Methods, devices, electronic equipment and media for microseismic monitoring and location in ultra-deep wells

Abstract

The present application discloses a method, device, electronic device and medium for monitoring and positioning microseismic in ultra-deep wells. The method includes: calculating the travel time combination time difference according to the perforation longitudinal wave travel time, transverse wave travel time and longitudinal and transverse wave travel time difference of a known well; fitting the perforation spatial position of the known well with the travel time combination time difference to obtain the radial positioning target function and the depth positioning target function respectively; calculating the travel time combination time difference of the microseismic, substituting it into the radial positioning target function and the depth positioning target function respectively to obtain the initial positioning result of the microseismic; establishing a microseismic grid with the initial positioning result as the center, forward modeling the travel time combination time difference of each grid, and determining the final positioning result of the microseismic. The present invention obtains the initial positioning result of the microseismic event by fitting the positioning target function, inputting the longitudinal and transverse wave travel time combination time difference of the microseismic event, and then using the grid search method to further search for a microseismic event positioning result with higher accuracy within a smaller range.

Description

Technical Field

[0001] The present invention relates to the field of microseismic signal processing in wells, and more specifically, to a method, device, electronic equipment and medium for monitoring and positioning microseismic signals in ultra-deep wells. Background Art

[0002] Well microseismic monitoring is one of the microseismic observation methods. Its characteristic is that the three-component geophones in the well receive the full wavefield signal of microseismic. Compared with the ground microseismic monitoring, the data received in the well has a higher signal-to-noise ratio and a richer number and type of microseismic events. However, due to the limited number of microseismic geophones in the well (generally 12 to 32 three-component geophones in the well), the monitoring range is small. At the same time, there are certain requirements for the selection of monitoring wells and observation wells. For example, the optimal radial distance from the fracturing section of the monitoring well to the geophone of the observation well is 200 to 800 meters internationally, but the actual distance is often larger, which usually leads to unstable and low-precision microseismic positioning phenomena.

[0003] At present, the main methods for microseismic positioning in wells are: one is based on the forward modeling of the travel time of longitudinal and transverse waves. Representative algorithms include network search method, simulated annealing method, Geiger method, etc. The advantage is that it is easy to implement, and the disadvantage is that the travel time of longitudinal and transverse waves of microseismic events is difficult to pick up accurately, which affects the positioning results; the second is based on wave equation convolution. Representative algorithms include interference method, reverse time migration method, and passive source imaging method. The advantage is that it does not need to pick up the first arrival of the event. The disadvantage is that it has high requirements on the data signal-to-noise ratio and velocity model, requires a large number of detectors, and has high calculation cost; the third is the difference between anisotropic and isotropic travel time calculations. In anisotropic media, the error of isotropic travel time calculation is large, and the corresponding positioning error is also large.

[0004] In recent years, with the continuous increase in the world's demand for energy and the advancement of exploration technology, the exploration and development of oil and gas resources has continued to develop in depth. More and more major exploration target layers have shown a trend of sinking overall, and the number of abnormally high-temperature deep wells with a depth of more than 4500m and a temperature exceeding 170°C is increasing. Fracturing, as the most effective measure to increase production in this type of reservoir, has also received more and more attention at home and abroad. However, the high temperature and high pressure of deep strata have also brought more difficulties to the transformation of oil and gas strata. A series of problems such as high-temperature fracturing fluid (above 180°C), the incompatibility of fracturing design theory and technology for ultra-high temperature reservoirs, and the optimization of large-scale fracturing have become the "bottlenecks" that restrict the realization of the benefits of exploration and development of this type of oil and gas fields. For ultra-deep microseismic positioning processing, the current positioning method cannot meet the positioning accuracy requirements.

[0005] Therefore, it is necessary to develop a method, device, electronic equipment and medium for microseismic monitoring and positioning in ultra-deep wells based on the combined time difference polynomial fitting of P- and S-wave travel times.

[0006] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to those skilled in the art. Summary of the invention

[0007] The present invention proposes a method, device, electronic equipment and medium for microseismic monitoring and positioning in ultra-deep wells, which can obtain the initial positioning result of the microseismic event by fitting the positioning target function, inputting the combined time difference of the longitudinal and transverse wave travel times of the microseismic event, and then using the grid search method to further search for microseismic event positioning results with higher accuracy within a smaller range.

[0008] In a first aspect, an embodiment of the present disclosure provides a method for microseismic monitoring and positioning in an ultra-deep well, comprising:

[0009] Calculate the combined travel time difference based on the perforation P-wave travel time, S-wave travel time, and P-wave and S-wave travel time difference of the known wells;

[0010] According to the perforation spatial position of the known well and the travel time combination time difference, a radial positioning target function and a depth positioning target function are respectively obtained;

[0011] Calculate the combined travel time difference of the microseismic earthquake and substitute it into the radial positioning objective function and the depth positioning objective function respectively to obtain the initial positioning result of the microseismic earthquake;

[0012] A microseismic grid is established with the initial positioning result as the center, and the combined travel time difference of each grid is forward modeled to determine the final positioning result of the microseismic.

[0013] Preferably, the combined travel time difference is calculated by formula (1):

[0014] T shoot,P,S,PS,m =T shoot,P,m +T shoot,S,m +T shoot,PS,m (1)

[0015] Among them, T shoot,P , T shoot,S , T shoot,PS are the perforation P-wave travel time, S-wave travel time, and P-wave and S-wave travel time difference of the known well, T shoot,P,S,PS The combined time difference is the travel time.

