the present invention;

[0026] Figure 7 A schematic diagram of the minimum inscribed circle at a grid point in the new search region, representing an exemplary embodiment of the present invention, is shown.

[0027] Figure 8 A schematic diagram illustrating the determination of the maximum value of the inscribed circle radius and the center coordinates within a new search region according to an exemplary embodiment of the present invention is shown.

[0028] Figure 9 A schematic diagram of the center after centering correction is shown in an exemplary embodiment of the present invention;

[0029] Figure 10 The diagram shows the centering correction method obtained by well logging at 2194.046m in well W1 using the casing variable well diameter logging centering correction method;

[0030] Figure 11 A schematic diagram showing the center obtained at 2194.046m in well W1 using the geometric centroid method is shown.

[0031] Figure 12 A schematic diagram showing the center obtained at 2194.046m in well W1 using the least squares method is shown.

[0032] Figure 13 A schematic diagram of a wellbore logging centering correction system for a casing variable wellbore, an exemplary embodiment of the present invention, is shown.

[0033] Figure label:

[0034] 100 - Data input unit, 200 - Data processing unit, 300 - Centering correction unit, 400 - Drawing display unit. Detailed Implementation

[0035] The following description, in conjunction with the accompanying drawings and exemplary embodiments, details the wellbore logging centering correction method, system, computer equipment, and medium of the present invention.

[0036] Exemplary Example 1

[0037] This exemplary embodiment provides a method for centering correction in well logging of variable well diameter.

[0038] Figure 1 A flowchart illustrating a wellbore logging centering correction method for a casing variable wellbore according to an exemplary embodiment of the present invention is shown. Figure 2 A schematic diagram of the original wellbore and the wellbore after casing modification is shown; Figure 3 This diagram illustrates a polygonal region gridded by the coordinates of each wellbore endpoint, representing an exemplary embodiment of the present invention. Figure 4 A schematic diagram of the minimum inscribed circle at a grid point is shown as an exemplary embodiment of the present invention; Figure 5 A schematic diagram illustrating the determination of the maximum value of the inscribed circle radius and the center coordinates in an exemplary embodiment of the present invention is shown. Figure 6 A schematic diagram of a new search region gridding is shown as an exemplary embodiment of the present invention; Figure 7 A schematic diagram of the minimum inscribed circle at a grid point in the new search region, representing an exemplary embodiment of the present invention, is shown. Figure 8 A schematic diagram illustrating the determination of the maximum value of the inscribed circle radius and the center coordinates within a new search region according to an exemplary embodiment of the present invention is shown. Figure 9 A schematic diagram of the center after centering correction is shown in an exemplary embodiment of the present invention; Figure 10 The diagram shows the centering correction method obtained by well logging at 2194.046m in well W1 using the casing variable well diameter logging centering correction method; Figure 11 A schematic diagram showing the center obtained at 2194.046m in well W1 using the geometric centroid method is shown. Figure 12 A schematic diagram showing the center obtained using the least squares method at 2194.046m in well W1 is shown. The following section combines... Figures 1 to 12 This exemplary embodiment describes a wellbore logging centering correction method for variable wellbore diameter. It should be noted that... Figure 2 ,as well as Figures 9 to 12 The circles formed by long dashed lines represent the original wellbore, the circles formed by dots and dashed lines represent the wellbore after the conversion, the circles formed by solid lines represent the wellbore after centering correction, the solid triangle symbol represents the original center, and the solid square symbol represents the center after centering correction.

[0039] like Figure 1 As shown, the wellbore logging centering correction method for variable wellbore diameter mainly includes the following steps:

[0040] S1, Preset wellbore measurement data vector representation.

[0041] S2. Transformation from polar coordinates to Cartesian coordinates, where the coordinates of each wellhead endpoint are represented as P. k .

[0042] S3, Measurement point data (P) k The polygonal region enclosed by is meshed, and the internal mesh points are represented as G. nij .

[0043] S4. Search for the smallest inscribed circle at each grid point and determine the maximum radius R. n and center coordinates.

[0044] S5, G nij Establish a new search region A as the apex of the new search region. n+1 The new search area is gridded, and new grid points G are established. (n+1),ij Determine the maximum value R of the minimum inscribed circle radius of the new grid points. n+1 and center coordinates.

[0045] S6. Set the calculation precision error, and determine whether the error meets the requirements. |R n+1 -R n If |≤error, then proceed to step S5 to continue updating the inscribed circle; if |≤error, then proceed to step S7.

