A method and system for microresistivity scan imaging borehole geometry correction

Abstract

The application discloses a kind of micro-resistivity scanning imaging wellbore geometry correction method and system, comprising: collecting the well diameter curve and azimuth of the test well scanned by electrical imaging instrument;The well diameter curve and azimuth are fitted, the parameter characteristics of wellbore fitting ellipse model are obtained, and the ellipse model is obtained;The intersection coordinates of elliptic equation and azimuth are calculated, the angle of intersection coordinates in elliptic coordinate system and the center of ellipse is obtained;Based on the rotation angle of elliptic coordinate system and the angle of intersection coordinates in elliptic coordinate system and the center of ellipse, the angle of each polar plate center is obtained;Based on the angle of each polar plate center, respectively in opposite direction, decrease and increase, judge whether the accumulated arc length is greater than threshold value, if yes, stop accumulation, obtain the position angle of the left and right boundary of polar plate;If not, continue to decrease and increase, until the condition is met.

Description

Technical Field

[0001] This invention belongs to the field of petroleum logging data processing and relates to a method and system for wellbore geometric correction using microresistivity scanning imaging. Background Technology

[0002] With the widespread application of imaging instruments, the role of fine evaluation technology in well logging data processing and interpretation is becoming increasingly important, and oilfields are demanding higher levels of fine evaluation of well logging data. In this context, the role of fine evaluation using electrical imaging is becoming increasingly crucial. Electrical imaging wellbore geometry correction technology can accurately reconstruct the precise location of the wellbore around the well, providing a foundation for subsequent evaluation. In irregular wellbore conditions, the diameter corresponding to the electrode plates reflects changes in the wellbore. Due to variations in the spacing between the electrodes, these changes need to be accurately reflected in the imaging image. Currently, the software used cannot adequately reflect these diameter changes on the imaging image. Summary of the Invention

[0003] The purpose of this invention is to solve the problems in the prior art and provide a method and system for geometric correction of micro-resistivity scanning imaging wellbore, which can correct the data of eccentric measurement of electrical imaging instruments, solve the problem that the eccentric measurement data of electrical imaging instruments cannot be corrected, and expand the application range of imaging instruments.

[0004] To achieve the above objectives, the present invention employs the following technical solution: A method for geometrological correction of a wellbore in microresistivity scanning imaging system includes: The wellbore diameter curve and azimuth angle of the test well were obtained by scanning with an electrical imaging instrument; Fit the wellbore curve and azimuth angle, and obtain the parameter characteristics of the wellbore fitting ellipse model based on the least squares method to obtain the ellipse model; Calculate the coordinates of the intersection point of the ellipse equation and the azimuth angle, and based on the intersection point coordinates, obtain the angle between the ellipse and the center of the ellipse in the elliptical coordinate system; The angle of each electrode center is obtained based on the rotation angle of the elliptical coordinate system and the angle between the intersection point and the center of the ellipse in the elliptical coordinate system. Based on the angle of the center of each electrode, the angle is decreased and increased sequentially in opposite directions. It is determined whether the accumulated arc length is greater than the set threshold. If so, the accumulation is stopped and the position angle of the left and right boundaries of the electrode is obtained. If not, the angle is decreased and increased again until the condition is met.

[0005] A further improvement of the present invention is that: The wellbore curve and azimuth angle are fitted, specifically as follows: Convert the wellbore curve and azimuth angle into coordinates

[0006]

[0007]

[0008] in, They are X and Y coordinates For azimuth curves, This is the wellbore curve.

[0009] Based on the least squares method, the parameter features of the wellbore fitting elliptical model are obtained, and the elliptical model is obtained; specifically: right The data is fitted, and the equation of the ellipse is given by...

[0010] Transform into

[0011] in, , , These are the x and y coordinates of the center of the ellipse, respectively. Given the ellipse parameters, the parameters of the wellbore fitting model are obtained by fitting using the least squares method.