[0016] m represents the perforation number, there are M perforations in total, n represents the detector number, there are N detectors in total, T shoot,P,m is the calculated travel time difference of the mth perforation P-wave, T shoot,S,m is the statistical travel time difference of the mth perforation shear wave, Tshoot,PS,m is the statistical travel time difference of the longitudinal and transverse waves of the mth perforation.

[0017] Preferably, the radial positioning objective function is:

[0018] OPJ L (T shoot,P,S,PS,m )=L shoot,m =A L +B L *T shoot,P,S,PS,m +C L *T 2 shoot,P,S,PS,m (2)

[0019] Among them, OPJ L is the radial positioning objective function.

[0020] Preferably, the depth positioning objective function is:

[0021] OPJ Z (T shoot,P,S,PS,m )=Z shoot,m =A Z +B Z *T shoot,P,S,PS,m +C Z *T 2 shoot,P,S,PS,m (3)

[0022] Among them, OPJ Z is the depth positioning objective function.

[0023] Preferably, forward modeling the combined travel time difference of each grid to determine the final positioning result of the microseismic event includes:

[0024] Forward model the combined travel time difference of each grid, compare it with the combined travel time difference of microseismic, and calculate the target error;

[0025] The grid position corresponding to the minimum target error is the final positioning result of the microearthquake.

[0026] Preferably, the target error is calculated by formula (4):

[0027] Δ=|T P,S,PS,i,j -T event,P,S,PS | (4)

[0028] Among them, T P,S,PS,i,j is the grid position {L i ,Z j}The corresponding travel time combination time difference, T event,P,S,PS is the combined time difference of the microearthquake's travel time.

[0029] As a specific implementation method of the embodiment of the present disclosure,

[0030] In a second aspect, the present disclosure also provides a microseismic monitoring and positioning device for ultra-deep wells, comprising:

[0031] The travel time combination time difference calculation module calculates the travel time combination time difference based on the perforation longitudinal wave travel time, transverse wave travel time, and longitudinal and transverse wave travel time difference of the known well;

[0032] A fitting module is used to fit the spatial position of the perforation of the known well with the travel time combination time difference to obtain a radial positioning target function and a depth positioning target function respectively;

[0033] The initial positioning result calculation module calculates the combined travel time difference of the microseismic movement and substitutes it into the radial positioning objective function and the depth positioning objective function to obtain the initial positioning result of the microseismic movement.

[0034] The final positioning result calculation module establishes a microseismic grid with the initial positioning result as the center, forward models the combined travel time difference of each grid, and determines the final positioning result of the microseismic.

[0035] Preferably, the combined travel time difference is calculated by formula (1):

[0036] T shoot,P,S,PS,m =T shoot,P,m +T shoot,S,m +T shoot,PS,m (1)

[0037] Among them, T shoot,P , T shoot,S , T shoot,PS are the perforation P-wave travel time, S-wave travel time, and P-wave and S-wave travel time difference of the known well, T shoot,P,S,PS The combined time difference is the travel time. m represents the perforation number, there are M perforations in total, n represents the detector number, there are N detectors in total, T shoot,P,m is the calculated travel time difference of the mth perforation P-wave, T shoot,S,m is the statistical travel time difference of the mth perforation shear wave, T shoot,PS,m is the statistical travel time difference of the longitudinal and transverse waves of the mth perforation.

[0038] Preferably, the radial positioning objective function is:

[0039] OPJ L (T shoot,P,S,PS,m )=L shoot,m =A L +B L *T shoot,P,S,PS,m +C L *T2 shoot,P,S,PS,m (2)

[0040] Among them, OPJ L is the radial positioning objective function.

[0041] Preferably, the depth positioning objective function is:

[0042] OPJ Z (T shoot,P,S,PS,m )=Z shoot,m =A Z +B Z *T shoot,P,S,PS,m +C Z *T 2 shoot,P,S,PS,m (3)

[0043] Among them, OPJ Z is the depth positioning objective function.

[0044] Preferably, forward modeling the combined travel time difference of each grid to determine the final positioning result of the microseismic event includes:

[0045] Forward model the combined travel time difference of each grid, compare it with the combined travel time difference of microseismic, and calculate the target error;

[0046] The grid position corresponding to the minimum target error is the final positioning result of the microearthquake.

[0047] Preferably, the target error is calculated by formula (4):

[0048] Δ=|T P,S,PS,i,j -T event,P,S,PS | (4)

[0049] Among them, T P,S,PS,i,j is the grid position {L i ,Z j}The corresponding travel time combination time difference, T event,P,S,PS is the combined time difference of the microearthquake's travel time.

[0050] In a third aspect, an embodiment of the present disclosure further provides an electronic device, the electronic device comprising:

[0051] A memory storing executable instructions;

[0052] A processor runs the executable instructions in the memory to implement the ultra-deep well microseismic monitoring and positioning method.

[0053] In a fourth aspect, an embodiment of the present disclosure further provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method for microseismic monitoring and positioning in ultra-deep wells.

[0054] The methods and apparatus of the present invention have other features and advantages that will be apparent from, or will be described in detail in, the accompanying drawings and subsequent detailed descriptions incorporated herein, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0056] Figure 1 A flow chart showing the steps of a method for microseismic monitoring and positioning in an ultra-deep well according to an embodiment of the present invention.

