琼东南盆地深水区北礁凹陷勘探潜力评价

Preliminary Evaluation of the exploring potentiality of the Beijiao Sag in the deep water area of the Qiongdongnan Basin

北礁凹陷位于琼东南盆地深水区,是一个北东向延伸南断北超的半地堑,面积约9600km2,古近系最大厚度6000m。钻井证实北礁凹陷崖城组发育具障壁海岸的泻湖—潮坪沉积环境,崖一段的海岸平原沼泽和崖三段的扇三角洲平原是煤系地层发育的有利相带,具有沉积厚度大和分布范围广的特点,有机碳含量高,生烃潜力大。松南低凸起处于北礁凹陷和松南-宝岛凹陷的缓坡方向,是崖城组烃源岩生成油气汇聚的主要方向,凸起大型构造圈闭发育,储盖组合优越,是有利的勘探区带,其中,XS圈闭是大中型有利勘探目标。

The Beijiao Sag is located in the deep water area of Qiongdongnan Basin,faulted in the south part and overlapped in the north part.It is a half graben extending to northeast with an area of 9600km2 and the thickness of its paleogene strata can reach 6000m.Drilling sites have confirmed that the Yacheng Formation developed a lagoon-tidal flat depositional environment of barrier coast developed.The coastal swamp depositional environment of the upper Yacheng Formation and the fan-delta plain sedimentary environment of the lower Yacheng Formation are favorable facies belt where the coal measure strata may exist.These strata are characterized by huge thickness and wide distribution,with high content of organic carbon and potential hydrocarbon.The Songnan Low Uplift lies in the gentle slope of the Beijiao Sag and the Songnan-Baodao Sag.It has been the main accumulation direction of oil and gas produced by the source rock of the Yacheng Formation.The Songnan Low Uplif bears a large structural trap with superior reservoir-cap association.It is the favorable exploration zone,within which,the XS trap is the large and medium-sized favorable exploration target.