[0046] S7. Determine the corrected center and update the wellbore length data and the coordinates of each wellbore endpoint.

[0047] Specifically, the wellbore logging centering correction method for variable-diameter wells may include the following steps:

[0048] S1. Preset wellbore measurement data vector representation: For a certain depth point k, the number of wellbores is n, and the wellbore length vector is represented as r. k The wellbore azimuth vector (i.e., the included angle vector) is represented by θ. k Here, for the k-th depth point, let the depth value be Depth, Depth = h0 + Δh × k, k = 0, 1, ..., m-1, and Δh is the depth sampling interval of the data input unit.

[0049] S2. Transformation from polar coordinates to Cartesian coordinates, where the coordinates of each wellhead endpoint are represented as P. k .

[0050] S3, with P k The circumscribed rectangle A of the enclosed polygonal region n To define the search area, the search area is gridded, i.e., search area A n Discretized into a two-dimensional grid, with grid points inside the grid represented as G.nij Search area A n It can consist of M rows and N columns. A n Internal grid point G nij The two-dimensional coordinates (excluding boundary grid points) can be represented as {g n,i,j ,g n,i,j}, (1≤i≤N-1, 1≤j≤M-1), where n represents the number of iterations, and i and j represent two-dimensional grid points.

[0051] S4, Traverse all grid points G nij Calculate the coordinates of point P with each grid point as the center. k The distance to the center of the circle is used, and the minimum distance is taken as the minimum inscribed circle radius for each grid point (illustrated). Figure 3 and Figure 4 Compare all grid points G nij Find the minimum inscribed radius of the circle, and then find its maximum value. Let the maximum radius be R. n The corresponding center is O n .

[0052] S5, G nij Establish a new search region A as the apex of the new search region. n+1 Discretize the new search region into a two-dimensional grid and establish new grid points G. (n+1),ij A n+1 Internal grid point G (n+1),ij The two-dimensional coordinates can be represented as {x n+1,i,j ,y n+1,i,j}, (1≤i≤N-1, 1≤j≤M-1). Repeating step S4, which involves traversing all grid points, will determine all new grid points G. (n+1),ij Find the updated minimum incircle at the specified location, compare it with the maximum value among the minimum incircles, and denote the maximum radius as R. n+1 The corresponding center is O n+1 Here, search area A. n+1 It can also consist of M rows and N columns. The values ​​of M and N in this step can be the same as or different from the values ​​of M and N in step S3.

[0053] S6. Set the calculation precision error, and determine whether the error between the updated inscribed circle radius and the original inscribed circle radius meets the error condition, |R n+1 -R n If |≤error, then proceed to step S5 to continue updating the inscribed circle; if |≤error, then proceed to step S7.

[0054] S7. If the center O of the inscribed circle is preset after the update... n+1 The center O of the k-th variable wellbore after centering correction kUpdate wellbore length r′ k and the coordinates P′ of each well diameter endpoint k .

[0055] In this exemplary embodiment, in step S1, the well diameter length vector r is... k It can be represented as r k =[r0,r1,…,r n-1 Let the azimuth angle of the high end of the first electrode be... (Azimuth of the first electrode at the k-th depth point), wellbore azimuth vector θ k It can be represented as Here, the azimuth angles of the other plates can be based on the high-end azimuth angle of plate number one. The derivation is based on the number of electrode well diameters, n.

[0056] In this exemplary embodiment, step S2, the transformation from polar coordinates to Cartesian coordinates, may include:

[0057] Let P be the coordinates of each wellbore endpoint at the k-th depth point. k Coordinates P of each wellbore endpoint k Represented as P k = [x, y]. Let the x-axis coordinates of all wellbore endpoints be x = [x0, x1, ..., xy]. n-1 Let the y-axis coordinates of all wellbore endpoints be y = [y0, y1, ..., y]. n-1 According to the trigonometric formula, the x-axis coordinate of the wellbore endpoint is x = sin(θ). k )·r k The y-axis coordinate of the wellbore endpoint is y = cos(θ) k )·r k .

[0058] In this exemplary embodiment, in step S4, the radius of the smallest inscribed circle at the grid point can be expressed as:

[0059]

[0060] Let {inner_r nij The center of the incircle corresponding to the largest radius in the circle is O. n And let the maximum radius be R. n .

