Study On Shale Gas Reservoir Fracability By Pre-stack Seismic Inversion Method

Shale gas reservoir fracturing prestack seismic evaluation method refers to the use of seismic data to shale gas reservoirs comprehensive evaluation of revamping,so as to achieve effective production technology.Pre-stack seismic inversion is an important means of predicting the sweetness of shale gas projects.For unconventional reservoirs,such as shale gas reservoirs,accurate prediction of engineering desserts in shale gas reservoirs based on seismic data is an important issue that is now widely studied.In this paper,the accurate prediction of engineering desserts is taken as the research goal.Based on the prestack inversion theory method,through the screening and analysis of the sensitive parameters of engineering desserts and using the prestack elastic impedance inversion theory to invert the target parameters,Comprehensive evaluation of shale gas reservoir fracturability.This paper presents a prediction method of prestack seismic inversion of shale gas reservoir engineering desserts,including shale brittleness prediction method based on prestack seismic inversion and seismic inversion inversion method of shale gas reservoir stress.In the aspect of brittleness prediction,the brittleness sensitive parameters are selected through the analysis of petrophysical confluence,and the objective function is deduced in the framework of Bayesian theory.Finally,the prestack elastic impedance equation is used to perform inversion to realize the shale gas reservoir Brittleness prediction.Based on the above,a method of direct inversion of brittleness is proposed.The method introduces the brittleness index directly into the equation and reduces the cumulative error of calculation.In the aspect of geostress prediction,based on the seismic rockphysical model,the quantitative relationship between stress indicator and fracture parameters was established,and the azimuth information of wide-azimuth seismic data was fully utilized.The azimuth elastic impedance inversion equation was deduced.Fracture parameters to predict the formation stress parameters,to guide shale gas reservoir fracturing prediction.After the prediction of brittleness and in-situ stress is completed,the information of both is integrated to predict the sweet spot of shale gas reservoir engineering.After the above inversion method is tested by model and the actual data,the inversion results obtained are more accurate and have certain credibility,which can be used to evaluate the fracturing of shale gas reservoirs and have practical value.