Experimental Study Of The Conductivity Model For Tight Oil Rock In The Jurassic Systen Of Sichuan Basin

The average porosity is 1.5% and the average permeability is 0.055 mD of tight oil reservoirs in Sichuan Basin.And these reservoirs ha ve the ultra-low porosity and ultra-low permeability and theirs pore structures are very complex,resulting in large errors in the area of reservoir oil saturation evaluation.The object of the thesis is to study the tight sandstone of Lianggaoshan Formation and the tight limestone of Daanzhai Formation in Jurassic System in Sichuan.There are several experimental methods have been used,such as core observation,composition analysis,high pressure mercury,NMR,SEM,rock electricity experiment and so on,to study the reservoir properties,microscopic pore structure and mechanism of conductive and analyze the microscopic pore structure characteristics of the tight oil reservoir.The parameter of Archie formula,m,n,were obtained by rock electrical experiments.And the relationship between electrical parameters of rock and pore structure parameters was analyzed.The result is that Archie microscopic pore structure parameters and parameter n have a good correlation in Lianggaoshan Formation due to less clay content.And the pore structure is the main factor which affects the electrical conductivity.Comparing to water saturation calculat ion by conductivity model and the actual saturation,there is high consistency between two water saturations.So the microscopic pore structure is the main factor which affects the reservoir in Lianggaoshan Formation.However,there is the opposite conclusion in Daanzhai Formation due to high clay content.And there is low consistency between two water saturations.So the clay content and the pore structure are two factors that affect the reservoir in Daanzhai Formation.