始新统油气系统:泰国湾东北部油气勘探新层系

Eocene petroleum play:New petroleum system in northeast Gulf of Thailand

泰国湾区域经历了前裂谷期、裂谷期、裂后期的构造演化阶段,形成了多个裂谷盆地。泰国湾区域东北部在渐新世经历了一次明显构造反转,较泰国湾区域大部分地区强烈。通过对比区内钻井,结合地震解释,对该区的沉积特征和构造演化进行了分析,认为这次反转构造导致了反转构造带上构造、沉积特征与邻区有较大的不同。由于这次反转构造,泰国湾东北部在新层系发育新类型的油气系统,即深部的始新统油气系统:烃源岩为中始新统湖相泥岩,储层为上始新统-渐新统三角洲相砂岩,盖层为下中新统三角洲前缘相泥岩和上中新统以上的海相泥岩。该油气成藏系统已被钻井钻遇油气显示,是本区有效油气成藏系统。

Gulf of Thailand experienced pre-rift, rift and post rift tectonic evolution stages. In sequence, there developed several rift basins. However, the northeast part was influenced by a reversion event, and stronger than other area. The wells in reversion structure and adjacent area and the seismic facies in this area were analyzed in this paper. Furthermore, we analyzed the sediment facies and tectonic evolution sta- ges. It can be concluded that the tectonic style and sediment facies have great difference with adjacent area. Thus, there developed newpetroleum play innew exploration formation that has not been discovered： Eocene lacustrine shale acts as efficient source rock; Eocene-Oligocene deltaic sandstone acts as reservoir; Lower Miocene delta front shale and Upper Miocene Marine shale act as seals in this play. Eocene petroleum play has been drilled by exploration well in study area, which is proved as effective play in Gulf of Thailand area.