Pressure field distribution testing device and method under the action of a focused perforation

Abstract

The application discloses a kind of polyenergetic perforation under wellbore pressure field distribution testing device and method, testing device includes several support columns, several layers of annular parts connected on support column;At least one hollow support column;Annular part is from inner wall and is opened annular groove, and the annular groove of each layer of annular part is connected with the hollow support column;Test method includes obtaining the wellbore parameter to be tested and perforation scheme, obtains perforation section casing parameter, perforating gun parameter;Determine the geometric structure and size of testing device;Design pressure sensor layout scheme;Install test casing, pressure sensor;Perforating gun is installed in test casing;Explode perforating bomb in perforating gun, and each pressure sensor obtains pressure data;Establish wellbore pressure field.The application is used to solve the problem that it is difficult to accurately obtain perforation explosion pressure field in prior art in advance, to realize accurate test to perforation explosion pressure field, to provide technical support for the purpose of perforation parameter optimization design and operation safety evaluation.

Description

Technical Field

[0001] This invention relates to the field of oil and gas development, and specifically to a device and method for testing the pressure field distribution inside a wellbore under the action of shaped charge perforation. Background Technology

[0002] Perforation completion technology is a key technology for achieving large-scale and efficient development of oil and gas resources by using a perforating projectile to create a metal jet that forms a perforation channel between the wellbore and the reservoir. The perforation effect directly affects the productivity and economic benefits of oil and gas wells, and the pressure field distribution generated by the perforating projectile explosion is the core factor determining the perforation effect.

[0003] In shaped charge perforation operations, the annular explosion pressure in the wellbore is typically acquired using a PT (Pressure Test) instrument installed at a fixed location. However, due to the irregular shape of the perforating projectile charge and the helical distribution of multiple perforating projectiles, this testing method can only provide single-point pressure time history data, failing to reflect the spatial distribution characteristics and dynamic evolution of the pressure field within the wellbore. This results in inaccurate calibration of the wellbore pressure calculation model during perforation operations, leading to significant deviations in the prediction of the perforated string's safety performance and risk assessment in subsequent operations, thus affecting the safety and effectiveness of perforation operations. Therefore, it is urgently necessary to conduct pressure field testing in ground simulation experiments to obtain a complete pressure field distribution within the wellbore, providing a reliable theoretical basis and technical support for field operations.

[0004] The pressure field of a traditional perforation explosion is mainly measured synchronously during the perforation operation. The following technical solutions can be used to obtain it: (1) Using sensor array technology, multiple pressure sensors are arranged in a preset position to collect the pressure time history data at the moment of the explosion and reconstruct the pressure field distribution through spatial interpolation; (2) Using laser interferometry technology, the medium interface motion and shock wave front propagation caused by the explosion are captured by high-speed optical means to reconstruct the spatiotemporal evolution process of the pressure field; (3) Using distributed fiber optic sensing technology, the fiber optic strain distribution caused by pressure changes is sensed by laying a fiber optic sensor network to achieve large-scale continuous measurement.

[0005] However, due to the multiple detonation points, strong directionality, and complex coupling characteristics of shaped charge perforations, the existing technology has the following technical defects: (1) The collected information is incomplete, and the existing testing methods cannot achieve full coverage and accurate testing of the three-dimensional pressure field inside the wellbore; (2) The sensor layout scheme lacks theoretical guidance, and the selection of measurement points is often based on experience judgment or uniform array, which has a large degree of arbitrariness and subjectivity, resulting in insufficient measurement accuracy in key areas or redundant measurement causing waste of resources; (3) The spatiotemporal resolution of the test data is insufficient, making it difficult to capture the fine characteristics of pressure wave propagation; (4) The pressure field coupling effect when multiple perforation projectiles detonate simultaneously is difficult to measure and analyze accurately; (5) It is difficult to balance the impact resistance and measurement accuracy of the testing device, affecting the reliability of the test results.

[0006] In summary, most existing technologies measure the explosion pressure field during perforation operations, but the measurement accuracy is limited, making it difficult to accurately obtain the pressure field of the perforation explosion in advance. It is necessary to design a testing device and its testing method to test the pressure field inside the wellbore under the action of shaped charge perforation. Summary of the Invention

[0007] This invention provides a device and method for testing the pressure field distribution inside a wellbore under shaped charge perforation, in order to solve the problem in the prior art that it is difficult to accurately obtain the pressure field of the perforation explosion in advance, and to achieve the purpose of accurately testing the pressure field of the perforation explosion and providing technical support for the optimization design of perforation parameters and the assessment of operational safety.

[0008] This invention is achieved through the following technical solution:

[0009] A device for testing the pressure field distribution inside a wellbore under shaped charge perforation includes several support columns and several layers of annular components distributed vertically on the support columns; at least one support column is hollow inside; the annular components have grooves formed on their inner walls, and the grooves of each layer of annular components are connected to the hollow support columns; the grooves are used to install several pressure sensors.

