Method for evaluating well cementation quality of gas storage well

Abstract

The invention provides a gas storage well cementation quality evaluation method which comprises the following steps: step 1, measuring the cementation quality of a casing cement annulus in a shaft after gas storage well cementation by using a logging winch and an ultrasonic imager to obtain a cement cementation quality spatial distribution diagram; step 2, establishing a corresponding relation between the color RGB and the cementing strength in the cement cementing quality spatial distribution diagram; 3, tracking an easy gas channeling channel and a backflow channel of the detected cement annulus; 4, the sealing effect of the interlayer separation sections is evaluated; 5, evaluating the sealing effect of the cap layer section; and 6, combining the sealing effect of the interlayer separation section and the sealing effect of the cover layer section, and evaluating and scoring the gas channeling prevention strength of the shaft. According to the method, the sealing effect of the interlayer separation section and the cover layer section is comprehensively considered, the gas channeling difficulty degree in the shaft is quantified, and the well cementation quality of the gas storage well and the gas well can be more visually and truly reflected.

Description

Technical Field

[0001] The invention belongs to the field of gas storage well drilling and completion engineering, and in particular relates to a gas storage well cementing quality evaluation method. Background Art

[0002] During the injection and production process of gas storage wells, the wellbore needs to withstand a gas load of up to tens of MPa. Compared with conventional oil and gas wells, gas storage wells have higher requirements for cement performance. The gas channeling problem of cement ring after cementing has always been one of the main bottlenecks that needs to be overcome in the field of gas storage drilling and completion engineering. After cementing, the cement slurry in a gelled liquid state is condensed and hardened to form cement stone. If the cement stone has channeling grooves or poor bonding with the casing and formation, gas will enter the cement annulus and even flow up to the wellhead, posing a major safety hazard. Therefore, after the cementing is completed, the cement sealing performance needs to be accurately evaluated. At present, the commonly used methods at home and abroad are to measure the wellbore filling degree and bonding strength based on detection methods such as acoustic amplitude-variable density, gamma density and ultrasonic imaging, and to evaluate the cementing quality by performing simple data statistics on these parameters. Since it cannot intuitively reflect the difficulty of gas channeling along the cement ring and the sealing effect of the cap layer section and the interlayer isolation section, the evaluation results are quite different from the actual situation, and it is difficult to meet the gas storage requirements for cement sealing evaluation of cement. Summary of the invention

[0003] In order to overcome the deficiencies in the prior art, the present invention provides a method for evaluating the cementing quality of a gas storage well, which comprehensively considers the sealing effects of interlayer separation sections and caprock sections, and quantifies the difficulty of gas upward migration in the wellbore, thereby being able to more intuitively and truly reflect the cementing quality of the gas storage well and the gas well.

[0004] The technical solution adopted by the present invention to solve the technical problem is:

[0005] A method for evaluating cementing quality of a gas storage well, comprising the following steps:

[0006] Step 1: Using a logging winch and an ultrasonic imager, measure the cement bonding quality of the casing cement annulus in the wellbore after cementing of the gas storage well, and obtain a spatial distribution map of the cement bonding quality;

[0007] Step 2: Establish the corresponding relationship between color RGB and bonding strength in the cement bonding quality spatial distribution map;

[0008] Step 3: Track the gas channel and reflux channel of the cement annulus under test;

[0009] Step 4: Evaluate the sealing effect of the interlayer partition;

[0010] Step 5: Evaluate the sealing effect of the caprock section;

[0011] Step 6: Based on the sealing effect of the interlayer separation section and the caprock section, evaluate and score the wellbore's anti-gas channeling strength.

[0012] Furthermore, the step 1 specifically includes:

[0013] Step 1.1: Connect the ultrasonic imager to the logging winch cable and lower the ultrasonic imager to the bottom of the well;

[0014] Step 1.2: Input parameters into the logging winch control system, including the cable rated breaking force F 0 , safety factor a;

[0015] Step 1.3: The logging winch drives the cable to move upward at a constant speed, starts the measurement system of the logging winch, and the ultrasonic imager starts to work to measure the cement bonding quality data;

[0016] Step 1.4: Record the downhole depth H and cable tension F each time the ultrasonic imager collects data during the cable upward movement; determine whether F is less than aF 0 , if F is less than aF 0 , proceed to step 1.5, if F is not less than aF 0 , send out an alarm signal;

[0017] Step 1.5: End the measurement when the ultrasonic imager moves up to the wellhead;

[0018] Step 1.6: Based on the cement bonding quality data detected by the ultrasonic imager, output a cement bonding quality spatial distribution map with the casing circumference as the horizontal axis and the well depth as the vertical axis.

[0019] Furthermore, the step 2 specifically includes:

[0020] Step 2.1: Obtain the color RGB representing the uncemented microvoids, liquid, gas or dry microvoids in the legend of the cement bonding quality spatial distribution map through image processing software, as well as the color RGB representing different bonding strengths in the bonding area;

[0021] Step 2.2: Establish the corresponding relationship between color RGB and cement bonding strength according to the bonding strength values ​​represented by different colors in the legend, where the bonding strength corresponding to the color RGB of unbonded microvoids, liquid, gas or dry micropores is 0;

[0022] Step 2.3: According to the corresponding relationship between the color RGB and the cement bonding strength obtained in step 2.2, find the pixel points whose bonding strength is not 0 in the cement bonding quality spatial distribution map;

[0023] Step 2.4: The pixel information whose bonding strength is not 0 is stored in the matrix M. At the same time, the pixel information whose bonding strength is 0, which represents bonding microvoids, liquids, gases or dry micropores, is stored in the matrix M. The pixel information includes the spatial position coordinates, pixel type and bonding strength.

[0024] Furthermore, step 3 includes:

[0025] Step 3.1: Set the surface where cement contacts the underground reservoir as the first type of gas inflow surface, the surface where cement contacts the casing joint as the second type of gas inflow surface, the pixel points on the first type of gas inflow surface and the second type of gas inflow surface as gas inflow points, and store the position coordinates of all gas inflow points into the matrix K;

[0026] Step 3.2: Based on the gas inflow point, trace the gas channel and reflux channel in the cement annulus.

