Application Of Pre-stack AVO Inversion In Shale Gas Prediction In Dingshan Area

With the deepening of seismic exploration research,exploration targets have turned from structural traps to lithologic traps,and petroleum reservoirs on land have been mined in large areas.In order to meet people's needs,shale gas reservoirs have become the target of exploration..Earlier,research on shale gas has been started in foreign countries.Our country has been in contact with this area in recent years.In particular,there have been more researches on shale gas reservoirs in southeast Sichuan in the past two years,such as in Chongqing.The shale gas reservoirs in the Jiaoshiba area of Fuling have been studied and have a certain research basis for shale gas reservoirs.At the same time,because the pre-stack seismic data contains the information that changes with the offset,it can better reflect the distribution characteristics of the underground reservoirs,while the conventional post-stack data retrieval method uses post-stack data,which may have some disadvantages that are due to The reversed phase,weak phase and other anomalies are superimposed on each other,so the pre-stack AVO inversion method is used.This paper takes the Dingshan area in southeastern Sichuan as the main research object,combines pre-stack AVO inversion with well logging data and seismic data in this area,and studies and analyzes the application effect,and draws an analysis of shale gas in this area.The response characteristics provide some guidance for future shale reservoir prediction in the region.By studying the areas that have been explored in southeastern Sichuan,some lithologic features of shale are summarized.Geological conditions such as geological stratification and structural development history are implemented,and preparations are made for fine interpretation of future seismic data.Based on the Zoeppritz equation in pre-stack AVO inversion,the following points are studied from the characteristics of shale reservoirs.Firstly,it is necessary to process the collected well logging data.A complete curve was obtained by splicing the logging curves and normalized to the standard.For the lack and absence of logging curves,the petrophysical analysis is used to obtain a more accurate S-wave logging of the destination interval.The sensitive parameter analysis of the TOC value of the work area can determine that there is a certain relationship between the TOC value and the density,and the relationship between them is obtained by the multiple regression method: TOC=0.69 *?*?-22.37?+56.59,which providing a formula basis for TOC prediction.Secondly,the CMP gathers are preprocessed,and the corresponding stacking effects of the corresponding parameters are analyzed to obtain the superposed data with high SNR and high credibility,which will lay the foundation for the next inversion research.Finally,through pre-stack AVO inversion and analysis of seismic data and well logging data,various elastic parameters of shale are calculated,and the results are analyzed and summarized: the parameters of shale are: low speed,low density,The low P-wave impedance,low S-wave impedance,and low P-wave speed ratio and ?? value are relatively low and ?? values are relatively high.