安达曼海丹老盆地油气地质特征及勘探潜力分析

近年来，在安达曼海陆续发现一系列油气田和多个大中型含油气构造，因此安达曼海成为东南亚油气勘探的热点地区之一。本文丹老盆地属于安达曼海的一个次级盆地，其构造演化、油气地质特征和勘探潜力整体研究程度较低。为指导丹老盆地油气勘探，本文从研究区域地质背景和构造演化出发，系统研究了该区域构造-沉积演化和盆地油气地质特征，并与北苏门答腊盆地进行比较，建立了盆地油气成藏模式，分析了其勘探潜力。研究结果认为：（1）区域构造-沉积演化可划分为前裂谷期、断陷期、裂陷期和弧后走滑拉分期4个时期；（2）丹老盆地主力烃源岩为也拉组海相页岩，拉廊组河流-三角洲相砂岩为主要储层，断裂和不整合面是油气运移的有利通道，圈闭类型包括构造圈闭和岩性圈闭，盆地可能的成藏模式为（1）下生-上储-背斜式；（2）下生-上储-断块式；（3）下生-上储-生物礁滩体；（3）盆地南部的中深层层系以及碳酸盐岩建隆是丹老盆地未来寻找油气的有利目标。

Analysis of hydrocarbon geological characters and exploration potential in Mergui Basin, Andaman Sea

In recent years, a series of oil and gas field as well as several hydrocarbon structure was found in Andaman Sea, thus, Andaman Sea has become a hot spot of hydrocarbon exploration. Mergui Basin belongs to a sub-basin of Andaman Sea, and its tectonic evolution, hydrocarbon geological conditions and exploration potential were under-discovered. In order to provide guidelines for hydrocarbon exploration in Mergui Basin, this paper starts with researching on geological background and tectonic evolution of this region, by studying the tectonic-sedimentary evolution of the region and the hydrocarbon characters of the Mergui Basin, then make a comparison with North Sumatra Basin, established hydrocarbon accumulation models and analyzed its hydrocarbon potential. The results show that: (1)The tectonic-sedimentary evolution of the region can be divided into four period, they are pre-rift, rifting, structural sag and back-arc strike-transtension (2)The main source rock of the basin is marine shales of Yela Formation, and the main reservoir is the fluvial-deltaic sandstones of Lalang Formation, while faults and unconformities are the favorable migration pathways, trap types including structural traps and lithological traps, the possible hydrocarbon accumulation model of the Mergui Basin including i)gas migrated vertically and accumulated within anticlines; ii)gas migrated vertically and accumulated within fault-blocks; iii)gas migrated vertically and accumulated within carbonate reef.(3)The southern mid-deep strata of the Mergui Basin and carbonate build-ups are the ideal targets for future exploration.