A method for evaluating cementing quality of a gas storage well

Abstract

The application provides a gas storage well cementing quality evaluation method, steps comprising: step 1: using a logging winch and an ultrasonic imager, cementing quality of a casing cement annulus in a wellbore after the gas storage well is cemented is measured, and a cementing quality space distribution diagram is obtained; step 2: a color RGB and cementing strength corresponding relationship in the cementing quality space distribution diagram is established; step 3: easy gas channeling channels and backflow channels of the measured cement annulus are tracked; step 4: a cementing effect of an interlayer separation section is evaluated; step 5: a cementing effect of a cap section is evaluated; step 6: the wellbore gas channeling strength is evaluated and scored in combination with the cementing effects of the interlayer separation section and the cap section. The application comprehensively considers the cementing effects of the interlayer separation section and the cap section, quantifies the gas upward channeling difficulty degree in the wellbore, and can more directly and truly reflect the cementing quality of the gas storage well and the gas well.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of gas storage well drilling and completion engineering, and particularly relates to a method for evaluating the cementing quality of a gas storage well. BACKGROUND

[0002] During the injection and production process of a gas storage well, the wellbore needs to bear a gas load of up to tens of MPa. Compared with conventional oil and gas wells, the gas storage well has higher requirements for the performance of cementing cement. The gas channeling problem of the cement sheath after cementing has been one of the main bottlenecks that need to be overcome in the field of gas storage well drilling and completion engineering. The cement slurry in the gel liquid state after cementing forms a cement stone through setting and hardening. If the cement stone has channeling or is poorly cemented with the casing and the formation, the gas will enter the cement annulus and even channel up to the wellhead, which poses a major safety hazard. Therefore, the sealing performance of the cement needs to be accurately evaluated after the cementing is completed. At present, the commonly used method at home and abroad is to measure the wellbore filling degree and cementing strength through acoustic amplitude-density, gamma density and ultrasonic imaging detection methods, and to evaluate the cementing quality by simply statistically processing these parameters. However, this method cannot directly reflect the difficulty of gas channeling along the cement sheath and the sealing effect of the cap layer section and the interlayer isolation section, and the evaluation result deviates greatly from the actual situation, which cannot meet the requirements of the gas storage well for the evaluation of the gas sealing performance of the cement. SUMMARY

[0003] In order to overcome the deficiencies in the prior art, the application provides a method for evaluating the cementing quality of a gas storage well, which comprehensively considers the cementing effect of the interlayer isolation section and the cap layer section and quantifies the difficulty of gas channeling in the wellbore, so as to more directly and truly reflect the cementing quality of the gas storage well and the gas well.

[0004] The technical scheme adopted by the application to solve the technical problem is:

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

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

[0007] Step 2: establishing a correspondence between the color RGB in the cementing quality spatial distribution map and the cementing strength;

[0008] Step 3: tracking the easy gas channeling channel and the reflux channel of the measured cement annulus;

[0009] Step 4: evaluating the cementing effect of the interlayer isolation section;

[0010] Step 5: evaluating the cementing effect of the cap layer section;

[0011] Step 6: Evaluate and score the gas channeling prevention strength of the wellbore by combining the sealing effect of the interlayer separation section and the cap section.

[0012] Further, the step 1 specifically comprises:

[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 in the logging winch control system, including the cable rated breaking force F0 and the safety factor a;

[0015] Step 1.3: Drive the cable upward at a constant speed by the logging winch, start the measurement system of the logging winch, and the ultrasonic imager starts to work to measure the cementing quality data;

[0016] Step 1.4: Record the downhole depth H and the cable tension F when the ultrasonic imager collects data each time 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;

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

[0018] Step 1.6: Output the cementing quality spatial distribution graph with the casing circumference as the horizontal axis and the well depth as the vertical axis according to the cementing quality data detected by the ultrasonic imager.

[0019] Further, the step 2 specifically comprises:

[0020] Step 2.1: Obtain the color RGB representing un-cemented micro gaps, liquid, gas or dry micro pores and the color RGB representing different cementing strengths in the legend of the cementing quality spatial distribution graph through the image processing software;

[0021] Step 2.2: Establish the corresponding relationship between the color RGB and the cementing strength according to the cementing strength values represented by different colors in the legend, wherein the color RGB of the un-cemented micro gaps, liquid, gas or dry micro pores corresponds to a cementing strength of 0;

[0022] Step 2.3: Look up the pixel points with a cementing strength not equal to 0 in the cementing quality spatial distribution graph according to the corresponding relationship between the color RGB and the cementing strength obtained in step 2.2;

[0023] Step 2.4: Store the pixel point information of the cementing strength not equal to 0 and the pixel point information of the cementing strength of 0 representing the un-cemented micro gaps, liquid, gas or dry micro pores in the matrix M, and the pixel point information includes the spatial position coordinates, the pixel point type and the cementing strength.

[0024] Furthermore, step 3 includes:

[0025] Step 3.1: Define the surface where cement contacts the underground reservoir as the first type of gas inflow surface, the surface where cement contacts the casing as the second type of gas inflow surface, and the pixels on the first and second type of gas inflow surfaces as gas inflow points. Store the position coordinates of all gas inflow points in matrix K.