[0061] In this exemplary embodiment, in step S7, the center O of the circle after the (n+1)th iteration that satisfies the error condition is determined. n+1 The center O of the variable wellbore after centering correction at the k-th depth point. k .

[0062] For the wellbore endpoint coordinate P at the kth depth point kCalculate coordinates P k With center O k The distance from (the center of the wellbore polygon) is used as the updated wellbore length r′. k r′ in the xy plane of the Cartesian coordinate system k Possible forms:

[0063]

[0064] After the update, the wellbore azimuth vector θ′ k It can be represented as:

[0065]

[0066] The high-end azimuth angle of the No. 1 electrode plate is Perform coordinate transformation

[0067] When x0 > 0, then

[0068] When x0 < 0, then

[0069] Where (x0, y0) are the Cartesian coordinates of the current endpoint of the first electrode plate.

[0070] Next, the polar coordinate data is converted to Cartesian coordinate data. After the conversion, the coordinates of the wellbore endpoint P′ are... k It can be represented as: P′ k = [x′, y′]; its x-axis coordinate is: x′ = sin(θ′) k )*r′ k The y-axis coordinate is: y′=cos(θ′) k )*r′ k .

[0071] To better understand the exemplary embodiments of the present invention described above, further explanation is provided below with reference to specific examples.

[0072] Example 1

[0073] This example uses a 24-arm logging system as an example. For well W1 at 2194.046m, the centering correction method for the casing-variable borehole is used to obtain the centering correction. This example combines... Figures 2 to 12 This section describes the wellbore centering correction method for variable wellbore logging in this example, comparing it with existing geometric centroid methods and least squares methods. Among them, Figures 2 to 10 This can be used to illustrate the wellbore logging centering correction method for variable wellbore diameter of the present invention.

[0074] The wellbore centering correction method for variable wellbore diameter logging includes the following steps:

[0075] 1) Pre-define the 24-arm borehole diameter measurement data vector representation, and represent the arm length vector as r. k The included angle vector is represented by θ. k .

[0076] 2) Transform from polar coordinates to Cartesian coordinates, with the coordinates of each arm endpoint represented as P. k .

[0077] 3) Transfer the measurement point data P k The enclosed polygonal region is meshed, and the grid points inside the grid are represented as G. nij .

[0078] 4) Search G nij The smallest inscribed circle at each grid point is determined, with a maximum radius R1 and a center at O1.

[0079] 5) G nij As the vertices of the new search region, establish the new search region and create new grid points G. (n+1),ij Determine the maximum value R2 of the minimum inscribed circle radius of the new grid point, with the center at O2.

[0080] 6) Determine if the error meets the requirements, |R n+1 -R n |≤error. Continue until the requirements are met, then complete the calculation.

[0081] 7) Determine the corrected center O k Update arm length r′ k and the coordinates of each endpoint P′ k .

[0082] The detailed explanation of steps 1) to 7) above is as follows.

[0083] Step 1) The specific operation of representing the 24-arm borehole diameter measurement data vector is as follows:

[0084] For a certain depth of 2194.046m, the corresponding depth number is marked as k. Assuming the number of arms is 24, the endpoints of the original wellbore and the wellbore after casing modification are as follows: Figure 2 As shown.

[0085] Let the arm length vector be:

[0086] r k =[r0,r1,…,r n-1 ];

[0087] Let the azimuth angle of the upper end of arm 1 be... Wellbore azimuth vector θ k Represented as:

[0088]

[0089] Step 2) The specific operations for transforming from polar coordinates to Cartesian coordinates are as follows:

[0090] Let P be the coordinates of each arm endpoint at the k-th depth point. k = [x, y], let the x-coordinates of all points be x = [x0, x1, ..., xy]. 23 Let the y-coordinates of all points be y = [y0, y1, ..., y2]. 23 According to the trigonometric function formula, we have: x = sin(θ) k )·r k y = cos(θ) k )·r k .

[0091] Step 3) Transfer the measurement point data P k The specific operations for meshing the enclosed polygonal region are as follows:

[0092] like Figure 3 As shown, the circumscribed rectangle A1 of the polygonal region is set, and the square rectangle A1 is discretized into a two-dimensional grid consisting of 3 rows and 3 columns. The two-dimensional coordinates of the grid point G1 inside square A1 (excluding the boundary grid points) are:

[0093] G1={g 1,i,j ,g 1,i,j},(1≤i≤2,1≤j≤2);

[0094] Step 4) The specific operation for determining the maximum radius of the smallest inscribed circle at each grid point in the search is as follows:

[0095] like Figure 4 As shown, traverse each grid point G1, and calculate P using it as the center. k The distance from each coordinate point in the grid to the center of the circle is calculated, and the minimum value is taken as the radius of the inscribed circle of that grid point.