[0027] Furthermore, step 3.2 specifically includes:

[0028] Step 3.2.1: Set the initial values ​​of loop variables i and j to 1;

[0029] Step 3.2.2: Take the gas inflow point as the reference point and name it P 10 , P 20 , ... P m0 The spatial positions of these reference points in the cylindrical coordinate system are stored in the matrix group Q i (i=1...m);

[0030] Step 3.2.3: Read the matrix group Q i The number of pixels is represented by n;

[0031] Step 3.2.4: Delete the reference point in the matrix M and the j-th one stored in Q i The pixel coordinates of the connecting line of the pixels are stored in the matrix D.

[0032] Step 3.2.5: Find the jth item in matrix D that is stored in Q i The pixel point with the smallest bonding strength adjacent to the pixel point of Q; if there is only one such pixel point, store the jth one in Q i Connect the pixel point with the pixel point and store the spatial coordinates of the pixel point in the matrix K i ; If the jth one is stored in Q i There are two or more pixels adjacent to each other and with the smallest bonding strength. The jth pixel is stored in Q i The pixel points of the pixel points are connected to these pixel points respectively, and the spatial coordinates of these pixel points are stored in the matrix K i ;

[0033] Step 3.2.6: Determine whether j is equal to n. If j≠n, j=j+1, and repeat steps 3.2.4 to 3.2.5; if j=n, proceed to step 3.2.7;

[0034] Step 3.2.7: Calculate the matrix K separately i The distance h between each spatial coordinate and the upper boundary of the spatial distribution diagram of cement bonding quality 1 、h 2 ……h p , and K i The distance hh between each spatial coordinate and the lower boundary of the cement bonding quality spatial distribution diagram 1 、hh 2 ...hh p ;

[0035] Step 3.2.8: Let h represent the vertical or horizontal distance between two adjacent pixels and determine K i Is there h in n <h(n=1,2……p)or hh n If the pixel points < h(n=1,2……p) do not exist, let Q i =K i , repeat steps 3.2.3 to 3.2.7; if there is h n <h (n = 1, 2 ... p) pixel point, mark the pixel point as the end point, and place its spatial coordinates in K i Delete it and proceed to step 3.2.9; if hh exists n <h(n=1,2……p), mark the pixel as a reflow point and place its spatial coordinates in K i Delete it and proceed to step 3.2.9;

[0036] Step 3.2.9: Judgment Matrix K i Is it an empty array? If not, let Q i =K i , repeat steps 3.2.3 to 3.2.7; if yes, proceed to step 3.2.10;

[0037] Step 3.2.10: Determine the relationship between i and m. If i=m, end the loop and proceed to step 3.2.11. If i<m, i=i+1, repeat steps 3.2.3 to 3.2.9.

[0038] Step 3.2.11: Output the trajectory from the reference point to the end point. This trajectory is the gas channel. 1 d 2 ……d p Output the trajectory from the reference point to the reflow point, which is the reflow channel, and use x 1 、x2 ……x n express.

[0039] Furthermore, the step 4 specifically includes:

[0040] Step 4.1: Input the depth range corresponding to each interlayer separation section in the wellbore, and store the pixel position coordinates within the depth range into matrix group B 1 , B 2 ……B e , stored in matrix group B 1 , B 2 ……B e The position coordinates of adopt cylindrical coordinate system, the z direction component indicates the well depth corresponding to the pixel point, the larger the absolute value of the z direction component, the farther the pixel point is from the ground, and the subscript e indicates the number of interlayer separation segments;

[0041] Step 4.2: Set the initial value of the inter-layer separation loop variable q to 1;

[0042] Step 4.3: In matrix B q Find all the pixels with the largest absolute value of the z-direction component in the matrix, mark them as the inter-layer separation segment reference points, and store the position coordinates of the inter-layer separation segment reference points in the cylindrical coordinate system into the matrix group F 1 、F 2 ……F v The first row of the matrix group F 1 、F 2 ……F v The third column of each matrix in B is used to store the z-direction component of the spatial position coordinates, and the subscript v represents the number of interlayer partition reference points; q Search for all pixel points with the smallest absolute value of the z-direction component and mark them as the termination points of the inter-layer separation segment; mark all pixel points except the inter-layer separation segment reference point and the inter-layer separation segment termination point as the middle points of the inter-layer separation segment;

[0043] Step 4.4: Set the initial value of the reference point loop variable f to 1;

[0044] Step 4.5: Set the matrix group row number loop variable c = 1;

[0045] Step 4.6: In matrix B q Find the matrix F f The pixels corresponding to the cth row are adjacent, and the absolute value of the z-direction component is greater than that of the matrix F f The middle point of the interlayer separation segment or the end point of the interlayer separation segment with the smallest absolute value of the element in the cth row and the third column, and whether the bonding strength of the middle point of the interlayer separation segment or the end point of the interlayer separation segment is 0;

[0046] Step 4.7: If there is an interlayer separation segment end point with a bonding strength of 0, store the position coordinates of the interlayer separation segment end point into the matrix F f c+1 row of the matrix F, and proceed to step 4.8; if there is a midpoint of the interlayer separation segment with a bonding strength of 0, store the position coordinates of the midpoint of the interlayer separation segment into the matrix F f The c+1 row of the matrix F is set to c=c+1, and steps 4.6 to 4.7 are repeated; if there is no interlayer partition midpoint with a bonding strength of 0 or no interlayer partition midpoint, let the matrix F f is an empty matrix;

[0047] Step 4.8: Output matrix F f ;

[0048] Step 4.9: Determine whether f is equal to v. If f = v, proceed to step 4.10. If f ≠ v, set f = f + 1 and repeat steps 4.5 to 4.8.

