Seismic data acquisition method based on reservoir prediction
By designing the range of the central angle and incident angle for seismic data acquisition, a seismic acquisition and observation system was established. By integrating new and old data, the problem of the inability of existing seismic data to effectively predict reservoirs was solved, resulting in more efficient reservoir and fracture prediction and reduced costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SINOPEC OILFIELD SERVICE CORPORATION
- Filing Date
- 2025-10-31
- Publication Date
- 2026-04-10
AI Technical Summary
Existing seismic data acquisition methods are mainly based on structural interpretation, resulting in narrow azimuth angles that cannot effectively support reservoir prediction. Furthermore, wide-azimuth seismic acquisition is costly and difficult to promote on a large scale.
By designing the range of the central angle and incident angle of the acquisition elements, determining the acquisition azimuth window and shot-receiver distance window, setting the number of coverages, establishing a seismic acquisition and observation system, and fusing new and old seismic data, a seismic data volume for accurate prediction of reservoirs and fractures is formed.
It increases the information content of seismic data, supports more accurate reservoir and fracture prediction, reduces costs, and is economically and technically feasible.
Smart Images
Figure CN121834640A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of oil and gas exploration, and in particular to a method for seismic data acquisition parameter design based on reservoir prediction. BACKGROUND
[0002] In the field of geophysical exploration, after obtaining seismic data by conventional seismic acquisition method, the seismic data needs to be processed, interpreted and inverted, and the obtained results are used for exploration well site demonstration. Therefore, the seismic data obtained by seismic acquisition has a great influence on subsequent work, and may determine the success or failure of subsequent related work.
[0003] A large number of exploration practices show that the previous seismic data acquisition is mainly based on structural interpretation, and the seismic data has the problem of narrow azimuth, which is not conducive to subsequent reservoir prediction work. For example, in the prediction of continental channel reservoirs in a certain area in northeast Sichuan, due to the narrow azimuth of the seismic data acquisition data, the accuracy of the related channel reservoir fracture prediction results is relatively poor, which also directly affects the deployment of well sites.
[0004] In general, the present seismic exploration technology has developed rapidly, and the reservoir prediction technology for lithology and fracture prediction has been widely applied in various oil field exploration. However, these technologies have very high requirements for seismic gather data, such as requiring the gather to have a certain resolution and signal-to-noise ratio, and some fracture prediction technologies also require the seismic gather data to have azimuthal characteristics, i.e. to ensure that the data within a certain azimuth range has a certain signal-to-noise ratio and resolution. At present, seismic data acquisition mainly serves structural interpretation, and less consideration is given to reservoir prediction. Such seismic data is not conducive to reservoir prediction and evaluation, and of course the accuracy of the reservoir prediction results is greatly reduced. In recent years, some oil fields have also implemented wide-azimuth seismic acquisition and 3D3C seismic acquisition, but these seismic acquisition technologies are high in cost and are not easy to be widely applied in oil and gas exploration, and the related processing and interpretation technologies are still in the exploration stage, and their practicality needs to be discussed.
[0005] Based on the comprehensive analysis of the present three-dimensional seismic acquisition technology, the following problems exist:
[0006] ① The data obtained by conventional seismic acquisition is mainly narrow-azimuth, which is not conducive to fracture prediction.
[0007] ② The full stack number of seismic data is often covered in a certain offset range, which is not conducive to AVO analysis.
[0008] ③ The full-azimuth seismic acquisition has the characteristics of high cost, which is not conducive to its promotion. SUMMARY
[0009] The application provides a method for seismic data acquisition based on reservoir prediction, which can solve the problem that the seismic data obtained by conventional seismic acquisition can only be used for structural interpretation and cannot be used for oil and gas bearing property prediction and evaluation of reservoirs, and has the characteristics of economic feasibility and strong technical operability. The method mainly increases the related seismic workload in the original working area to improve the defects of previous seismic data in reservoir prediction, or implements the seismic acquisition method of the application to the designed drilling point position, and the obtained seismic data volume is beneficial to further evaluate the feasibility of related drilling.
[0010] Technical scheme:
[0011] The application provides a method for seismic data acquisition based on reservoir prediction, which comprises the following steps:
[0012] ① Determining the center angles of the seismic acquisition to be implemented according to the acquisition parameters of the previous three-dimensional seismic data, and determining the azimuth range according to the center angles to obtain the acquisition window of each center angle;
[0013] ② Setting the stacking times of different offset ranges for the acquisition window of each center angle, and designing the related observation system to implement new seismic data acquisition;
[0014] ③ Implementing seismic data fusion of the seismic data obtained by the previous three-dimensional seismic data acquisition and the newly acquired three-dimensional seismic data according to the determined related parameters to obtain a seismic data volume for accurate prediction of reservoirs and fractures.
