Study of the producing degree and contribution ratio of matrix in fractured reservoir during water flooding

Seepage process of the fractured dual-porosity media reservoirs is complicated and water cut rises rapidly which are all made it is difficult to develop this kind of reservoirs with water flooding. Aiming at answering the questions, such as whether oil in the matrix can be produced effectively by water flooding, the mechanism, producing degree and laws of matrix development are studied. By using ECLIPSE reservoir simulation software, recovery degree of the fracture and matrix systems and the ration of the production oil in the matrix to the total oil production were analyzed. The influences of the interporosity flow factor, matrix permeability, fractured permeability and water injection rate on the contribution rate of the water flooding in matrix were investigated. Results show that the more developed the fractures, the higher the matrix permeability, and effect of oil seepage and displacement were easily noticeable which affords benefit for enhancing oil displacement effect. The water drive effects could be greatly improved when fracture developed is better and water injection rate are lower. Variation laws and numerical ranges of the matrix contribution rate and producing degree were obtained. It is recommended that strategy of lower water injection rate for the fractured reservoir should be taken.