[0012] Calculate the coordinates of the intersection point of the ellipse equation and the azimuth angle, specifically: Based on azimuth To obtain the current angle of the electrode plate, the current angle of the electrode plate is...

[0013]

[0014] in, Pi; ; When the azimuth angle is 0 degrees or 180 degrees, the equation of the straight line is:

[0015]

[0016]

[0017] ,

[0018] Solve the system of equations to obtain the coordinates of the intersection points. ; When the azimuth angle is not 0 degrees or 180 degrees, the equation of the line is: , , The slope;

[0019]

[0020] ,

[0021] Solve the system of equations to obtain the coordinates of the intersection points. .

[0022] Based on the intersection point coordinates, obtain the angle with the center of the ellipse in the elliptical coordinate system, specifically: Based on the coordinates of the intersection point Obtain the angle between the ellipse and the center of the ellipse in the elliptical coordinate system. Specifically:

[0023] in, It is a square root function. It is an inverse cosine function.

[0024] The rotation angle of the elliptical coordinate system is the angle between the line segment formed by the origin of the elliptical coordinate system and the origin of the instrument axis coordinate system, and the positive half-axis of the X-axis of the instrument axis coordinate system.

[0025] The instrument axis coordinate system is a coordinate system built into the imaging instrument, used to represent the position of the wellbore diameter curve and azimuth angle of the test well.

[0026] Based on the rotation angle in the elliptical coordinate system and the angle between the intersection point and the center of the ellipse in the elliptical coordinate system, the angle of the center of each electrode is obtained; specifically: The angle of the center of the electrode plate is ,but

[0027] in, The rotation angle of the fitted elliptical coordinate system. For the first The center angle position of each electrode plate.

[0028] Based on the angle at the center of each electrode, the angles are successively decreased and increased in opposite directions, specifically as follows: The angles at the center of each electrode plate are successively decreased and increased in opposite directions. The lengths of the two boundaries of each electrode plate are calculated by looking up a table and integrating.

[0029] A system for microresistivity scanning imaging wellbore geometry correction includes: The acquisition module is used to acquire the wellbore diameter curve and azimuth angle of the test well obtained by the electro-imaging instrument. The fitting module is used to fit the wellbore curve and azimuth angle, and obtain the parameter features of the wellbore fitting ellipse model based on the least squares method to obtain the ellipse model. The calculation module is used to calculate the coordinates of the intersection point of the ellipse equation and the azimuth angle, and based on the intersection point coordinates, obtain the angle with the center of the ellipse in the elliptical coordinate system. The acquisition module obtains the angle of the center of each electrode plate based on the rotation angle of the elliptical coordinate system and the angle between the intersection point coordinates and the center of the ellipse in the elliptical coordinate system. The judgment module is used to determine whether the accumulated arc length is greater than a set threshold by successively decreasing and increasing the angle of the center of each electrode in opposite directions until the condition is met.

[0030] Compared with the prior art, the present invention has the following beneficial effects: This invention fits an ellipse equation using the caliper curve and azimuth angle, and obtains the angle of each electrode center by rotating the elliptical coordinate system and using the angle between the intersection point and the ellipse center in the elliptical coordinate system. Based on the angle of each electrode center, the elliptical angle and arc length are calculated, and combined with the azimuth curve, the electrical imaging data is accurately calculated. This invention solves the problem of uncorrectable eccentric measurement data in electrical imaging instruments, expanding the application range of multi-arm caliper instruments. The correction process of this invention is innovative, easy to operate, and has good processing results. It has been applied to the data processing of multi-arm caliper instruments and has received high recognition. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a flowchart of the method for geometrological correction of a wellbore using microresistivity scanning imaging according to the present invention; Figure 2 This is a schematic diagram illustrating the principle of ellipse fitting. Figure 3 A schematic diagram of BHCD data; Figure 4 A schematic diagram showing the change in well diameter reflected by the blank width; Figure 5 The images show a comparison of the processing effects of the present invention and mainstream foreign software; (a) shows the processing effect of the present invention, and (b) shows the processing effect of mainstream foreign software. Figure 6This is a system structure diagram of the micro-resistivity scanning imaging wellbore geometry correction of the present invention.