[0015] Further, the center angles of the seismic acquisition to be implemented are determined according to the acquisition parameters of the previous three-dimensional seismic data, and the azimuth range is determined according to the center angles to obtain the acquisition window of each center angle, which specifically comprises the following steps:
[0016] The design of the center angle sets the north direction as 0°, rotates clockwise to 360°, converts the 0°-360° azimuth to 0°-180° azimuth based on the symmetry principle of seismic acquisition, determines the related old center angle and azimuth range according to the previous three-dimensional seismic acquisition data, and designs the center angle and related azimuth range of the three-dimensional seismic data to be acquired in the 0°-180° azimuth by using the two parameters. The designed center angle of the three-dimensional seismic data to be acquired should ensure that there are two or more acquisition center angles; if there is no previous seismic data, the number of the center angles of the three-dimensional seismic data to be acquired is required to be three or more. The setting of the center angle should be determined according to the fracture development direction of the exploration area, the seismic exploration precision requirement, expert experience, etc., and in principle, the center angles should be fixed angle values.
[0017] According to the design, the azimuth angle window range related to each acquisition center angle is set, that is, each acquisition center angle is added or subtracted by a fixed angle value to obtain each acquisition azimuth angle window value.
[0018] Further, the stacking times of different offset ranges are set for the acquisition window of each center angle, and a new seismic data acquisition is implemented by designing a related observation system, specifically including:
[0019] According to the acquisition window of each center angle, the stacking times of different offset ranges are determined, and the stacking times of different offsets are required to be equal or approximately consistent. The stacking times of each offset range can be determined according to the seismic acquisition requirements and actual conditions. In principle, the stacking times of different offset ranges can be averagely distributed according to the stacking times of the previous three-dimensional seismic acquisition. The number of different offset ranges is required to be greater than three in principle. The offset in the invention refers to the distance from the shooting point to the center of any geophone group, that is, the offset distance.
[0020] According to the acquisition window data designed above, a corresponding field acquisition observation system is designed, and then the seismic data acquisition is implemented in the exploration area. Through the seismic data acquisition, a new three-dimensional seismic data body is obtained. In principle, the trace interval of the newly acquired three-dimensional seismic data is required to be consistent with the trace interval of the previously acquired three-dimensional receiving line, and the shot line interval and the inter-shot distance, the receiving line interval can be designed according to the requirements of the stacking times.
[0021] Further, the seismic data body acquired by the previous three-dimensional seismic data acquisition and the new three-dimensional seismic data body are fused according to the determined related parameters to obtain a seismic data body for accurate prediction of reservoirs and fractures, specifically including:
[0022] The newly acquired three-dimensional seismic data is geometrically defined and placed in the head in the seismic processing system, the same bin as the previous three-dimensional seismic data is determined, and the previous three-dimensional seismic data and the newly acquired three-dimensional seismic data are fused in the same processing bin to obtain a seismic data body for reservoir and fracture prediction.
[0023] If there is no previous three-dimensional seismic data in the exploration area, this step can be omitted.
[0024] Advantages of the invention
[0025] The application provides a method for seismic acquisition parameter design for reservoir prediction, which comprises the following steps: designing each acquisition central angle and related incident angle range of an acquisition bin, and performing related calculation to obtain each acquisition azimuth angle window value and shot-receiver distance window value; obtaining an acquisition window by using each acquisition azimuth angle window value and shot-receiver distance window value, and determining the fold number in the acquisition window, so as to obtain an acquisition window parameter; and designing a corresponding seismic acquisition observation system according to the acquisition window parameter, and performing seismic data acquisition. The seismic data obtained by the method can be used for structure interpretation, lithology and reservoir prediction, fracture prediction and other work, and has the characteristics of more information, economic feasibility and reliable technology compared with the seismic data obtained by conventional seismic acquisition. BRIEF DESCRIPTION OF DRAWINGS
[0026] Figure 1 FIG. 1 is a flowchart of a seismic acquisition parameter design method according to an embodiment of the application.
[0027] Figure 2 FIG. 2 is a diagram of a method for designing a central angle and an azimuth angle range according to an embodiment of the application.
[0028] Figure 3 FIG. 3 is a diagram of a seismic acquisition window parameter design method according to an embodiment of the application. DETAILED DESCRIPTION
[0029] The application will be further described below in combination with embodiments, but the protection scope of the application is not limited to the embodiments.
