Assessment of residual oil saturation with time-differentiated variable multiple material balance model.

This study aims to improve the evaluation of residual oil saturation in water flooded zones based on the material balance model (MBM) with variable multiple for injected water. We investigated the change patterns of rock-electro parameters during waterflooding through the analysis of displacement tests. Our work differentiated the waterflooding into numerous displacement processes and accordingly propose an improved time-differentiated variable multiple MBM. The calculation results of the improved model are more consistent with the displacement experiment data of cores. Furthermore, the improved method was integrated into the comprehensive interpretation platform of offshore logging to analyze water flooded zones of a well in the A oilfield. As a result, the residual oil saturation calculated is in close agreement with the results of experiments on cores. Our results indicate that the time-differentiation and variable multiplier for injected water can effectively enhance the assessment accuracy of the residual oil saturation of water-flooded zones. [ABSTRACT FROM AUTHOR]