摘要
侏罗系和下白垩统下段在库车坳陷南缘由北向南尖灭 ,形成一系列地层超覆圈闭。侏罗系圈闭以侏罗系下段滨浅湖砂体为储层 ,中上段滨浅湖沼泽相泥质岩为盖层。下白垩统下段滨浅湖砂体为储层 ,中上段浅 -半深湖泥质岩为盖层 ,具有良好的储盖组合。圈闭底板为前震旦系和震旦 -下奥陶统 ,其底板的封堵性直接影响圈闭的有效性。研究认为 3种情况下底板可以形成较好的封堵 :( 1)底板为前震旦系 ;( 2 )底板为震旦 -奥陶系碳酸盐岩 ,当圈闭前端底板岩溶不发育 ,可成为有效封堵面 ,形成有效圈闭 ;( 3 )底板为震旦 -奥陶系岩溶发育的碳酸盐岩 ,但地层圈闭储层与底板岩溶储集体连为一体 ,圈闭前端震旦 -奥陶系与前震旦系呈断层接触 ,上覆下白垩统中上段盖层 ,构成复合圈闭。库车坳陷具有丰富的油气资源 ,南缘地处坳陷内三叠系 -侏罗系烃源岩油气运移指向区 ,油源、运移聚集和圈闭条件都比较优越。因此库车坳陷南缘地层超覆圈闭具有良好的含油气前景。
A series of stratigraphic overlap traps were formed as a result of depositional thin out from north to south in the Jurassic and Lower Cretaceous in Kuqa Depression.Reserviors of the Jurassic traps consist of the Lower Jurassic sandstones of coastal shallow lake facies,and the cap rocks are the Middle and Upper Jurassic mudstone of marsh facies.The lower Lower Cretaceous sandstones formed the reserviors of the Lower Cretaceous traps and the mudstones of shallow deep lake facies are their cap rocks.The floor of traps consists of pre Sinian or Sinian Lower Ordovician,its blocking ability directly infleunce effectiveness of traps.The following 3 conditions may form effeetive blocking:(1) the floor is Pre Sinian;(2) floor is the Sinian Ordovician carbonates and karst of floor in the front of trap is undeveloped;(3) the floor is Sinian Ordovician carbonates with development of karst and the karst forms one part of reserviors,which is covered by the upper Cretaceous cap rocks. It was suggested that there was rich hydrocarbon resource in the Kuqa Depression,and the south margin was a hydrocarbon accumulation area migrated from the Triassic Jurassic source rocks of the depression.The stratigraphic overlap traps in the south margin of the Kuqa Depression is a favourable target for hydrocarbon exploration.
出处
《石油实验地质》
CAS
CSCD
北大核心
2000年第1期40-45,共6页
Petroleum Geology & Experiment
基金
国家"九五"重点科技攻关项目!( 96-111-0 3 -0 7-0 1)
关键词
库车坳陷
地层超覆圈闭
侏罗系
下白垩统下段
Kuqa depression
stratigraphic overlap traps
Jurassic
Lower Cretaceous
