Micro-pore Structure and Water Drive Characteristics of Yan10 Reservoir in Zhenbei Oilfield

Abstract

AbstractUltra-low permeability reservoir has poor physical properties, complex pore structure and poor water drive effect. Taking yan10 ultra-low permeability reservoir in Zhenbei area of Ordos Basin as an example, the micro pore structure, micro water drive characteristics and influencing factors of ultra-low permeability reservoir are studied by using the analysis and test data of casting thin section, scanning electron microscope, mercury injection curve and micro water drive experiment of sandstone model. The results show that yan10 reservoir is mainly composed of lithic arkose and feldspathic lithic sandstone. The reservoir space is mainly intergranular pore, followed by feldspar dissolution pore, intergranular pore and debris dissolution pore, which belongs to the pore micro throat reservoir. The characteristics of micro water flooding are mainly network displacement and finger displacement. The residual oil of network displacement is mainly membrane and isolated, and the residual oil of finger displacement is mainly cluster. The final displacement efficiency of network displacement is higher than that of finger displacement. The study on the influencing factors of oil displacement efficiency shows that the correlation between reservoir permeability and oil displacement efficiency is high, and micro heterogeneity is an important factor affecting oil displacement efficiency.KeywordsZhenbei oilfieldUltra-low permeability reservoirPore structureHeterogeneityWater displacement efficiency