[0026] Step 3.2: Using the gas inflow point as a reference, trace the gas channel and return 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: Using the gas inflow point as the reference point, name it P. 10 P 20 ...P m0 The spatial positions of these reference points in the cylindrical coordinate system are stored in matrix Q. i (i = 1...m);

[0030] Step 3.2.3: Read the data stored in matrix group Q i The number of pixels, denoted by n;

[0031] Step 3.2.4: Delete the reference point and the point already stored in Q in matrix M. i Find the pixel coordinates of the line connecting the pixels, and store the remaining pixel coordinates into matrix D;

[0032] Step 3.2.5: Find the element in matrix D that corresponds to the j-th element and store it in Q. i The pixel that is adjacent to the pixel and has the smallest bonding strength; if there is only one such pixel, store the j-th pixel in Q. i Connect the pixel to the given pixel and store the spatial coordinates of this pixel in matrix K. i If it is stored in Q with the j-th element... i If there are two or more adjacent pixels with the lowest bonding strength, store the j-th pixel in Q. i Connect each pixel to a line and store the spatial coordinates of these pixels in matrix K. i ;

[0033] Step 3.2.6: Determine if 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 matrix K respectively.i the upper boundary distance h1, h2,..., h of the cementation quality spatial distribution map at each spatial coordinate p , and K i the lower boundary distance hh1, hh2,..., hh of the cementation quality spatial distribution map at each spatial coordinate p ;

[0035] Step 3.2.8: the vertical or horizontal distance between two adjacent pixel points is represented by h, and it is determined whether there is h i in K n < h (n = 1, 2,..., p) or hh n < h (n = 1, 2,..., p), if none of them exists, let Q i = K i , repeat steps 3.2.3-3.2.7; if there is a pixel point of h n < h (n = 1, 2,..., p), mark the pixel point as a termination point, delete its spatial coordinates in K i , and proceed to step 3.2.9; if there is a pixel point of hh n < h (n = 1, 2,..., p), mark the pixel point as a reflux point, delete its spatial coordinates in K i , and proceed to step 3.2.9;

[0036] Step 3.2.9: it is determined whether the matrix K i is empty, if not, let Q i = K i , repeat steps 3.2.3-3.2.7; if so, proceed to step 3.2.10;

[0037] Step 3.2.10: it is determined whether i and m are related, if i = m, end the loop, and proceed to step 3.2.11; if i < m, i = i + 1, repeat steps 3.2.3-3.2.9;

[0038] Step 3.2.11: output the trajectory connected from the reference point to the termination point, which is the easy gas channeling channel, represented by d1, d2,..., d p ; output the trajectory connected from the reference point to the reflux point, which is the reflux channel, represented by x1, x2,..., x n .

[0039] Further, the step 4 specifically comprises:

[0040] Step 4.1: input the well depth range corresponding to each interlayer separation section in the wellbore, and store the pixel point position coordinates in the well depth range in matrix groups B1, B2,..., B e , and store the pixel point position coordinates in the well depth range in matrix groups B1, B2,..., B eThe position coordinates of the pixel points in the cylindrical coordinate system, and the z-direction component represents the well depth corresponding to the pixel point. The greater the absolute value of the z-direction component, the farther the distance between the pixel point and the ground. The subscript e represents the number of interlayer separation sections.

[0041] Step 4.2: Set the initial value of the interlayer separation section loop variable q as 1.

[0042] Step 4.3: Find all pixel points with the maximum absolute value of the z-direction component in the matrix B q , mark them as interlayer separation section reference points, and store the position coordinates of the interlayer separation section reference points in the cylindrical coordinate system into the matrix group F1, F2, …, F v , respectively. The first row of the matrix group F1, F2, …, F v is composed of the z-direction components of the position coordinates of the interlayer separation section reference points. The subscript v represents the number of interlayer separation section reference points. q Find all pixel points with the minimum absolute value of the z-direction component in the matrix B q , mark them as interlayer separation section termination points, and mark other pixel points except the interlayer separation section reference points and the interlayer separation section termination points as interlayer separation section intermediate points.

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

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

[0045] Step 4.6: Find the interlayer separation section intermediate points or the interlayer separation section termination points adjacent to the pixel points corresponding to the c-th row of the matrix F f in the matrix B q , and the absolute value of the z-direction component is smaller than the absolute value of the element in the third column of the c-th row of the matrix F f , and determine whether the cementation strength of the interlayer separation section intermediate point or the interlayer separation section termination point is 0.

[0046] Step 4.7: If there is an interlayer separation section termination point with a cementation strength of 0, store the position coordinates of the interlayer separation section termination point into the c+1-th row of the matrix F f , and proceed to step 4.8. If there is an interlayer separation section intermediate point with a cementation strength of 0, store the position coordinates of the interlayer separation section intermediate point into the c+1-th row of the matrix F f , set c = c + 1, and repeat steps 4.6-4.7. If there is no interlayer separation section intermediate point or interlayer separation section intermediate point with a cementation strength of 0, set the matrix F f as an empty matrix.

[0047] Step 4.8: Output the matrix F f .

