CN-122017980-A - Method for fault detection based on local angle domain reflection angle imaging gather

CN122017980ACN 122017980 ACN122017980 ACN 122017980ACN-122017980-A

Abstract

The invention provides a fault detection method based on a local angle domain reflection angle imaging gather, and relates to the technical field of petroleum exploration and development. The method comprises the steps of S1, preprocessing an all-dimensional local angle domain reflection angle imaging gather, S2, determining an azimuth dividing scheme, S3, carrying out azimuth dividing superposition on all-dimensional local angle domain reflection angle imaging gather data according to the azimuth dividing scheme of the S2 to obtain an azimuth dividing superposition imaging data body, S4, carrying out seismic attribute calculation according to the azimuth dividing superposition imaging data body obtained in the S3, S5, carrying out principal component analysis and multi-attribute fusion according to the seismic attribute obtained in the S4 to calculate a fusion attribute body, and S6, carrying out fault interpretation and analysis in a three-dimensional space according to the fusion attribute body obtained in the S5 to obtain a fault three-dimensional space layout. The method of the invention improves the identification precision of the trunk fault and the secondary fault, thereby improving the precision of the fault detection.

Inventors

GU WEIXIN
Xin Tianliang
Liao maohui
Ni Liangjian
XU SHAN
CHENG LAN

Assignees

中国石油化工股份有限公司
中国石油化工股份有限公司西北油田分公司

Dates

Publication Date: 20260512
Application Date: 20241111

Claims (10)

1. The method for fault detection based on the local angle domain reflection angle imaging gather is characterized by comprising the following steps: Step S1, preprocessing an omnibearing local angle domain reflection angle imaging gather; s2, determining a azimuth dividing scheme; S3, carrying out azimuth-dividing superposition on the imaging gather data of the reflection angles of the omnibearing local angle domain according to the azimuth dividing scheme of the step S2 to obtain an azimuth-dividing superposition imaging data body; s4, carrying out seismic attribute calculation according to the azimuth superposition imaging data volume obtained in the step S3; s5, performing principal component analysis and multi-attribute fusion according to the seismic attributes obtained in the step S4, and calculating a fusion attribute body; And S6, performing fault interpretation and analysis in a three-dimensional space according to the fusion attribute body obtained in the step S5 to obtain a fault three-dimensional space layout diagram.
2. The method of claim 1, wherein in step S1, the preprocessing specifically includes performing signal-to-noise ratio analysis on the imaging gather of the reflection angle of the omnibearing local angle domain, and improving the quality of the imaging gather data of the reflection angle of the local angle domain by adopting modes such as random noise attenuation, multiple coherent noise suppression and the like.
3. The method of claim 1, wherein in step S1, the preprocessing aims at removing noise and improving the quality of data, and the noise removal is performed by performing time-frequency analysis on the fully superimposed seismic data and then removing high-frequency noise and low-frequency noise outside an effective frequency band by a band-pass filtering method, so that the signal-to-noise ratio of the data is improved.
4. The method according to claim 1, wherein the determining the azimuth dividing scheme in step S2 specifically includes dividing different azimuth sectors according to the fracture trend of the study area, overlapping the imaging gathers of the reflection angles of the local angle domain, and selecting an optimal azimuth dividing scheme according to the identifiability of fracture in the overlapping imaging result.
5. The method of claim 1, wherein in step S4, the seismic attributes include coherence attributes, curvature attributes, and maximum likelihood attributes.
6. The method according to claim 1, wherein in step S5, the calculating the fusion attribute body specifically includes extracting feature information of different seismic attributes, selecting a feature vector corresponding to a maximum feature value as a main feature of the multi-type seismic attributes, reconstructing data based on the main feature, and calculating the fusion attribute body.
7. The method of claim 1, wherein the fault interpretation and analysis in the step S6 is specifically implemented by extracting root mean square amplitude attribute along the target layer based on the coherence and maximum likelihood data body obtained in the step S4 to obtain a target layer coherence attribute and maximum likelihood attribute flat sheet diagram, obtaining a plane spread form of the target layer fracture, then restricting the azimuth superposition data body obtained in the step S3 by using the coherence and maximum likelihood data body obtained in the step S4, interpreting the fracture on the seismic section, referencing the coherence attribute and maximum likelihood attribute flat sheet diagram to the plane trend of the fracture during interpretation, and finally, performing plane combination on the projection point of the fracture interpreted on the section on the target layer, and performing space fracture surface mapping on the fracture to obtain a final fracture interpretation result.
8. A tomographic three-dimensional spatial layout, characterized in that it is obtained by the method according to any one of claims 1 to 7.
9. Use of the method of any one of claims 1-7 in oil and gas exploration, geologic structure analysis, or computer data processing.
10. The use according to claim 9, in particular in high-precision fault detection.

