| Xihu sag is in the northeast of the East China sea shelf basin, and the area ofabout4.6×104km2, Central Inversion Structural Belt is NNE-extension, which is inthe Xihu sag, includes Tiantai, Huangyan, Ningbo and Jiaxing tectonic belts fromsouth to north. The Eocene-Miocene boundary of the purpose of the objectiveinterval have marine and continental sedimentary environments, and the Eocenehave marine ssedimentary environments, the Oligocene-Miocene have continentalsedimentary environments. The Eocene Pinghu Formation and the OligoceneHuagang Formation are very important hydrocarbon source rocks is the area. The mostimportant sandy rock of fine sandy rock is mainly reservoir rock type in the Eocene PinghuFormation and the Oligocene Huagang Formation.Many Reservoirs and Seals in the Central Inversion Structural Belt, and theymake up many reservoir-seal assemblages. The Huagang tectonic belt is the bestreservoir-seal assemblage in north of Miocene Longjing Formation, and the Yuquantectonic belt is better, the sorth is worse; The Huagang tectonic belt is the bestreservoir-seal assemblage in north of Oligocene Huagang Formation; Thedevelopment levels of reservoir-seal assemblage are difference in the Eocene PinghuFormation, and the best is the area of TWT1.The Room temperature layer of Central Inversion Structural Belt is3.8℃/100m, its higher than others. In the Central Inversion Structural Belt, shallowpressure coefficient of about1.0, is a normal pressure system, the interface at3700m case roughly, and small scale of pressure, the pressure coefficients much less than1.25, with weak overpressure primarily.Based on the structure of Xihu depression, the characteristics of sedimentaryevolution, the characteristics of source rock and the characteristics of abnormal porefluid pressure distribution,4migration-accumulation dynamics systems can bevertically classified in this region. The migration-accumulation dynamics system ofself source is the main objective of oil and gas exploration and development, weshould continue to find of self source reservoir in the Pinghu Formation and Huagang Formation of Huagang, Canxue, Tianwaitian, Chunxiao and YuQuan tectonic belts,while strengthening the exploration of the migration-accumulation dynamics systemof other source in the Longjing Formation, in the sorth of Duanqiao, Chunxiao,Huangyan tectonic belts and the north of Huagang tectonic belt. Horizontally, theTiantai tectonic belt and Huangyan tectonic belt of sorth Central Inversion StructuralBelt is the most favorable exploration area, its have remarkable achievements andhigh success rate and lower the risk in oil and gas exploration. The Ningbo tectonicbelt is the for more favorable exploration area, it has the basic condition of oil and gasaccumulation explorations and large oil and gas exploration prospects. |
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