酒泉盆地营尔凹陷长沙岭构造带油气勘探前景

Prospect of Petroleum Exploration in Changshaling Structural Belt of Ying'er Sag in Jiuquan Basin

长沙岭构造带位于营尔断陷湖盆西斜坡,是被一系列断层复杂化的大型鼻状隆起,下白垩统赤金堡组是该带的主要含油气层系。构造带的形成经历了早白垩世早期拉张块断、中后期南北向挤压褶皱和第三纪改造定型三个阶段。赤金堡组下段暗色泥岩十分发育,而赤金堡组上段砂层较为发育,断层是沟通烃源岩和储集层的重要通道,下生上储是该带主要的储盖组合类型。构造带上已有多口探井在赤金堡组砂层中获得油气流,优越的石油地质条件已使得该带成为玉门油田近期重点勘探地区之一。

Changshaling structural belt,located in west slope of lake basin in Ying'er sag,is a large-scale nose-like uplift shaped by a series of complex faults,and the main hydrocarbon-bearing sequence in it is in Chijingbao formation of Lower Cretaceous.The formation of structural belt underwent such three stages as tensional block faulting in the early of Early Cretaceous,com-paction folding of S-N direction in Middle-Late Cretaceous and reconstructing and shaping in Tertiary.Dark shale is well devel-oped in the lower section of Chijingbao formation.Sandstone is mostly found in the upper section of it.Faults are the major channels for connecting source rocks and reservoir rocks.And its primary type of reservoir-cap rock assemblage is source bed in lower forma tion and reservoir bed in upper formations.Many prospecting wells have been penetrated in sandstone layers of Chi -jingbao formation on the structural belt and obtained oil-gas flow.Hence,superior petroleum geological conditions allow this struc-tural belt to become one of key exploratory areas in Yumen oilfield in the near future.