[0048] Step 4.9: judge whether f is equal to v, if f=v, go to step 4.10, if f≠v, let f=f+1, repeat steps 4.5-4.8;

[0049] Step 4.10: judge whether there is non-empty matrix in matrix F1, F2, …, F v , if there is non-empty matrix, it means that the qth interlayer partition section has gas channeling channel, and the evaluation result of the qth interlayer partition section is output as "unqualified"; if there is no non-empty matrix, it means that the qth interlayer partition section has no gas channeling channel, and the evaluation result of the qth interlayer partition section is output as "qualified";

[0050] Step 4.11: judge whether q is equal to e, if q=e, go to step 4.12, if q≠e, let q=q+1, repeat steps 4.3-4.10;

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

[0052] Further, the step 5 specifically comprises:

[0053] Step 5.1: input the well depth range corresponding to the caprock section in the wellbore, and store the position coordinates of the pixel points in the well depth range in matrix C respectively, the position coordinates stored in matrix C adopt cylindrical coordinate system, the z direction component represents the well depth corresponding to the pixel point, the greater the absolute value of the z direction component, the farther the distance between the pixel point and the ground;

[0054] Step 5.2: find all pixel points with the maximum absolute value of z direction component in matrix C, mark them as caprock section reference points, and store the position coordinates of the caprock section reference points in cylindrical coordinate system in matrix group R1, R2, …, R w , the first row of the matrix group R1, R2, …, R w , the third column of each matrix in the matrix group is used to store the z direction component of the spatial position coordinates, and the subscript w represents the number of caprock section reference points; find all pixel points with the minimum absolute value of z direction component in matrix C, mark them as caprock section termination points; mark other pixel points except the caprock section reference points and the caprock section termination points as caprock section intermediate points;

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

[0056] Step 5.4: let the row loop variable c of the matrix group be 1;

[0057] Step 5.5: find the pixel point with the minimum absolute value of z direction component in matrix C, which is the caprock section reference point corresponding to the matrix R fThe pixel point corresponding to the cth row is adjacent, and the absolute value of the z direction component is smaller than the matrix R f The cth row, the third column element of the capping layer section intermediate point or the capping layer section termination point, and the capping layer section termination point of the capping layer section termination point are determined whether the capping layer section termination point is 0;

[0058] Step 5.6: if there is a capping layer section termination point with a cementing strength of 0, the position coordinates of the capping layer section termination point are stored in the matrix R f The c+1th row of the c+1th row is stored in the matrix R f , and c=c+1, repeat steps 5.5-5.6; if there is no capping layer section termination point or capping layer section intermediate point with a cementing strength of 0, the matrix R f is empty matrix;

[0059] Step 5.7: output the 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, f=f+1, repeat steps 5.5-5.7;

[0061] Step 5.9: determine whether there is a non-empty matrix in the matrix R1, R2……R w If there is a non-empty matrix, it means that the capping layer section has a gas channeling channel, and the overall evaluation result of the capping layer section is "unqualified"; if there is no non-empty matrix, it means that the capping layer section has no gas channeling channel, and the overall evaluation result of the capping layer section is "qualified".

[0062] Further, step 6 specifically includes:

[0063] Step 6.1: determine whether the overall evaluation result of the interlayer separation section and the overall evaluation result of the capping layer section are both "qualified", if both are "qualified", proceed to step 6.2; otherwise, the anti-channeling performance score A is 0, proceed to step 6.8;

[0064] Step 6.2: let the loop variable i initial value be 1, take the maximum value of the cementing strength in the matrix M, and denote it as c f ;

[0065] Step 6.3: find the cementing strength corresponding to each pixel point on the easy gas channeling channel d i (i=1……p) in the matrix M, denoted as c1, c2……c u ;

[0066] Step 6:4: sum c1, c2……c u , denoted as W i ;

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

[0068] Step 6.6: Take W1, W2...W p minimum value W f And determine the minimum value W. f The corresponding gas leakage channel d f ;

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

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

[0071] Step 6.9: Determine the acceptable range for gas channeling prevention performance score according to the evaluation department's needs, and comprehensively evaluate the cementing quality.

[0072] Furthermore, the formula for calculating the anti-gas channeling performance score A is as follows:

[0073]

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

[0075] Furthermore, matrix M is an n1-row, 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 matrix M represent the spatial coordinates of the pixels, the fourth column is a number from 1 to 4, used to represent the type of pixel, where 1 represents unbonded micro-cracks, 2 represents liquid, 3 represents gas or dry micro-pores, and 4 represents bonded. The fifth column represents the bonding strength of the pixel.

[0076] The beneficial effects of this invention include:

[0077] This invention provides a method for evaluating the cementing quality of gas storage wells. It utilizes an ultrasonic imager to measure the spatial distribution map of cement bond quality in the casing annulus within the wellbore. A correspondence between the RGB colors within the cement bond quality spatial distribution map and the bond strength is established, revealing the gas-prone channels and backflow channels in the tested casing annulus. The original evaluation method, which simply statistically analyzed wellbore filling degree and cement bond strength, is optimized into a comprehensive cementing quality evaluation method that considers the sealing effect of interlayer separators and caprock sections, and quantifies the ease of gas upward movement within the wellbore. This results in more practical evaluation results. Furthermore, the anti-gas-channeling strength of the gas-prone channels is scored, providing a more intuitive and accurate reflection of the cementing quality of gas storage wells and gas wells. Attached Figure Description

[0078] Figure 1 is the cementing quality spatial distribution map measured by the embodiment 1 of the present application. DETAILED DESCRIPTION

[0079] The technical solutions of the present application will be clearly and completely described below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of them. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

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

[0081] Embodiment 1

[0082] The present embodiment provides a cementing quality evaluation method for gas storage wells, which establishes a cementing quality evaluation method taking the cementing quality spatial distribution map as input and the anti-gas channeling strength score as output.

