南黄海崂山隆起二叠系砂岩储层特征及其油气勘探前景

Characteristics and hydrocarbon prospects of the Permian sandstone reservoirs of the Laoshan Uplift, South Yellow Sea

  • 摘要: 南黄海崂山隆起二叠系发育典型致密砂岩,具备“源储互层”、“油气近源聚集”的成藏条件,具有较大的油气资源潜力。基于崂山隆起内唯一钻井CSDP-2井,通过物性实验、铸体薄片、阴极发光、X-射线衍射、流体包裹体鉴定等分析测试方法,结合地震储层预测,研究了崂山隆起二叠系砂岩储层特征、分布规律及主控因素。结果显示,崂山隆起二叠系砂岩储层致密,成岩演化复杂,超低孔、超低渗,但裂缝发育,属于致密改造型储层;该储层具有“横向相控、垂向叠置、裂缝连通”的分布特点;储层物性及空间展布受控于沉积环境、成岩作用和构造事件的复合作用;崂山隆起二叠系具有两期油气充注,砂岩储层经历了致密储集体的形成、裂缝化改造两个过程。研究认为,崂山隆起二叠系油气资源前景较好,寻找保存条件较好的储层发育区是该区未来油气勘探的重点方向。

     

    Abstract: The tight sandstone reservoirs of Permian are well developed on the Laoshan Uplift of the South Yellow Sea, where the reservoirs are interbedded with source rocks and have excellent conditions for near-source hydrocarbon accumulation. Based on the borehole of CSDP-2 recently drilled on the Laoshan Uplift, the characteristics, distribution patterns and the main controlling factors of the reservoirs are comprehensively studied by this paper with the data from seismic reservoir prediction and laboratory testing, which includes reservoir properties, casting thin sections, scanning electron microscopy, x-ray diffraction, fluid inclusion, et al. The results suggest that the Permian sandstone reservoirs belong to the kind of tight reworked reservoir, which have suffered strong compaction and complex diagenetic evolution and are characterized by extremely low porosity and permeability. However, fractures are well developed. The distribution of the reservoirs is controlled by three factors: sedimentary facies change laterally, source rock overlapping vertically, and fracture connection internally. Reservoir properties and their spatial distribution are jointly controlled by sedimentary environment, diagenesis and tectonic events. There are two periods of hydrocarbon charging in Permian on the Laoshan Uplift and the sandstone reservoir has experienced two major processes: the formation of tight reservoirs and fracture transformation. According to this research, the Permian of the Laoshan Uplift has great exploration prospect, and future exploration should focus more on reservoirs with better preservation conditions.

     

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