Development of four-dimensional model for remaining oil distribution under control of reservoir sedimentary facies

The sedimentary facies and reservoir heterogeneity are the main control factors for the distribution of remaining oil.Taking N reservoir of M Oilfield as an example,the variation of oil saturation in the development of oilfield was analyzed.Two methods for calculating remaining oil saturation of oilfield including the pulse neutron lifetime log and the production profile log were investigated.The calculation method of oil saturation at different time in development stage was proposed.The sedimentary facies were taken as the control condition,and the random modeling method was used to establish four-dimensional model for studying the distribution of remaining oil in different development stage according to the chronological order.Some measurements such as subdivision of reservoir,killing formation and water block-off,re-perforation were applied in the objective oilfield.The better economic results were obtained.The production practice proved that it was available to develop four-dimensional model of remaining oil distribution under the control of reservoir sedimentary facies using the new method.