[0049] Step 4.10: Judgment Matrix F 1 、F 2 ……F v Whether there is a non-empty matrix in , if there is a non-empty matrix, it means that there is a gas channel in the qth interlayer partition segment, and the evaluation result of the qth interlayer partition segment is output as "unqualified"; if there is no non-empty matrix, it means that there is no gas channel in the qth interlayer partition segment, and the evaluation result of the qth interlayer partition segment is output as "qualified";

[0050] Step 4.11: Determine whether q is equal to e. If q = e, proceed to step 4.12. If q ≠ e, set q = q + 1 and repeat steps 4.3 to 4.10.

[0051] Step 4.12: Determine whether the evaluation results of all interlayer partitions are "qualified". If they are all "qualified", the overall evaluation result of the interlayer partitions is output as "qualified"; if there are "unqualified" interlayer partitions, the overall evaluation result of the interlayer partitions is output as "unqualified".

[0052] Furthermore, the step 5 specifically includes:

[0053] Step 5.1: Input the well depth range corresponding to the wellbore cap layer section, and store the pixel position coordinates within the well depth range into the matrix C. The position coordinates stored in the matrix C adopt the cylindrical coordinate system, and its z-direction component represents the well depth corresponding to the pixel point. The larger the absolute value of the z-direction component, the farther the pixel point is from the ground.

[0054] Step 5.2: Find all the pixel points with the largest absolute value of the z-direction component in the matrix C, mark them as the base point of the cover layer segment, and store the position coordinates of the base point of the cover layer segment in the cylindrical coordinate system into the matrix group R 1 , R2 ……R w The first row of the matrix group R 1 , R 2 ……R w The third column of each matrix in is used to store the z-direction component of the spatial position coordinates, and the subscript w represents the number of the reference points of the cover layer segment; all the pixel points with the smallest absolute value of the z-direction component in the matrix C are searched and marked as the end points of the cover layer segment; the other pixel points except the reference points of the cover layer segment and the end points of the cover layer segment are marked as the middle points of the cover layer segment;

[0055] Step 5.3: Set the initial value of the reference point loop variable f to 1;

[0056] Step 5.4: Set the matrix group row number loop variable c = 1;

[0057] Step 5.5: Find the value in matrix C that matches the value in matrix R f The pixels corresponding to the cth row are adjacent, and the absolute value of the z-direction component is greater than the matrix R f The middle point of the cap layer segment or the end point of the cap layer segment with the smallest absolute value of the element in the cth row and the third column, and whether the bonding strength of the middle point of the cap layer segment or the end point of the cap layer segment is 0;

[0058] Step 5.6: If there is a caprock segment end point with a bonding strength of 0, store the position coordinates of the caprock segment end point into the matrix R f c+1 row of the matrix R, and proceed to step 5.7; if there is a midpoint of the cap layer segment with a bonding strength of 0, store the position coordinates of the midpoint of the cap layer segment into the matrix R f Let c = c + 1, and repeat steps 5.5 to 5.6; if there is no end point of the cap layer segment or the middle point of the cap layer segment with a bonding strength of 0, let the matrix R f is an empty matrix;

[0059] Step 5.7: Output matrix R f ;

[0060] Step 5.8: Determine whether f is equal to w. If f = w, proceed to step 5.9. If f ≠ w, set f = f + 1 and repeat steps 5.5 to 5.7.

[0061] Step 5.9: Judgment Matrix R 1 , R 2 ……R w Whether there is a non-empty matrix in the cap layer, if there is a non-empty matrix, it means that there is a gas channel in the cap layer section, and the overall evaluation result of the cap layer section is output as "unqualified"; if there is no non-empty matrix, it means that there is no gas channel in the cap layer section, and the overall evaluation result of the cap layer section is output as "qualified".

[0062] Furthermore, step 6 specifically includes:

[0063] Step 6.1: Determine whether the overall evaluation results of the interlayer partition section and the overall evaluation results of the cap layer section are both "qualified". If both are "qualified", proceed to step 6.2; otherwise, the anti-gas channeling performance score A is 0 points, and proceed to step 6.8;

[0064] Step 6.2: Set the initial value of the loop variable i to 1, take the maximum bonding strength in the matrix M, and use c f express;

[0065] Step 6.3: Find the gas channel d in the matrix M i The bonding strength corresponding to each pixel point on (i=1……p) is expressed as c 1 、c 2 ……c u ;

[0066] Step 6:4: C 1 、c 2 ……c u Sum, use W i express;

[0067] Step 6.5: Determine whether i is greater than p. If i>p, end the loop and output W. i , proceed to step 6.6. If i≤p, set i=i+1 and repeat steps 6.3 to 6.4;

[0068] Step 6.6: Get W 1 , W 2 ...W p The minimum value W f , and determine the minimum value W f Corresponding gas channel d f ;

[0069] Step 6.7: According to c f , W f and d f Calculate the anti-gas channeling performance score A of the cement;

[0070] Step 6.8: Output the anti-gas channeling performance score;

[0071] Step 6.9: According to the needs of the evaluation department, determine the qualified range of anti-gas channeling performance scores and comprehensively evaluate the cementing quality.

[0072] Furthermore, the calculation formula of the anti-gas channeling performance score A is:

[0073]

[0074] Where u is the gas channel d f The number of pixels in the image.

[0075] Furthermore, the matrix M is n 1 A matrix with five rows and five columns, n 1 The value is the number of all pixels in the spatial distribution map of cement bonding quality. The first three columns of the matrix M represent the spatial coordinates of the pixels. The fourth column is a number from 1 to 4, which is used to represent the pixel type, where 1 represents uncemented microvoids, 2 represents liquid, 3 represents gas or dry micropores, and 4 represents bonding. The fifth column represents the bonding strength of the pixel.

