Physical Properties and Main Controlling Factors of Low-Permeability Sandstone Gas Reservoir

Abstract

In order to guide the resource prediction and exploration evaluation of low-permeability sandstone gas reservoir, the physical properties of this kind of gas reservoir are summarized from such aspects as lithology, porosity, permeability and the characteristics of capillary force, and the main controlling factors of the gas reservoir are analyzed. The analysis show that low-permeability sandstone gas reservoir is mainly characteristic of high capillary pressure, high bound water saturation, low and high porosity as well as low permeability. Rock composition and structural characteristics of the reservoir is the basis of the factors that can affect the compactness of the reservoir. The formation of the reservoir is mainly affected by deposition, diagenesis and late tectogenesis: deposition can affect the composition of minerals, the original physical properties of clastic sediments and others; diagenesis is the main stages of the densification of reservoir, where compaction, pressure solution, cementation and late dissolution are the causes of the densification of reservoir. Dissolution and rim chlorite cementation improve reservoir property; tectonization can have an effect of late transformation on the physical properties of clastic reservoir. At the same time, the fluid characteristics in the reservoir can also affect the permeability of reservoirs.