Construction of efficient-sensitive factor for complex carbonate reservoirs and its applications

Currently, increasing the proportion of highly efficient wells is of great significance for enhancing both the reservation and production of the carbonate reservoirs in the Tarim Basin. Research has shown that the relationship between P-wave velocity and gas saturation is mostly nonlinear, which implies that velocity information or velocity-related parameters are not available for highly efficient well identification. Based on the differences between highly efficient wells and the others, a new type of efficient-sensitive factor is established by summarizing the pre-stack elastic information of the highly efficient ones, which takes into account the combination of density and porosity. Then, the effectiveness of this factor is verified by practical production in the Tazhong area, which demonstrates that the constructed factor is remarkably sensitive to highly efficient wells, while low efficiency wells, water wells and mud filled wells always fail. Furthermore, an approximate linear relationship is achieved between cumulative production and the efficient-sensitive factor, which can be used as an important indicator for commercial reservoir evaluation and highly efficient well optimization.