[0083] Based on the cementing quality spatial distribution map of the casing annulus in the wellbore measured by the ultrasonic imager, the present scheme establishes the corresponding relationship between the color RGB in the cementing quality spatial distribution map and the cementing strength, obtains the easy-gas channeling channel of the measured cement sheath and the anti-gas channeling strength of the channel, scores the anti-gas channeling strength in combination with the cementing effect of the interlayer separation section and the cap section, and more directly and truly reflects the cementing quality.

[0084] The specific steps include:

[0085] Step 1: connect the ultrasonic imager on the logging winch cable and lower the ultrasonic imager to the bottom of the well; in the present embodiment, the model of the logging winch is ES5250TCJ6 and the model of the ultrasonic imager is CCL-MCM600-UHI73D;

[0086] Step 2: input parameters in the logging winch control system, including the rated breaking force F0 of the cable and the safety factor a; in the present embodiment, F0 is 8t and a is 0.8;

[0087] Step 3: drive the cable to move upward at a constant speed, start the measurement system of the logging winch, and the ultrasonic imager starts to work to measure the cementing quality data; in the present embodiment, the upward moving speed of the cable is 500-800m / h;

[0088] Step 4: record the downhole depth H and the cable tension F when the ultrasonic imager collects data each time during the upward movement of the cable; judge whether F is less than aF0, if F is less than aF0, proceed to step 5, if F is not less than aF0, issue an alarm signal;

[0089] Step 5: end the measurement when the ultrasonic imager moves to the wellhead;

[0090] Step 6: output a cementing quality spatial distribution graph with the casing circumference as the horizontal axis and the well depth as the vertical axis according to the cementing quality data detected by the ultrasonic imager; the cementing quality spatial distribution graph is shown in Fig. 2 Figure 1 ;

[0091] Step 7: obtain the color RGB representing the un-cemented micro gap, liquid, gas or dry micro pore and the color RGB representing different cementing strengths in the legend of the cementing quality spatial distribution graph through the image processing software; in this embodiment, the color RGB of the un-cemented micro gap is (0, 255, 0), the color RGB of the liquid is (0, 0, 255), and the color RGB of the gas or dry micro pore is (219, 112, 147);

[0092] Step 8: establish the corresponding relationship between the color RGB and the cementing strength according to the cementing strength values represented by different colors in the legend, wherein the color RGB of the un-cemented micro gap, liquid, gas or dry micro pore corresponds to a cementing strength of 0;

[0093] Step 9: find the pixel points with a cementing strength of 0 in the cementing quality spatial distribution graph according to the corresponding relationship between the color RGB and the cementing strength obtained in step 8;

[0094] Step 10: store the pixel point information of the cementing strength of 0 into the matrix M, and store the pixel point information of the cementing strength of 0 such as the un-cemented micro gap, liquid, gas or dry micro pore into the matrix M. The pixel point information includes the spatial position coordinates, the pixel point type and the cementing strength, M is an n1 row and five column matrix, n1 takes the number of all pixel points in the spatial distribution graph, the first three columns of the matrix M represent the spatial position coordinates of the pixel points, the fourth column is a number from 1 to 4, which is used to represent the pixel point type, wherein 1 represents the un-cemented micro gap, 2 represents the liquid, 3 represents the gas or dry micro pore, and 4 represents the cementing, and the fifth column represents the cementing strength of the pixel point;

[0095] Step 11: set the surface where the cement contacts the underground reservoir as the first type of gas inflow surface, set the surface where the cement contacts the casing as the second type of gas inflow surface, set the pixel points on the first type of gas inflow surface and the second type of gas inflow surface as the gas inflow points, and store the position coordinates of all the gas inflow points into the matrix K, K is an n2 row and three column matrix, n2 is the number of the 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: track the gas channeling channel and the backflow channel based on the gas inflow points;

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

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

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

[0100] Step 12.4: Delete the pivot point and the point already stored in Q in matrix M. i The pixel coordinates of the line connecting the pixels are stored in matrix D;

[0101] Step 12.5: Find the element in matrix D that corresponds to the j-th element and store it in Q. i The pixel that is adjacent to the pixel and has the smallest bonding strength; if there is only one such pixel, store the j-th pixel in Q. i Connect the pixel to the given pixel and store the spatial coordinates of this pixel in matrix K. i If it is stored in Q with the j-th element... i If there are two or more adjacent pixels with the lowest bonding strength, store the j-th pixel in Q. i Connect each pixel to a line and store the spatial coordinates of these pixels in matrix K. i ;

