Brittleness index prediction method of tight reservoir based on grey correlation and analytic hierarchical process.

In order better to evaluate the brittleness of tight reservoir, some studies were conducted to build the new prediction method of brittleness index. First, mechanical properties of tight formation are obtained by triaxial mechanical tests. Subsequently, the correlation analysis between brittleness index and logging parameters was conducted to determine the potential sensitive parameters to brittleness index. Then, based on grey correlation, the initial sequence of sensitive parameters was determined and normalized. On this basis, based on the analytic hierarchy process, the two-two comparison judgment matrix of sensitive parameters was built, the weight vector was determined. Finally, the relationship model between the brittle index and sensitive parameter was established, which meant that a new prediction model of brittleness index was established. Compared with experiment measurement and elastic parameters methods, new method could also have high precision, and reflect the brittleness of reservoir, moreover not depending on the shear wave logging. Therefore, new method provides a new idea for predicting brittleness index and guidance for reservoir fracturing. [ABSTRACT FROM AUTHOR]