[0010] To address the problem of accurately obtaining the pressure field of a perforation explosion in advance in existing technologies, this application first proposes a device for testing the pressure field distribution inside a wellbore under shaped charge perforation. This device uses several support columns to support several vertically distributed annular components, which clamp and stabilize the test casing. Simultaneously, annular grooves are formed on the inner wall of each annular component, and each groove connects to the hollow area inside at least one support column, facilitating cable routing. In this application, annular components of different heights correspond to pressure monitoring planes at different heights. Therefore, this application allows for flexible configuration of different heights and numbers of annular components to obtain pressure monitoring planes at different heights. Furthermore, the presence of annular grooves allows for the installation of pressure sensors on each annular component at 360°. The number and orientation of pressure sensors on each monitoring plane can be flexibly installed according to specific needs, providing greater autonomy and operability in sensor placement. This facilitates accurate measurement of critical areas while avoiding measurement redundancy and reducing resource waste.

[0011] It can be seen that this application can accurately obtain the complete pressure field of downhole perforation explosion through testing, thereby providing technical support for perforation parameter optimization design and operation safety assessment. At the same time, compared with existing simulation and other technologies, the accuracy and reliability of the pressure field obtained by this application can be significantly improved because it is based on physical testing.

[0012] Furthermore, a cable groove is formed on the surface of the hollow support column, which is connected to the annular groove; it also includes a cable outlet installed on the uppermost annular component, which is connected to the annular groove of the uppermost annular component.

[0013] The cable trays and cable outlets facilitate the routing of the pressure sensors, ensuring that regardless of how the pressure sensors are arranged, their cables can be stably and easily connected to the external receiving equipment of the testing device.

[0014] A method for testing the pressure field distribution inside a wellbore under shaped charge perforation, implemented based on the testing device of this application, includes the following steps:

[0015] S1. Obtain the wellbore parameters and perforation scheme to be tested, and obtain the casing parameters and perforation gun parameters of the perforated section.

[0016] S2. Based on the perforation section casing parameters and perforation gun parameters, determine the geometry and dimensions of the testing device;

[0017] S3. Design a pressure sensor layout scheme; the pressure sensor layout scheme includes an axial layout scheme and a circumferential layout scheme;

[0018] S4. Prepare a test sleeve of the same material and size as the perforation section sleeve, install the test sleeve and pressure sensor; install the perforation gun inside the test sleeve;

[0019] S5. Detonate the perforating bullet inside the perforating gun, and each pressure sensor acquires pressure data;

[0020] S6. Based on the pressure data obtained from each pressure sensor, establish the pressure field inside the wellbore.

[0021] This method first obtains the wellbore parameters and perforation scheme under actual well conditions, and extracts the perforated section casing parameters and perforating gun parameters from them. Based on the extracted perforated section casing parameters and perforating gun parameters, the parameters of the test casing and the corresponding test perforating gun can be obtained, thereby determining the geometry and dimensions of the test device. Then, the layout scheme of the pressure sensors in the test device is designed in both the axial and circumferential directions. After that, the test can be carried out by detonating the perforating projectile in the perforating gun, and the pressure sensors acquire pressure data to establish the pressure field inside the wellbore.

[0022] The pressure field inside the wellbore obtained by this method can be equivalent to the actual pressure field of the section to be perforated when perforating according to the current perforation scheme. Through this pressure field, key characteristic parameters such as the pressure distribution in the wellbore, the peak values ​​of positive and negative pressure, and the duration of positive and negative pressure can be extracted. This allows for comprehensive and accurate measurement and dynamic evolution analysis of the pressure field inside the wellbore during the shaped charge perforation explosion before the actual perforation operation, providing technical support for the optimization design of perforation parameters and the assessment of operational safety.

[0023] Furthermore, in step S1:

[0024] The parameters of the perforated section casing include: casing material, casing inner diameter, and casing outer diameter;

[0025] The parameters of the perforating gun include: the outer diameter of the perforating gun, the length of the perforating gun, the perforation density of the perforating projectile, the helical phase angle of the perforating projectile, the type of perforating projectile, and the location of the detonation point.

[0026] Accurately obtaining the casing parameters and perforating gun parameters of the perforated section is beneficial to ensuring that the test conditions are consistent with the actual downhole conditions, thereby improving the accuracy of the obtained pressure field distribution.

[0027] Furthermore, in step S2, determining the geometry and dimensions of the testing device includes:

[0028] Make the inner diameter of the annular component in the test device equal to the outer diameter of the perforated section sleeve;

[0029] The total axial length L of the test device shall satisfy: In the formula, L0 is the length of the perforating gun; L t To reserve the length, the following conditions must be met:

[0030] ;

[0031] In the formula: l f denoted as denoted as the far-field reduced distance of the explosive charge at the top perforation point; W is the explosive equivalent of the perforation charge; and n is the geometric dimension of the explosive.

[0032] In this scheme, the reserved length refers to the length of the testing device located above the perforating gun. This scheme clearly defines the specific calculation formula for the reserved length to avoid situations where the reserved length is too small, leading to compromised safety and integrity of the pressure field during the testing process, while also preventing resource waste due to an excessively large reserved length.

[0033] Furthermore, the axial layout scheme is designed using the following method:

[0034] The test device is divided axially into a perforated section facing the perforating gun and a reserved section above the perforating gun.

