Enhanced Oil Recovery Technology Research And Application Of F4 Reservoir In Zarzaitine Oilfield In Algeria

Reservoir F4 of Zarzaitine Oilfield in Algeria belongs to medium porosity and medium permeability anticline reservoir with gas cap and edge water.After layer F4-??F4-?entering the late stage of development,production efficienccy become lower,because the development method does not fit for the stratum with strong heterogeneity.To carry out detailed study of residual oil distribution with logging,integrated reservoir analysis and numerical simulation techniques will lay a solid geological foundation for rebuilding the injection-production pattern.Based on the detailed studies of structure and reservoir,we have studied residual oil distribution law with the application of reservoir engineering thesis analysis and numerical simulations.Reservoir engineering analysis method is based on analysis of injection and production conditions and find the law of residual oil distribution through the Production decline law,oil displacement efficiency and conditions of new drilled wells;Numerical simulation study repeats whole development process of the reservoir to study residual oil and its distribution law quantitatively through geological parameters,seepage and development mechanism calculus.On the basis of the potential and distribution law of remaining oil,we have made the development technique policy and reservoir development program.The main results and understanding summarized from papers are:(1)The structure is an asymmetric anticline with axis NNW-SSE,which belongs to the underwater fan in the marine environment.The reservoir is a thick massive sandstone,intercalated with thin mudstone layer.The oil and gas reservoir does not have a gas cap and edge water,but high porosity and permeability,which is controlled by fault anticline.(2)The researchers have defined that the residual oil in the reservoir is mainly distributed near the structural high part of gas/oil interface,furthermore,a part of residual oil has entered the original top region,little of that is scattered in the edge angle.(3)We have put forward to adopting injection-production pattern,which is "Injection in the low structural part,and production in the high",used to improve the degree of reserves control,reconstruction or restoration of local injection-production pattern by the aid of new or some old wells.(4)Our work have finally established the deployment scheme,deployed of 8 new wells,taken 14 measures in oil and water wells,which has achieved considerable effect.