Characteristics and controlling factors about the reservoir of Huangliu Formation in the central canyon of Qiongdongnan Basin

Based on the use of drilling and core data, combined with the identification of casting thin sections, scanning electron microscopy, capilllary pressure experiment and so on, we analyze the reservoir characteristics and controlling factors of Huangliu Formation in the central canyon of Qiongdongnan Basin. The research shows that the finely granular lithic quartz-sandstone is dominated in the Huangliu Formation, and the sorting degree of sandstone is good, indicating the high maturity of rock composition and structure. Primary intergranular pore is the dominant reservoir space type, and the pore texture of sandstone is characterized by medium pore and fine throat at large. The reservoir propertity has the characterise of medium-ultrahigh porosity and medium-ultrahigh permeability. Sedimentary facies and diagenesis are the main factors on reservoir property. The channel sandstone of deep-water turbidity current deposits is the precondition of the development of high-quality reservoir, and the special water depth and temperature-pressure condition are the important factors that affect the diagenesis of reservoir. Because of deep seawater and shallowly buried stratum, the reservoir of Huangliu Formation is in the environment of low temperature and normal pressure in general, so that the diagenesis is generally not strong. But the differences of reservoir porosity and permeability is mainly controlled by compaction. From the west to the east in the central canyon, the depth of seawater increases gradually and the buried depth of stratum gets shallower, the compaction in the west is stronger than the east of central canyon, so the porosity and permeability of reservoir in the east is relatively high, as also as the gas saturation.