[0102] Step 12.6: Determine if j equals 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 matrix K respectively i The distances h1, h2...h between the spatial coordinates of each location and the upper boundary of the spatial distribution map of cement bond quality. p and K i The distances hh1, hh2...hh between the spatial coordinates of each location and the lower boundary of the spatial distribution map of cement bond quality. p ;

[0104] Step 12.8: The vertical or horizontal distance between two adjacent pixels is represented by h. Determine K. i Does h exist in it? n <h(n=1,2……p) or hh n What are the pixels < h (n = 1, 2, ..., p)? If none of them exist, let Q i =Ki Repeat steps 12.3~12.7; if h n < h(n=1,2……p), mark the pixel point as a termination point, delete its spatial position coordinates in K i , and go to step 12.9; if h n < h(n=1,2……p), mark the pixel point as a reflux point, delete its spatial position coordinates in K i , and go to step 12.9; in this embodiment, h is 0.76 cm;

[0105] Step 12.9: judge whether the matrix K i is empty? If not, let Q i = K i , repeat steps 12.3~12.7; if yes, go to step 12.10;

[0106] Step 12.10: judge the relationship between i and m, if i=m, end the loop, and go to step 12.11; if i

[0107] Step 12.11: output the trajectory connected from the reference point to the termination point, which is called gas channeling channel, and is represented by d1, d2……d p ; output the trajectory connected from the reference point to the reflux point, which is called reflux channel, and is represented by x1, x2……x n ;

[0108] Step 13: evaluate the interlayer partition section;

[0109] Step 13.1: input the well depth range corresponding to each interlayer partition section in the wellbore, and store the position coordinates of the pixel points in the well depth range in matrix groups B1, B2……B e , respectively. The position coordinates stored in the matrix groups B1, B2……B e are in cylindrical coordinate system, the z-direction component represents the well depth corresponding to the pixel point, the greater the absolute value of the z-direction component, the farther the distance between the pixel point and the ground, and the subscript e represents the number of interlayer partition sections;

[0110] Step 13.2: let the initial value of the interlayer partition section loop variable q be 1;

[0111] Step 13.3: find all pixel points with the largest absolute value of z-direction component in the matrix B q , mark them as interlayer partition section reference points, and store the position coordinates of the interlayer partition section reference points in the first row of matrix groups F1, F2……F v , respectively. The matrix groups F1, F2……F vThe third column of each matrix is used for storing the z-direction component of the space position coordinate, and the subscript v represents the number of interlayer separation section reference points; in matrix B q find all the pixel points with the minimum absolute value of the z-direction component, and mark them as interlayer separation section end points; mark other pixel points except the interlayer separation section reference points and the interlayer separation section end points as interlayer separation section intermediate points;

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

[0113] Step 13.5: set the matrix group row loop variable c as 1;

[0114] Step 13.6: find, in matrix B q , the interlayer separation section intermediate points or the interlayer separation section end points adjacent to the pixel points corresponding to the cth row of matrix F f , and having the absolute value of the z-direction component smaller than that of the element in the third column of the cth row of matrix F f , and determine whether the cementation strength of the interlayer separation section intermediate points or the interlayer separation section end points is 0?

[0115] Step 13.7: if there is an interlayer separation section end point with the cementation strength of 0, store the position coordinates of the interlayer separation section end point in the c+1th row of matrix F f , and proceed to Step 13.8; if there is an interlayer separation section intermediate point with the cementation strength of 0, store the position coordinates of the interlayer separation section intermediate point in the c+1th row of matrix F f , set c as c+1, and repeat Steps 13.6-13.7; if there is no interlayer separation section intermediate point or interlayer separation section intermediate point with the cementation strength of 0, set F f as an empty matrix;

[0116] Step 13.8: output matrix F f ;

[0117] Step 13.9: determine whether f is equal to v? If yes, proceed to Step 13.10; if no, set f as f+1, and repeat Steps 13.5-13.8;

[0118] Step 13.10: determine whether there is a non-empty matrix in matrices F1, F2, …, F v ? If yes, it indicates that the qth interlayer separation section has a gas channeling channel, and the evaluation result of the qth interlayer separation section is output as “unqualified”; if no, it indicates that the qth interlayer separation section has no gas channeling channel, and the evaluation result of the qth interlayer separation section is output as “qualified”;

[0119] Step 13.11: judge whether q is equal to e? If q = e, go to step 13.12, if q ≠ e, let q = q + 1, repeat steps 13.3-13.10;

[0120] Step 13.12: judge whether all interlayer separation segments are "qualified"? If all are "qualified", output the overall evaluation result of the interlayer separation segments as "qualified"; if there is an "unqualified" interlayer separation segment, output the overall evaluation result of the interlayer separation segments as "unqualified";

[0121] Step 14: evaluate the caprock segment;

[0122] Step 14.1: input the well depth range corresponding to the caprock segment in the wellbore, and store the position coordinates of the pixel points in the well depth range in matrix C respectively. The position coordinates stored in the matrix C adopt the cylindrical coordinate system, and the z-direction component represents the well depth corresponding to the pixel point. The greater the absolute value of the z-direction component, the farther the distance between the pixel point and the ground.