[0096] The radius of the smallest inscribed circle can be expressed as:

[0097]

[0098] Let O1 be the inscribed center of the circle with the largest radius in {inner_r1}, and let R1 be the maximum radius. The coordinates of the maximum radius and center of the inscribed circle are as follows: Figure 5 As shown.

[0099] Step 5) Use the boundary points of G1 as the vertices of the new rectangular search region A2, subdivide the mesh, establish a new mesh system G2, obtain the maximum value R2 in the smallest inscribed circle, and determine the center as O2. The specific operations are as follows:

[0100] like Figure 6As shown, the boundary points of G2 are used as vertices to establish a rectangular search region A2. The rectangular region A2 is discretized into a two-dimensional grid consisting of 3 rows and 3 columns.

[0101] like Figure 7 As shown, the two-dimensional coordinates of the grid points inside A2 are represented as follows:

[0102] G2={g 2,i,j ,g 2,i,j},(1≤i≤2,1≤j≤2);

[0103] Using each grid point G2 as the center, search for the minimum radius of the inscribed circle:

[0104]

[0105] like Figure 8 As shown, the inscribed center of the circle corresponding to the maximum radius in {inner_r2} is determined to be O2, and the maximum radius is denoted as R2.

[0106] Step 6) Determine if the error meets the requirements, set the error value, and calculate |R2-R1|≤error. Continue until the requirements are met to complete the calculation.

[0107] Step 7) If |R2-R1|≤error, the error requirement is met, and the center O of the k-th depth point after centering correction can be determined. k =O2.

[0108] For the coordinates P of the k-th depth point k , P′ k Represented as: P′ k =[x′,y′], calculate their relationship with the center O of the well diameter polygon. k The distance is used as the updated radius, denoted as r′. k After the update, the coordinates in the xy plane are denoted as r′. k , r′ k for:

[0109]

[0110] After the update, the wellbore azimuth vector θ′ k It can be represented as:

[0111]

[0112] The high-end azimuth angle of the No. 1 electrode plate is Perform coordinate transformation

[0113] When x0 > 0, then

[0114] When x0 < 0, then

[0115] Where (x0, y0) are the Cartesian coordinates of the current endpoint of the first electrode plate.

[0116] Next, the polar coordinate data is converted to Cartesian coordinate data. After the conversion, the coordinates of the wellbore endpoint P′ are... k The x-axis coordinate is: x′=sin(θ′) k )*r′ k The y-axis coordinate is: y′=cos(θ′) k )*r′ k The center O of the casing-type wellbore after centering correction is obtained by using the casing-type wellbore logging centering correction method. k like Figure 9 As shown.

[0117] The calculations for well W1 at a depth of 2194.046m were performed using the wellbore logging centering correction method (iterative search method), least squares method, and geometric centroid method. The results are shown in Table 1 below. Figures 10 to 12 .contrast Figures 10 to 12 As can be seen from the data in Table 1, the iterative search method yields the highest accuracy, the least squares method yields an overestimated result, and the geometric centroid method yields an underestimated result.

[0118] Table 1. Statistical table of calculated parameters for Well W1 at a depth of 2194.046m.

[0119] Eccentricity (mm) 8.96 17.74 18.76 Eccentricity angle (°) 89.36 89.96 99.43 Eccentricity radius (mm) 46.97 59.30 56.45 Evaluation results Small Too big High accuracy

[0120] Exemplary Example 2

[0121] This exemplary embodiment provides a well logging centering correction system for variable well diameter.

[0122] Figure 13 A schematic diagram of a wellbore logging centering correction system for a variable wellbore diameter of the present invention is shown below. Figure 13 This exemplary embodiment describes a wellbore logging centering correction system for variable wellbore diameter.

[0123] like Figure 13 As shown, the wellbore logging centering correction system for variable wellbore mainly includes a data input unit 100, a data processing unit 200, a centering correction unit 300, and a drawing display unit 400 connected in sequence.

