Prestack Inversion Technology And Its Application In A Block In Pakistan

Restoring the spatial variations of underground lithology,physical properties and fluids is the ultimate target of petroleum geophysical research.Travel time information of seismic data always provides a basis for structural interpretation in sedimentary basins,furthermore,lithology and fluid interpretations using other seismic data attributes such as amplitude and frequency are developing rapidly.How to fully tap the potential of seismic data and reduce the risk of exploration and development becomes the research focus and hotspot of petroleum geophysicists.In recent years,prestack inversion technology has been rapidly developed and applied.In the study of prestack inversion in specific areas,it is very important to select an optimal inversion flow and optimize inversion parameters for the reservoir and fluid research.This paper introduces basic theories and methods of prestack inversion,and summarizes a technical sequence for seismic reservoir research and fluid detection aiming at lower Goru formation in a Pakistan block,including normalization processing and interpretation of welllog data,establishment of rock physics templates in the study area,rock physics modeling and prediction of shear wave,AVO forward modeling,AVO attributes analysis,pre-stack simultaneous inversion,pre-stack multi-attribute comprehensive analysis,etc.This paper systematically considers the four key factors of geology,logging,seismic and inversion,and establishes key parameters for multi-well interpretation criteria,rock physics modeling,prestack simultaneous inversion,et,al.for the work area,and achieves quantitative reservoir and fluid interpretation in the work area for the first time.In the late stage of the study,the pre-stack inversion results were used for the evaluation of a well being drilled,which showed that the target layers were absent of good reservoir and hydrocarbon indications.Ultimately,the drilling results verified this understanding.The prestack inversion study provides important reference for subsequent exploration in the area,and achieves good results.