Geological Characteristics And EOR Application Of Low Permeability Reservoirs In Wei 42 And Wei 43 Blocks

The reserves of waterflooding development in deep low permeability reservoirs of Zhongyuan Oilfield are 17172.09×10~4tons,accounting for 87%of the reserves of deep low permeability reservoirs,but the average recovery rate is only 15.2%.The oil reserves of Pu Cheng Oilfield are 392.3×10~4 tons.The water injection pressure of the reservoir is high and the water injection development is difficult.The recovery rate is only 13.7%.The geological structure,reservoir physical properties,reservoir architecture,geological modeling and numerical modeling of Wei 42 and Wei 43 blocks in Pu Cheng Oilfield are studied to determine the characteristics of remaining oil.This paper analyzes the feasibility of the application of carbon dioxide flooding technology,and explores the method to improve the recovery rate of low permeability reservoir.Combining well seismic research with regional structure of Wei 42 and Wei 43 blocks,small faults are depicted,and the breakpoint combination mode of pinnate fault is mainly studied.Two echelon faults in the South and north of Wei 42 block are combined into four pinnate faults.Fine reservoir interlayer research describes the rhythmic structure within the reservoir layer,dissects the main small layer configuration,further describes the reservoir,to clarify the influence of formation characteristics on reservoir development,defines five kinds of inter well sand configuration pattern,compares vertical and parallel source dense sections,and studies the influence of plane configuration distribution on reservoir development.The dual medium model with artificial fracture is established,and PVTi component simulation is used to describe reservoir characteristics,which provides basis for well pattern adjustment and deployment.A large number of production data are collected and sorted out to simulate reservoir production history and analyze the distribution characteristics of remaining oil.On the basis of geological research,the feasibility analysis of carbon dioxide is carried out.The local tectonic framework of Wei 42 and Wei 43 blocks has been re recognized,Influence of reservoir physical properties on reservoir development.The research results of fine reservoir configuration characteristics,artificial fracture modeling and numerical modeling,analysis of sensitive factors of carbon dioxide flooding effect,parameter optimization and other technical application achievements have provided solid technical support for the popularization and application of low permeability water injection reservoir to carbon dioxide flooding.The high pressure water injection reservoir converted to carbon dioxide flooding greatly reduced the injection pressure.The comprehensive water cut of well group corresponding to carbon dioxide flooding in block Wei 42 decreased by 20%,and the oil increase effect was obvious,and the oil recovery rate could be increased by 15%.