[0124] The data input unit is configured to input the two-dimensional coordinates of the well trajectory and the two-dimensional spatial coordinates of the well diameter after casing modification. The data processing unit is configured to use depth as an index to associate the well trajectory data (including parameters such as depth, inclination angle, and azimuth angle) and the well diameter logging data after casing modification (including parameters such as depth, well diameter length vector, and included angle vector), and convert the well diameter polar coordinate data into Cartesian coordinate data. The well diameter Cartesian coordinate data is the input to the centering correction unit, which is configured to perform operations including the well diameter logging centering correction method for casing-modified wells described in Exemplary Example 1 above, as well as conventional geometric centroid methods and least squares methods, to determine the center of the casing-modified wellbore at a specific depth after centering correction. The plotting and display unit is configured to display the calculation results of the centering correction unit, allowing users to see the relative accuracy of several centering correction methods.

[0125] In this exemplary embodiment, the data input unit may include modules for inputting well trajectory data, wellbore logging data, casing inner diameter, and depth sampling interval. The data processing unit may include modules for data conversion and data storage. The centering correction unit may include modules for calculating and storing raw data, calculating and storing geometric centroid method data, calculating and storing least squares method data, and calculating and storing data for the casing-variable wellbore logging centering correction method (iterative search method). The plotting and display unit may include modules for depth setting and two-dimensional display of the calculation results of each centering correction method.

[0126] The wellbore logging centering correction method for variable wellbore diameter of the present invention can be programmed into a computer program and the corresponding program code or instructions can be stored in a computer-readable storage medium. When the program code or instructions are executed by a processor, the processor performs the above-mentioned wellbore logging centering correction method for variable wellbore diameter. The processor and memory can be included in a computer device.

[0127] Exemplary Example 3

[0128] This exemplary embodiment provides a computer-readable storage medium storing a computer program. The computer-readable storage medium stores a computer program that, when executed by a processor, causes the processor to execute the wellbore logging centering correction method according to the present invention. The computer-readable recording medium is any data storage device capable of storing data read by a computer system. Examples of computer-readable recording media include: read-only memory, random access memory, read-only optical disc, magnetic tape, floppy disk, optical data storage device, and carrier waves (such as data transmission via the Internet through wired or wireless transmission paths).

[0129] Exemplary Example 4

[0130] This exemplary embodiment provides a computer device. The computer device includes a processor and a memory. The memory stores a computer program. The computer program is executed by the processor, causing the processor to execute the computer program of the wellbore logging centering correction method according to the present invention.

[0131] In summary, the advantages proposed by this invention include at least one of the following:

[0132] (1) The well logging centering correction method for casing-modified wells proposed in this invention can be applied to situations where the wellbore shape is complex after casing modification.

[0133] (2) The well logging centering correction method for variable well diameter proposed in this invention is more accurate than the geometric centroid method and the least squares method.

[0134] (3) The well logging centering correction method for variable borehole diameter proposed in this invention can accurately obtain the center of the cross section of various shaped boreholes, laying the foundation for accurately establishing a three-dimensional model of variable borehole and calculating the throughput of commonly used tool strings.

[0135] Although the wellbore logging centering correction method, system, computer equipment, and medium of the present invention have been described above in conjunction with exemplary embodiments, those skilled in the art should understand that various modifications and changes can be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined by the claims.

Claims

1. A method for centering correction in well logging of variable diameter wells, characterized in that, The centering correction method includes the following steps: S1. Preset wellbore measurement data vector representation: For a certain depth point k, the number of wellbores is n, and the wellbore length vector is represented as r. k The wellbore azimuth vector is represented by θ. k ; S2. Transformation from polar coordinates to Cartesian coordinates, where the coordinates of each wellhead endpoint are represented as P. k ; S3, with P k The circumscribed rectangle A of the enclosed polygonal region n To define the search region, the search region is gridded, and the grid points within the grid are represented as G. nij ; S4. Traverse each grid point G nij Using it as the center, calculate the coordinates of point P. k The distance to each circle's center is used, and the minimum distance is taken as the radius of the inscribed circle at each grid point. The minimum inscribed circle at each grid point is determined, and the maximum radius of the inscribed circle among all minimum inscribed circles is denoted as R. n Let the center of its inscribed circle be O. n ; S5, G nij Establish a new search region A as the apex of the new search region. n+1 The new search area is gridded, and new grid points G are established. (n+1)，ij Determine the minimum incircle updated at the new grid point, and determine the maximum radius of its incircle as R. n+1 Determine the center of its inscribed circle as O. n+1 ; S6. Set the calculation precision error and determine whether the error between the updated inscribed circle radius and the inscribed circle radius before the update meets the error condition. If it does not meet the condition, proceed to step S5 to continue updating the inscribed circle. If it meets the condition, proceed to step S7. S7. The center of the updated inscribed circle is the center of the wellbore after centering correction, and the updated wellbore length r′ is... k and the coordinates P′ of each well diameter endpoint k .

