A method for quantitatively evaluating the performance of an observation system

Abstract

The present invention relates to the technical field of three-dimensional seismic exploration, and specifically provides a method for quantitatively evaluating the performance of an observation system. The steps include: S1. Determine the target area of the three-dimensional seismic observation system, and evenly divide the target area of the observation system into multiple bins according to the required size; S2. Calculate the overall shot-receiver contribution coefficient, coverage distribution coefficient, shot-receiver distance contribution coefficient, azimuth contribution coefficient, and concentration distribution coefficient in the target area respectively according to the bins; S3. Calculate the quantitative evaluation comprehensive factor of the three-dimensional seismic observation system for the target layer according to the overall shot-receiver contribution coefficient, coverage distribution coefficient, shot-receiver distance distribution coefficient, azimuth contribution coefficient, and concentration distribution coefficient. The evaluation comprehensive factor is used to determine the comprehensive performance of the observation system suitable for the target layer. The present invention provides a quantitative analysis method, enabling the optimized observation system to better meet the requirements of project geological tasks in the actual design of seismic acquisition observation systems.

Description

Technical Field

[0001] The present invention relates to the technical field of three-dimensional seismic exploration, and particularly to a method for quantitatively evaluating the performance of an observation system. Background Art

[0002] In the seismic exploration industry, obtaining underground information through seismic data acquisition has become an effective method. There have been more and more studies on the design performance of different types of observation systems for seismic data acquisition. However, they basically do not deviate from acquisition costs, acquisition workloads, the number of coverage times within a bin, shot-receiver offsets, and the distribution of midpoint information. However, there is currently no more comprehensive and effective method to completely evaluate the design performance of an observation system. Currently, mainstream observation system design software provides a variety of different methods for attribute analysis of the observation system from different angles, such as the shot-receiver offset distribution map of a bin, the curve of the number of coverage times of a shot-receiver line, the overall uniformity of the number of coverage times, etc. However, the overall effect evaluation of an observation system is not determined by a single factor. A good single factor does not mean that the overall design effect of the observation system becomes better. Even if it is known that the overall effect becomes better, the degree of influence of a single factor is unknown. It requires years of exploration experience and the design and analysis experience of technical personnel to judge. As a result, unstable human factors are incorporated into the evaluation of the design effect of the observation system, affecting the final overall evaluation of the design of the observation system.

[0003] Currently, an observation system evaluation method based on similarity analysis establishes a typical geological model of a target work area according to existing geological data, uses a theoretically designed observation system combined with a theoretical model to obtain a simulated profile of forward modeling, then uses the simulated wavelet used in the forward modeling process to convolve with the reflection coefficient model to obtain a self-excitation self-reception-like simulated profile, and then uses two methods to calculate the similarity coefficient to evaluate the quality of the observation system, and judges the pros and cons of the imaging effect of the observation system to evaluate and optimize the observation system, so as to best optimize the observation system, without considering the performance of the observation system from the design stage or the overall design effect.

[0004] Currently, a method for homogenizing the bin attributes of a three-dimensional seismic observation system, which is mainly used to judge the degree of homogenization of the bin attributes of a three-dimensional seismic observation system. For the number of coverage times, the range of shot-receiver offsets, and the range of azimuth angles of each bin, the bin attributes of the three-dimensional seismic observation system are homogenized, which is beneficial to weakening the "acquisition footprint" effect, can improve the accuracy of subsequent seismic data processing and interpretation results, and improve the quality of attribute slices, but cannot form a quantitative factor for the overall evaluation of the observation system.

[0005] At present, the analysis of the attributes of the observation system, such as the density of shot and receiver points, the number of coverage, the shot-receiver distance, and the azimuth angle, can be recognized and accepted by the industry. However, the application and analysis methods of various attribute indicators are quite different. Different 3D seismic observation systems will have different effects on the imaging effect and imaging accuracy of geological targets for the acquired data. The main problems existing in the evaluation, selection, and application of 3D observation systems are as follows: 1. A more concise and convenient method is needed to evaluate the effectiveness of the observation system and judge the superiority of the designed observation system performance from a quantitative perspective; 2. An effective index is needed to comprehensively measure the subtle differences between different observation systems, so as to make an optimal choice among similar observation systems.

