琼东南盆地三亚组SY1、SY2层序低位域砂体特征与油气成藏的关系

Relationship between characteristics of LSI sanbodies and hydrocarbon accumulation in SY1 and SY2 sequences of Sanya Fm in Qiongdongnan basin

从层序地层学的概念出发,通过岩性、测井及地震反射特征分析,在琼东南盆地三亚组中识别出两个 三级层序:SY1、SY2层序。在这两个三级层序的低水位体系域发现了"下切谷、盆底扇、斜坡扇、低位楔"等 沉积砂体。这些低位城砂体沉积在古近系裂陷期的沉积物之上,具备良好的储集体条件,其上的海侵和高 位体系域中的大套泥岩,可以为其提供充足的油源供应,同时又可作为盖层对其形成良好的封盖。琼东南 盆地三亚组的低位域砂体具有良好的成藏条件,找寻这些砂体对于琼东南盆地的油气勘探具有重要意义。

Two 3rd grade sequences, SY1 and SY2, are identified in Sanya Fm in Qiongdongnan basin through analyzing lithology, logging and seismic reflection signatures and by using concept of sequence stratigraphy. Sandbodies including 'downcutting valley, basin floor fan, slope fan and lowstand wedge' are discovered in the LST (lowstand system tract) of these two 3rd grade sequences. These LST sandbodies were deposited on the Eogene chasmic stage sediments and had favorable reservoir conditions. The above thick claystone in ingression and highstand system tract might supply enough oil sources and act as good cap rocks at the same time. The LST sandbodies of Sanya Fm in Qiongdongnan basin have good reservoiring conditions, thus have great significances to petroleum exploration in this area.