Research And Application Of AVO Technology In The Prediction Of Reef Reservoir Of A Region In East Sichuan

The study area is located at the northeast of Sichuan Kaijiang-Liangping trough belt,which the target layer is the Chaingxing Formation biohermal carbonates.Recent years,important exploration discoveries have been made in the Changxin and Feixianguan formation of Sichuan basin,for example,Puguang gas field,Longgang gas field and so on.There are some features about the purples reservoir;for instance,the interface of reef reservoir rock is relatively rough,internal reflection is messy,the stable seismic event is lack.And the conventional wave impedance inversion can't identify the reef reservoir.To solve these problems,this paper based on high-resolution 3D seismic data of the reef fine description,combined with seismic facies constrained prestack inversion results,prediction of reef reservoir using reservoir identification factor,carried out research work as follows: ?1 From the angle of geology,using forward modeling and comparison of actual seismic profile method,summarizes the seismic response characteristics of conventional reef,and on this basis,depicts the reef favorable facies belt distribution,constraints on the reef reservoir with the high precision of the favorable facies belt.?2 The AVO technique is derived by the equation of rock physics,which is rigorous and systematic.The analysis of seismic data based on Zeoppritz equation can not only obtain longitudinal wave information,but also obtain shear wave information.The rock physics basis of AVO analysis,the theoretical basis of AVO analysis method and the simplified formula of Zeoppritz equation are discussed in detail in this paper.On this basis,for the different inversion methods,through the forward analysis,the appropriate simplified formula is selected.?3 Analysis of feasibility of the implementation of the actual inversion in the study area,the response of different fluid identification factors in the study area,the actual seismic data as the foundation,the post stack impedance inversion,prestack wave inversion,AVO inversion and attribute analysis,the actual data processing results.By comparing the inversion effects of different inversion methods,it is found that pre stack inversion is suitable for reservoir prediction in the study area.The prediction results of reef reservoirs in a certain area in eastern Sichuan are in good agreement with the actual drilling data,which proves that the method used in this paper is of high reliability...