[0035] For the section where the projectiles are to be pierced: a plane is made at the axial center position of two adjacent projectiles, and the resulting plane is used as the sensor mounting surface for the section where the projectiles are to be pierced.

[0036] For the reserved section: taking the uppermost perforated projectile as the starting point, it is divided into a near-field section, a mid-field section, and a far-field section from bottom to top; in the near-field section, the mid-field section, and the far-field section, respectively, with density ρ c ρ m ρ f Divide the plane to obtain the sensor mounting surface of the reserved section; where ρ c >ρ m >ρ f .

[0037] This scheme divides the testing device into two different sections along the axial direction: the perforated section and the reserved section. The axial layout scheme of each section is designed, that is, the pressure sensor mounting plane of each section is designed, so as to provide a scientific basis for the arrangement of the annular component.

[0038] For the perforated section, a sensor mounting surface is set at the center of any two adjacent perforated projectiles at different heights in the longitudinal direction. For the reserved section, starting from the uppermost perforated projectile, it is divided into a near-field section, a mid-field section, and a far-field section, with sensor mounting surfaces set at different densities; among them, the sensor mounting surface density is maximized in the near-field section, followed by the mid-field section, and minimized in the far-field section.

[0039] This scheme can be used to measure and analyze the non-uniform distribution of the pressure field of perforating projectile explosions and the superimposed interference between perforating projectiles; it can also be used to accurately measure and analyze the propagation and evolution of the explosion pressure of perforating projectiles, and to rationally design the axial layout of sensors to reduce sensor redundancy and test costs. In the perforation section, the sensors are installed at the axial center plane of every two perforating projectiles.

[0040] Furthermore, the circumferential layout scheme is designed using the following method:

[0041] S301. Divide the sensor mounting surface into several calculation nodes evenly along the inner diameter of the casing, simulate the perforation explosion process, and extract the peak overpressure value of each calculation node; based on the pressure change of the peak overpressure value at each calculation node, and taking the calculation node with pressure change as the boundary, divide each sensor mounting surface into several circumferential regions.

[0042] S302. Calculate the lower limit and upper limit of the number of sensors in each circumferential region;

[0043] S303. Round the number of sensors to the nearest integer between the lower limit and the upper limit to obtain the number of sensors n in each circumferential region. tj;n tj This represents the number of sensors deployed within the j-th circumferential region;

[0044] S304. For each circumferential region, set (n tj -1) Pressure sensors are evenly distributed along the circumference to obtain the layout scheme of the j-th circumferential region;

[0045] S305. Combine the layout schemes of each circumferential region to obtain the circumferential layout scheme of the current sensor mounting surface.

[0046] The computing nodes can be adaptively divided according to specific working conditions, with uniform division as the premise.

[0047] In this scheme, the sensor mounting surface is divided into several circumferential regions based on the calculation nodes where pressure changes occur. This means that the area between two adjacent calculation nodes with pressure changes (including themselves) is considered a circumferential region. For example, if a sensor mounting surface is divided into 6 calculation nodes, defined as nodes 1-6; and the calculated peak overpressure values ​​at nodes 2 and 4 change abruptly, defined as a change-of-pressure node; then the sensor mounting surface can be divided into two circumferential regions: one consisting of nodes 2-3-4, and the other consisting of nodes 4-5-6-1-2.

[0048] In this scheme, a circumferential layout scheme for the pressure sensors is designed for each sensor mounting surface. The shape of the perforated projectile charge is considered using simulation technology. Furthermore, based on the circumferential non-uniformity of the initial explosion pressure distribution on the plane, the area is divided into several circumferential regions, and a sensor arrangement scheme is set for each circumferential region.

[0049] In this scheme, circumferential non-uniformity is characterized by judging the abrupt changes in peak overpressure values. The sensor mounting surface is divided into several circumferential regions, with the calculation nodes of peak overpressure value abrupt changes serving as boundaries. Then, a lower limit and an upper limit for the number of sensors within each circumferential region are determined. By selecting a reasonable value between the lower and upper limits, the number of sensors, n, can be obtained. tj To ensure that each measuring point has good representativeness within the circumferential region and can comprehensively reflect the load distribution characteristics within the region, thereby improving the accuracy and reliability of interpolation results in the subsequent pressure field reconstruction process, this scheme adopts (n) in the actual layout. tj -1) Pressure sensors are evenly distributed in the corresponding circumferential area.

[0050] This solution significantly improves the accuracy of pressure field testing and data acquisition in key areas, while avoiding performance redundancy and waste of testing resources, thereby enhancing the accuracy and reliability of perforation pressure field acquisition.

[0051] Furthermore, in step S302:

[0052] ;

[0053] ;

[0054] Where: n sj P represents the number of computation nodes in the j-th circumferential region; i Represents the peak overpressure value of the i-th computing node; This is the average of the peak overpressure values ​​of all computing nodes within the sensor mounting surface; The non-uniformity coefficient threshold is denoted by ceil, which represents the rounding function; n is the total number of computing nodes within the sensor mounting surface. Minimum angular spacing for installing pressure sensors.

