The Research On Air-Foam Flooding In Low Permeability Reservoir

With the growing demand for oil,the low permeability reservoir,which is of greatexploration potential and promising future,has been becoming one of difficult problems of theoil workers focused. Because of the impact of natural fractures and artificial fractures, waterbreakthrough is occurred in the low permeability reservoir after long time water flooding.With rapid development of technology, many researches has proved that air foam flooding canincrease sweep efficiency and enhance oil recovery. This technology has been proposed andapplied in low permeability reservoir development.Yanchang Oilfield is a typical low-permeability reservoirs, where Z block was put intooperation in2006, water injection in December2008, after long time water flooding, most ofwells are characterized by high water cut, poor sweep efficiency. So it is necessary to studythe foam efficiency in low permeability reservoir. The goal of the paper is to study thesuitability of air foam flooding in low permeability.In this paper, the mechanism of air foam flooding and development characteristics in lowpermeability reservoir are studied. By analysising the problems of the Z block, on the base ofthe fuzzy comprehensive evaluation method and rough set of knowledge, a new method todefined the weight of properties is development and application of well selection is applied.Based on the subtly geological model of Z block, a numerical simulation model which applysto air foam flooding was built and a typical well group was chosen to carry out the numericalsimulation. Based on production history matching, the distribution of the remaining oil of theZ block is delineated. The influence law of the factoes:Foam injection, gas injection rate,gas-liquid ratio, the foam concentration and foam liquid injection rate factors has been foundin this paper. The purpose of this paper is to optimize the operating conditions based on thenumerical simulation, which has great theoretical significance for the air fome floodingadjustment of the block and provides great reference for the reasonable injection/productionstrategy in low permeability reservoir.