Tight Clastic Reservoir Earthquake Prediction Research

With development of oil and gas exploration, the prediction technique of tight clasticreservoir with lower porosity and lower permeability is attracted more attention. Recently,much work have been done, and made plenty of useful results. For the complication of theproblem, it is hard to make the precise results using the reservoir prediction technique. So,based on studying seismic wave field character by mathematic modeling and temporalresolution improvement of post-stack seismic data with the compensation of the highfrequency absorption attenuation in f-x domain, combined with the lithology information,geological background together with log data, the seismic prediction methods of tightclastic reservoir in Guandu structure belts is discussed through the integration of elaboratestructure description, seismic attributes analysis, seismic facies technique, post-stackimpedance inversion and other ways. The achievements and recognitions are achievementas follows.1. The effectiveness of the phase shift compensation method of the high frequencyabsorption and attenuation in f-x domain is proved, and the applying situation of theseismic and geology in surface has been given in which the attenuation of highfrequency absorption of seismic wave ban be compensated by numerical simulations.The properly modified function of Quality-Velocity derived from field information inwestern area and library analysis is applied in Sichuan basin first time. The frequencyband of post stack seismic data processed is widened properly and the temporalresolution is increased efficiently without decreasing the S-N ratio in Guandu structurebelt.2. The geology model is established with log data and seismic inversion. The seismicwavefield characteristic of Xiashaximiao formation sand is summarized by the FourierFinite Difference seismic simulation. Using S and P log data of the Guandu structuralbelts, the EI model is carried out aimed for tight sand of Xujiahe 4 member andXiashaximiao formation. On the basis of analysis AVO action characteristic, the gasreservoir is identified in aimed formation.3. With the utilization different seismic attributes, clustering analysis of attributes andseismic facies studying as well as spectrum decomposition methods and so on, thedegree of the tight sand of Xiashaximiao formation is researched, and pointed outfavorable reservoir distribution areas. Besides that, Based on the coherence,dipscanning and square variance cube, not only the fault-fracture system distribution law ofdifferent formation is accounted, but also its distribution areas is forecasted.4. The reservoir sand of the Guandu structural belt is not only thin and tight, but also variedviolently in the space, so, the multi-attributes regression method with neural network isapplied to inverse the acoustic impedance and reservoir parameters; the thickness ofsand is calculated by tuning thickness theory. The distribution of sand is predicted accurately and its thickness and depth is fitting with the drilling very well with themethod discussed in the article. The method of forecasting the sand is established whichis applicable in the non-marine tight clastic rock with the combination of geophysicsand geology.