[0006] In practical applications, there is an urgent need for a method that can directly combine multiple factors for comprehensive evaluation of the observation system. By using the influence of key factors such as the distribution of shot and receiver points, azimuth angle, shot-receiver distance, number of coverage, and the concentration degree of CMP points on the evaluation of the observation system attributes, an expression that can characterize the value of various factors is constructed to realize the comprehensive value evaluation of the observation system attributes, providing a powerful means for quantitative analysis of the designed performance of the observation system in seismic exploration projects. Summary of the Invention

[0007] The present invention overcomes the above technical problems, establishes a method that can directly combine multiple factors for comprehensive evaluation of the observation system, and proposes a method for quantitatively evaluating the performance of the observation system.

[0008] In order to achieve the above invention purpose, the present invention provides the following technical solutions:

[0009] A method for quantitatively evaluating the performance of an observation system, comprising the following steps:

[0010] S1. Determine the target area of the 3D seismic observation system, and evenly divide the target area of the 3D seismic observation system into multiple bins according to the required size;

[0011] S2. According to the bins, calculate the overall shot-receiver point contribution coefficient, the number of coverage distribution coefficient, the shot-receiver distance contribution coefficient, the azimuth angle contribution coefficient, and the concentration degree distribution coefficient in the target area for the target layer respectively;

[0012] S3. According to the overall shot-receiver point contribution coefficient, the number of coverage distribution coefficient, the shot-receiver distance distribution coefficient, the azimuth angle contribution coefficient, and the concentration degree distribution coefficient, calculate the quantitative evaluation comprehensive factor of the 3D seismic observation system for the target layer, and the evaluation comprehensive factor is used to determine the size of the comprehensive performance of the observation system for the target layer.

[0013] As a preferred solution of the present invention, the calculation formula of the overall shot-receiver point contribution coefficient is:

[0014]

[0015] Among them, Rc is the contribution coefficient of the shot-receiver point, Ls is the shot line distance of the three-dimensional seismic acquisition system in the target area, Ds is the shot point distance, Lr is the receiver line distance, Dr is the receiver point distance, B i is the longitudinal bin size, B x is the transverse bin size.

[0016] As a preferred embodiment of the present invention, the coverage fold distribution coefficient is:

[0017]

[0018] Among them, F c is the coverage fold distribution coefficient, U f is the full coverage fold distribution uniformity coefficient, F e is the overall effective coefficient of the three-dimensional seismic acquisition system, is the average value of the depth coverage folds of the target layer in the target area.

[0019] As a preferred embodiment of the present invention, the calculation formula of the shot-receiver distance contribution coefficient is:

[0020]

[0021] Among them, X c is the shot-receiver distance contribution coefficient, O x is the best matching coefficient of the maximum shot-receiver distance of the acquisition system scheme, U x is the change uniformity of the shot-receiver distance distribution coefficient, is the average value of the shot-receiver distance distribution coefficient within the depth bin of the target layer in the target area.

[0022] As a preferred embodiment of the present invention, the calculation formula of the azimuth contribution coefficient is:

[0023]

[0024] Among them, A c is the azimuth contribution coefficient, A e is the overall azimuth effective coefficient of the acquisition system design, U a is the azimuth uniformity coefficient within the depth bin of the target layer in the target area, is the average value of the azimuth uniformity within the depth bin of the target layer in the target area.

[0025] As a preferred embodiment of the present invention, the calculation formula of the concentration distribution coefficient is:

[0026]

[0027] Among them, D c is the bin concentration coefficient, B iis the longitudinal element size, B x is the transverse element size, is the average distance value of each CMP point in the element from the center point.