[0057] Figure 2 A schematic side view of an in-well microseismic observation system according to an embodiment of the present invention is shown.

[0058] Figure 3 A schematic side view of a microseismic event design in a well according to an embodiment of the present invention is shown.

[0059] Figure 4 A schematic diagram showing the quadratic polynomial fitting of the combined travel time difference of perforation longitudinal and shear wave travel times with the radial position of the perforation according to an embodiment of the present invention is shown.

[0060] Figure 5 A schematic diagram showing the quadratic polynomial fitting of the combined travel time difference of perforation longitudinal and shear waves with the perforation depth position according to an embodiment of the present invention is shown.

[0061] Figure 6 A schematic side view of the positioning result and the actual position of the microseismic event according to an embodiment of the present invention is shown.

[0062] Figure 7 A block diagram of a microseismic monitoring and positioning device in an ultra-deep well according to an embodiment of the present invention is shown.

[0063] Description of reference numerals:

[0064] 201, travel time combined time difference calculation module; 202, fitting module; 203, initial positioning result calculation module; 204, final positioning result calculation module. DETAILED DESCRIPTION

[0065] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0066] The carbonate reservoirs in Tahe Oilfield in Tabei are characterized by deep burial, weak seismic reflection signals and strong heterogeneity. The reservoirs in Songnan area are complex, have large reserves, are deep and have ultra-low permeability. Ultra-deep oil and gas reservoir fracturing is one of the most challenging measures to increase production in low-permeability reservoirs. It is necessary to formulate a complete set of high-performance fracturing technologies to achieve huge production in deep oil and gas reservoirs and deep tight gas reservoirs. Among them are the requirements for ultra-deep microseismic monitoring and processing technology to eliminate or reduce the instability and inaccuracy of microseismic event positioning. Therefore, the present invention utilizes the characteristics of the combination of the longitudinal wave travel time, the transverse wave travel time and the longitudinal and transverse wave time difference of the ultra-deep perforation signal to present a high degree of polynomial, fits the positioning target function, inputs the combined time difference of the longitudinal and transverse wave travel time of the microseismic event, obtains the initial positioning result of the microseismic event, and then uses the grid search method to further search for microseismic event positioning results with higher accuracy within a smaller range.

[0067] The present invention provides a method for microseismic monitoring and positioning in an ultra-deep well, comprising:

[0068] The combined travel time difference is calculated based on the perforation P-wave travel time, S-wave travel time, and P-wave and S-wave travel time difference of the known well. In one example, the combined travel time difference is calculated using formula (1):

[0069] T shoot,P,S,PS,m =T shoot,P,m +T shoot,S,m +T shoot,PS,m (1)

[0070] Among them, T shoot,P , T shoot,S , T shoot,PS are the perforation P-wave travel time, S-wave travel time, and P-wave and S-wave travel time difference of the known well, T shoot,P,S,PS The combined time difference is the travel time. m represents the perforation number, there are M perforations in total, n represents the detector number, there are N detectors in total, T shoot,P,m is the calculated travel time difference of the mth perforation P-wave, T shoot,S,m is the statistical travel time difference of the mth perforation shear wave, T shoot,PS,m is the statistical travel time difference of the longitudinal and transverse waves of the mth perforation.

[0071] Specifically, calculate the known perforation longitudinal wave travel time Tshoot,P , transverse wave travel time T shoot,S 、Time difference between longitudinal and transverse waves T shoot,PS , the known perforation longitudinal wave travel time T is converted into shoot,P , transverse wave travel time T shoot,S 、Time difference between longitudinal and transverse waves T shoot,PS Combining a new time difference - travel time combination time difference T shoot,P,S,PS .

[0072] According to the perforation spatial position of the known well and the combined travel time difference, the radial positioning objective function and the depth positioning objective function are respectively obtained; in an example, the radial positioning objective function is:

[0073] OPJ L (T shoot,P,S,PS,m )=L shoot,m =A L +B L *T shoot,P,S,PS,m +C L *T 2 shoot,P,S,PS,m (2)

[0074] Among them, OPJ L is the radial positioning objective function.

[0075] In one example, the depth localization objective function is:

[0076] OPJ Z (T shoot,P,S,PS,m )=Z shoot,m =A Z +B Z *T shoot,P,S,PS,m +C Z *T 2 shoot,P,S,PS,m (3)

[0077] Among them, OPJ Z is the depth positioning objective function.

[0078] Specifically, due to the combined travel time difference T of the perforation P-wave and S-wave monitored in the ultra-deep well shoot,P,S,PS,m It has the characteristics of a polynomial. Taking the quadratic polynomial as an example, the other multiple terms have the same principle. Therefore, the combined travel time difference of the perforation longitudinal and transverse waves is T shoot,P,S,PS,m As an independent variable, the radial position of the known perforation L shoot,m , Perforation depth position Z shoot,m Quadratic polynomial fitting, radial positioning objective function is formula (2), fitting OPJ Z The objective function for depth positioning is formula (3).

[0079] The combined travel time difference of the microseismic event is calculated and substituted into the radial positioning objective function and the depth positioning objective function respectively to obtain the initial positioning result of the microseismic event.