[0030] The execution subject of the embodiment is seismic acquisition parameter design, and an observation system for the designed seismic acquisition parameter is established.
[0031] Figure 1 FIG. 1 is a flowchart of a seismic acquisition parameter design method according to an embodiment of the application. Figure 1 The method provided by the application comprises the following steps:
[0032] In step 101, each central angle of the seismic acquisition to be implemented is determined according to the acquisition parameters of previous three-dimensional seismic data, and an azimuth angle range is determined according to the central angle, so as to obtain an acquisition window of each central angle.
[0033] Specifically, the acquisition bin refers to a CDP bin in three-dimensional seismic data acquisition, and the size of the general bin is 20mX20m. The edge length of the bin is determined by considering three factors: target scale, highest alias-free frequency calculated from dip angle, and lateral resolution.
[0034] Furthermore, the design of each acquisition center angle specifically involves setting true north as 0° and rotating clockwise to 360°. Based on the symmetry principle of seismic data acquisition, the 0°–360° azimuth is converted to a 0°–180° azimuth. The relevant old center angles and azimuth ranges are determined based on previous 3D seismic acquisition data. Using these two parameters, the center angles and related azimuth ranges for the proposed 3D seismic data acquisition are designed within the 0°–180° azimuth range. The designed center angles for the proposed 3D seismic data acquisition should include two or more acquisition center angles; if no previously acquired seismic data is available, the number of center angles should be three or more. The setting of the center angles should be determined based on the fracture development direction of the exploration area, the required seismic exploration accuracy, and expert experience. In principle, the center angles should be fixed angle values. In practice, the acquisition center angles are mainly designed by equal division and interpolation within the 0°–180° azimuth range. The calculation formula is as follows:
[0035]
[0036] In formula (1) Let k be the data value of the i-th central angle, where k is a multiple. To collect the increment of the central angle, To design the minimum acquisition center angle,
[0037] Based on the center angles of each acquisition element in the design, the relevant azimuth window range is set. This is achieved by adding or subtracting a fixed angle value from each center angle to obtain the azimuth window value. The formula for calculating the azimuth window range is as follows:
[0038]
[0039] In equations (2) and (3) Let be the minimum azimuth angle of the i-th acquisition azimuth window. The maximum azimuth angle of the i-th acquisition azimuth window. Δm represents the i-th collected center angle data value, and Δm is the set fixed azimuth angle value.
[0040] The determination of the offset range mainly involves setting different incident angle ranges for the target layer and determining them based on acquisition requirements and actual conditions, with a maximum incident angle ≥30°. Different incident angle ranges are set between 0° and 30° according to relevant requirements, and different offset ranges are determined based on the incident angle range and the average burial depth of the target layer. In principle, the method for determining the offset range is as follows:
[0041] a, determine the average depth of the target layer. The specific operation is to obtain the maximum and minimum depth values of the target layer by using relevant data, and the average value of the two is the depth of the target layer. The calculation formula of the average depth of the target layer is as follows:
[0042] h = 1 / 2 (h min +h mmax ) (4)
[0043] In formula (4), h is the depth of the target layer, h min is the minimum depth value of the target layer, and h max is the maximum depth value of the target layer.
[0044] b, set different incidence angle range values for the target layer, and determine different offset ranges according to the average depth value of the target layer and the related calculation formula. The calculation related to offset is as follows:
[0045] x = 2 * k * h * tan theta (5)
[0046] In formula (5), h is the depth of the target layer, k is a constant value generally selected as an integer value between 0.8-1.2, and the principle is to take 1, theta is the incidence angle value, and x is the offset value. According to the set incidence angle range value (the maximum incidence angle and the minimum incidence angle), and according to the formula (5), the minimum offset and the maximum offset value are calculated.
[0047] Generally, for each different incidence angle range of the target layer, the related range is set to three incidence angle ranges of 3°-10°, 10°-20°, and 20°-30° in principle, and the number of incidence angle ranges can be increased according to actual needs, which can be set to equal interval or unequal interval. The stacking times in the same offset range should be relatively uniform.
[0048] Preferably, if there is only two-dimensional seismic data result in the study area, the approximate position and depth of the target layer, the fracture development area and direction, and other data of the reservoir can be determined according to the two-dimensional seismic data result, the center angle of the new seismic data collection is determined, the azimuth range is determined according to the center angle, and the collection window of each center angle is obtained.
[0049] Step 102, determine the stacking times of different offset ranges for the collection window of each center angle, and implement new seismic data collection.