[0033] Wherein, 1-origin of the instrument axis coordinate system, 2-origin of the elliptical coordinate system, 3-fitted ellipse, 4-accumulated arc length. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0036] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0037] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0038] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0039] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0040] The present invention will now be described in further detail with reference to the accompanying drawings: See Figure 1 and Figure 2 This invention discloses a method for geometric correction of wellbore in microresistivity scanning imaging, comprising: S101, the wellbore diameter curve and azimuth angle of the test well are obtained by scanning with an electrical imaging instrument; S102, Fit the wellbore curve and azimuth angle, and obtain the parameter characteristics of the wellbore fitting ellipse model based on the least squares method to obtain ellipse model 3; Convert the wellbore curve and azimuth angle into coordinates

[0041]

[0042]

[0043] in, They are X and Y coordinates For azimuth curves, This is the wellbore curve.

[0044] right The data is fitted, and the equation of the ellipse is given by...

[0045] Transform into

[0046] in, , , These are the x and y coordinates of the center of the ellipse, respectively. Given the ellipse parameters, the parameters of the wellbore fitting model are obtained by fitting using the least squares method.

[0047] S103, calculate the coordinates of the intersection point of the ellipse equation and the azimuth angle, and obtain the angle with the center of the ellipse in the elliptical coordinate system based on the intersection point coordinates. Calculate the coordinates of the intersection point of the ellipse equation and the azimuth angle, specifically: Based on azimuth To obtain the current angle of the electrode plate, the current angle of the electrode plate is...

[0048]

[0049] in, Pi; ; When the azimuth angle is 0 degrees or 180 degrees, the equation of the straight line is:

[0050]

[0051]

[0052] ,

[0053] Solve the system of equations to obtain the coordinates of the intersection points. ; When the azimuth angle is not 0 degrees or 180 degrees, the equation of the line is: , , The slope;

[0054]

[0055] ,

[0056] Solve the system of equations to obtain the coordinates of the intersection points. .

[0057] Based on the intersection point coordinates, obtain the angle with the center of the ellipse in the elliptical coordinate system, specifically: Based on the coordinates of the intersection point Obtain the angle between the ellipse and the center of the ellipse in the elliptical coordinate system. Specifically:

[0058] in, It is a square root function. It is an inverse cosine function.

[0059] S104: Based on the rotation angle of the elliptical coordinate system and the angle between the intersection point coordinates and the center of the ellipse in the elliptical coordinate system, obtain the angle of the center of each electrode plate.

[0060] The rotation angle of the elliptical coordinate system is the angle between the line segment formed by the origin 2 of the elliptical coordinate system and the origin 1 of the instrument axis coordinate system, and the positive half-axis of the X-axis of the instrument axis coordinate system.

[0061] The origin 2 of the elliptical coordinate system is the center of the ellipse.

[0062] The instrument axis coordinate system is a coordinate system built into the imaging instrument, used to represent the position of the wellbore diameter curve and azimuth angle of the test well.

[0063] The angle of the center of the electrode plate is ,but

[0064] in, The rotation angle of the fitted elliptical coordinate system. For the first The center angle position of each electrode plate.

[0065] Calculate eccentricity E Then, based on the eccentricity, the nearest integral table is found using a lookup table method.

[0066]

[0067] in, To fit the major axis of the ellipse, The minor axis is used to fit the ellipse.

[0068] S105, based on the angle of the center of each electrode plate, decrease and increase sequentially in opposite directions, determine if the accumulated arc length 4 is greater than the set threshold, if so, stop the accumulation and obtain the position angle of the left and right boundaries of the electrode plate; if not, continue to decrease and increase until the condition is met.