[0055] This scheme clearly defines the methods for obtaining the lower and upper limits of the number of sensors, facilitating the determination of the number of sensors n to be deployed within the circumferential area. tj For example, if the lower limit is 2.6 and the upper limit is 5, then n tj The value can be taken from 3, 4, or 5.

[0056] Furthermore, in step S4, the method for installing the test sleeve and pressure sensor includes:

[0057] Based on the pressure sensor layout scheme, mounting holes are opened on the surface of the test sleeve so that the mounting holes correspond one-to-one with the pressure sensors.

[0058] Install the test sleeve inside the test device, so that each annular component is fitted outside the test sleeve; install pressure sensors in each mounting hole, so that the detection end of the pressure sensor faces radially inward;

[0059] Adjust each pressure sensor so that the sensing end of the pressure sensor is located on the inner wall of the test sleeve.

[0060] In this solution, a pressure sensor layout scheme is used to set up the test sleeve and install the corresponding pressure sensors to ensure that the installed pressure sensors meet the design requirements, thereby ensuring the accuracy of data acquisition in key areas.

[0061] Furthermore, step S6 specifically includes:

[0062] S601. Filter and denoise the pressure data acquired by each pressure sensor;

[0063] S602. Based on the radial basis function interpolation method, the following interpolation function is used to reconstruct the three-dimensional pressure field:

[0064] ;

[0065] In the formula: P(r) is the pressure value at any point r in space; Represents the q-th measuring point; p is the total number of measuring points; The radial basis function weights are for the q-th measurement point; Represents radial basis functions; From point r to point The Euclidean distance; represents the k-th polynomial basis function; m is the total number of polynomial basis functions; These are the polynomial coefficients;

[0066] S603. Optimize the reconstruction results of the three-dimensional pressure field reconstruction using the following objective function:

[0067]

[0068] In the formula: For the observation operator, For observation data, As background scene, and These are the covariance matrices of observation error and background error, respectively. For regularization operators, Let x be the regularization parameter; x be the state vector; and satisfy:

[0069] ; where T is the transpose operator.

[0070] This scheme reconstructs the three-dimensional pressure field distribution within the wellbore using radial basis function interpolation combined with physical constraints. To ensure physical plausibility, mass and momentum conservation constraints are introduced. Furthermore, variational data assimilation methods are employed to optimize the reconstruction results, and a specific objective function is defined. This scheme fully realizes comprehensive and accurate measurement and dynamic evolution analysis of the pressure field within the wellbore during shaped charge perforation explosions.

[0071] Compared with the prior art, the present invention has at least the following advantages and beneficial effects:

[0072] 1. The present invention provides a device and method for testing the pressure field distribution inside a wellbore under the action of shaped charge perforation. It can accurately obtain the complete pressure field of a downhole perforation explosion through testing, thereby providing technical support for the optimization design of perforation parameters and the assessment of operational safety. At the same time, compared with existing simulation and other technologies, the accuracy and reliability of the pressure field obtained by this application can be significantly improved because it is based on physical testing.

[0073] 2. The present invention provides a device and method for testing the pressure field distribution inside a wellbore under shaped charge perforation. By obtaining the pressure field, key characteristic parameters such as the pressure distribution inside the wellbore, the peak values ​​of positive and negative pressure, and the duration of positive and negative pressure can be extracted. This allows for comprehensive and accurate measurement and dynamic evolution analysis of the pressure field inside the wellbore during the shaped charge perforation explosion before actual perforation operations, providing technical support for the optimized design of perforation parameters and the assessment of operational safety.

[0074] 3. The present invention provides a device and method for testing the pressure field distribution inside a wellbore under the action of shaped charge perforation. It clearly defines the specific calculation method for the reserved length of the testing device, so as to avoid the safety of the testing process and the integrity of the pressure field being compromised due to the reserved length being too small, and also to avoid the waste of resources caused by the reserved length being too large.

[0075] 4. This invention provides a device and method for testing the pressure field distribution inside a wellbore under shaped charge perforation. The testing device is divided axially into a perforated section and a reserved section. A separate axial layout scheme is designed for each section, including a separate pressure sensor mounting plane, providing a scientific basis for the arrangement of the annular components. This device can be used to measure and analyze the non-uniform distribution of the pressure field from the perforation projectile explosion and the superposition interference between perforation projectiles. It is also used to accurately measure and analyze the propagation and evolution of the perforation projectile explosion pressure, and to rationally design the axial layout of the sensors to reduce sensor redundancy and testing costs.

[0076] 5. This invention discloses a device and method for testing the pressure field distribution inside a wellbore under shaped charge perforation. It characterizes circumferential non-uniformity by judging abrupt changes in peak overpressure values. Using the calculation node of the peak overpressure value abrupt change as the boundary, the sensor mounting surface is divided into several circumferential regions. Then, a lower limit and an upper limit for the number of sensors in each circumferential region are determined. By reasonably selecting values ​​between the lower and upper limits, the number of sensors can be obtained. This application significantly improves the accuracy of pressure field testing and data acquisition in key areas, while avoiding performance redundancy and waste of testing resources, thereby improving the accuracy and reliability of perforation pressure field acquisition.

