Remaining Oil Distribution Pattern of Massive Matured Oilfield with Strong Bottom Water: an Integrated Reservoir View

The highlight of this study is to establish the distribution pattern of remaining oil in massive matured oilfield developed by bottom water under water cut over 90%. The approach combines reservoir engineering and numerical simulation to demonstrate the controlling factor and distribution pattern of remaining oil and complexity water oil movement. The study involves dynamically describing of water oil movement and studying of remaining oil enrichment mechanism and conducting a detailed typical numerical reservoir simulation of H oilfield. The results of the integrated reservoir study show that remaining oil distribution pattern was seven distribution forms (that is flower-like oil, isolated-island oil, ridge oil, attic oil, banded oil, roof oil, sandwich oil) controlled by micro-structure, inter-beds, rhythm, heterogeneity, faults, well pattern and development strategy, and water movement was affected by the transformation of water energy and the formation of water-flooding advantage flow channel, and which was formed for heterogeneity that is production rate heterogeneity, reservoir heterogeneity such as dual porosity and high permeability heterogeneity. Furthermore, the horizontal oil mainly located in flower-like oil which controlled by structure and well pattern, vertical oil mainly located in attic oil controlled by structure, isolated-island oil controlled by local micro-structure, and roof oil controlled by structure and rhythm. The mechanism study also show that inter-bed can affect the distribution of remaining oil when the dimensionless inter-bed radius larger than 0.6 and has little effect on remaining oil when smaller than 0.2, and remaining oil may located on upper zone, lower part and cross inter-bed, and the high oil viscosity also made oil be remained under the inter-bed. The mechanism study show a great agreement with the simulation study of H oilfield, and can support the following development adjustment and EOR study.