Shale Reservoir Characteristics of the Lower 3th Member of Shahejie Formation, Luojia Area, Zhanhua Sag

Key words: 
• Zhanhua sag /
• Luojia area /
• Shahejie Formation /
• shale /
• reservoir characteristics

Abstract: The thickness of shale in the Lower 3th Member of Shahejie Formation, Luojia area, Zhanhua sag ranges 100~300 m, which has a larger amount of oil and gas resources and exploration potential. Studies have shown that, the sedimentary environment of the shale is deep-semi-deep lake with high salinity, strong reduction; the rock types of the Lower 3th Member of Shahejie Formation, Luojia area, Zhanhua sag include mudstone, limestone, and the transitional types between them, content of carbonate is generally higher than 50%, according to the thickness, the combination way, different proportions and stability of the lamina, the rocks are divided into different types, the most important rock types are thin laminated-bedded argillaceous limestone. Reservoir porosity is 1.4%~13.7%, average value is 5.3%, reservoir permeability changes significantly, general ranges from 1×10^-3 μm² to 10×10^-3 μm², average value is 7.5×10^-3 μm², which is low porosity and permeability reservoir, Reservoir fractures include tectonic fractures, micro- fractures between layers and diagenetic fractures, pores include minerals intergranular pores, dissolution pores and the organic matter micro-pores; reservoir properties are controlled by mineral composition and rock types, diagenesis, organic matter content and other factors, organic matter is a major internal factor that affects shale reservoir properties.