[0028] As a preferred embodiment of the present invention, the calculation formula of the quantitative evaluation comprehensive factor is:

[0029] G c = R c ·F c ·X c ·A c ·D c

[0030] wherein, G c is the quantitative evaluation comprehensive factor, R c is the source-receiver contribution coefficient, F c is the coverage distribution coefficient, X c is the source-receiver offset contribution coefficient, A c is the azimuth contribution coefficient, D c is the element concentration coefficient.

[0031] Based on the same concept, a system for quantitatively evaluating the performance of an observation system is also proposed, including at least one processor and a memory communicatively connected to the at least one processor; the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the method of any one of the above.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] 1) The present invention proposes a quantitative analysis method based on the comprehensive evaluation of exploration cost and cost performance, which is designed according to the geometric exploration cost requirements and the target, and has important guiding significance in the actual design of seismic acquisition observation systems, enabling the selected observation system to better meet the project geological task requirements.

[0034] 2) The quantitative analysis and evaluation are carried out by using the multi-attribute uniformity of the observation systems that are relatively mature at home and abroad, and the contribution coefficient factors such as source-receiver distribution, coverage, source-receiver offset, and azimuth with practical significance are given. The meaning of the quantitative factors is simple and clear, and the application is simple and convenient, and it can be well applied to actual production.

[0035] 3) Quantitatively express the influence degrees of various key factors for evaluating the observation system, making it easier to clarify the objectives of optimizing and selecting the observation system, thus contributing to improving the quantification and optimization design level of the 3D observation system, and evaluating the value of the observation system more from the perspectives of method design and exploration target, reducing the influence of human factors on the comprehensive evaluation of the observation system attributes.

[0036] 4) Establishment of the comprehensive attribute contribution factor of the observation system, which gives an objective quantitative evaluation value to different observation systems, can comprehensively evaluate the three-dimensional observation system for the target layer as a whole, more effectively guide the optimization design of the observation system, and can more optimally meet the geological exploration objectives of the observation system, improving the imaging accuracy of data. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is the main flowchart of a method for quantitatively evaluating the performance of an observation system in Embodiment 1 of the present invention;

[0038] Figure 2 is the detailed flowchart of a method for quantitatively evaluating the performance of an observation system in Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] The present invention will be further described in detail below in conjunction with test examples and specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments. All technologies implemented based on the content of the present invention belong to the scope of the present invention.

[0040] Embodiment 1

[0041] The present invention proposes a method for quantitatively evaluating the performance of an observation system. The main flowchart is as Figure 1 shown, and the steps include: S1. Determine the target area of the three-dimensional seismic observation system, and evenly divide the target area of the observation system into multiple bins according to the required size; S2. Calculate the overall source-receiver contribution coefficient, coverage distribution coefficient, source-receiver offset contribution coefficient, azimuth contribution coefficient, and concentration distribution coefficient of the target layer in the target area respectively according to the bins; S3. Calculate the quantitative evaluation comprehensive factor of the three-dimensional seismic observation system for the target layer according to the overall source-receiver contribution coefficient, coverage distribution coefficient, source-receiver offset distribution coefficient, azimuth contribution coefficient, and concentration distribution coefficient. The evaluation comprehensive factor is used to determine the size of the comprehensive performance of the observation system for the target layer.

[0042] A method for quantitatively evaluating the design performance of a three-dimensional seismic observation system is used to quantitatively evaluate the performance of the designed observation system for the target area. The specific steps include:

[0043] According to the set three-dimensional seismic observation system, design the source-receivers for the target area, and evenly divide the target area of the three-dimensional seismic observation system into multiple bins according to the required size;

[0044] Calculate the total number of source-receivers in the target area, the density of source-receiver distribution within a unit array, the coverage times of each bin of the target layer, the source-receiver offset of each source-receiver pair, the azimuth of each source-receiver pair, and the position of the midpoint of each source-receiver pair;

[0045] Calculate the shot-receiver contribution coefficient based on the total number of shot-receiver points in the target area and the density of shot-receiver point distribution within a unit array. In particular, calculate for the full-coverage area of the target layer.

