Method for obtaining minor fault for seismic tectonic interpretation

Abstract

The invention discloses a method for obtaining a minor fault for seismic tectonic interpretation. The method comprises the steps that (a) spectral analysis is carried out on seismic data so that the spectral range of the seismic data can be obtained; (b) spectral decomposition is carried out through generalized S conversion, the parameters of fractional frequency are determined according to the spectral range obtained in the step (a); (c) high-resolution coherence analysis is carried out on high-frequency fractional frequency seismic data, middle-frequency fractional frequency seismic data and low-frequency fractional frequency seismic data by adopting a coherence method, and the coherence bodies of data bodies of different frequency bands are obtained; (d) fault lines of strata slice interpretation projection are extracted at the corresponding positions on the seismic sections of the fractional frequency seismic data bodies of the corresponding frequency bands, and the extending and spreading conditions of the fault on a time section are interpreted. According to the method for obtaining the minor fault for seismic tectonic interpretation, coherence body fault plane recognition is carried out by adopting a strata slice mode, the situation of loss, caused by tectonic reasons, of minor fault information can be eliminated, and tiny faults can be recognized more easily. The faults are interpreted on the sections of the fractional frequency seismic data bodies of the different frequency bands, the fault information of different scales can be recognized, and the interpretation of the minor fault is facilitated.

Description

technical field [0001] The invention relates to a seismic signal processing method, in particular to a small fault acquisition method for seismic structure interpretation. Background technique [0002] A fault is a geological phenomenon in which the crustal rock layer is ruptured due to the force reaching a certain strength, and there is obvious relative movement along the rupture surface. In the field of oil and gas exploration and development, faults have both communication and sealing functions. Faults affect and control oil and gas storage conditions, migration channels, sealability of caprocks, and effectiveness of traps, etc., affect trap evaluation, reserve calculation, deployment and adjustment of development plans, and affect the design of development well group plans, Water injection, profile control and water shutoff scheme design, remaining oil distribution, etc. Therefore, the interpretation of faults appears to be crucial. [0003] At present, the seismic da...

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Problems solved by technology

However, this method has high requirements for interpreters' experience and low efficiency. The interpretation results obtained by different interpreters are very different, and it is almost impossible to identify small faults on the seismic section.

2. The computer-aided identification method can effectively improve the efficiency of fault interpretation and improve the correctness of fault combinations, but it is difficult to identify small faults

The existing frequency-division-assisted fault interpretation method is interpreted in the frequency domain, which has the problems of high identification difficulty, automatic identification, manual identification only, and the large difference from the conventional time section, which makes fault identification operation difficult

Traditional fault interpretation based on coherent data volumes usually uses the original seismic data in the full frequency band for coherent analysis. Geological phenomena of different scales are mixed together, which easily conceals tiny geological features. The analysis method usually uses isochronous slices , and almost all commercial seismic interpretation software do not support fault interpretation on stratigraphic slices or horizon slices, this interpretation method is likely to affect the identification of small faults due to structural fluctuations

3. The computer automatic identification method can greatly improve the efficiency of fault interpretation, but the fault combination is more difficult, and it is necessary to manually carefully screen the small fault slices identified by the computer, and then complete the combination. It is less applicable to work areas with low seismic data quality. Poor, and because there are too many small fault slices identified, it is very difficult to distinguish small faults, and it is almost difficult to achieve

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