Study On Microscopic Characteristics And Remaining Oil Distribution Of Sandstone Reservoirs For Waterflooding Oilfield

Exploration and development practice shows that fluid seepage rule in long-term waterflooding oilfield reservoir and the microscopic remaining oil distribution are closely related to the microscopic pore structure,and the differences in microscopic pore structure can often determine the reservoir capacity and development effect on macroscopic scale.The paper base on the study of microscopic pore structure for reservoirs,carrying out the indoor physical simulation experiments and analysis,doing researches on characteristics of microscopic parameters and microscopic distribution of residual oil,then revealing the distribution law of microscopic remaining oil.It could not only provide geological basis for research of micro seepaging law,but also provide effective experimental and theoretical basis for sandstone reservoir fine exploration.Accordingly choosing sandstone reservoir specimens conducts water oil displacement experiments,and combined with the nuclear magnetic resonance tests and oil fluorescence analysis technology,then paper summarizes the distribution rules of microscopic remaining oil during different flooding stages.The experimental results show that the main residual oil types are pore filling type,pore half filling,throat stranded,dispersive oil droplets,oil film and the corner type.The oil in great pore throat is firstly displaced during low expansion water flooding.After high expansion water flooding,remaining oil is mainly distributed in smaller pore throats and poor connectivity pore throat for middle level,while remaining oil in great pore throat is less.