[0076] The beneficial effects of the present invention include:

[0077] The present invention provides a method for evaluating the cementing quality of a gas storage well. An ultrasonic imager is used to measure the spatial distribution map of cement bonding quality in the casing annulus in the wellbore, and a corresponding relationship between the color RGB and the bonding strength in the cement bonding quality spatial distribution map is established to obtain the gas channeling channel and the reflux channel in the measured casing annulus. The original evaluation method of simply counting the wellbore filling degree and cement bonding strength is optimized to a cementing quality evaluation method that comprehensively considers the sealing effect of the interlayer separation section and the cap layer section and quantifies the difficulty of gas upward migration in the wellbore. The evaluation result is more practical. In addition, the anti-gas channeling strength of the gas channeling channel is scored to more intuitively and truly reflect the cementing quality of the gas storage well and the gas well. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 It is the spatial distribution diagram of cement bonding quality measured in Example 1 of the present invention. DETAILED DESCRIPTION

[0079] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0080] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0081] Example 1

[0082] This embodiment provides a method for evaluating the cementing quality of a gas storage well, and establishes a cementing quality evaluation method with a cement bonding quality spatial distribution map as input and an anti-gas channeling strength score as output.

[0083] Based on the spatial distribution map of cement bonding quality in the casing annulus in the wellbore measured by ultrasonic imaging, this scheme establishes the corresponding relationship between color RGB and bonding strength in the spatial distribution map of cement bonding quality, obtains the gas channeling channel of the measured cement ring and the anti-gas channeling strength of the channel, and scores the anti-gas channeling strength in combination with the sealing effect of the interlayer separation section and the cap layer section, which can reflect the cementing quality more intuitively and truly.

[0084] The specific steps include:

[0085] Step 1: Connect an ultrasonic imager to the logging winch cable and lower the ultrasonic imager to the bottom of the well. In this embodiment, the logging winch model is ES5250TCJ6, and the ultrasonic imager model is CCL-MCM600-UHI73D.

[0086] Step 2: Enter the parameters in the logging winch control system, including the cable rated breaking force F 0 , safety factor a; in this embodiment, F 0 is 8t, a is 0.8;

[0087] Step 3: The logging winch drives the cable to move upward at a constant speed, starts the measurement system of the logging winch, and the ultrasonic imager starts to work to measure the cement bonding quality data; in this embodiment, the cable upward speed is 500-800m / h;

[0088] Step 4: Record the downhole depth H and cable tension F each time the ultrasonic imager collects data during the cable upward movement; determine whether F is less than aF 0 , if F is less than aF 0 , proceed to step 5, if F is not less than aF 0 , send out an alarm signal;

[0089] Step 5: When the ultrasonic imager moves up to the wellhead, the measurement is ended;

[0090] Step 6: Based on the cement bonding quality data detected by the ultrasonic imager, output the cement bonding quality spatial distribution map with the casing circumference as the horizontal axis and the well depth as the vertical axis; the cement bonding quality spatial distribution map is referenced Figure 1 ;

[0091] Step 7: Obtain the color RGB of the unbonded microvoids, liquid, gas or dry micropores in the legend of the cement bonding quality spatial distribution map through image processing software, as well as the color RGB of different bonding strengths in the bonding area; in this embodiment, the color RGB of the unbonded microvoids is (0, 255, 0), the color RGB of the liquid is (0, 0, 255), and the color RGB of the gas or dry micropores is (219, 112, 147);

[0092] Step 8: Establish the corresponding relationship between color RGB and bonding strength according to the bonding strength values ​​represented by different colors in the legend, where the bonding strength corresponding to the color RGB of unbonded microvoids, liquid, gas or dry micropores is 0;

[0093] Step 9: Find the pixel points whose bonding strength is not 0 in the cement bonding quality spatial distribution map according to the corresponding relationship between the color RGB and the cement bonding strength obtained in step 8;

[0094] Step 10: Store the pixel information whose bonding strength is not 0 into the matrix M, and store the pixel information whose bonding strength is 0, such as bonding microvoids, liquids, gases or dry micropores, into the matrix M. The pixel information includes the spatial position coordinates, pixel type and bonding strength. 1 A matrix with five rows and five columns, n 1 The value is the number of all pixels in the spatial distribution map. The first three columns of the matrix M represent the spatial position coordinates of the pixels. The fourth column is a number from 1 to 4, which is used to represent the type of pixel, where 1 represents unbonded microvoids, 2 represents liquid, 3 represents gas or dry microvoids, and 4 represents bonding. The fifth column represents the bonding strength of the pixel.

[0095] Step 11: Set the surface where cement contacts the underground reservoir as the first type of gas inflow surface, the surface where cement contacts the casing joint as the second type of gas inflow surface, and the pixel points on the first type of gas inflow surface and the second type of gas inflow surface as gas inflow points. Store the position coordinates of all gas inflow points into the matrix K, where K is n. 2 A matrix with three rows and three columns, n 2 is the number of gas inflow points, and the three elements in each row of the matrix K represent the spatial position coordinates of the gas inflow points;

[0096] Step 12: Based on the gas inflow point, trace the gas channel and the reflux channel;

[0097] Step 12.1: Set the initial values ​​of loop variables i and j to 1;

[0098] Step 12.2: Take the gas inflow point as the reference point and name it P 10 , P 20 , ... P m0 The spatial positions of these reference points in the cylindrical coordinate system are stored in the matrix group Q i (i=1...m);

[0099] Step 12.3: Read the stored matrix Q i The number of pixels is represented by n;

[0100] Step 12.4: Delete the reference point in the matrix M and the j-th one stored in Q iThe pixel coordinates of the connecting line of the pixels are stored in the matrix D;

[0101] Step 12.5: Find the jth element in matrix D that is stored in Q i The pixel point with the smallest bonding strength adjacent to the pixel point of Q; if there is only one such pixel point, store the jth one in Q i Connect the pixel point with the pixel point and store the spatial coordinates of the pixel point in the matrix K i ; If the jth one is stored in Q i There are two or more pixels adjacent to each other and with the smallest bonding strength. The jth pixel is stored in Q i The pixel points of the pixel points are connected to these pixel points respectively, and the spatial coordinates of these pixel points are stored in the matrix K i ;

[0102] Step 12.6: Determine whether j is equal to n? If j≠n, j=j+1, repeat steps 12.4 to 12.5; if j=n, proceed to step 12.7;