[0077] 6. The present invention provides a device and method for testing the pressure field distribution inside a wellbore under shaped charge perforation. The test casing is set up by a pressure sensor layout scheme, and pressure sensors are installed accordingly to ensure that the installed pressure sensors meet the design requirements, thereby ensuring the accuracy of data acquisition in key areas. Attached Figure Description

[0078] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0079] Figure 1This is an elevation view of the testing device according to a specific embodiment of the present invention;

[0080] Figure 2 This is a partial structural diagram of the testing device in a specific embodiment of the present invention;

[0081] Figure 3 This is a schematic diagram of the pressure sensor installation density in the near-field section of a specific embodiment of the present invention;

[0082] Figure 4 This is a schematic diagram of the pressure sensor installation density in the far-field and mid-field sections of a specific embodiment of the present invention;

[0083] Figure 5 This is a schematic diagram of the method flow in a specific embodiment of the present invention;

[0084] Figure 6 This is a schematic diagram of the arrangement of some perforating projectiles and measuring points in a specific embodiment of the present invention;

[0085] Figure 7 This is a test diagram of the circumferential peak pressure distribution at layer 4 in a specific embodiment of the present invention;

[0086] Figure 8 This is a test diagram of the circumferential peak pressure distribution at layer 5 in a specific embodiment of the present invention;

[0087] Figure 9 This is a time-pressure curve test diagram of measuring point 1 in a specific embodiment of the present invention;

[0088] Figure 10 This is a time-pressure curve test diagram of measuring point 2 in a specific embodiment of the present invention;

[0089] Figure 11 This is a time-pressure curve test diagram of measuring point 3 in a specific embodiment of the present invention.

[0090] The attached diagram shows the markings and corresponding component names:

[0091] 1-Support column, 2-Ring component, 3-Ring groove, 4-Pressure sensor, 5-Cable groove, 6-Cable outlet, 7-Protective device, 8-Data acquisition and processing system, 9-Test sleeve, 10-Perforation gun. Detailed Implementation

[0092] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are for explaining the invention only and are not intended to limit the invention. In the description of this application, it should be understood that terms such as "front," "rear," "left," "right," "upper," "lower," "vertical," "horizontal," "high," "low," "inner," and "outer," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description. They 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 limiting the scope of protection of this application.

[0093] Example 1:

[0094] like Figure 1 and Figure 2 The device shown is a pressure field distribution test device in a wellbore under the action of shaped charge perforation. It includes several support columns 1 and several layers of annular components 2 connected to the support columns 1 and distributed vertically. At least one support column 1 is hollow inside. The annular components 2 have annular grooves 3 on their inner walls. The annular grooves 3 of each layer of annular components 2 are connected to the hollow support columns 1. The annular grooves 3 are used to install several pressure sensors 4.

[0095] In this embodiment, a cable groove 5 is formed on the surface of the hollow support column 1, which is connected to the annular groove 3; it also includes a cable outlet 6 installed on the uppermost annular component 2, which is connected to the annular groove 3 of the uppermost annular component 2.

[0096] In this embodiment, the entire testing device is located inside the protective device 7, which has sealed and explosion-proof performance, such as by using an explosion-proof box.

[0097] In this embodiment, the signal output terminals of each pressure sensor 4 are led out from the cable outlet 6 via cables and connected to the data acquisition and processing system 8; the data acquisition and processing system 8 can be implemented using processing equipment such as computers.

[0098] In this embodiment, during actual operation, the test sleeve 9 is placed inside each annular component 2, and the perforating gun 10 is installed inside the test sleeve 9. The annular area formed by the inside of the test sleeve 9 and the outside of the perforating gun 10 is filled with perforating fluid.

[0099] Example 2:

[0100] A method for testing the pressure field distribution inside a wellbore under shaped charge perforation is implemented based on the testing device described in Example 1. The testing method is as follows: Figure 5 As shown, it includes the following steps:

[0101] Step S1: Obtain the wellbore parameters and perforation scheme to be tested, and obtain the perforated section casing parameters and perforation gun parameters.

[0102] In this embodiment, the parameters of the perforated section casing include: casing material, casing inner diameter, and casing outer diameter;

[0103] The parameters of the perforating gun include: the outer diameter of the perforating gun, the length of the perforating gun, the perforation density of the perforating projectile, the helical phase angle of the perforating projectile, the type of perforating projectile, and the location of the detonation point.

[0104] Step S2: Based on the parameters of the perforating section casing and the perforating gun, determine the geometry and dimensions of the testing device.

[0105] In this embodiment, the inner diameter of the annular component in the testing device is equal to the outer diameter of the perforation section sleeve;

[0106] In this embodiment, as Figure 3 and Figure 4 As shown, the total axial length L of the testing device satisfies: In the formula, L0 is the length of the perforating gun; L t To reserve the length, the following conditions must be met:

[0107] ;

[0108] In the formula: l f denoted as denoted as the far-field reduced distance of the explosive charge at the top perforation point; W is the explosive equivalent of the perforation charge; and n is the geometric dimension of the explosive.

[0109] Preferably, the length of the test sleeve is equal to the total axial length of the test device, which is equal to the length of the support column.

