STUDY ON THE EVOLUTION OF THE MICROVADOSE FIELD IN THE RESERVOIRS OF THE SECOND DISTRICT OF SHENGTUO OILFIELD

Taking the reservoirs of the Sha-2 Member in the second district of Shengtuo oilfield long-term developed by waterflood as an example and using the data of core analysis and physical vadose simulation in laboratory, the evolutionary rules of the microvadose field in the reservoirs long-term developed by waterflood were studied from the changes of rock wettability, pore structure and relative permeability three respects. It was considered that the rock wettability and hydrophicity in reservoirs got enhanced with the degree of waterflood development increasing. The pore structure of reservoirs had the evolutionary trend that pore uniformity degree, throat isotropic degree, pore-throat connectivity and the ability to control fluid flow got better. The saturability of bound water tended to rising, and the relative permeability of water phase in residual oil tended to descending; but the shanges were not great. The evolution of the vadose field in reservoirs controlled and affected the amount and space distribution of residual oil in reservoirs.