歧口凹陷湖盆特征及对油气成藏控制作用研究

通过分析歧口凹陷湖盆基本特征,剖析构造断裂演化与油气成藏关系,探索其对油气成藏的控制作用.歧口凹陷湖盆自古近纪-新近纪经历了断陷期、断坳转换期、拗陷期三大演化阶段,现今表现为多隆多凹、盆岭相间的分布特征.受区域构造应力场及幕式演化影响,湖盆断裂以NE、近EW向为主,主断裂以侧接、转换为特色.凹陷主要发育潜山构造带、断阶构造带、盖层滑脱型断裂构造带,不同构造带油气成藏模式富集特点差异明显.根据断裂构造与油气成藏关系,认为海陆调解带裂缝油气藏的勘探、远源缓坡区沿断裂构造脊的中浅层勘探及大断裂控制的"Y"字型浅层构造及两侧火成岩勘探是下步工作重点方向.

THE HYDROCARBON FORMATION AND ACCUMULATION CONTROL FACTORS RESEARCH OF QIKOU DEPRESSION

The paper analyses the fundamental feature of Qikou depression and dissects the connection between fracture evolution and hydrocarbon formation and accumulation.Moreover,it researches whether fracture evolution has the effect of the accumulation of oil and gas.Nowadays there are many uplifts and sags in Qikou depression,which distribute in interval.As to the effect of tectonic stress field and episodic evolution,north-east and east-west are the main strike of lake basin fracture.The master fractures are the dominant of side joint faults and transform faults.Qikou depression mainly develops buried hill,fracture bench and cover-slipping-fracture tectonic belts.The models of hydrocarbon formation and accumulation have apparent deviatiou in different structure belts.According to elemental searching,it is prospect priority targets in the next stage that explore fractured hydrocarbon reservoir in land-and-sea transition zone,the shallow and middle-levels of distal shelving along faulted structure ridge and igneous rocks,which distribute in shallow levels and lateral laver of "Y" type fracture controlled by major fault.