[0080] Specifically, according to the least squares method, the combined travel time difference T of the M perforation P-wave and S-wave is shoot,P,S,PS,m , respectively forming the following quadratic polynomial coefficient matrices:

[0081]

[0082]

[0083] Similar to solving the matrix "XA = Y", solving the coefficient matrix "A = X -1 Y". Similarly, calculate the radial positioning objective function coefficient (A L , B L , C L ) and the depth positioning objective function (A Z , B Z , C Z ), the specific expression is omitted. Since the coefficient matrices of formulas (5) and (6) are real logarithmic matrices, for special quadratic polynomials, they can be regarded as solving a system of three-variable linear equations.

[0084] Then, input the picked microseismic event longitudinal and transverse wave travel time T event,P , T event,S , calculate the time difference T event,PS , similar to the perforation travel time combination, calculate the event travel time combination time difference T event,P,S,PS , and substitute them into the radial positioning objective function OPJ L , depth positioning objective function OPJ Z , get the initial location result of microseismic event RT event ={L event ,Z event}.

[0085] Similar to perforation, picking up the travel time of longitudinal and transverse waves of microseismic events T event,P,n , T event,S,n , calculate the combined time difference of the event longitudinal and transverse wave travel time T event,P,S,PS , T event,P,S,PS Substitute the corresponding objective function OPJ into formula (2) and (3) respectively L OPJ Z , calculate the initial location results of microseismic events, where the polynomial coefficients (A L , B L , C L )、(A Z , B Z , C Z) is obtained by formula (5) and (6) based on the combined travel time difference of M perforation P-wave and S-wave, and L event , Z event They are the initial radial position and depth position of the microseismic event, respectively.

[0086] A microseismic grid is established with the initial positioning result as the center, and the combined travel time difference of each grid is forward modeled to determine the final positioning result of the microseismic.

[0087] In one example, forward modeling the combined travel time difference of each grid to determine the final positioning result of the microseism includes: forward modeling the combined travel time difference of each grid, comparing it with the combined travel time difference of the microseism, and calculating the target error; the grid position corresponding to the minimum target error is the final positioning result of the microseism.

[0088] In one example, the target error is calculated by formula (4):

[0089] Δ=|T P,S,PS,i,j -T event,P,S,PS | (4)

[0090] Among them, T P,S,PS,i,j is the grid position {L i ,Z j}The corresponding travel time combination time difference, T event,P,S,PS is the combined time difference of the microearthquake's travel time.

[0091] Specifically, a rectangular grid is designed with the initial location result of the microseismic event as the center. i ∈(L event -ΔL,L event +ΔL) to design the rectangular grid length, according to Z j ∈(Z event -ΔZ,Z event +ΔZ) to design the rectangular grid width. i , Z j are the radial position and depth position corresponding to the grid point (i, j), and ΔL and ΔZ are the rectangular grid sizes.

[0092] In order to quickly realize event relocation, the rectangular grid is designed to be relatively small. According to the ultra-deep positioning error analysis, it is generally required that ΔL is less than 5 meters and ΔZ is less than 30 meters. Assuming that a source is placed at each grid point (i, j), based on the known acoustic logging and the spatial position of the geophone, the ray tracing forward modeling is carried out using Snell's law to calculate the longitudinal wave travel time T from the source point to the geophone P,i,j , transverse wave travel time T S,i,j and time difference T PS,i,j , sum the three and calculate the combined time difference of longitudinal and transverse waves T P,S,PS,i,j .

[0093] The combined time difference T of the longitudinal and transverse waves at each grid point is P,S,PS,i,j The actual value of the combined travel time difference between the longitudinal and transverse waves of the microseismic event T event,P,S,PS Compare them and calculate the error between them by formula (4). Find the grid point L within the rectangular grid range where the error Δ is the smallest. * event , Z * event , which is the final microseismic event location result RT * event ={L * event ,Z * event}.

[0094] The present invention also provides a microseismic monitoring and positioning device in an ultra-deep well, comprising:

[0095] The travel time combination time difference calculation module calculates the travel time combination time difference according to the perforation longitudinal wave travel time, transverse wave travel time, and longitudinal and transverse wave travel time difference of the known well. In one example, the travel time combination time difference is calculated by formula (1):

[0096] T shoot,P,S,PS,m =T shoot,P,m +T shoot,S,m +T shoot,PS,m (1)

[0097] Among them, T shoot,P , T shoot,S , T shoot,PS are the perforation P-wave travel time, S-wave travel time, and P-wave and S-wave travel time difference of the known well, T shoot,P,S,PS The combined time difference is the travel time.

[0098] m represents the perforation number, there are M perforations in total, n represents the detector number, there are N detectors in total, T shoot,P,m is the calculated travel time difference of the mth perforation P-wave, T shoot,S,m is the statistical travel time difference of the mth perforation shear wave, T shoot,PS,m is the statistical travel time difference of the longitudinal and transverse waves of the mth perforation.

[0099] Specifically, calculate the known perforation longitudinal wave travel time T shoot,P , transverse wave travel time T shoot,S 、Time difference between longitudinal and transverse waves T shoot,PS , the known perforation longitudinal wave travel time T is converted into shoot,P , transverse wave travel time T shoot,S 、Time difference between longitudinal and transverse waves T shoot,PSCombining a new time difference - travel time combination time difference T shoot,P,S,PS .

