杭州湾入海口处浅层气成因与类型

杭州湾地区浅层天然气主要赋存于第四纪全新世和晚更新世地层中。气样组分分析表明 ,该区天然气属甲烷型生物成因气。有机地球化学分析表明 ,生物气气源层具强—较强的还原环境 ,同时具有较高的有机质丰度、较好的有机质类型等有利条件。钻井资料表明 ,浅层天然气气藏类型有 :顶凸型透镜状砂体气藏、底凸型透镜状砂体气藏、侧缘尖灭型砂体气藏、厚层块状型砂体气藏。具有良好的勘探前景。

Analysis on the Cause of Shallow layer Gas at the Entrance of Hangzhou Gulf and Its Types

The shallow layer nature gas at the extrance of Hangzhou Gulf mainly existed in the stratums between Holocene epoch and Pleistocene epoch of the 4th Era. The sample analysis showed that the nature gas at this area belonged to methane biogenetic gas. Organic geochemistry analysis showed that the gas source layer of biogas had strong reverting environment. At the same time, it had high organic thickness and fine organic type. Materials obtained from drilling well showed that shallow layer nature gas had four types: top protruding lenticular sand gas reservoir, bottom protruding lenticular sand gas reservoir, side pinching sand gas reservoir and thick block sand gas reservoir. All had great perspective for prospecting.