Study on Lower Limit of Property of Chang-81 Reservoir of HuaQing Area

HuaQing area chang-81 reservoir belongs to the typical low porosity,low permeability reservoir.It's porous structure is complex,strong heterogeneity.Aiming at its porous structure,making an intensive core study on the relationship of porosity,permeability oil-saturation and relative permeability,the lower limit of physical property may be determined by a Statistics method and an integrated method of porosity,water saturation and relative-permeability curve.The limit of its porosity is 6%,and the limit of its permeability is 0.08×10-3μm2.