[0046] Calculate the mean and variance of the effective coverage times of all bins in the target layer within the target area, and calculate the coverage times distribution coefficient, by combining the coverage times of each bin in the target area with the vertical and horizontal coverage times of the acquisition system. In particular, calculate for the full-coverage area of the target layer.

[0047] Calculate the optimum matching coefficient, effective coefficient, uniformity coefficient, and contribution coefficient of the offset for the depth range of the target layer, based on the offset of each shot-receiver wave point pair of each bin in the target area and the buried depth of the target layer of the acquisition system in the target area. Then calculate the comprehensive contribution factor of the offset according to the three coefficients. In particular, calculate for the full-coverage area of the target layer.

[0048] Calculate the azimuth distribution coefficient of all bins in the target layer within the target area based on the azimuth of each shot-receiver wave point pair of each bin. Mainly calculate the effective distribution coefficient of the azimuth, then calculate the mean and variance of the azimuth distribution coefficient, and use the mean and variance to calculate the contribution coefficient of the overall azimuth distribution in the target area. In particular, calculate for the full-coverage area of the target layer.

[0049] Calculate the midpoint distribution concentration coefficient of each bin based on the position of the midpoint of each shot-receiver wave point pair of all bins in the target area. Then calculate the mean and variance of the midpoint distribution concentration coefficient in the target area, and calculate the overall midpoint distribution coefficient value in the target area. In particular, calculate for the full-coverage area of the target layer.

[0050] Calculate the quantitative evaluation comprehensive factor of the acquisition system based on the overall shot-receiver contribution coefficient, coverage times contribution coefficient, offset distribution coefficient, azimuth distribution coefficient, and midpoint concentration distribution coefficient of the target layer in the target area. Determine the comprehensive performance of the acquisition system suitable for the target layer according to the comparison of the factor values. In particular, calculate for the full-coverage area of the target layer.

[0051] Compared with the method in the prior art that only determines the uniformity degree of bin attributes of the three-dimensional seismic observation system through the observation and practical experience of designers, in one embodiment, first, a theoretical design of the observation system is carried out for the exploration target, the total number of shot points and geophone points required and the density of the designed distribution of shot and geophone points in the target area are calculated, then the target area is divided into bins, and for each bin, the offset size, azimuth value of each shot-geophone pair included, and the CMP midpoint position coordinates generated are calculated. Then, the shot-geophone contribution coefficient, coverage times contribution coefficient, offset distribution coefficient, azimuth distribution coefficient, and CMP concentration distribution coefficient are calculated by using the total number and distribution density of shot-geophone points and the offset, azimuth, and CMP position information of the shot-geophone pairs for the target layer in each bin. Finally, the total contribution coefficient factor value of the observation system is comprehensively calculated according to each contribution coefficient, and the three-dimensional observation system is overall evaluated comprehensively to determine the adaptability performance of the three-dimensional seismic observation system for the target layer, so as to optimize and select a suitable three-dimensional seismic observation system. Therefore, by using the technical solution provided by the present invention, the performance factor of the observation system can be quickly determined, and the subtle comparison of multiple observation systems can be realized, so as to optimize and select among multiple similar observation systems, improve the quality of seismic exploration acquisition data, and facilitate high-precision and high-quality seismic imaging of subsequent geological targets.

[0052] Calculating the shot-geophone contribution coefficient of the observation system specifically includes the following steps:

[0053] Calculating the shot-geophone contribution coefficient R c , it is necessary to use the shot line distance Ls, shot point distance Ds, geophone line distance Lr, geophone point distance Dr of the observation system in the target area and the longitudinal bin size B i and the transverse bin size B x .