[0103] Step 12.7: Calculate the matrix K separately i The distance h between the coordinates of each spatial position and the upper boundary of the spatial distribution diagram of cement bonding quality 1 、h 2 ……h p , and K i The distance hh between the coordinates of each spatial position and the lower boundary of the spatial distribution diagram of cement bonding quality 1 、hh 2 ...hh p ;

[0104] Step 12.8: The vertical or horizontal distance between two adjacent pixels is represented by h, and K is determined. i Is there h in n <h(n=1,2……p)or hh n <h(n=1,2……p)? If none of them exist, let Q i =K i , repeat steps 12.3 to 12.7; if there is h n <h (n = 1, 2 ... p) pixel point, mark the pixel point as the end point, and its spatial position coordinates in K i Delete it and proceed to step 12.9; if hh exists n <h(n=1,2……p), mark the pixel as a reflow point, and place its spatial coordinates in K i Delete from the table and proceed to step 12.9; in this embodiment, h is 0.76 cm;

[0105] Step 12.9: Judgment Matrix K iIs it an empty array? If not, let Q i =K i , repeat steps 12.3 to 12.7; if yes, proceed to step 12.10;

[0106] Step 12.10: Determine the relationship between i and m. If i=m, end the loop and proceed to step 12.11. If i<m, set i=i+1 and repeat steps 12.3 to 12.9.

[0107] Step 12.11: Output the trajectory from the reference point to the end point. This trajectory is called the gas channel. 1 d 2 ……d p Output the trajectory from the reference point to the reflow point. This trajectory is called the reflow channel and is represented by x. 1 、x 2 ……x n express;

[0108] Step 13: Evaluate the interlayer separation section;

[0109] Step 13.1: Input the depth range corresponding to each interlayer separation segment in the wellbore, and store the pixel position coordinates within the depth range into matrix group B 1 , B 2 ……B e , stored in matrix group B 1 , B 2 ……B e The position coordinates of adopt cylindrical coordinate system, the z direction component indicates the well depth corresponding to the pixel point, the larger the absolute value of the z direction component, the farther the pixel point is from the ground, and the subscript e indicates the number of interlayer separation segments;

[0110] Step 13.2: Set the initial value of the inter-layer separation segment loop variable q to 1;

[0111] Step 13.3: In matrix B q Find all the pixels with the largest absolute value of the z-direction component in the matrix, mark them as the inter-layer separation segment reference points, and store the position coordinates of the inter-layer separation segment reference points in the cylindrical coordinate system into the matrix group F 1 、F 2 ……F v The first row of the matrix group F 1 、F 2 ……F v The third column of each matrix in B is used to store the z-direction component of the spatial position coordinates, and the subscript v represents the number of interlayer partition reference points; qSearch for all pixel points with the smallest absolute value of the z-direction component and mark them as the termination points of the inter-layer separation segment; mark all pixel points except the inter-layer separation segment reference point and the inter-layer separation segment termination point as the middle points of the inter-layer separation segment;

[0112] Step 13.4: Set the initial value of the reference point loop variable f to 1;

[0113] Step 13.5: Set the matrix group row number loop variable c = 1;

[0114] Step 13.6: In the matrix B q Find the matrix F f The pixels corresponding to the cth row are adjacent, and the absolute value of the z-direction component is greater than that of the matrix F f The middle point of the interlayer partition segment or the end point of the interlayer partition segment with the smallest absolute value of the element in the cth row and the third column, and whether the bonding strength of the middle point of the interlayer partition segment or the end point of the interlayer partition segment is 0?

[0115] Step 13.7: If there is an interlayer separation segment end point with a bonding strength of 0, store the position coordinates of the interlayer separation segment end point into the matrix F f c+1 row of the matrix F, and proceed to step 13.8; if there is a midpoint of the interlayer separation segment with a bonding strength of 0, store the position coordinates of the midpoint of the interlayer separation segment in the matrix F f The c+1 row of the layer, let c=c+1, repeat steps 13.6 to 13.7; if there is no interlayer separation segment midpoint with a bonding strength of 0 or an interlayer separation segment midpoint, let F f is an empty matrix;

[0116] Step 13.8: Output matrix F f ;

[0117] Step 13.9: Determine whether f is equal to v. If so, proceed to step 13.10. If not, set f = f + 1 and repeat steps 13.5 to 13.8.

[0118] Step 13.10: Judgment Matrix F 1 、F 2 ……F v Does a non-empty matrix exist in ? If a non-empty matrix exists, it means that there is a gas channel in the qth interlayer partition, and the evaluation result of the qth interlayer partition is output as "unqualified"; if a non-empty matrix does not exist, it means that there is no gas channel in the qth interlayer partition, and the evaluation result of the qth interlayer partition is output as "qualified";

[0119] Step 13.11: Determine whether q is equal to e. If q = e, proceed to step 13.12. If q ≠ e, set q = q + 1 and repeat steps 13.3 to 13.10.

[0120] Step 13.12: Determine whether all interlayer partitions are "qualified"? If all are "qualified", the overall evaluation result of the interlayer partitions is output as "qualified"; if there are "unqualified" interlayer partitions, the overall evaluation result of the interlayer partitions is output as "unqualified";

[0121] Step 14: Evaluate the caprock segment;

[0122] Step 14.1: Input the well depth range corresponding to the wellbore cap layer section, and store the pixel position coordinates within the well depth range into the matrix C. The position coordinates stored in the C matrix adopt the cylindrical coordinate system, and its z-direction component represents the well depth corresponding to the pixel point. The larger the absolute value of the z-direction component, the farther the pixel point is from the ground.

