缝洞型油藏波动和流动耦合模型井底压力分析

Abstract

Fractured vuggy reservoirs consist of matrix, fractures and vugs. Researchers usually treat the matrix-fracture-vug interaction as inter-porosity flow due to their complex pore system and flow mechanism.In fact, vugs play an important role in fractured vuggy reservoirs and can’t be simplified to one homogeneous medium. The idea that pressure spreading in vugs is in form of wave, which is similar to pressure decline, was proposed. Based on that, an analytical well test model for fractured vuggy reservoirs combined with seepage equations for outer formation was presented. Then the log-log type curves of the wellbore pressure and its derivative were obtained through the Laplace transform and numerical inversion. The results show that, the pressure curve forms were influenced by dimensionless parameters related to flow and wave propagation, also by dimensionless parameters related to the outer formation. Sensitivity analysis of these parameters were done. Lastly, a field example was demonstrated to validate the accuracy of the proposed model, which matched the real geological data well.