[0050] Specifically, the stacking times of different offset ranges for the collection window of each center angle are determined. The full stacking times of the previous three-dimensional seismic data are obtained to determine the stacking times of different offset ranges in each center angle, and the stacking times of different offset ranges are required to be basically the same or substantially consistent. Generally, the determination formula of the stacking times is as follows:
[0051] pi = A i *|P / T| (6)
[0052] In equation (6), p i Let A be the number of stacks for the i-th offset range, P be the number of full stacks for a designed azimuth range, which is generally taken as the number of full stacks for previous 3D seismic data. i is the coefficient value of the i-th offset range, which is generally greater than 0.75, and T is the number of different offset ranges designed.
[0053] Based on the azimuth and offset window values for each acquisition, the relevant acquisition window range is determined. A predetermined number of coverage operations is then designed for each acquisition window, establishing a field seismic acquisition observation system to facilitate seismic data acquisition in the exploration area. Through field seismic data acquisition, new 3D seismic data can be obtained.
[0054] Step 103: The seismic data volume acquired previously and the newly acquired 3D seismic data volume are fused according to the determined relevant parameters to obtain a seismic data volume for accurate prediction of reservoirs and fractures.
[0055] The specific operation involves geometrically defining and assigning trace heads to the new 3D seismic data in the seismic processing system, identifying the same surface cells as the previous 3D seismic data, and then performing gather fusion on the previous 3D seismic data and the newly acquired 3D seismic data based on the same surface cell location, thereby obtaining a seismic data volume for reservoir and fracture prediction.
[0056] The following specific embodiments illustrate the above steps.
[0057] This example demonstrates the design of seismic acquisition parameters for marine shale layers in a 3D work area, primarily based on the invented technical process. Figure 1 ), and establish a related seismic observation system to acquire seismic data. First, design the acquisition center angles and optimal incident angles for each acquisition element. Based on previous 3D seismic data, determine the range of center angles and azimuth angles for this 3D data. Figure 2 In the example, the central angle of previous 3D seismic data was 90°, and the azimuth range was 70° to 110°. Therefore, two central angles were designed in the new 3D seismic data acquisition, with data values of 30° and 140°, and azimuth ranges of 10° to 50° and 120° to 160°, respectively.
[0058] Second step is to determine each acquisition window parameter. According to each acquisition center angle, set the number of stack of different offset range in the relevant azimuth angle window, the number of stack of different offset range should be consistent, and the number of stack in the same offset range should be relatively uniform. In the example, the incident angle value of offset range in each center angle is set as three incident angle ranges of 5°-12°, 12°-20° and 20°-30°. According to the average depth of the target layer of 2430m, and according to the relevant calculation formula and integer, the three offset range values are determined as 430-1040m, 1040-1780m and 1780-2810m. Therefore, the acquisition window parameters are obtained by comprehensively considering the above acquisition azimuth angle window and offset window parameters. Figure 3 Since the full stack number of the data of the previous three-dimensional seismic acquisition is 290, the coverage number of each offset range is designed as 100.
[0059] The third step is to fuse the newly acquired three-dimensional seismic data with the previous three-dimensional seismic acquisition data to obtain a fused three-dimensional seismic data volume. Specifically, a 20mX20m bin is determined in the relevant processing system, and the new and old three-dimensional seismic data are reconstructed according to each bin to obtain a new three-dimensional data volume. The three-dimensional data volume can be used for subsequent oil and gas and fracture detection, and the results show that the accuracy of the relevant prediction results is widely improved compared with the previous prediction results.
[0060] In this example two, the relevant shale gas pilot hole point in a two-dimensional work area is implemented local three-dimensional seismic data acquisition, mainly according to the technical process of the invention to carry out Figure 1 ), and a relevant seismic observation system is established to implement seismic data acquisition. The subsequent seismic data is used to evaluate the shale reservoir and determine the subsequent horizontal well trajectory position. First, the acquisition center angle and the best incident angle of each acquisition bin are designed. According to the previous three-dimensional seismic data, the center angle and the azimuth angle range of the three-dimensional data are determined. In the example, six center angles are designed in the three-dimensional seismic data acquisition, and the center angle data values are 15°, 45° and 75°, 105°, 135° and 165°, and the azimuth angle ranges are 0°-30°, 30°-60°, 60°-90°, 90°-120°, 120°-150° and 150°-180°. The full coverage area of the designed pilot hole location is 18km 2 .
