The Rock Physical Property And AVO Forward Modeling Of Shale Gas Reservoirs

With the continuous development of society, people’s environmental awareness continues to improve. The demand for clean energy in the world is growing increasingly. Along with the conventional oil and gas resources are increasingly nervous, the importance of the unconventional oil and gas reservoirs such as the shale gas has been gradually revealed. And the shale gas resource potential is huge. According to statistics, the prospect of shale gas resource amount is twice of the conventional natural gas. At present only in America shale gas exploration and production is successful. The exploration and development of shale gas in China is still in its infancy, and still needs the development and progress in all aspects of technology. Geophysical method is required to support the shale gas exploration.Based on the mineral composition standard and the thickness standard of the shale gas reservoirs, the shale gas reservoirs model has been designed. According to the Gassmann’ equation and a series of rock physics formulas fluid sensitivity of the shale gas reservoirs to identify sensitive parameters for shale gas have been analyzed. And then the relationship between the mineral composition (quartz, calcite and clay) of the shale gas and rock properties (Poisson’s ratio, Young’s modulus and Rock brittleness) has been analyzed. And the paper believes that the quartz on rock brittle contribution is greater than calcite and clay. AVO forward modeling of the shale gas reservoirs has been carried out by the integrated Zoeppritz’ equation and its approximate equations. And the effects of various factors on AVO are analyzed, especially the seismic wavelet, reservoirs thickness, saturation, porosity and so on. The type of pore fluid has an impact on the cross-plot which is analyzed.Finally, According to the well logging data at home and abroad, the rock physical analysis and AVO forward modeling analysis of the shale gas has been carried out.Compared with the theoretical model, the conclusion has been verified. And the shale gas reservoirs have been evaluated.