[0100] The fitting module performs fitting based on the perforation spatial position of the known well and the combined travel time difference to obtain the radial positioning objective function and the depth positioning objective function respectively; in an example, the radial positioning objective function is:

[0101] OPJ L (T shoot,P,S,PS,m )=L shoot,m =A L +B L *T shoot,P,S,PS,m +C L *T 2 shoot,P,S,PS,m (2)

[0102] Among them, OPJ L is the radial positioning objective function.

[0103] In one example, the depth localization objective function is:

[0104] OPJ Z (T shoot,P,S,PS,m )=Z shoot,m =A Z +B Z *T shoot,P,S,PS,m +C Z *T 2 shoot,P,S,PS,m (3)

[0105] Among them, OPJ Z is the depth positioning objective function.

[0106] Specifically, due to the combined travel time difference T of the perforation P-wave and S-wave monitored in the ultra-deep well shoot,P,S,PS,m It has the characteristics of a polynomial. Taking the quadratic polynomial as an example, the other multiple terms have the same principle. Therefore, the combined travel time difference of the perforation longitudinal and transverse waves is T shoot,P,S,PS,m As an independent variable, the radial position of the known perforation L shoot,m , Perforation depth position Z shoot,m Quadratic polynomial fitting, radial positioning objective function is formula (2), fitting OPJ Z The objective function for depth positioning is formula (3).

[0107] The initial positioning result calculation module calculates the combined travel time difference of the microseismic movement and substitutes it into the radial positioning objective function and the depth positioning objective function respectively to obtain the initial positioning result of the microseismic movement.

[0108] Specifically, according to the least squares method, the combined travel time difference T of the M perforation P-wave and S-wave is shoot,P,S,PS,m, respectively forming quadratic polynomial coefficient matrices as formulas (5) and (6). Similar to solving the matrix “XA=Y”, solving the coefficient matrix “A=X -1 Y". Similarly, calculate the radial positioning objective function coefficient (A L , B L , C L ) and the depth positioning objective function (A Z , B Z , C Z ), the specific expression is omitted. Since the coefficient matrices of formulas (5) and (6) are real logarithmic matrices, for special quadratic polynomials, they can be regarded as solving a system of three-variable linear equations.

[0109] Then, input the picked microseismic event longitudinal and transverse wave travel time T event,P , T event,S , calculate the time difference T event,PS , similar to the perforation travel time combination, calculate the event travel time combination time difference T event,P,S,PS , and substitute them into the radial positioning objective function OPJ L , depth positioning objective function OPJ Z , get the initial location result of microseismic event RT event ={L event ,Z event}.

[0110] Similar to perforation, picking up the travel time of longitudinal and transverse waves of microseismic events T event,P,n , T event,S,n , calculate the combined time difference of the event longitudinal and transverse wave travel time T event,P,S,PS , T event,P,S,PS Substitute the corresponding objective function OPJ into formula (2) and (3) respectively L OPJ Z , calculate the initial location results of microseismic events, where the polynomial coefficients (A L , B L , C L )、(A Z , B Z , C Z ) is obtained by formula (5) and (6) based on the combined travel time difference of M perforation P-wave and S-wave, and L event , Z event They are the initial radial position and depth position of the microseismic event, respectively.

[0111] The final positioning result calculation module establishes a microseismic grid with the initial positioning result as the center, forward models the combined travel time difference of each grid, and determines the final positioning result of the microseism.

[0112] In one example, forward modeling the combined travel time difference of each grid to determine the final positioning result of the microseism includes: forward modeling the combined travel time difference of each grid, comparing it with the combined travel time difference of the microseism, and calculating the target error; the grid position corresponding to the minimum target error is the final positioning result of the microseism.

[0113] In one example, the target error is calculated by formula (4):

[0114] Δ=|T P,S,PS,i,j -T event,P,S,PS | (4)

[0115] Among them, T P,S,PS,i,j is the grid position {L i ,Z j}The corresponding travel time combination time difference, T event,P,S,PS is the combined time difference of the microearthquake's travel time.

[0116] Specifically, a rectangular grid is designed with the initial location result of the microseismic event as the center. i ∈(L event -ΔL,L event +ΔL) to design the rectangular grid length, according to Z j ∈(Z event -ΔZ,Z event +ΔZ) to design the rectangular grid width. i , Z j are the radial position and depth position corresponding to the grid point (i, j), and ΔL and ΔZ are the rectangular grid sizes.

[0117] In order to quickly realize event relocation, the rectangular grid is designed to be relatively small. According to the ultra-deep positioning error analysis, it is generally required that ΔL is less than 5 meters and ΔZ is less than 30 meters. Assuming that a source is placed at each grid point (i, j), based on the known acoustic logging and the spatial position of the geophone, the ray tracing forward modeling is carried out using Snell's law to calculate the longitudinal wave travel time T from the source point to the geophone P,i,j , transverse wave travel time T S,i,j and time difference T PS,i,j , sum the three and calculate the combined time difference of longitudinal and transverse waves T P,S,PS,i,j .

[0118] The combined time difference T of the longitudinal and transverse waves at each grid point is P,S,PS,i,j The actual value of the combined travel time difference between the longitudinal and transverse waves of the microseismic event T event,P,S,PS Compare them and calculate the error between them by formula (4). Find the grid point L within the rectangular grid range where the error Δ is the smallest. * event , Z * event, which is the final microseismic event location result RT * event ={L * event ,Z * event}.