[0123] Step 14.2: Find all the pixel points with the largest absolute value of the z-direction component in the matrix C, mark them as the base point of the cover layer segment, and store the position coordinates of the base point of the cover layer segment in the cylindrical coordinate system into the matrix group R 1 , R 2 ……R w The first row of the matrix group R 1 , R 2 ……R w The third column of each matrix in is used to store the z-direction component of the spatial position coordinates, and the subscript w represents the number of the reference points of the cover layer segment; all the pixel points with the smallest absolute value of the z-direction component in the matrix C are searched and marked as the end points of the cover layer segment; the other pixel points except the reference points of the cover layer segment and the end points of the cover layer segment are marked as the middle points of the cover layer segment;

[0124] Step 14.3: Set the initial value of the reference point loop variable f to 1;

[0125] Step 14.4: Set the matrix group row number loop variable c = 1;

[0126] Step 14.5: Find the value in matrix C that is consistent with matrix R f The pixels corresponding to the cth row are adjacent, and the absolute value of the z-direction component is greater than the matrix R f The middle point of the cap layer segment or the end point of the cap layer segment with the smallest absolute value of the element in the cth row and the third column, and whether the bonding strength of the middle point of the cap layer segment or the end point of the cap layer segment is 0?

[0127] Step 14.6: If there is a caprock segment end point with a bonding strength of 0, store the position coordinates of the caprock segment end point in the matrix R f c+1 row of the matrix R, and proceed to step 14.7; if there is a midpoint of the cap layer segment with a bonding strength of 0, store the position coordinates of the midpoint of the cap layer segment into the matrix R fc+1 row, let c=c+1, repeat steps 14.5~14.6; if there is no end point of the cap layer segment or the middle point of the cap layer segment with a bonding strength of 0, let R f is an empty matrix;

[0128] Step 14.7: Output Matrix R f ;

[0129] Step 14.8: Determine whether f is equal to w? If f = w, proceed to step 14.9. If f ≠ w, set f = f + 1 and repeat steps 14.5 to 14.7.

[0130] Step 14.9: Judgment Matrix R 1 , R 2 ……R w Does a non-empty matrix exist in the ? If a non-empty matrix exists, it means that there is a gas channel in the cap layer section, and the overall evaluation result of the cap layer section is output as "unqualified"; if a non-empty matrix does not exist, it means that there is no gas channel in the cap layer section, and the overall evaluation result of the cap layer section is output as "qualified";

[0131] Step 15: Evaluate and score the wellbore gas channeling prevention strength;

[0132] Step 15.1: Determine whether the overall evaluation results of the interlayer partition section and the overall evaluation results of the cap layer section are both "qualified"? If both are "qualified", proceed to step 15.2; otherwise, the anti-gas channeling performance score A is 0 points, and proceed to step 15.8;

[0133] Step 15.2: Set the initial value of the loop variable i to 1, take the maximum bonding strength in the matrix M, and use c f express;

[0134] Step 15.3: Find the gas channel d in the matrix M i The bonding strength corresponding to each pixel point on (i=1……p) is expressed as c 1 、c 2 ……c u ;

[0135] Step 15:4: C 1 、c 2 ……c u Sum, use W i express:

[0136] W i =c 1 +c 2 +…c u (1)

[0137] Step 15.5: Determine whether i is greater than p. If i>p, end the loop and output W. i, proceed to step 15.6, if i≤p, i=i+1, repeat steps 15.3~15.4;

[0138] Step 15.6: Get W 1 , W 2 ...W p The minimum value of W and the gas channel corresponding to the minimum value are determined. f and d f express;

[0139] Step 15.7: According to c f , W f and d f Calculate the anti-gas channeling performance score A of the cement:

[0140]

[0141] Where u is the gas channel d f The number of pixels in the

[0142] Step 15.7: Output the anti-gas channeling performance score;

[0143] Step 15.8: According to the needs of the evaluation department, determine the qualified range of anti-gas channeling performance scores and comprehensively evaluate the cementing quality.

[0144] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for evaluating the cementing quality of a gas storage well, wherein the characteristic steps are include: Step 1: Using a logging winch and an ultrasonic imager, measure the cement bonding quality of the casing cement annulus in the wellbore after cementing of the gas storage well, and obtain a spatial distribution map of the cement bonding quality; Step 2: Establish the corresponding relationship between color RGB and bonding strength in the cement bonding quality spatial distribution map; Step 3: Track the gas channel and reflux channel of the cement annulus under test; Step 4: Evaluate the sealing effect of the interlayer partition; Step 5: Evaluate the sealing effect of the caprock section; Step 6: Based on the sealing effect of the interlayer separation section and the caprock section, evaluate and score the wellbore's anti-gas channeling strength.

2. A method for evaluating cementing quality of a gas storage well according to claim 1, characterized in that: The step 1 specifically includes: Step 1.1: Connect the ultrasonic imager to the logging winch cable and lower the ultrasonic imager to the bottom of the well; Step 1.2: Input parameters into the logging winch control system, including the cable rated breaking force F0 and safety factor a; Step 1.3: The logging winch drives the cable to move upward at a constant speed, starts the measurement system of the logging winch, and the ultrasonic imager starts to work to measure the cement bonding quality data; Step 1.4: Record the downhole depth H and cable tension F each time the ultrasonic imager collects data during the cable upward movement; determine whether F is less than aF0. If F is less than aF0, proceed to step 1.

5. If F is not less than aF0, issue an alarm signal; Step 1.5: End the measurement when the ultrasonic imager moves up to the wellhead; Step 1.6: Based on the cement bonding quality data detected by the ultrasonic imager, output a cement bonding quality spatial distribution map with the casing circumference as the horizontal axis and the well depth as the vertical axis.

3. A method for evaluating cementing quality of a gas storage well according to claim 1, characterized in that: The step 2 specifically includes: Step 2.1: Obtain the color RGB representing the uncemented microvoids, liquid, gas or dry microvoids in the legend of the cement bonding quality spatial distribution map through image processing software, as well as the color RGB representing different bonding strengths in the bonding area; Step 2.2: Establish the corresponding relationship between color RGB and cement bonding strength according to the bonding strength values ​​represented by different colors in the legend, where the bonding strength corresponding to the color RGB of unbonded microvoids, liquid, gas or dry micropores is 0; Step 2.3: According to the corresponding relationship between the color RGB and the cement bonding strength obtained in step 2.2, find the pixel points whose bonding strength is not 0 in the cement bonding quality spatial distribution map; Step 2.4: The pixel information whose bonding strength is not 0 is stored in the matrix M. At the same time, the pixel information whose bonding strength is 0, which represents bonding microvoids, liquids, gases or dry micropores, is stored in the matrix M. The pixel information includes the spatial position coordinates, pixel type and bonding strength.