[0123] Step 14.2: find all pixel points with the maximum absolute value of the z-direction component in the matrix C, mark them as caprock segment reference points, and store the position coordinates of the caprock segment reference points in the cylindrical coordinate system in matrix group R1, R2, …, R w The first row of the matrix group R1, R2, …, R w The third column of each matrix in the matrix group is used to store the z-direction component of the spatial position coordinates, and the subscript w represents the number of caprock segment reference points. Find all pixel points with the minimum absolute value of the z-direction component in the matrix C, mark them as caprock segment termination points; mark other pixel points except the caprock segment reference points and the caprock segment termination points as caprock segment intermediate points.

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

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

[0126] Step 14.5: find the caprock segment intermediate points or caprock segment termination points adjacent to the pixel points corresponding to the c-th row of the matrix R f in the matrix C, and whose absolute value of the z-direction component is smaller than that of the element in the third column of the c-th row of the matrix R f , and judge whether the cementation strength of the caprock segment intermediate points or caprock segment termination points is 0?

[0127] Step 14.6: if there is a caprock segment termination point with cementation strength of 0, store the position coordinates of the caprock segment termination point in the c+1-th row of the matrix R f , and go to step 14.7; if there is a caprock segment intermediate point with cementation strength of 0, store the position coordinates of the caprock segment intermediate point in the c+1-th row of the matrix R fc+1th row of R, let c=c+1, repeat step 14.5-14.6; if there is no cap segment end point or cap segment middle point with cementation strength of 0, let R f be a null matrix;

[0128] Step 14.7: output matrix R f ;

[0129] Step 14.8: judge whether f is equal to w? If f=w, proceed to step 14.9, if f≠w, let f=f+1, repeat step 14.5-14.7;

[0130] Step 14.9: judge whether there is a non-null matrix in R1, R2……R w ? If there is a non-null matrix, it means that there is a gas channeling channel in the cap segment, and the overall evaluation result of the cap segment is "unqualified"; if there is no non-null matrix, it means that there is no gas channeling channel in the cap segment, and the overall evaluation result of the cap segment is "qualified";

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

[0132] Step 15.1: judge whether the overall evaluation results of the interlayer separation segment and the cap segment are both "qualified"? If both are "qualified", proceed to step 15.2; otherwise, the gas channeling prevention performance score A is 0, and proceed to step 15.8;

[0133] Step 15.2: let the loop variable i be initially 1, and take the maximum cementation strength in the matrix M, denoted as c f ;

[0134] Step 15.3: find the cementation strength of each pixel point corresponding to the easy gas channeling channel d i (i=1……p) in the matrix M, denoted as c1, c2……c u ;

[0135] Step 15:4: sum c1, c2……c u , denoted as W i :

[0136] W i =c1+c2+…c u (1)

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

[0138] Step 15.6: take W1, W2……W pthe minimum value, and determine the gas channeling channel corresponding to the minimum value, respectively, W f and d f represent;

[0139] Step 15.7: Calculate the cement gas channeling performance score A according to c f , W f and d f ;

[0140]

[0141] Wherein, u is the number of pixel points in the gas channeling channel d f ;

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

[0143] Step 15.8: According to the needs of the evaluation department, determine the gas channeling performance score qualified interval, comprehensive evaluation of cementing quality.

[0144] Obviously, the above examples are only examples for the sake of clarity, and not limited to the embodiments. For those of ordinary skill in the art, on the basis of the above description, other different forms of changes or variations can also be made. Here it is not necessary and impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for evaluating the cementing quality of gas storage wells, characterized by the following steps: include: Step 1: Using a logging winch and an ultrasonic imager, measure the cement bonding quality of the casing annulus after cementing of the gas storage well to obtain a spatial distribution map of the cement bonding quality. Step 2: Establish the correspondence between RGB colors and bonding strength in the spatial distribution diagram of cement bond quality; Step 3: Trace the air leakage channels and return channels of the tested cement annulus; Step 4: Evaluate the sealing effect of the interlayer partition; Step 5: Evaluate the sealing effect of the cap layer section; Step 6: Evaluate and score the gas channeling prevention strength of the wellbore by combining the sealing effect of the interlayer separation section and the capping section; Step 3 includes: Step 3.1: Define the surface where cement contacts the underground reservoir as the first type of gas inflow surface, the surface where cement contacts the casing as the second type of gas inflow surface, and the pixels on the first and second type of gas inflow surfaces as gas inflow points. Store the position coordinates of all gas inflow points in matrix K. Step 3.2: Using the gas inflow point as a reference, trace the gas channel and return channel in the cement annulus; 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: Using the gas inflow point as the reference point, name it P. 10 P 20 ...P m0 The spatial positions of these reference points in the cylindrical coordinate system are stored in matrix Q. i (i=1……m); Step 3.2.3: Read the data stored in matrix group Q i The number of pixels, denoted by n; Step 3.2.4: Delete the reference point and the point already stored in Q in matrix M. i Find the pixel coordinates of the line connecting the pixels, and store the remaining pixel coordinates into matrix D; Step 3.2.5: Find the element in matrix D that corresponds to the j-th element and store it in Q. i The pixel that is adjacent to the pixel and has the smallest bonding strength; if there is only one such pixel, store the j-th pixel in Q. i Connect the pixel to the given pixel and store the spatial coordinates of this pixel in matrix K. i If it is stored in Q with the j-th element... i If there are two or more adjacent pixels with the lowest bonding strength, store the j-th pixel in Q. i Connect each pixel to a line and store the spatial coordinates of these pixels in matrix K. i ; Step 3.2.6: Determine if 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 matrix K respectively. i The distances h1, h2...h between each spatial coordinate and the upper boundary of the spatial distribution map of cement bond quality p and K i The distances hh1, hh2...hh between each spatial coordinate and the lower boundary of the spatial distribution map of cement bond quality p ; Step 3.2.8: Represent the vertical or horizontal distance between two adjacent pixels as h, and determine K. i Does h exist in it? n <h (n=1,2……p) or hh n If none of the pixels < h (n=1,2...p) exist, let Q i =K i Repeat steps 3.2.3 to 3.2.7; if h exists n For pixels < h (n=1,2……p), mark the pixel as the termination point and assign its spatial coordinates to K. i Delete it, proceed to step 3.2.9; if hh exists n For pixels <h (n=1,2……p), mark the pixel as a reflow point and assign its spatial coordinates to K. i Delete it and proceed to step 3.2.9; Step 3.2.9: Determine 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 so, 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, and repeat steps 3.2.3 to 3.2.