[0119] The present invention also provides an electronic device, which includes: a memory storing executable instructions; and a processor, which runs the executable instructions in the memory to implement the above-mentioned microseismic monitoring and positioning method in ultra-deep wells.

[0120] The present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the above-mentioned ultra-deep well microseismic monitoring and positioning method is implemented.

[0121] To facilitate understanding of the solutions and effects of the embodiments of the present invention, four specific application examples are given below. Those skilled in the art should understand that the examples are only for facilitating understanding of the present invention, and any specific details thereof are not intended to limit the present invention in any way.

[0122] Example 1

[0123] Figure 1 A flow chart showing the steps of a method for microseismic monitoring and positioning in an ultra-deep well according to an embodiment of the present invention.

[0124] like Figure 1 As shown, the method for monitoring and positioning microseismicity in ultra-deep wells includes: step 101, calculating the combined travel time difference according to the perforation longitudinal wave travel time, transverse wave travel time, and longitudinal and transverse wave travel time difference of a known well; step 102, fitting the perforation spatial position of the known well with the combined travel time difference to obtain a radial positioning target function and a depth positioning target function respectively; step 103, calculating the combined travel time difference of the microseismicity, substituting it into the radial positioning target function and the depth positioning target function respectively, to obtain an initial positioning result of the microseismicity; step 104, establishing a microseismic grid with the initial positioning result as the center, forward modeling the combined travel time difference of each grid, and determining the final positioning result of the microseismicity.

[0125] Figure 2 A schematic side view of an in-well microseismic observation system according to an embodiment of the present invention is shown.

[0126] Figure 3 A schematic side view of a microseismic event design in a well according to an embodiment of the present invention is shown.

[0127] 16 downhole geophones monitor microseismic signals, 11 known perforation signals and 27 event signals. The geometric relationship between radial and depth coordinates of the observation system is as follows: Figure 2 , Figure 3 As shown in the figure, 11 perforations are arranged along a straight line and are far away from the detector in radial direction (about 2000 meters), and 27 events are distributed near the perforations. This system belongs to a typical long-distance well microseismic monitoring system. Figure 2 , Figure 3 The observation mode is to perform the P- and S-wave travel time of each perforation and event reaching the detector as a known true observation value. The present invention does not consider the influence of lateral velocity variation and is only a two-dimensional model. In addition, acoustic logging provides the vertical velocity of P- and S-waves as known inputs.

[0128] Figure 4 A schematic diagram showing the quadratic polynomial fitting of the combined travel time difference of perforation longitudinal and shear wave travel times with the radial position of the perforation according to an embodiment of the present invention is shown.

[0129] Figure 5 A schematic diagram showing the quadratic polynomial fitting of the combined travel time difference of perforation longitudinal and shear waves with the perforation depth position according to an embodiment of the present invention is shown.

[0130] First, the 11 known perforation longitudinal wave travel times T shoot,P , transverse wave travel time T shoot,S , calculate the time difference between longitudinal and transverse waves T shoot,PS , further calculate the travel time combination time difference T in formula (1) shoot,P,S,PS Combined with the known spatial position of the perforation, the travel time difference T of the perforation longitudinal and transverse waves is used shoot,P,S,PS As the independent variable, the radial position and depth position of the perforation are taken as unknown quantities, and the radial positioning objective function OPJ is fitted by polynomials respectively. L , depth positioning objective function OPJ Z ,like Figure 4 , Figure 5 According to the least squares method, the combined travel time difference T of the 11 perforation P-wave and S-wave shoot,P,S,PS,m , respectively, forming the quadratic polynomial coefficient matrix:

[0131] OPJ L (T P,S,PS )=L=-4269.5+1443.9*T P,S,PS -65.011*T 2 P,S,PS (7)

[0132] OPJ Z (T P,S,PS )=Z=1773.1+144.39*T P,S,PS -6.5011*T 2 P,S,PS (8)

[0133] Formulas (7) and (8) are the specific expressions of microseismic event location formulas (2) and (3).

[0134] Then, input the picked microseismic event longitudinal and transverse wave travel time T event,P , T event,S , calculate the time difference T event,PS , similar to the perforation travel time combination, calculate the event travel time combination time difference T event,P,S,PS , and substitute them into the radial positioning objective function OPJ L (Formula (7)), depth positioning objective function OPJ Z (Formula (8)), the initial location result RT of the microseismic event is obtained event ={L event ,Z event}.

[0135] Figure 6 A schematic side view of the positioning result and the actual position of the microseismic event according to an embodiment of the present invention is shown.

[0136] Finally, the initial radial result L of the microseismic event event , initial depth result Z event As the center, a smaller range grid is established, with a specific grid size of + / -15 meters in radial direction and + / -15 meters in depth, to achieve rapid repositioning. Based on the known acoustic logging, the position of each grid point is performed by the known high-precision ray tracing algorithm. i ,Z j The longitudinal wave travel time when it reaches the detector is T P,i,j , transverse wave travel time T S,i,j and the time difference between longitudinal and transverse waves T PS,i,j , and then obtain the combined target time difference T P,S,PS,i,j , and combine it with the true value of the time difference between the longitudinal and transverse wave travel time of the microseismic event T event,P,S,PS Compare and find the error Δ=|T within the grid range. P,S,PS,i,j -T event,P,S,PS |The grid point position corresponding to the minimum L * event , Z * event , which is the final location result of the microseismic event RT * event ={L * event ,Z * event},like Figure 6 It can be seen that the radial error of the microseismic event positioning result is controlled within 2 meters, and the depth error is controlled within 3 meters, as shown in Table 1, which shows that the present invention has high microseismic positioning accuracy in the well and has a high promotion value.