[0069] The angle at the center of each electrode is: The angles of the two boundaries of each electrode are calculated by looking up a table and integrating based on the angle of the center of the electrode. , .

[0070] The angles at the center of each electrode plate are successively decreased and increased in opposite directions. The lengths of the two boundaries of each electrode plate are calculated by looking up a table and integrating.

[0071] The angle at the center of each electrode is: Based on this angle, the angles of the two boundaries of each electrode are calculated using a lookup table and integration. , .

[0072] by Starting from the first angle, decrease the arc length by one angle at a time, and integrate the sum of the arc lengths. When the cumulative arc length is greater than the sum of the arc lengths, the result is obtained. Stop the calculation; the angle at this point is the left boundary angle of the plate. , This represents the width of a single electrode. Similarly, with... Starting from the first angle, increment by one angle in sequence, and integrate the arc lengths. When the accumulated arc length is greater than the sum of the previous angles, the result is obtained. Stop the calculation; the angle at this point is the right boundary angle of the plate. .

[0073] See Figure 3 , Figure 4 and Figure 5 This invention fits an ellipse and uses a lookup table method to calculate the ellipse angle and arc length. Combined with the azimuth curve, it accurately calculates the distribution of electrical imaging data around the well. The processing results are basically consistent with those of mainstream foreign software, and it has achieved good application results.

[0074] See Figure 6 This invention discloses a system for geometrological correction of wellbore in microresistivity scanning imaging, comprising: The acquisition module is used to acquire the wellbore diameter curve and azimuth angle of the test well obtained by the electro-imaging instrument. The fitting module is used to fit the wellbore curve and azimuth angle, and obtain the parameter features of the wellbore fitting ellipse model based on the least squares method to obtain the ellipse model. The calculation module is used to calculate the coordinates of the intersection point of the ellipse equation and the azimuth angle, and based on the intersection point coordinates, obtain the angle with the center of the ellipse in the elliptical coordinate system. The acquisition module obtains the angle of the center of each electrode plate based on the rotation angle of the elliptical coordinate system and the angle between the intersection point coordinates and the center of the ellipse in the elliptical coordinate system. The judgment module is used to determine whether the accumulated arc length is greater than a set threshold by successively decreasing and increasing the angle of the center of each electrode in opposite directions until the condition is met.

[0075] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for geometric correction of a wellbore in microresistivity scanning imaging, characterized in that, include: The wellbore diameter curve and azimuth angle of the test well were obtained by scanning with an electrical imaging instrument; Fit the wellbore curve and azimuth angle, and obtain the parameter characteristics of the wellbore fitting ellipse model based on the least squares method to obtain the ellipse model; Calculate the coordinates of the intersection point of the ellipse equation and the azimuth angle, and based on the intersection point coordinates, obtain the angle between the ellipse and the center of the ellipse in the elliptical coordinate system; The calculation of the coordinates of the intersection point of the ellipse equation and the azimuth angle is specifically as follows: Based on azimuth To obtain the current angle of the electrode plate, the current angle of the electrode plate is... in, Pi; ; When the azimuth angle is 0 degrees or 180 degrees, the equation of the straight line is: , Solve the system of equations to obtain the coordinates of the intersection points. ; When the azimuth angle is not 0 degrees or 180 degrees, the equation of the line is: , , The slope; , Solve the system of equations to obtain the coordinates of the intersection points. ; Based on the rotation angle of the elliptical coordinate system and the angle between the intersection point and the center of the ellipse in the elliptical coordinate system, the angle of the center of each electrode plate is obtained; the angle of the center of each electrode plate is... The angles of the two boundaries of each electrode are calculated by looking up a table and integrating based on the angle of the center of the electrode. , ; Based on the intersection point coordinates, obtain the angle with the center of the ellipse in the elliptical coordinate system, specifically: Based on the coordinates of the intersection point Obtain the angle between the ellipse and the center of the ellipse in the elliptical coordinate system. Specifically: in, It is a square root function. It is the inverse cosine function; The angle of each electrode center is obtained by using the rotation angle and the angle between the intersection point coordinates and the center of the ellipse in the elliptical coordinate system; specifically: The angle of the center of the electrode plate is ,but in, The rotation angle of the fitted elliptical coordinate system. For the first The center angle position of each electrode plate; Based on the angle of the center of each electrode, the process is to decrease and increase in opposite directions, and then determine whether the accumulated arc length is greater than the set threshold. If so, the accumulation is stopped and the position angles of the left and right boundaries of the electrode are obtained. If not, the process continues to decrease and increase until the condition is met. by Starting from the first angle, decrease the arc length by one angle at a time, and integrate the sum of the arc lengths. When the cumulative arc length is greater than the sum of the arc lengths, the result is obtained. Stop the calculation; the angle at this point is the left boundary angle of the plate. , For the width of a single electrode, similarly, with Starting from the first angle, increment by one angle in sequence, and integrate the arc lengths. When the accumulated arc length is greater than the sum of the previous angles, the result is obtained. Stop the calculation; the angle at this point is the right boundary angle of the plate. .