[0054]

[0055] Calculating the coverage times contribution coefficient F for the depth of the target layer in the target area c , including the following steps:

[0056] Calculating the overall effective coefficient F for the depth of the target layer in the target area e , it is necessary to obtain according to the total coverage times Ft, longitudinal coverage times Fi and transverse coverage times Fx of the three-dimensional observation system:

[0057]

[0058] Calculating the coverage times distribution uniformity coefficient U within the bin for the depth of the target layer in the target area f , it is necessary to use the effective coverage times F k of each bin and the average coverage times of the target layer within the bin

[0059]

[0060] Calculate the contribution coefficient F of the coverage times for the target layer depth in the target area c , which needs to combine the uniform distribution factor U of the coverage times f , the overall coverage times effective coefficient F e and the average value of the coverage times within the bin

[0061]

[0062] Calculate the offset contribution coefficient X for the target layer depth in the target area c , including:

[0063] According to the optimal target layer depth H, calculate the optimal matching coefficient value O of the overall maximum offset Xmax in the acquisition system design index x , combined with the seismic data processing method, using the default selection principle for the maximum offset selection, considering that the reflected energy of the target layer can be close to 100%, we select the optimal maximum offset as 1.5 times the target layer depth, that is, 1.5H. Therefore, the calculation formula for the offset effective coefficient value can be:

[0064]

[0065] Calculate the offset effective coefficient O in each bin c . Judging whether an offset is effective is based on the actual offset O within the bin tk and the ideal offset O rk . If the absolute value of the difference between them is less than or equal to half of the ideal offset change increment ΔO, it should be regarded as an effective offset. If this gap becomes larger, the effectiveness of the bin becomes smaller. Therefore, use the weighting coefficient W k to define the offset effective coefficient O within each bin c The expression is, the formula is:

[0066]

[0067] Calculate the change uniformity U of the effective distribution coefficient of the target layer depth in the target area x , which needs to combine the offset effective distribution coefficient O in each bin ck and the average value of the offset effective coefficient of the target layer within the bin The formula is:

[0068]

[0069] Calculate the offset contribution coefficient X for the target layer depth in the target area c, it is necessary to utilize the optimal matching coefficient value O of the maximum offset Xmax of the observation system scheme x , and combine the uniformity degree U of the variation of the offset distribution coefficient within the bin in the target area x and the average value of the offset distribution coefficient to calculate the offset contribution coefficient X c . The formula is:

[0070]

[0071] Calculate the azimuth contribution coefficient A for the target layer depth in the target area c , including:

[0072] Calculate the azimuth contribution coefficient A within the bin for the target layer depth in the target area e , it is necessary to utilize the longitudinal width D of the observation system array slice iL , the transverse width D xL , the gun line distance Ls, the shot point distance Ds, the receiver line distance Lr, and the receiver point distance Dr to calculate the azimuth effective coefficient A of the overall observation system design e . The formula is:

[0073]

[0074] Calculate the azimuth distribution uniformity coefficient U within the bin for the target layer depth in the target area a , it is necessary to utilize the azimuth A in each bin k and the average value of all azimuths of the target layer within the bin The formula is:

[0075]

[0076] Calculate the azimuth contribution coefficient A within the bin for the target layer depth in the target area c , it is necessary to utilize the azimuth uniformity degree distribution coefficient U in each bin a and the overall effective azimuth A e , and combine the average value of the azimuth uniformity degree within the target layer bin in the target area The formula is:

[0077]

[0078] Calculate the CMP concentration distribution coefficient D of the observation system c , including:

[0079] It is necessary to consider the distribution of CMP points in each bin within the target area. Different combinations of shot and receiver points will result in different distribution patterns of CMP points within the bin. Or when the bin size is changed from a large size to a small size, it will also cause changes in the distribution trend of CMP points within the bin. Calculate the bin concentration coefficient D c : It is necessary to consider the longitudinal bin size B i and the transverse bin size B x and the average distance value of each CMP point within the bin from the center point The calculation formula is:

[0080]