9. Step 3.2.11: Output the trajectory of the line connecting the reference point to the endpoint. This trajectory is the easy gas flow channel, denoted by d1, d2...d p This indicates that the output line traces the path from the reference point to the return point; this path is the return path, represented by x1, x2, ..., x. n express.

2. The method for evaluating the cementing quality of a gas storage well according to claim 1, characterized in that, 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 rated breaking force of the cable F0 and the safety factor a; Step 1.3: The logging winch drive cable moves upward at a constant speed, the logging winch measurement system is started, the ultrasonic imager starts working, and the cement bonding quality data is measured; Step 1.4: Record the downhole depth H and cable tension F when the ultrasonic imager collects data each time during the cable relocation process; 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: The measurement ends 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 spatial distribution map of cement bonding quality with the casing circumference as the horizontal axis and the well depth as the vertical axis.

3. The method for evaluating the cementing quality of a gas storage well according to claim 1, characterized in that, Step 2 specifically includes: Step 2.1: Use image processing software to obtain the RGB colors representing unbonded micropores, liquids, gases, or dry micropores in the legend of the spatial distribution map of cement bonding quality, as well as the RGB colors representing different bonding strengths in the bonded areas; Step 2.2: Establish the correspondence between the RGB colors and the cement bonding strength based on the bonding strength values ​​represented by different colors in the legend. The bonding strength corresponding to the RGB colors of unbonded micropores, liquids, gases, or dry micropores is 0. Step 2.3: Based on the correspondence between the RGB colors and cement bonding strength obtained in Step 2.2, find the pixels in the spatial distribution map of cement bonding mass where the bonding strength is not 0; Step 2.4: Store the information of pixels with non-zero bonding strength into matrix M. At the same time, store the information of pixels with zero bonding strength that represent bonding micro-gap, liquid, gas or dry micropores into matrix M. The pixel information includes spatial location coordinates, pixel type and bonding strength.

4. The method for evaluating the cementing quality of a gas storage well according to claim 1, characterized in that, Step 4 specifically includes: Step 4.1: Input the well depth range corresponding to each interlayer separation section within the wellbore, and store the pixel coordinates within that well depth range into matrix groups B1, B2...B1 respectively. e Store in matrix groups B1, B2...B e The position coordinates are in cylindrical coordinates. The z-axis component represents the well depth corresponding to the pixel. The larger the absolute value of the z-axis component, the farther the pixel is from the ground. The subscript e represents the number of interlayer segments. Step 4.2: Initialize the interlayer separator loop variable q to 1; Step 4.3: In matrix B q Find all pixels with the largest absolute value of the z-axis component and mark them as reference points for the interlayer separator. Store the position coordinates of the reference points for the interlayer separator in cylindrical coordinates into matrices F1, F2, ..., F1 respectively. v The first row of the matrix consists of matrix groups F1, F2...F v The third column of each matrix stores the z-direction component of the spatial position coordinates, and the subscript v indicates the number of reference points for the interlayer segment; in matrix B q Find all pixels with the smallest absolute value of the z-direction component and mark them as the end points of the interlayer segment; mark all other pixels except the reference point and the end point of the interlayer segment as the midpoint of the interlayer segment. Step 4.4: Initialize the baseline loop variable f to 1; Step 4.5: Set the loop variable c for the number of rows in the matrix group to 1; Step 4.6: In matrix B q Searching for matrix F f The pixels in row c are adjacent, and the absolute value of the z-direction component is greater than that of matrix F. f Find the midpoint or end point of the interlayer separator with the smallest absolute value of the element in row c and column 3, and determine whether the bonding strength of the midpoint or end point of the interlayer separator is 0. Step 4.7: If there is a termination point of the interlayer separator with a bonding strength of 0, store the position coordinates of the termination point of the interlayer separator into matrix F. f In line c+1, proceed to step 4.8; if there is a midpoint of the interlayer separator with a bonding strength of 0, store the position coordinates of the midpoint of the interlayer separator into matrix F. f For row c+1, let c = c+1, and repeat steps 4.6~4.7; if there is no interlayer separator midpoint with bond strength of 0, let matrix F f An empty matrix; Step 4.8: Output matrix F f ; Step 4.9: Determine if 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: Determine the matrix F1, F2...F v If a non-empty matrix exists, it indicates that the q-th interlayer separator has an air channel, and the evaluation result of the q-th interlayer separator is "unqualified"; if no non-empty matrix exists, it indicates that the q-th interlayer separator has no air channel, and the evaluation result of the q-th interlayer separator is "qualified". Step 4.11: Determine if q equals e? If q = e, proceed to step 4.12; if q ≠ e, let q = q + 1, and repeat steps 4.3 to 4.