[0110] Step S3: Design a pressure sensor layout scheme; the pressure sensor layout scheme includes an axial layout scheme and a circumferential layout scheme.

[0111] Design an axial layout scheme:

[0112] The test device is divided axially into a perforated section facing the perforating gun and a reserved section above the perforating gun.

[0113] For the section where the projectiles are to be pierced: a plane is made at the axial center position of two adjacent projectiles, and the resulting plane is used as the sensor mounting surface for the section where the projectiles are to be pierced.

[0114] For the reserved section: taking the uppermost perforated projectile as the starting point, it is divided into a near-field section, a mid-field section, and a far-field section from bottom to top; in the near-field section, the mid-field section, and the far-field section, respectively, with density ρ c ρ m ρ fDivide the plane to obtain the sensor mounting surface of the reserved section; where ρ c >ρ m >ρ f For specific density distribution details, please refer to [reference needed]. Figure 3 and Figure 4 The illustration.

[0115] Where, ρ c ρ m ρ f The values ​​for each can be set according to the different propellant loading conditions of the perforation projectiles. In this embodiment, it is preferred that ρ... c :ρ m :ρ f =5:2.5:1.

[0116] The preferred method for dividing the near-field segment, mid-field segment, and far-field segment is as follows:

[0117] Using the uppermost perforated projectile as the detonation point, calculate the equivalent radius R (dimensionless) from each point within the reserved section to that detonation point:

[0118] If R≤25, then the point belongs to the near-field region;

[0119] If 25 < R < 100, then the point belongs to the midfield area;

[0120] If 100 ≤ R, then the point belongs to the far field region.

[0121] The equivalent radius R is calculated using the following formula: R0 is the equivalent radius of the propellant charge of the projectile at the uppermost firing port, l z This is to reserve the distance from the point within the section to the bullet's detonation point at the uppermost firing port.

[0122] Design a circumferential layout scheme:

[0123] S301. Divide the sensor mounting surface into several computational nodes circumferentially along the inner diameter of the casing, simulate the perforation explosion process, and extract the peak overpressure value of each computational node. Based on the pressure abrupt changes of the peak overpressure value at each computing node, and taking the computing node with the pressure abrupt change as the boundary, the mounting surface of each sensor is divided into several circumferential regions.

[0124] S302. Calculate the lower limit and upper limit of the number of sensors in each circumferential region;

[0125] ;

[0126] ;

[0127] Where: n sjP represents the number of computation nodes in the j-th circumferential region; i Represents the peak overpressure value of the i-th computing node; This is the average of the peak overpressure values ​​of all computing nodes within the sensor mounting surface; The non-uniformity coefficient threshold is denoted by ceil, which represents the rounding function; n is the total number of computing nodes within the sensor mounting surface. Minimum angular spacing for installing pressure sensors.

[0128] S303. Round the number of sensors to the nearest integer between the lower limit and the upper limit to obtain the number of sensors n in each circumferential region. tj ;n tj This represents the number of sensors deployed within the j-th circumferential region.

[0129] S304. For each circumferential region, set (n tj -1) Pressure sensors are evenly distributed along the circumference to obtain the layout scheme of the j-th circumferential region.

[0130] S305. Combine the layout schemes of each circumferential region to obtain the circumferential layout scheme of the current sensor mounting surface.

[0131] Preferably, the method based on the pressure abrupt changes of the peak overpressure value at each calculation node is as follows:

[0132] ;

[0133] in, δ is the average of the peak overpressure values ​​of each computing node on the sensor mounting surface; δ is the abrupt change threshold, which is dimensionless and can be set adaptively according to specific working conditions.

[0134] Step S4: Prepare a test sleeve of the same material and size as the perforation section sleeve, install the test sleeve and pressure sensor; install the perforation gun inside the test sleeve.

[0135] The methods for installing the test sleeve and pressure sensor include:

[0136] Based on the pressure sensor layout scheme, mounting holes are opened on the surface of the test sleeve so that the mounting holes correspond one-to-one with the pressure sensors.

[0137] Install the test sleeve inside the test device, so that each annular component is fitted outside the test sleeve; install pressure sensors in each mounting hole, so that the detection end of the pressure sensor faces radially inward;

[0138] Adjust each pressure sensor so that the sensing end of the pressure sensor is located on the inner wall of the test sleeve.

[0139] Step S5: Detonate the perforating bullet inside the perforating gun, and each pressure sensor acquires pressure data.

[0140] Step S6: Based on the pressure data acquired by each pressure sensor, establish the pressure field inside the wellbore. Specifically, this includes:

[0141] S601, Filter and denoise the pressure data acquired by each pressure sensor.

[0142] Preferably, the filtering and noise reduction can employ digital filtering technology, and a piecewise linear fitting method can be used for baseline drift correction.

[0143] Preferably, the impact tube calibration method can also be used to dynamically calibrate the pressure sensor's data acquisition; the specific calibration formula is as follows:

[0144] ;

[0145] in: Output pressure at time t after calibration; Sensor sensitivity (mV / MPa); This is the original voltage signal, i.e., the pressure signal before calibration; This is the zero-point offset voltage; Gain of the signal conditioning circuit; This is a nonlinear correction term.