[0081] To calculate the design performance coefficient of the acquisition geometry for the target layer depth in the target area, it is necessary to combine the shot-receiver contribution coefficient R c , the coverage contribution coefficient F c , the offset contribution coefficient X c , the azimuth contribution coefficient A c and the CMP concentration distribution coefficient D c to construct an evaluation factor G for quantitatively evaluating the design performance of the acquisition geometry c . By the magnitude of the value of the quantitative evaluation factor, the design performance of an acquisition geometry for the target layer can be judged. The calculation formula is:

[0082] G c = R c · F c · X c · A c · D c

[0083] The detailed flowchart of the above method for quantitatively evaluating the performance of an acquisition geometry is as shown in Figure 2 .

[0084] The foregoing has shown and described the basic principles, main features and advantages of the present invention. For those skilled in the art, it is obvious that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, in whatever aspect, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

[0085] In addition, it should be understood that although this specification is described according to embodiments, the embodiments do not only include an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in the embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for quantitatively evaluating the performance of an observation system, characterized in that, It includes the following steps: S1. Determine the target area of the 3D seismic observation system, and evenly divide the target area of the 3D seismic observation system into multiple bins according to the required size; S2. According to the bins, calculate the overall shot-receiver contribution coefficient, coverage distribution coefficient, shot-receiver distance contribution coefficient, azimuth contribution coefficient, and concentration distribution coefficient for the target layer in the target area respectively; S3. Calculate the quantitative evaluation comprehensive factor of the 3D seismic observation system for the target layer according to the overall shot-receiver contribution coefficient, coverage distribution coefficient, shot-receiver distance contribution coefficient, azimuth contribution coefficient, and concentration distribution coefficient. The evaluation comprehensive factor is used to determine the comprehensive performance of the observation system for the target layer; The calculation formula for the overall shot-receiver contribution coefficient is: Among them, R c is the contribution coefficient of shot-receiver points, Ls is the shot line distance of the three-dimensional seismic acquisition system in the target area, Ds is the shot point distance, Lr is the receiver line distance, Dr is the receiver point distance, is the longitudinal bin size, is the lateral bin size; The coverage distribution coefficient is: F c = F e · Among them, F c is the coverage number distribution coefficient, is the full coverage number distribution uniformity coefficient, is the overall effective coefficient of the three-dimensional seismic observation system, is the average value of the depth coverage number of the target layer in the target area; The calculation formula for the shot-receiver distance contribution coefficient is: X c = O x · Among them, X c is the shot-receiver offset contribution coefficient, O x is the best matching coefficient of the maximum shot-receiver offset in the acquisition system scheme, is the degree of uniformity of the change in the shot-receiver offset distribution coefficient, is the average value of the shot-receiver offset distribution coefficient within the depth bin of the target layer in the target area; The calculation formula for the azimuth contribution coefficient is: A c = A e · Among them, A c is the azimuth contribution coefficient, the azimuth effective coefficient of the overall acquisition system design, U a is the azimuth uniformity coefficient within the depth bin of the target layer in the target area, and is the average value of the azimuth uniformity within the depth bin of the target layer in the target area; The calculation formula for the concentration distribution coefficient is: Among them, is the surface element concentration coefficient, is the longitudinal surface element size, is the transverse surface element size, is the average distance value of each CMP point in the surface element from the center point; The calculation formula for the quantitative evaluation comprehensive factor is: G c = R c ·F c ·X c ·A c · Among them, G c is the quantitative evaluation comprehensive factor, R c is the shot-receiver point contribution coefficient, F c is the coverage number distribution coefficient, X c is the shot-receiver offset contribution coefficient, A c is the azimuth contribution coefficient, is the bin concentration coefficient.

2. A system for quantitatively evaluating the performance of an observation system, characterized in that, It includes at least one processor and a memory communicatively connected to the at least one processor; The memory stores instructions executable by the at least one processor. The instructions are executed by the at least one processor so that the at least one processor can execute the method according to claim 1.

Images