The Seismic Methods For Predicting Carbonate Reservoir Cracks Of Yangxin Series In Southeast Area Of Sichuan

Sichuan Basin is China's major oil and gas basins. Southwestern China is also an important production base of natural gas.This exploration area is located in the southeast Sichuan Basin,with high and steep structural belt in east Sichuan and low-tectonic belt in southern Sichuan, including Fuling, Qijiang, Chishui external block,etc.The exploration area of Paleozoic gas exploration for new fields, exploration and research level low. In recent years the research and exploration work shows that the study area has good prospects for natural gas exploration, as the next step in Sichuan Basin natural gas exploration strategy to replace the area.Yangxin series in southeast area of Sichuan carbonate reservoir matrix with low porosity and low ermeability, highly heterogeneous characteristics of the fractured reservoir is the main space and infiltration routes, in the reservoir prediction, the use of a single subject or a single way to predict its often very difficult. As a result of carbonate reservoir pore space is very complicated sewing hole size, shape, type, changes in the nature of filling a great way to use a single comprehensive understanding of the situation and development of carbonate reservoir cracks is almost impossible.Under such circumstances, must take advantage of multi-disciplinary, multi-method to predicting reservoir cracks in order to reduce the number of solvability.In this article, first is geological analysis, seismic modeling and seismic response characteristics of speech analysis, Discussed Identifiable and identify the principle of Seismic methods to predicting the fractured zone,and editing a number of the computer program for them.Respectively, the use of seismic attribute analysis technology, P-wave anisotropy of cracks detection technology, absorption processing technology coefficient of the carbonate reservoir cracks of Maokou formation in this area, and analysis of a number of ways in the reservoir cracks prediction results. Make comparative analysis with predicted results, the geological and drilling data in order to reach the purpose of predicting the favorable reservoir region. Several studies through the work, in this Carbonate reservoir cracks prediction had achieve the following main research awareness:1.Through seismic forward modeling and the characteristics of seismic response analysis in Maokou formation carbonate reservoir showed that, paragraph with fractured reservoir rock performance for the amplitude ratio of low amplitude, and whether it contains fluid or with their gas, the changes in amplitude and frequency greater than the rate of volume change, and the amplitude ratio is more sensitive to the frequency of the cracks. Therefore, the choice of amplitude attributes to detect cracks is better than the frequency attributes.2.As collected seismic data is two-dimensional in this area, cracks crack detection can be divided into detecting of cracks azimuth and detecting of cracks density.Combining the characteristics of seismic wave in fractured medium, made through the fractal two-dimensional seismic technology to detect the cracks azimuth, and to achieve the detection of cracks density.3.During the pliocene of predicting carbonate reservoir cracks in Yangxin series, absorption is a very important parameter, which reflects changes in lithology with higher sensitivity.The use of absorption and in line with the speed, amplitude and frequency of seismic or other seismic information, Has its unique role and effectiveness of the reservoir cracks prediction.Particularly in the reservoir descripting or fluid predicting. Absorption process technology will play a unique role and can greatly enhance the accuracy of the interpretation of lateral reservoir prediction accuracy and the success rate of exploration.In this paper, the research ideas and research results for detection and prediction of reservoir distribution of cracks using of seismic data provided new technology ideas and methods. For oil field exploration and development of new research tools, At the same time, these methods also in-depth study of reservoir cracks for us accumulated experiences, enriched the reservoir cracks prediction means.