关键词: 结构构造, 古构造面貌, 沉积充填, 盐湖密度流, 隐蔽油藏, 潜江组, 潜江凹陷

Abstract:

During the deposition of Qianjiang-Jinghezhen formations,Qianjiang salt lake tectonically experienced three evolution phases,i.e.,downfaulting,downwarping, and uplifting-erosion-finalization,each with different paleostructural features.Controlled by the paleostructural features,sources,paleoclimates,and water bodies,(fan)deltaic and salt lake depositional systems,as well as four patterns of salt-lake sedimentary fill(fault slope zones,slope break zones,salt lake density flows and southern ramp gypsic salt),were developed in Qianjiang depression during the deposition of the Qianjiang Formation.In Qiangjiang depression,the paleostructural features of the Qianjiang depression Formation control the patterns of depositional fill;the present tectonic setting controls the hydrocarbon reservoiring;the water media condition have an influence on the extension and distribution of the sandbodies,and the genetic types of sandbodies control the types and sizes of the oil reservoirs.The central part of the depression is favorable for exploration of structural-lithologic reservoirs;the eastern slope zone is favorable for prospecting regional updip pinchout lithologic reservoirs;and the peripheral area of the synclines is favorable for explorations of local updip pinchout lithologic reservoirs.

Key words: structural tectonics, palaeostructural feature, sedimentary fill, salt lake density flow, subtle reservoir, Qianjing Fosmation, Qianjiang depression