思茅坳陷油气地质特征与勘探远景展望

思茅坳陷在晚古生代-三叠纪属于三江特提斯构造域双岛弧后活动边缘海盆地，沉积了区域展布的P、T₂₊₃和J₂海相烃源岩系，“盆台相间”格局和由“东隆西坳”转到“走滑挤隆冲断与构造逸脱”演变史控制了海相烃源的运聚，被盆地相区包围的继承性孤立碳酸盐岩台地是油气聚集成藏最佳指向区。中燕山期以来由南向北的持续性挤压造山和走滑、构造逸脱作用使得思茅坳陷J-K区域盖层遭受肢解并和E+N走滑盆地叠置，最终形成封存体系各不尽同的五大持续-肢解型含油气保存单元。处于构造逸脱体系喇叭口的呵叻盆地发现气田和思茅坳陷见气水同喷、原油显示表明，思茅坳陷海相地层仍有油气勘探前景，以存在K₃-N区域盖层、断裂改造较弱、源岩成熟度较低、构造发育的英德-景谷、勐腊-勐满含油气保存单元为首选靶区。

OIL AND GAS GEOLOGICAL CHARACTERISTICS AND EXPLORATION POTENTIAL IN SIMAO DEPRESSION

The Simao Depression was a double island back arc active marginal sea basin of Sanjiang Tethys tectonic province in Late Paleozoic—Triassic, in which the marine hydrocarbon source rocks of P, T2+3 and J2 were widely deposed. The migration and accumulation of the oil and gas originated from the marine hydrocarbon source rocks were controlled by the framework of “basins alternating with tablelands” and the evolution history from “eastern uplifting and western downwarping” to “strike slip compressive uplift thrust and structural detachment”; and the inherited and isolated carbonate platform surrounded by basin facies regions was the optimal guiding area of oil and gas accumulation and reservoiring. Since Middle Yanshan epoch, the successive south to north compression and orogeny and strike slip structural detachment had caused the J—K regional cap rocks to be dismembered and E+N strike slip basins to be superposed in Simao Depression, and the five successive dismembered hydrocarbon bearing preservation units with different seal systems were formed at last. The gas field was discovered in Hele Basin at the bell mouth of structural detachment system and the gas water flowing and crude oil shows were found in the wells drilled in Simao Depression, so that the depression is still possessed of oil and gas exploration potential, the Yingde—Jinggu and Mengla—Mengman hydrocarbon bearing preservation units, with good K3—N regional caprocks, slight fault transform, low source rock maturity and many structures, being the first selected target areas.