2. The method for geometric correction of a wellbore using microresistivity scanning imaging according to claim 1, characterized in that, The fitting of the wellbore diameter curve and azimuth angle is specifically as follows: Convert the wellbore curve and azimuth angle into coordinates in, They are X and Y coordinates For azimuth curves, This is the wellbore curve.

3. The method for geometric correction of a wellbore using microresistivity scanning imaging according to claim 2, characterized in that, The method based on least squares is used to obtain the parameter features of the wellbore fitting elliptical model, and then obtain the elliptical model; specifically: right The data is fitted, and the equation of the ellipse is given by... Transform into in, , , These are the x and y coordinates of the center of the ellipse, respectively. Given the ellipse parameters, the parameters of the wellbore fitting model are obtained by fitting using the least squares method.

4. The method for geometric correction of a wellbore in microresistivity scanning imaging according to claim 1, characterized in that, The rotation angle of the elliptical coordinate system is the angle between the line segment formed by the origin of the elliptical coordinate system and the origin of the instrument axis coordinate system, and the positive half-axis of the X-axis of the instrument axis coordinate system.

5. The method for geometric correction of a wellbore using microresistivity scanning imaging according to claim 4, characterized in that, The instrument's axisymmetric coordinate system is the built-in coordinate system of the imaging instrument, used to represent the position of the wellbore diameter curve and azimuth angle of the test well.

6. The method for geometric correction of a wellbore using microresistivity scanning imaging according to claim 1, characterized in that, The angles based on the center of each electrode plate are sequentially decreased and increased in opposite directions, specifically as follows: The angles at the center of each electrode plate are successively decreased and increased in opposite directions. The lengths of the two boundaries of each electrode plate are calculated by looking up a table and integrating.

7. A system for microresistivity scanning imaging wellbore geometry correction using the method of claim 1, characterized in that, include: The acquisition module is used to acquire the wellbore diameter curve and azimuth angle of the test well obtained by the electro-imaging instrument. The fitting module is used to fit the wellbore curve and azimuth angle, and obtain the parameter features of the wellbore fitting ellipse model based on the least squares method to obtain the ellipse model. The calculation module is used to calculate the coordinates of the intersection point of the ellipse equation and the azimuth angle, and based on the intersection point coordinates, obtain the angle with the center of the ellipse in the elliptical coordinate system. The acquisition module obtains the angle of the center of each electrode plate based on the rotation angle of the elliptical coordinate system and the angle between the intersection point coordinates and the center of the ellipse in the elliptical coordinate system. The judgment module is used to determine whether the accumulated arc length is greater than a set threshold by successively decreasing and increasing the angle of the center of each electrode in opposite directions until the condition is met.

Images