Study On Quantitative Characterization Of Microscropic Remaining Oil In Huabei Oilfield Sandstone Reservoirs

The reservoir types of Huabei Oilfield are mainly multi-layer sandstone reservoirs.The types are diverse and affected by many factors.The distribution of oil and water is complex.The large amount of remaining oil exists in the reservoir in various forms,making it difficult to tap the potential,and to describe the enrichment,distribution,control factors and potential scale of remaining oil.The present understanding of remaining oil distribution can no longer meet the need of oilfield development,and the research on remaining oil requires the development of new technologies and methods.This thesis studies the microscopic status of remaining oil and the micro mechanisms of the remaining oil distribution,and provides a quantitative characterization method of remaining oil.This study is aimed to guide the preparation of the remaining oil potential tapping plan in the later stage of the oil field and consolidate the stable production foundation of the entire sandstone reservoir.In this study,Maps-QEMScan-CT,a high-precision quantitative characterization method was used to scan the microscopic remaining oil.Core samples of various quality were selected from different layers of Liu 70 fault block in the south of Dawangzhuang oilfield.Microscopic remaining oil quantification characterization experiments were carried out through CT scanning of dry cores,cores saturated with water,cores after oil flooding to initial oil saturation and cores after water flooding to remaining oil.Based on those four conditions of a same core,the dynamic microscopic oil distribution was revealed and the different types of oil distribution were clarified,and a high-precision quantitative characterization method was found suitable for this area.Pore,oil and water were accurately divided in the reservoir spaces;make it possible for the three-dimensional visualization of the remaining oil in pores.The results of the study show that the remaining oil in high-quality reservoirs in the study area is mostly distributed in a network,while the remaining oil in a medium-quality reservoir is distributed in a branch-like shape.The remaining oil in a poor reservoir was distributed in a short branch-like shape.The main controlling factors of microscopic remaining oil were analyzed and summarized.Finally,a set of microscopic remaining oil quantitative characterization experimental methods suitable for sandstone reservoirs were developed,which provides a reference for the later management of reservoirs of the same type.This method was applied to the Gao 30 fault block,a sandstone reservoir of the same type in the North China Oilfield.The micro quantitative characterization of remaining oil with different main macro control factors was carried out in the research on the next step to tap the potential.Targeted measures were proposed to further tape potential of remaining oil distributed in different forms,providing a basis for the formation of development plans,and eventually contributing to the high and stable production of old oilfields.