[0146] S602. Based on the radial basis function interpolation method, the following interpolation function is used to reconstruct the three-dimensional pressure field:

[0147] ;

[0148] In the formula: P(r) is the pressure value at any point r in space; Represents the q-th measuring point; p is the total number of measuring points; The radial basis function weights are for the q-th measurement point; Represents radial basis functions; From point r to point The Euclidean distance; represents the k-th polynomial basis function; m is the total number of polynomial basis functions; These are the polynomial coefficients;

[0149] S603. Optimize the reconstruction results of the three-dimensional pressure field reconstruction using the following objective function:

[0150]

[0151] In the formula: For the observation operator, For observation data, As background scene, and These are the covariance matrices of observation error and background error, respectively. For regularization operators, Let x be the regularization parameter; x be the state vector; and satisfy:

[0152] ; where T is the transpose operator.

[0153] Thus, the pressure field inside the wellbore during the perforation explosion process is obtained. Based on engineering application requirements, key engineering parameters such as pressure distribution in the wellbore, peak positive pressure, peak negative pressure, duration of positive pressure, and duration of negative pressure can be extracted. These parameters provide quantitative basis for perforation effect evaluation and parameter optimization.

[0154] Example 3:

[0155] This embodiment uses the testing device described in Embodiment 1 and the testing method described in Embodiment 2 to conduct a test on an oil well.

[0156] This oil well uses DPxxRDX25 perforating projectiles, with a single charge of 25g, a perforation spacing of 0.23m, a 120° phase angle, and a casing specification of 5. 1 / 2 "The number of perforating guns was 89, and the perforation medium was water. The arrangement of some of the perforating projectiles and sensor mounting surfaces during the test is as follows..." Figure 6 As shown:

[0157] Figure 6 Five sensor mounting surfaces are divided from top to bottom, defined as layers 1 to 5. Layer 1 is located in the far-field section, layer 2 in the mid-field section, and layer 3 in the near-field section, with layers 1-3 all within the reserved section defined in this application. Layers 4 and 5 are both within the perforated section defined in this application. The phase angle of perforating projectile 1 is 240°, the phase angle of perforating projectile 2 is 120°, and the phase angle of perforating projectile 3 is 0°.

[0158] Please refer to the test results. Figures 7 to 11 , Figure 7 The peak pressures monitored by five measuring points (i.e., five pressure sensors) in layer 4 are shown. Figure 7 The peak pressures monitored by five measuring points (i.e., five pressure sensors) in layer 5 are shown. Figures 9-11 The time-pressure curves measured at measuring points 1 through 3 are shown respectively.

[0159] Based on the above experimental results, it can be seen that the peak circumferential pressure in the wellbore annulus exhibits a significant non-uniform distribution, indicating that the circumferential zonal sensor arrangement strategy based on the peak overpressure abrupt change characteristics is reasonable. The peak axial near-field, mid-field, and far-field test pressures decrease significantly with increasing detonation center distance, consistent with the theoretical law of shock wave attenuation. Furthermore, each measuring point successfully captured the complete pressure-time history. The near-field measuring points clearly exhibit typical characteristics of underwater explosion shock waves, such as microsecond-level steep rise edges and negative pressure pulsations, demonstrating that this method possesses sufficient spatiotemporal resolution. In addition, the differences in the circumferential distribution morphology of the perforation section effectively reflect the pressure coupling effect of simultaneous detonation of multiple perforation projectiles. All sensors functioned normally and provided complete and reliable data under strong impact conditions at peak pressure. These results fully demonstrate the engineering feasibility and testing accuracy of the perforation explosion pressure field distribution testing device and method proposed in this application. It can achieve comprehensive coverage and accurate measurement of the three-dimensional pressure field within the wellbore with a reasonable number of measuring points, effectively solving technical problems in existing technologies such as incomplete data acquisition, lack of theoretical guidance for the layout scheme, insufficient spatiotemporal resolution, and difficulty in accurately measuring the multi-projectile coupling effect.

[0160] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. 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.

[0161] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Furthermore, the term “connection” as used herein, unless otherwise specified, can mean a direct connection or an indirect connection via other components.

