陆相箕状断陷缓坡带层序地层学研究与勘探实践——以埕岛东坡东营组为例

Sequence stratigraphy and exploration practice on continental half graben gentle slope:A case study with the Dongying formation on the Chengdao east slope

济阳坳陷陆相箕状断陷缓坡带地层是逐渐超覆于中生界、古生界潜山上的披覆状沉积。这类沉积在渤海湾下第三系地层中广泛发育,并极大地受古地貌特征的控制。在特定的古地貌条件下,基准面旋回控制下的沉积充填序列及生储盖组合的分析加深了对储层及隐蔽油气藏成藏机理的认识,并对济阳坳陷缓坡带油气勘探具有较大的指导作用。埕岛地区东部斜坡带东营组勘探程度相对较低,进行层序地层学研究、建立其地层格架是油气勘探的重要研究内容。将层序地层学原理应用于陆相断陷盆地缓坡带,并结合沉积发育特征、厘定地层界线、划分地震旋回,建立层序地层序列,有效地指导了济阳坳陷缓坡带油气的勘探。

The gentle slope formation in the continental half graben of the Jiyang depression is a gradual drape deposition overlapping on the Mesozoic and Paleozoic buried hills.Such deposits had widely developed in the lower Tertiary of the Bohai Bay,and are greatly dominated by palaeogeomorphology.Under certain palaeogeomorphic conditions,the analysis of sedimentary filling sequence and source-reservoir-cap assemblage controlled by base level cycles has enhanced the understanding of hydrocarbon accumulation mechanism of the reservoirs and subtle reservoirs,thus guiding oil and gas exploration on the gentle slope of the Jiyang depression.The Dongying formation in the eastern slope of the Chengdao region is relatively less explored,so that performing sequence stratigraphy study and constructing stratigraphic framework are crucial issues for oil and gas exploration.Oil and gas exploration on the gentle slope of the Jiyang depression has been carried out effectively by applying sequence stratigraphy,coupling with deposition characteristics,determining stratigraphic boundary,delineating seismic cycle and establishing stratigraphic sequence.