10. Step 4.12: Determine whether all inter-layer partition segment evaluation results are "qualified". If all are "qualified", output the overall evaluation result of the inter-layer partition segment as "qualified"; if there are any "unqualified" inter-layer partition segments, output the overall evaluation result of the inter-layer partition segment as "unqualified".

5. The method for evaluating the cementing quality of a gas storage well according to claim 1, characterized in that, Step 5 specifically includes: Step 5.1: Input the well depth range corresponding to the inner cover section of the well barrel, and store the position coordinates of the pixels within the well depth range into matrix C. The position coordinates stored in matrix C adopt a cylindrical coordinate system, and its z-direction component represents the well depth corresponding to the pixel. The larger the absolute value of the z-direction component, the farther the pixel is from the ground. Step 5.2: Find all pixels with the largest absolute value of the z-direction component in matrix C, mark them as reference points for the caprock segment, and store the position coordinates of the reference points in the cylindrical coordinate system into matrix groups R1, R2...R... w The first row contains matrix groups R1, R2...R w The third column of each matrix is ​​used to store the z-direction component of the spatial position coordinates, and the subscript w indicates the number of reference points of the cover segment; find all pixels with the smallest absolute value of the z-direction component in matrix C and mark them as the end point of the cover segment; mark the other pixels except the reference points and the end points of the cover segment as the intermediate points of the cover segment. Step 5.3: Initialize the baseline loop variable f to 1; Step 5.4: Set the loop variable c for the number of rows in the matrix group to 1; Step 5.5: Find the match between matrix C and matrix R. f The pixels in row c are adjacent, and the absolute value of the z-direction component is greater than that of matrix R. f Find the midpoint or end point of the cap layer segment with the smallest absolute value of the element in row c and column 3, and determine whether the bonding strength of the midpoint or end point of the cap layer segment is 0. Step 5.6: If there is a cap layer segment termination point with a bonding strength of 0, store the position coordinates of the cap layer segment termination point into matrix R. f In line c+1, proceed to step 5.7; if there is a midpoint of the cap layer segment with a bonding strength of 0, store the coordinates of the midpoint of the cap layer segment into matrix R. f For row c+1, let c = c+1, and repeat steps 5.5~5.6; if there is no end point or midpoint of the cap layer segment with a bonding strength of 0, let matrix R f An empty matrix; Step 5.7: Output matrix R f ; Step 5.8: Determine if 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: Determine the matrix R1, R2...R w If a non-empty matrix exists, it indicates that there is a gas channel in the cover layer, and the overall evaluation result of the cover layer is "unqualified". If no non-empty matrix exists, it indicates that there is no gas channel in the cover layer, and the overall evaluation result of the cover layer is "qualified".

6. The method for evaluating the cementing quality of a gas storage well according to claim 1, characterized in that, Step 6 specifically includes: Step 6.1: Determine whether the overall evaluation results of the interlayer separation 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: Initialize the loop variable i to 1, take the maximum bonding strength in matrix M, and use c f express; Step 6.3: Locate the easily transmissible channel d in matrix M. i The bonding strength corresponding to each pixel in (i=1……p) is represented as c1, c2……c u ; Step 6:4: For c1, c2...c u Summation, use W i express; Step 6.5: Determine if i is greater than p. If i > p, end the loop and output W. i Proceed to step 6.

6. If i ≤ p, let i = i + 1, and repeat steps 6.3 to 6:

4. Step 6.6: Take W1, W2...W p minimum value W f And determine the minimum value W. f The corresponding gas leakage channel d f ; Step 6.7: According to c f W f and d f Calculate the gas channeling resistance score A of the cement; Step 6.8: Output the anti-gas leakage performance score; Step 6.9: Determine the acceptable range for gas channeling prevention performance score according to the evaluation department's needs, and comprehensively evaluate the cementing quality.

7. The method for evaluating the cementing quality of a gas storage well according to claim 6, characterized in that, The formula for calculating the anti-gas channeling performance score A is: Where u is the gas channel d f The number of pixels in the middle.

8. A method for evaluating the cementing quality of a gas storage well according to any one of claims 1, 3, and 6, characterized in that, Matrix M is an n1-row, 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 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 type of the pixel, where 1 represents unbonded micro-cracks, 2 represents liquid, 3 represents gas or dry micro-pores, and 4 represents bonded. The fifth column represents the bonding strength of the pixel.

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