Claims

1. A method for testing the pressure field distribution inside a wellbore under shaped charge perforation, characterized in that, The test device includes several support columns (1) and several layers of annular components (2) connected to the support columns (1) and distributed vertically. At least one support column (1) is hollow inside. The annular component (2) has an annular groove (3) on its inner wall. The annular groove (3) of each layer of annular component (2) is connected to the hollow support column (1). The annular groove (3) is used to install several pressure sensors (4). The testing method includes the following steps: S1. Obtain the wellbore parameters and perforation scheme to be tested, and obtain the casing parameters and perforation gun parameters of the perforated section. S2. Based on the perforation section casing parameters and perforation gun parameters, determine the geometry and dimensions of the testing device; S3. Design a pressure sensor layout scheme; the pressure sensor layout scheme includes an axial layout scheme and a circumferential layout scheme; The axial layout scheme is designed using the following method: The test device is divided axially into a perforated section facing the perforating gun and a reserved section above the perforating gun. For the section where the projectiles are to be pierced: a plane is made at the axial center position of two adjacent projectiles, and the resulting plane is used as the sensor mounting surface for the section where the projectiles are to be pierced. For the reserved section: taking the uppermost perforated projectile as the starting point, it is divided into a near-field section, a mid-field section, and a far-field section from bottom to top; in the near-field section, mid-field section, and far-field section, respectively, density ρ is used as the starting point. c ρ m ρ f Divide the plane to obtain the sensor mounting surface of the reserved section; where ρ c >ρ m >ρ f ; The circumferential layout scheme is designed using the following method: S301. Divide the sensor mounting surface into several calculation nodes evenly along the inner diameter of the casing, simulate the perforation explosion process, and extract the peak overpressure value of each calculation node; based on the pressure change of the peak overpressure value at each calculation node, and taking the calculation node with pressure change as the boundary, divide each sensor mounting surface into several circumferential regions. S302. Calculate the lower limit and upper limit of the number of sensors in each circumferential region; ； ； Where: n sj P represents the number of computation nodes in the j-th circumferential region; i This represents the peak overpressure value of the i-th computing node; This is the average of the peak overpressure values ​​of all computing nodes within the sensor mounting surface; The non-uniformity coefficient threshold is denoted by ceil, which represents the rounding function; n is the total number of computing nodes within the sensor mounting surface. Minimum angular spacing for installing pressure sensors; S303. Round the number of sensors to the nearest integer between the lower limit and the upper limit to obtain the number of sensors n in each circumferential region. tj ;n tj This represents the number of sensors deployed within the j-th circumferential region; S304. For each circumferential region, set (n tj -1) Pressure sensors are evenly distributed along the circumference to obtain the layout scheme of the j-th circumferential region; S305. Combine the layout schemes of each circumferential region to obtain the circumferential layout scheme of the current sensor mounting surface; S4. Prepare a test sleeve of the same material and size as the perforation section sleeve, install the test sleeve and pressure sensor; install the perforation gun inside the test sleeve. S5. Detonate the perforating bullet inside the perforating gun, and each pressure sensor acquires pressure data; S6. Based on the pressure data obtained from each pressure sensor, establish the pressure field inside the wellbore.

2. The method for testing the pressure field distribution inside a wellbore under shaped charge perforation as described in claim 1, characterized in that, In step S1: The parameters of the perforated section casing include: casing material, casing inner diameter, and casing outer diameter; The parameters of the perforating gun include: the outer diameter of the perforating gun, the length of the perforating gun, the perforation density of the perforating projectile, the helical phase angle of the perforating projectile, the type of perforating projectile, and the location of the detonation point.

3. The method for testing the pressure field distribution inside a wellbore under shaped charge perforation as described in claim 1, characterized in that, In step S2, determining the geometry and dimensions of the testing device includes: Make the inner diameter of the annular component in the test device equal to the outer diameter of the perforated section sleeve; The total axial length L of the test device shall satisfy: In the formula, L0 is the length of the perforating gun; L t To reserve the length, the following conditions must be met: ； In the formula: l f denoted as denoted as the far-field reduced distance of the explosive charge at the top perforation point; W is the explosive equivalent of the perforation charge; and n is the geometric dimension of the explosive.

4. The method for testing the pressure field distribution inside a wellbore under shaped charge perforation as described in claim 1, characterized in that, In step S4, the method for installing the test sleeve and pressure sensor includes: Based on the pressure sensor layout scheme, mounting holes are opened on the surface of the test sleeve so that the mounting holes correspond one-to-one with the pressure sensors. Install the test sleeve inside the test device, so that each annular component is fitted outside the test sleeve; install pressure sensors in each mounting hole, so that the detection end of the pressure sensor faces radially inward; Adjust each pressure sensor so that the sensing end of the pressure sensor is located on the inner wall of the test sleeve.

5. The method for testing the pressure field distribution inside a wellbore under shaped charge perforation as described in claim 1, characterized in that, Step S6 specifically includes: S601. Filter and denoise the pressure data acquired by each pressure sensor; S602. Based on the radial basis function interpolation method, the following interpolation function is used to reconstruct the three-dimensional pressure field: ； In the formula: P(r) is the pressure value at any point r in space; Represents the q-th measuring point; p is the total number of measuring points; The radial basis function weights are for the q-th measurement point; Represents radial basis functions; From point r to point The Euclidean distance; represents the k-th polynomial basis function; m is the total number of polynomial basis functions; These are the polynomial coefficients; S603. Optimize the reconstruction results of the three-dimensional pressure field reconstruction using the following objective function: ； In the formula: For the observation operator, For observation data, As background scene, and These are the covariance matrices of observation error and background error, respectively. For regularization operators, Let x be the regularization parameter; x be the state vector; and satisfy: ; where T is the transpose operator.

6. The method for testing the pressure field distribution inside a wellbore under shaped charge perforation as described in claim 1, characterized in that, The testing device includes a cable groove (5) on the surface of the hollow support column (1) that is connected to the annular groove (3); it also includes a cable outlet (6) installed on the uppermost annular component (2), which is connected to the annular groove (3) of the uppermost annular component (2).

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