北海盆地油气分布特点及石油地质条件

OIL AND GAS DISTRIBUTION PATTERN AND PETROLEUM GEOLOGICAL CONDITION OF THE NORTH SEA BASIN

依据IHS数据库2009年资料,统计了北海盆地不同构造单元和储集层系发现的油气田及大型油气田的个数和油气储量,分析了北海盆地油气分布特点。通过分析得出,北海一半以上的油气资源集中在储量>5亿桶的大油气田中,北部油气俱丰,以油为主,南部则以气为主。通过对南、北北海盆地的石油地质条件的分析,认为北海盆地发育多套含油气系统。北北海盆地油气分布主要受控于烃源岩和储集岩分布,最重要烃源岩是基末利黏土组,最重要的储层是中、下侏罗统砂岩,北海北部一半以上的油气资源储存在该层系,上石炭统威斯特伐利亚煤系是最大含油气系统的烃源岩;南北海盆地最重要储层是上二叠系赤底统砂岩,富集了北海南部86%以上的天然气,油气分布主要受控于区域性盖层蔡西斯坦统的发育。

Based on the data from IHS database 2009,this paper analyzed the hydrocarbon resources distribution pattern in the North Sea Basin by counting up the numbers and reserves of oil and gas fields as well as giant oil and gas fields in different geological units and reservoirs.More than half of the hydrocarbon resources are preserved in the giant oil and gas fields over 5 billon barrels of oil equivalent.The northern North Sea Basin is rich in both oil and gas,but dominated by oil,while the southern North Sea is predominated by gas.The analysis of the petroleum geological condition shows that there are several petroleum systems developed in the North Sea Basin.The hydrocarbon distribution in the northern North Sea Basin is mainly controlled by of source and reservoir rocks.The Kimmeridge Clay Formation is the most important source rock,and the middle and lower Jurassic and the upper Permian System are the richest reservoirs which contains more than half of the reserves of the northern North Sea Basin.The Upper Carboniferous Westphalian coal is the source rock of the largest petroleum system of the Basin,and the most important reservoir is the Upper Permian Rotliegendian sandstone which stores more than 86% gas reserves in the southern North Sea Basin.The gas distribution is largely controlled by the availability of the regional cover of the Zechstein Series.