[0137] Table 1

[0138]

[0139]

[0140] Example 2

[0141] Figure 7 A block diagram of a microseismic monitoring and positioning device in an ultra-deep well according to an embodiment of the present invention is shown.

[0142] like Figure 7 As shown, the ultra-deep well microseismic monitoring and positioning device includes:

[0143] The travel time combination time difference calculation module 201 calculates the travel time combination time difference according to the perforation longitudinal wave travel time, transverse wave travel time, and longitudinal and transverse wave travel time difference of the known well;

[0144] A fitting module 202 is used to fit the spatial position of the perforation of the known well and the travel time combination time difference to obtain a radial positioning target function and a depth positioning target function respectively;

[0145] The initial positioning result calculation module 203 calculates the combined travel time difference of the microseismic earthquake and substitutes it into the radial positioning target function and the depth positioning target function respectively to obtain the initial positioning result of the microseismic earthquake;

[0146] The final positioning result calculation module 204 establishes a microseismic grid with the initial positioning result as the center, forward models the combined travel time difference of each grid, and determines the final positioning result of the microseismic.

[0147] As an optional solution, the combined travel time difference is calculated using formula (1):

[0148] T shoot,P,S,PS,m =T shoot,P,m +T shoot,S,m +T shoot,PS,m (1)

[0149] Among them, T shoot,P , T shoot,S , T shoot,PS are the perforation P-wave travel time, S-wave travel time, and P-wave and S-wave travel time difference of the known well, T shoot,P,S,PS The combined time difference is the travel time.

[0150] m represents the perforation number, there are M perforations in total, n represents the detector number, there are N detectors in total, T shoot,P,m is the calculated travel time difference of the mth perforation P-wave, Tshoot,S,m is the statistical travel time difference of the mth perforation shear wave, T shoot,PS,m is the statistical travel time difference of the longitudinal and transverse waves of the mth perforation.

[0151] As an alternative, the radial positioning objective function is:

[0152] OPJ L (T shoot,P,S,PS,m )=L shoot,m =A L +B L *T shoot,P,S,PS,m +C L *T 2 shoot,P,S,PS,m (2)

[0153] Among them, OPJ L is the radial positioning objective function.

[0154] As an alternative, the depth positioning objective function is:

[0155] OPJ Z (T shoot,P,S,PS,m )=Z shoot,m =A Z +B Z *T shoot,P,S,PS,m +C Z *T 2 shoot,P,S,PS,m (3)

[0156] Among them, OPJ Z is the depth positioning objective function.

[0157] As an optional solution, forward modeling the combined travel time difference of each grid to determine the final location results of the microearthquake includes:

[0158] Forward model the combined travel time difference of each grid, compare it with the combined travel time difference of microseismic, and calculate the target error;

[0159] The grid position corresponding to the minimum target error is the final positioning result of the microearthquake.

[0160] As an alternative, the target error is calculated using formula (4):

[0161] Δ=|T P,S,PS,i,j -T event,P,S,PS | (4)

[0162] Among them, T P,S,PS,i,j is the grid position {L i ,Z j}The corresponding travel time combination time difference, T event,P,S,PS is the combined time difference of the microearthquake's travel time.

[0163] Example 3

[0164] The present disclosure provides an electronic device, which includes: a memory storing executable instructions; a processor running the executable instructions in the memory to implement the above-mentioned microseismic monitoring and positioning method in ultra-deep wells.

[0165] An electronic device according to an embodiment of the present disclosure includes a memory and a processor.

[0166] The memory is used to store non-temporary computer-readable instructions. Specifically, the memory may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may, for example, include read-only memory (ROM), hard disk, flash memory, etc.

[0167] The processor may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions. In one embodiment of the present disclosure, the processor is used to run the computer-readable instructions stored in the memory.

[0168] Those skilled in the art should be able to understand that in order to solve the technical problem of how to obtain a good user experience, the present embodiment may also include well-known structures such as a communication bus and an interface, and these well-known structures should also be included in the protection scope of the present disclosure.

[0169] For detailed description of this embodiment, reference may be made to the corresponding descriptions in the aforementioned embodiments, which will not be repeated here.

[0170] Example 4

[0171] An embodiment of the present disclosure provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the method for microseismic monitoring and positioning in ultra-deep wells.

[0172] According to the computer-readable storage medium of the embodiment of the present disclosure, non-transitory computer-readable instructions are stored thereon. When the non-transitory computer-readable instructions are executed by a processor, all or part of the steps of the above-mentioned methods of each embodiment of the present disclosure are executed.

[0173] The above-mentioned computer-readable storage media include, but are not limited to: optical storage media (e.g., CD-ROM and DVD), magneto-optical storage media (e.g., MO), magnetic storage media (e.g., magnetic tape or mobile hard disk), media with built-in rewritable non-volatile memory (e.g., memory card) and media with built-in ROM (e.g., ROM box).

[0174] Those skilled in the art should understand that the purpose of the above description of the embodiments of the present invention is only to exemplarily illustrate the beneficial effects of the embodiments of the present invention, and is not intended to limit the embodiments of the present invention to any given examples.

