Research Of Transverse Wave Prediction Method In Stratigraphic Development Area

With the gradual advancement of oil and gas exploration and development,turbidite oil and gas reservoirs have become the key exploration targets of Dongying Sag,and the difficulty of exploration and development is also growing.The investigation and analysis of the previous research results in the area shows that the reservoir thickness of the research area is generally thin,the change is severe,and the gray matter content is very high.If only relying on the seismic section,it is difficult to accurately identify the sand body and mudstone,and the accuracy of the reservoir prediction is seriously affected by the mixed gray matter in the reservoir.For the specific problem of the work area,the method of petrophysical analysis can be adopted.Petrophysics is a discipline that studies the correspondence between rock elastic properties and rock parameters.Based on the petrophysical analysis,the pre-stack seismic data is used to study the AVO pre-stack method based on the lithology identification factor,so as to improve the prediction accuracy of the turbidite reservoir in the gray matter development area,so as to accurately determine the effective reservoir.Seismic inversion technology is one of the main technical aspects of seismic exploration and is the mainstream method for reservoir prediction and fluid identification.The shear wave velocity is a very important parameter information in the prestack inversion.However,in practice,the shear wave logging is difficult and costly.Most of the work areas often lack the information of the shear wave speed,which seriously restricts the smooth progress of the subsequent inversion work.This paper first briefly introduces the theory of differential equivalent medium and the theoretical knowledge of petrophysics such as Gassman theory,which is used to obtain the elastic parameters needed for fluid replacement based on Gassman equation.The effects of petrophysical parameters such as gray matter content,water saturation and porosity on the shear wave velocity were quantitatively analyzed.The results show that the gray matter content has a great influence on the shear wave velocity.If the gray matter is neglected,the obtained shear wave velocity is very large.Error.Aiming at the characteristics of the gray matter in the research area,the traditional Xu-White two-phase model was improved,and the limestone sandstone model was constructed to predict the transverse wave.By comparing and analyzing the measured transverse wave curve and estimating the transverse wave curve,it is found that the method can estimate the shear wave velocity of the research area more accurately.Secondly,using the well-optimized inversion method to obtain the formation parameters such as gray matter content,mud content and sandy content.The sensitivity of the multiple petrophysical parameters of the project area was quantitatively evaluated.The sensitive lithology identification factor F of the research area was optimized by histogram technique.The complete Zoeppritz equation was used to reconstruct the deformation,and the approximate approximation was simplified.The AVO approximation formula of the sexual recognition factor F,with reference to Connolly's idea of pushing the missile wave impedance,derives the prestack elastic impedance equation based on the above AVO approximation.Applying the method to the actual work area,the application effect is good,and it also confirms the accuracy of the input predicted shear wave parameters.