Influencing factors of sandstone properties of the second member of Funing Formation in the Jinhu Sag, Subei Basin

The lithologic characteristics of minerals, reservoir physical properties and pore structure of sandstones in the second member of Funing Formation in the Jinhu Sag of Subei Basin were studied based on petrographic thin sections, casting thin sections, porosity and permeability, and the influencing factors for reservoir physical properties were discussed. The sandstones in the second member of Funing Formation are generally fine grained. The average maturity of rock composition is similar among different regions, and range widely. The sandstones on the western slope of Jinhu Sag have better physical properties while those in the other areas are featured by low porosity and low to extra low permeability. Compaction and carbonate cementation are the main reasons leading to poor reservoir physical properties. Dissolution and hydrocarbon filling are important factors to restrain diagenesis and improve reservoir characteristics. The western slope has relatively better porosity and permeability and is a favorable target for hydrocarbon pools.