Study On Detection Method Of Oil And Gas In Southern Sichuan Seismic Attribute A Multi-scale Fusion

Seismic exploration technique as the main oil and gas exploration means, the main target is structure and reservoir information extracted from seismic data, interpretation and use of the information for the subsurface structure, strata, lithology and hydrocarbon bearing characteristics. For a long time, seismic attribute extraction and analysis technology are regarded as important seismic processing and interpretation methods are widely used, and provide a great help for reservoir prediction. Along with the surge of seismic attribute data, it is beneficial to seismic interpretation on the one hand, but it also brings new challenges. The problem of multiple solutions of attribute has been perplexing the interpretation staff, and there are often inconsistencies and contradictions among various attributes. In order to solve the contradiction between multiple attributes, and to improve the credibility of the interpretation, it is proposed that multi attribute fusion technology.Therefore, this paper to a work area of South Sichuan as the research object, in seismic structure interpretation based, attribute analysis and research, and the seismic attribute frequency decomposition, the research on fusion of multi-scale seismic attributes. Through the above research to obtain the following results and understanding:(1) Collecting and sorting out the geological and logging data of the study area and the surrounding area to obtain the general geological conditions of the area. By well logging and drilling data made synthetic seismogram, established the seismic response characteristics and completed the horizon calibration. Based on the above, the tracking and interpretation of the Ts layer and the interpretation of the fault are completed, and the T0 map of the Ts layer is obtained.(2) The seismic attribute extraction and analysis are studied in the study area. Through the calculation of the Ts layer, the root mean square amplitude attribute graph of the layer, can better reflect the underground seismic reflection intensity, reflect the lithology changes; Gradient structure tensor method is used for Ts Angle and inclination Angle are calculated, the visual Angle of p, q, inclination and azimuth attributes, has very good detection effect to the fault, radial curved edge and also have better recognition ability; In order to better display the underground strata discontinuity, using the azimuth angle attribute display; With the improved C3 coherence algorithm to obtain the Ts layer coherent property, can detailed characterization of fault and fracture distribution and development condition; In addition, to calculate the Ts layer maximum curvature, minimum curvature, the most positive curvature and negative curvature properties.(3) Frequency division processing of seismic attributes, to obtain more detailed geological conditions of the underground. The time frequency analysis of seismic data in the study area is carried out, and the amplitude spectrum is obtained. According to the above, the amplitude and the coherent properties are separately processed to obtain the multiple single frequency attributes from the 15 Hz to the 55 Hz frequency band. The underground geological conditions in different frequency band of seismic attributes can reflect the different underground scale.(4) The seismic attribute in the studied area for multi-scale fusion research. Based on the analysis of frequency division of seismic attributes, this information is combined with the combination of multi attribute fusion technology. This paper mainly used the multi-scale RGB color fusion technology, multiple attribute PCA fusion technology and wavelet multi-scale seismic attribute fusion technology for fusion research of attribute in the study area, found that the three have their own advantages, after fusion is better than a single attribute of rich information. But they are quite different, which RGB color fusion due to the multi-scale fusion frequency, the result is very rich. And relative to the PCA transform multiple attribute fusion, because just using the principal component analysis to calculate the correlation coefficient weighted fusion, the result is relatively poor. Multi-scale seismic attribute fusion based on wavelet transform, the details better performance ability, while eliminating some of the redundant information, enhance the geological characteristics of the structure.Seismic attribute multi-scale fusion, can effectively extract the attributes of the advantages and characteristics of information, eliminate the multiple attribute information redundancy and contradictions, improve the reliability and accuracy of prediction and provides a powerful method for oil and gas reservoir prediction.