The Research Of Fracture Prediction Based On Stress Field

In the process of oil and gas exploration and development,the existence of fractures can affect the migration and accumulation of oil and gas reservoirs.Therefore,research on fracture play a significant role in the development and utilization of oil and gas reservoirs.The research on identification and prediction of fractured reservoir at home and abroad has been conducted for decades.Fracture identification and prediction in logging,seismic and other areas have made great progress.A variety of factors affected the development of fracture,and the causes of fracture are very complex,therefore fracture description is one of the problems of oil and gas exploration.More fracture analysis and forecasting technology is still in the process of continuous improvement and development.This paper aims to study stress distribution of horizon using the seismic interpreted horizon,and thus speculates the spatial distribution of fracture combined with the spatial distribution of seismic attributes to predict porosity,and then analyzes the relationship of fracture porosity and total porosity.This study is divided into three parts: First,we study on the stress field analysis based on plate theory which utilizes information of layer and lithological information to estimate the stress field of purpose horizon,resulting in the formation of the curvature parameters,the main stress direction and the principal strain intensity for analysis of tectonic fractures.Secondly,we extract seismic attributes associated with the fracture and the composition of the sample log data using the relevance vector machine(RVM)to establish non-linear estimation model of attributes sets and reservoir porosity,so that the information can extrapolate the well results to predict porosity in target horizons.Finally,Conducting statistical analysis and fracture characteristics Visualization with stress field predictions of fracture,using rose diagram to characterize fracture information.In order to verify the correctness of the proposed method,we tested the method with the field data of Shengli Oilfield,stress field analysis corresponds to the actual situation of the working area,the estimated results have a high consistency with the actual well logging data at the location of the well,and at the location away from wells,the estimated results could match the seismic data and geological background.