2. The wellbore logging centering correction method for variable wellbore diameter as described in claim 1, characterized in that, The step of gridding the search region includes: dividing the search region A into grids. n Discretized into a two-dimensional grid, search region A n Composed of M rows and N columns, A n Internal grid point G nij The two-dimensional coordinates are represented as {g n，i，j g n，i，j }, (1≤i≤N-1, 1≤j≤M-1), where n represents the number of iterations, and i and j represent two-dimensional grid points.

3. The wellbore logging centering correction method for variable wellbore diameter as described in claim 1, characterized in that, The radius of the smallest inscribed circle at each grid point is expressed as: Let {inner_r nij The center of the incircle corresponding to the largest radius in the circle is O. n And let the maximum radius be R. n .

4. The wellbore logging centering correction method for variable wellbore diameter as described in claim 1, characterized in that, The error condition includes |R n+1 -R n |≤error.

5. The wellbore logging centering correction method for variable wellbore diameter as described in claim 1, characterized in that, The well diameter length vector r k Represented as r k = [r0, r1, ..., r n-1 ]; Let the high-end azimuth angle of the first electrode plate be... Wellbore azimuth vector θ k Represented as 6. The wellbore logging centering correction method for variable wellbore diameter as described in claim 5, characterized in that, The transformation from the polar coordinate system to the Cartesian coordinate system includes: Let P be the coordinates of each wellbore endpoint at the k-th depth point. k Coordinates P of each wellbore endpoint k Represented as P k = [x, y]; Let the x-axis coordinates of all wellbore endpoints be x = [x0, x1, ..., x2]. n-1 Let the y-axis coordinates of all wellbore endpoints be y = [y0, y1, ..., y2]. n-1 ]; According to the trigonometric function formula, the x-axis coordinate of the wellbore endpoint is x = sin(θ). k )·r k The y-axis coordinate of the wellbore endpoint is y = cos(θ) k )·r k .

7. The wellbore logging centering correction method for variable wellbore diameter as described in claim 6, characterized in that, Determine the center O of the circle after the (n+1)th iteration that satisfies the aforementioned error condition. n+1 The center O of the variable wellbore after centering correction at the k-th depth point. k Simultaneously update the wellbore endpoint coordinates, and denote the updated wellbore endpoint coordinates as P′. k ; For the wellbore endpoint coordinate P at the kth depth point k Calculate coordinates P k With center O k The distance is used as the updated wellbore length r′. k r′ in the xy plane of the Cartesian coordinate system k for:

8. The wellbore logging centering correction method for variable wellbore diameter as described in claim 7, characterized in that, The updated wellbore endpoint coordinate P′ k Represented as: P′ k = [x′, y′]; its x-axis coordinate is: x′ = sin(θ′) k )*r′ k The y-axis coordinate is: y′=cos(θ′) k )*r′ k ; Updated wellbore azimuth vector θ′ k Represented as: Coordinates to When x0 > 0, then When x0 < 0, then Where (x0, y0) are the Cartesian coordinates of the current endpoint of the first electrode plate.

9. A wellbore logging centering correction system for variable wellbore diameter, characterized in that, The system includes a data input unit, a data processing unit, a centering correction unit, and a drawing display unit connected in sequence. The data input unit is configured to input the two-dimensional coordinates of the well trajectory and the two-dimensional spatial coordinates of the well diameter after the casing change; The data processing unit is configured to integrate and correlate well trajectory data and well logging data after casing change; The centering correction unit is configured to perform the centering correction method for wellbore logging of the casing variable wellbore as described in any one of claims 1 to 8, and to obtain the center of the casing variable wellbore after centering correction at a specific depth; The plotting display unit is configured to display the calculation results of the centering correction unit.

10. A computer device, characterized in that, The device includes: processor; and The memory stores a computer program that, when executed by a processor, implements the wellbore logging centering correction method for casing variable wells as described in any one of claims 1 to 8.

11. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the well logging centering correction method for casing variable wells as described in any one of claims 1 to 8.

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