Effects and practical applications of present-day in-situ stress on reservoir quality in ultra-deep layers of Kuqa Depression, Tarim Basin, China

Abstract

There is a significant relationship between in-situ stress and reservoir quality, to reinvent the theoretical understanding and technical methods of reservoir evaluation from the perspective of in-situ stress. Based on rock mechanical test and logging data, combined with regional evolution and structural deformation, this study carried out systematic geomechanics research, proposing the quantitative characterization of stress concentration parameters to realize the optimization of favorable zones. The results show that in-situ stress and fracture permeability under its control are important factors in determining the productivity in the ultra-deep reservoir. It is preferable to choose a location with low stress and good fracture activity, rather than an adverse location such as a local stress concentration area characterized by frequent borehole breakouts. The imbalance between in-situ stress and rock strength causes high stress. Moreover, the accuracy of reservoir classification is improved by incorporating the relevant parameters under the influence of in-situ stress into the evaluation method of reservoir quality. It is vital to fully utilize the multiple advantages of highly deviated wells with various favorable areas and multiple vertical fractures to address complex problems and improve the efficiency of exploration and development.