[0061] The second step is to determine the parameters of each acquisition window. Based on the acquisition center angle, the number of superpositions for different offset ranges within the azimuth window is set. The number of superpositions for different offset ranges should be roughly consistent, and the number of superpositions within the same offset range should be relatively uniform. In the example, the incident angle values for the offset ranges targeting the target layer in each center angle are set to three ranges: 5°–10°, 12°–18°, and 22°–30°. Assuming the average burial depth of the target layer is 2710m, and based on relevant calculation formulas and rounding to the nearest integer, the three offset range values are determined to be 480–960m, 1150–1760m, and 2190–3250m, respectively. Therefore, combining the above acquisition azimuth window and shot-receiver distance window parameters, the acquisition window ( Figure 3 The data overlay for this 3D seismic acquisition was set at 720 times, with 120 times coverage at each central corner. Therefore, the coverage for each offset range was designed to be 40 times. Based on the above design, the relevant acquisition window parameters were obtained, and a seismic acquisition and observation system was designed using existing commercial seismic acquisition design software to meet the requirements of this acquisition design.
[0062] Practical operation shows that the seismic data obtained using the small-area, high-coverage acquisition method for evaluating shale reservoirs around the wellbore effectively revealed the location of high-quality shale reservoirs and identified small faults not interpreted in 2D seismic data, thus avoiding the problem of horizontal well trajectories crossing these faults. Furthermore, after processing the gather data by azimuth and offset, AVO calculations were performed to obtain gradient and intercept data for each central angle. These data were used to effectively evaluate the gas content and fracture development intensity of the target layer, achieving the geological objectives.
[0063] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
Claims
1. A method of seismic data acquisition based on reservoir prediction, characterized in that It comprises: ①According to the acquisition parameters of the previous three-dimensional seismic data, the center angles of the seismic acquisition are determined, and the azimuth range is determined according to the center angle, and the acquisition window of each center angle is obtained; ②The stacking times of different offset ranges are set for the acquisition window of each center angle, and the related observation system is designed to implement new seismic data acquisition; ③The seismic data volume of the previous three-dimensional seismic data acquisition and the new three-dimensional seismic data volume are fused according to the determined related parameters to obtain a seismic data volume for accurate prediction of reservoirs and fractures.
2. The method of claim 1, wherein, Step ① specifically comprises: The design of the acquisition center angle is to set the north direction as 0°, clockwise rotation as 360°, based on the symmetry principle of seismic acquisition, 0°-180° azimuth is converted from 0°-360° azimuth; According to the related old center angle and azimuth range determined by the previous three-dimensional seismic acquisition data, the center angle and the related azimuth range of the three-dimensional seismic data to be collected are designed in 0°-180° azimuth; Among them, the designed center angle of the three-dimensional seismic data to be collected should ensure that there are two or more acquisition center angles; If there is no previous three-dimensional seismic acquisition data, the number of center angles of the three-dimensional seismic data to be collected requires three or more.
3. The method of claim 1, wherein, In step ①, the setting of the center angle is determined according to the fracture development direction of the exploration area, the seismic exploration precision requirement and expert experience.
4. The method of claim 1, wherein, In step ①, the center angles are fixed angle values.
5. The method of claim 1, wherein, In step ①, each acquisition center angle plus or minus a fixed angle value is obtained as each acquisition azimuth window value.
6. The method of claim 1, wherein, In step ②, the stacking times of different offset ranges are determined according to the acquisition window of each center angle, and the stacking times of different offsets are required to be equal or approximately consistent; The stacking times of each offset range are determined according to the actual situation and the requirements of seismic acquisition.
7. The method of claim 6, wherein, In step ②, the stacking times of different offset ranges are averagely distributed according to the stacking times of the previous three-dimensional seismic acquisition; The number of different offset ranges is required to be greater than three.
8. The method of claim 1, wherein, In step ②, the trace interval of the newly collected three-dimensional seismic data is consistent with the receiving line trace interval of the previously collected three-dimensional data, and the shot line interval and the inter-shot distance, the receiving line interval are designed according to the requirements of the stacking times.
9. The method of claim 1, wherein, In step ③, the new three-dimensional seismic data is geometrically defined, and the trace head is set in the seismic processing system, and the bin is determined as the same as the previous three-dimensional seismic data, and the previous three-dimensional seismic data and the new three-dimensional seismic data are fused in the same processing bin. Get a seismic data volume for reservoir and fracture prediction.
10. The method of claim 1, wherein, In step ③, if there is no previous three-dimensional seismic data in the exploration area, the new three-dimensional seismic data volume is directly used as a seismic data volume for accurate prediction of reservoirs and fractures.