摘要:
沾化凹陷罗家地区古近系沙河街组沙三下段发育100~300 m厚的暗色泥页岩,具有较大的油气资源量和勘探潜力.研究表明,罗家地区的这套泥页岩为盐度较高、强还原性的深湖—半深湖沉积,岩石类型以泥岩、灰岩及之间的过渡岩性为主,碳酸盐矿物含量一般高于50%.根据泥页岩纹层厚度、组合方式、比例和稳定性,将深水泥页岩划分为6种类型,其中以薄层状泥质灰岩为主.泥页岩储层孔隙度为2%~8%,平均5.3%;渗透率变化较大,一般为(1~10)×10-3 μm2,平均为7.5×10-3 μm2,为低孔低渗的非常规储层.储集空间类型多,储层发育的裂缝包括构造裂缝、层间微裂缝和成岩缝,孔隙包括矿物晶间孔、溶蚀孔、有机质孔等.储层质量受矿物组成和岩相、成岩作用、有机质含量等因素共同控制,其中有机质含量是控制该套泥页岩储层物性的主要内在因素.
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.
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