Effect of tuffaceous components on physical property of sandstone reservoir

Compared with the normal sandstones, the tuffaceous sandstones have the properties of diversity origination, complex mineral components, easily transformed mineral, complex digenesis and porosity evolution. The comprehensive analyses of cores, thin slices, SEM, mercury-injection data and former research outcome of Xing’anling oil layer in the Suderte area of Beier Depression indicate that the diversities of the property, components, content and origin of tuffaceous sandstone have different effects on the porous structure and reservoir physical property of sandstones. The tuffaceous alteration is different under different burial phase and diagenetic environment and has different effects on the porosity of sandstone. The devitrification can improve the accumulation conditions of sandstones reservoir in some degree, and the corrosion of coarse grain have a constructive affection to the secondary porosity. The clay, abnormal mineral originated from tuff and the translation of mineral generated during the late burial phases are beneficial to the development of the secondary porosity, but not very efficient to the improvement of permeability.