4. A method for evaluating cementing quality of a gas storage well according to claim 3, characterized in that: Step 3 includes: Step 3.1: Set the surface where cement contacts the underground reservoir as the first type of gas inflow surface, the surface where cement contacts the casing joint as the second type of gas inflow surface, the pixel points on the first type of gas inflow surface and the second type of gas inflow surface as gas inflow points, and store the position coordinates of all gas inflow points into the matrix K; Step 3.2: Based on the gas inflow point, trace the gas channel and reflux channel in the cement annulus.

5. A method for evaluating cementing quality of a gas storage well according to claim 4, characterized in that: Step 3.2 specifically includes: Step 3.2.1: Set the initial values ​​of loop variables i and j to 1; Step 3.2.2: Take the gas inflow point as the reference point and name it P 10 , P 20 , ... P m0 The spatial positions of these reference points in the cylindrical coordinate system are stored in the matrix group Q i (i=1...m); Step 3.2.3: Read the matrix group Q i The number of pixels is represented by n; Step 3.2.4: Delete the reference point in the matrix M and the j-th one stored in Q i The pixel coordinates of the connecting line of the pixels are stored in the matrix D. Step 3.2.5: Find the jth item in matrix D that is stored in Q i The pixel point with the smallest bonding strength adjacent to the pixel point of Q; if there is only one such pixel point, store the jth one in Q i Connect the pixel point with the pixel point and store the spatial coordinates of the pixel point in the matrix K i ; If the jth one is stored in Q i There are two or more pixels adjacent to each other and with the smallest bonding strength. The jth pixel is stored in Q i The pixel points of the pixel points are connected to these pixel points respectively, and the spatial coordinates of these pixel points are stored in the matrix K i ; Step 3.2.6: Determine whether j is equal to n. If j≠n, j=j+1, and repeat steps 3.2.4 to 3.2.5; if j=n, proceed to step 3.2.7; Step 3.2.7: Calculate the matrix K separately i The distances h1, h2, ..., h between the spatial coordinates and the upper boundary of the spatial distribution diagram of cement bonding quality p , and K i The distance between each spatial coordinate and the lower boundary of the cement bonding quality spatial distribution diagram is hh1, hh2...hh p ; Step 3.2.8: Let h represent the vertical or horizontal distance between two adjacent pixels and determine K i Is there h in n <h(n=1,2……p)or hh n If the pixel points < h(n=1,2……p) do not exist, let Q i =K i , repeat steps 3.2.3 to 3.2.7; if there is h n <h (n = 1, 2 ... p) pixel point, mark the pixel point as the end point, and place its spatial coordinates in K i Delete it and proceed to step 3.2.9; if hh exists n <h(n=1,2……p), mark the pixel as a reflow point and place its spatial coordinates in K i Delete it and proceed to step 3.2.9; Step 3.2.9: Judgment matrix K i Is it an empty array? If not, let Q i =K i , repeat steps 3.2.3 to 3.2.7; if yes, proceed to step 3.2.10; Step 3.2.10: Determine the relationship between i and m. If i=m, end the loop and proceed to step 3.2.

11. If i<m, i=i+1, repeat steps 3.2.3 to 3.2.

9. Step 3.2.11: Output the trajectory from the reference point to the end point. This trajectory is the gas channel. Use d1, d2, ... d p Output the trajectory from the reference point to the return point. This trajectory is the return channel. n express.

6. A method for evaluating cementing quality of a gas storage well according to claim 1, characterized in that: The step 4 specifically includes: Step 4.1: Input the depth range corresponding to each interlayer separation segment in the wellbore, and store the pixel position coordinates within the depth range into matrix groups B1, B2, ..., B e , stored in matrix groups B1, B2...B e The position coordinates of adopt cylindrical coordinate system, the z direction component indicates the well depth corresponding to the pixel point, the larger the absolute value of the z direction component, the farther the pixel point is from the ground, and the subscript e indicates the number of interlayer separation segments; Step 4.2: Set the initial value of the inter-layer separation loop variable q to 1; Step 4.3: In matrix B q Find all the pixels with the largest absolute value of the z-direction component, mark them as the inter-layer separation segment reference points, and store the position coordinates of the inter-layer separation segment reference points in the cylindrical coordinate system into the matrix groups F1, F2, ..., F v The first row of the matrix group F1, F2, ... F v The third column of each matrix in B is used to store the z-direction component of the spatial position coordinates, and the subscript v represents the number of interlayer partition reference points; q Search for all pixel points with the smallest absolute value of the z-direction component and mark them as the termination points of the inter-layer separation segment; mark all pixel points except the inter-layer separation segment reference point and the inter-layer separation segment termination point as the middle points of the inter-layer separation segment; Step 4.4: Set the initial value of the reference point loop variable f to 1; Step 4.5: Set the matrix group row number loop variable c = 1; Step 4.6: In matrix B q Find the matrix F f The pixels corresponding to the cth row are adjacent, and the absolute value of the z-direction component is greater than that of the matrix F f The middle point of the interlayer separation segment or the end point of the interlayer separation segment with the smallest absolute value of the element in the cth row and the third column, and whether the bonding strength of the middle point of the interlayer separation segment or the end point of the interlayer separation segment is 0; Step 4.7: If there is an interlayer separation segment end point with a bonding strength of 0, store the position coordinates of the interlayer separation segment end point into the matrix F f c+1 row of the matrix F, and proceed to step 4.8; if there is a midpoint of the interlayer separation segment with a bonding strength of 0, store the position coordinates of the midpoint of the interlayer separation segment into the matrix F f The c+1 row of the matrix F is set to c=c+1, and steps 4.6 to 4.7 are repeated; if there is no interlayer partition midpoint with a bonding strength of 0 or no interlayer partition midpoint, let the matrix F f is an empty matrix; Step 4.8: Output matrix F f ; Step 4.9: Determine whether f is equal to v. If f = v, proceed to step 4.