Description

Method for fault detection based on local angle domain reflection angle imaging gather Technical Field The invention belongs to the technical field of petroleum exploration and development, and particularly relates to a fault detection method based on a local angle domain reflection angle imaging gather, in particular to a fault detection method based on an omnibearing local angle domain reflection angle imaging gather. Background The fracture activity makes the adjacent carbonate reservoir of fault easily break, becomes the passageway of oil gas migration to strong fracture activity is crucial to reservoir reformation, also has important influence to the distribution of oil gas simultaneously. Reservoir development scale is controlled by the sliding fracture system of multi-stage activities and fracture erosion. The Oregano system integrally contains oil, and the high-yield stable-yield wells are mainly distributed along the fracture zones of the trunk, which shows that the accumulation and enrichment of oil and gas are mainly controlled by the fracture zones. With the development of computing technology, the processing and analysis capabilities of seismic data have been greatly improved. The omnibearing local angle domain imaging method is a common seismic data processing method, and the prestack omnibearing local angle domain reflection angle gather data obtained through processing can provide richer underground information, thereby being beneficial to improving the fault identification precision. Chinese patent No. CN115877446a discloses a method, computer device and computer readable storage medium for generating azimuth reflection angle gathers. The method comprises the steps of recording excitation amplitude information of a seismic source forward wave field in a reverse time migration process based on excitation amplitude imaging conditions, wherein the excitation amplitude information comprises excitation moments corresponding to the excitation amplitudes and direction vectors corresponding to the excitation amplitudes, approximately reconstructing the seismic source forward wave field by utilizing high-dimensional wavelet function joint excitation amplitude information, obtaining imaging results by applying cross-correlation imaging conditions, calculating direction vectors of a wave-detector reverse wave field in a reverse time continuation process, calculating azimuth angles and reflection angles of illumination of an underground imaging point wave field by means of the recorded direction vectors corresponding to the excitation amplitudes and the wave-detector reverse wave field direction vectors, and distributing the imaging results to the corresponding azimuth angles and reflection angles to obtain azimuth reflection angle gathers. The Chinese patent CN118244347A discloses a reverse time migration reflection angle gather generation method, electronic equipment and a storage medium, wherein the method comprises the following steps of extrapolating a shot point and a wave field of a wave point in reverse time, constructing an energy target functional under gradient constraint on each time slice, iteratively solving the wave field vector directions of the shot point end and the wave field end at the current moment, constructing an adaptive threshold value through global amplitude scanning, screening and generating an effective point table at the current moment, calculating the reflection opening angle and/or azimuth angle of effective points in the table, carrying out interpolation calculation of the reflection opening angle or azimuth angle of invalid points in the set range of each effective point in the table, and determining the gather at an underground imaging point by applying azimuth angle domain cross-correlation imaging conditions. The conventional fault detection technology has the following problems that (1) due to the fact that an Otto target layer is buried deeply, a plurality of volcanic rock speed abnormal bodies exist on the target layer, azimuth anisotropy is caused in the deep layer, so that the fault identification and analysis are challenged, (2) slip fracture is mostly high-angle or vertical development, so that azimuth anisotropy is generated when seismic waves propagate, the difficulty of fault detection is further increased, and (3) due to the fact that the signal-to-noise ratio is low and the resolution ratio is poor, secondary fracture identification of a beaded development area is difficult when the conventional fault detection technology processes post-stack seismic data, great trouble is brought to fault identification and analysis, and Otto fault control reservoir body research is not facilitated. Based on the defects and shortcomings of the traditional method for fault identification by utilizing post-stack seismic data, in order to improve the precision of fault detection, the invention provides a method for fault detection based on an omnibearing local angle domai