[0175] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for microseismic monitoring and positioning in ultra-deep wells, characterized in that: include: Calculate the combined travel time difference based on the perforation P-wave travel time, S-wave travel time, and P-wave and S-wave travel time difference of the known wells; According to the perforation spatial position of the known well and the travel time combination time difference, a radial positioning target function and a depth positioning target function are respectively obtained; Calculate the combined travel time difference of the microseismic earthquake and substitute it into the radial positioning objective function and the depth positioning objective function respectively to obtain the initial positioning result of the microseismic earthquake; Establishing a microseismic grid with the initial positioning result as the center, forward modeling the combined travel time difference of each grid, and determining the final positioning result of the microseismic; The combined travel time difference is calculated by formula (1): T shoot,P,S,PS,m =T shoot,P,m +T shoot,S,m +T shoot,PS,m (1) Among them, T shoot,P 、T shoot,S 、T shoot,PS are the perforation P-wave travel time, S-wave travel time, and P-wave and S-wave travel time difference of the known well, T shoot,P,S,PS The combined time difference is the travel time. m represents the perforation number, there are M perforations in total, n represents the detector number, there are N detectors in total, T shoot,P,m is the calculated travel time difference of the mth perforation P-wave, T shoot,S,m is the statistical travel time difference of the mth perforation shear wave, T shoot,PS,m is the statistical travel time difference of the longitudinal and transverse waves of the mth perforation.

2. The method for microseismic monitoring and positioning in ultra-deep wells according to claim 1, wherein: The radial positioning objective function is: OPJ L (T shoot,P,S,PS,m )=L shoot,m =A L +B L *T shoot,P,S,PS,m +C L *T 2 shoot,P,S,PS,m (2) Among them, OPJ L is the radial positioning objective function, T shoot,P,S,PS,m A is the combined travel time difference of perforation longitudinal and transverse waves, L , B L , C L is the radial positioning objective function coefficient.

3. The method for microseismic monitoring and positioning in ultra-deep wells according to claim 1, wherein: The depth positioning objective function is: OPJ Z (T shoot,P,S,PS,m )=Z shoot,m =A Z +B Z *T shoot,P,S,PS,m +C Z *T 2 shoot,P,S,PS,m (3) Among them, OPJ Z is the depth positioning objective function, T shoot,P,S,PS,m A is the combined travel time difference of perforation longitudinal and transverse waves, Z , B Z , C Z is the depth positioning objective function coefficient.

4. The method for microseismic monitoring and positioning in ultra-deep wells according to claim 1, wherein: The combined travel time difference of each grid is forward modeled to determine the final location results of the microearthquake, including: Forward model the combined travel time difference of each grid, compare it with the combined travel time difference of microseismic, and calculate the target error; The grid position corresponding to the minimum target error is the final positioning result of the microearthquake.

5. The method for microseismic monitoring and positioning in ultra-deep wells according to claim 4, wherein: The target error is calculated by formula (4): Δ=|T P,S,PS,i,j -T event,P,S,PS | (4) Among them, T P,S,PS,i,j is the grid position {L i ,Z j }The corresponding travel time combination time difference, T event,P,S,PS is the combined time difference of the micro-earthquake's travel time.

6. A microseismic monitoring and positioning device in an ultra-deep well, characterized in that: include: The travel time combination time difference calculation module calculates the travel time combination time difference based on the perforation longitudinal wave travel time, transverse wave travel time, and longitudinal and transverse wave travel time difference of the known well; A fitting module is used to fit the spatial position of the perforation of the known well with the travel time combination time difference to obtain a radial positioning target function and a depth positioning target function respectively; The initial positioning result calculation module calculates the combined travel time difference of the microseismic earthquake and substitutes it into the radial positioning objective function and the depth positioning objective function respectively to obtain the initial positioning result of the microseismic earthquake; The final positioning result calculation module establishes a microseismic grid with the initial positioning result as the center, forward models the combined travel time difference of each grid, and determines the final positioning result of the microseismic; The combined travel time difference is calculated by formula (1): T shoot,P,S,PS,m =T shoot,P,m +T shoot,S,m +T shoot,PS,m (1) Among them, T shoot,P 、T shoot,S 、T shoot,PS are the perforation P-wave travel time, S-wave travel time, and P-wave and S-wave travel time difference of the known well, T shoot,P,S,PS The combined time difference is the travel time. m represents the perforation number, there are M perforations in total, n represents the detector number, there are N detectors in total, T shoot,P,m is the calculated travel time difference of the mth perforation P-wave, T shoot,S,m is the statistical travel time difference of the mth perforation shear wave, T shoot,PS,m is the statistical travel time difference of the longitudinal and transverse waves of the mth perforation.

7. The ultra-deep well microseismic monitoring and positioning device according to claim 6, wherein: The combined travel time difference of each grid is forward modeled to determine the final location results of the microearthquake, including: Forward model the combined travel time difference of each grid, compare it with the combined travel time difference of microseismic, and calculate the target error; The grid position corresponding to the minimum target error is the final positioning result of the microearthquake.

8. An electronic device, characterized in that: The electronic device comprises: A memory storing executable instructions; A processor, wherein the processor runs the executable instructions in the memory to implement the method for microseismic monitoring and positioning in ultra-deep wells according to any one of claims 1 to 5.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the method for microseismic monitoring and positioning in ultra-deep wells according to any one of claims 1 to 5.

Images