10. If f ≠ v, set f = f + 1 and repeat steps 4.5 to 4.

8. Step 4.10: Judgment matrix F1, F2, ... F v Whether there is a non-empty matrix in , if there is a non-empty matrix, it means that there is a gas channel in the qth interlayer partition segment, and the evaluation result of the qth interlayer partition segment is output as "unqualified"; if there is no non-empty matrix, it means that there is no gas channel in the qth interlayer partition segment, and the evaluation result of the qth interlayer partition segment is output as "qualified"; Step 4.11: Determine whether q is equal to e. If q = e, proceed to step 4.

12. If q ≠ e, set q = q + 1 and repeat steps 4.3 to 4.

10. Step 4.12: Determine whether the evaluation results of all interlayer partitions are "qualified". If they are all "qualified", the overall evaluation result of the interlayer partitions is output as "qualified"; if there are "unqualified" interlayer partitions, the overall evaluation result of the interlayer partitions is output as "unqualified".

7. A method for evaluating cementing quality of a gas storage well according to claim 1, characterized in that: The step 5 specifically includes: Step 5.1: Input the well depth range corresponding to the wellbore cap layer section, and store the pixel position coordinates within the well depth range into the matrix C. The position coordinates stored in the matrix C adopt the cylindrical coordinate system, and its z-direction component represents the well depth corresponding to the pixel point. The larger the absolute value of the z-direction component, the farther the pixel point is from the ground. Step 5.2: Find all the pixel points with the largest absolute value of the z-direction component in the matrix C, mark them as the base point of the cover layer segment, and store the position coordinates of the base point of the cover layer segment in the cylindrical coordinate system into the matrix groups R1, R2, ..., R w The first row of the matrix group R1, R2, ... R w The third column of each matrix in is used to store the z-direction component of the spatial position coordinates, and the subscript w represents the number of the reference points of the cover layer segment; all the pixel points with the smallest absolute value of the z-direction component in the matrix C are searched and marked as the end points of the cover layer segment; the other pixel points except the reference points of the cover layer segment and the end points of the cover layer segment are marked as the middle points of the cover layer segment; Step 5.3: Set the initial value of the reference point loop variable f to 1; Step 5.4: Set the matrix group row number loop variable c = 1; Step 5.5: Find the value in matrix C that matches the value in matrix R f The pixels corresponding to the cth row are adjacent, and the absolute value of the z-direction component is greater than the matrix R f The middle point of the cap layer segment or the end point of the cap layer segment with the smallest absolute value of the element in the cth row and the third column, and whether the bonding strength of the middle point of the cap layer segment or the end point of the cap layer segment is 0; Step 5.6: If there is a caprock segment end point with a bonding strength of 0, store the position coordinates of the caprock segment end point into the matrix R f c+1 row of the matrix R, and proceed to step 5.7; if there is a midpoint of the cap layer segment with a bonding strength of 0, store the position coordinates of the midpoint of the cap layer segment into the matrix R f Let c = c + 1, and repeat steps 5.5 to 5.6; if there is no end point of the cap layer segment or the middle point of the cap layer segment with a bonding strength of 0, let the matrix R f is an empty matrix; Step 5.7: Output matrix R f ; Step 5.8: Determine whether f is equal to w. If f = w, proceed to step 5.

9. If f ≠ w, set f = f + 1 and repeat steps 5.5 to 5.

7. Step 5.9: Judgment matrix R1, R2, ... R w Whether there is a non-empty matrix in the cap layer, if there is a non-empty matrix, it means that there is a gas channel in the cap layer section, and the overall evaluation result of the cap layer section is output as "unqualified"; if there is no non-empty matrix, it means that there is no gas channel in the cap layer section, and the overall evaluation result of the cap layer section is output as "qualified".

8. A method for evaluating cementing quality of a gas storage well according to claim 5, characterized in that: Step 6 specifically includes: Step 6.1: Determine whether the overall evaluation results of the interlayer partition section and the overall evaluation results of the cap layer section are both "qualified". If both are "qualified", proceed to step 6.2; otherwise, the anti-gas channeling performance score A is 0 points, and proceed to step 6.8; Step 6.2: Set the initial value of the loop variable i to 1, take the maximum bonding strength in the matrix M, and use c f express; Step 6.3: Find the gas channel d in the matrix M i The bonding strength corresponding to each pixel point on (i=1...p) is expressed as c1, c2...c u ; Step 6:4: For c1, c2...c u Sum, use W i express; Step 6.5: Determine whether i is greater than p. If i>p, end the loop and output W. i , proceed to step 6.

6. If i≤p, set i=i+1 and repeat steps 6.3 to 6.4; Step 6.6: Take W1, W2, ... W p The minimum value W f , and determine the minimum value W f Corresponding gas channel d f ; Step 6.7: According to c f , W f and d f Calculate the anti-gas channeling performance score A of the cement; Step 6.8: Output the anti-gas channeling performance score; Step 6.9: According to the needs of the evaluation department, determine the qualified range of anti-gas channeling performance scores and comprehensively evaluate the cementing quality.

9. A method for evaluating cementing quality of a gas storage well according to claim 8, characterized in that: The calculation formula of the anti-gas channeling performance score A is: Where u is the gas channel d f The number of pixels in the image.

10. A method for evaluating cementing quality of a gas storage well according to any one of claims 3, 4, 5 and 8, characterized in that: The matrix M is an n1-row and five-column matrix, where n1 is the number of all pixels in the spatial distribution map of cement bonding quality. The first three columns of the matrix M represent the spatial coordinates of the pixels, and the fourth column is a number from 1 to 4, which is used to represent the pixel type, where 1 represents uncemented microvoids, 2 represents liquid, 3 represents gas or dry micropores, and 4 represents bonding. The fifth column represents the bonding strength of the pixel.

Images