松辽盆地北部深层层序地层格架建立与模式研究——以古龙—常家围子断陷沙河子组为例

The Establishment of Sequence Stratigraphic Framework and Its Models of Deep Formation in Northern Songliao Basin:Taking the Shahezi Formation of Gulong-Changjiaweizi Fault Depression as an example

松辽盆地北部徐家围子等地区深层勘探相继取得了一系列重大突破,但由于古龙—常家围子断陷深层地质认识程度较低,该区还处于深层勘探初期阶段。古龙—常家围子断陷区沙河子组充填了一套扇三角洲和湖泊沉积,是该区重要的储层和生油层。综合利用测井、钻井、地震等资料,将层序地层学原理应用于陆相断陷湖盆沉积,识别出沙河子组三级层序顶底界面,将其划分为2个三级层序,并在层序内部识别出高水位体系域、水进体系域、低水位体系域,建立了该区高精度的等时层序地层格架。根据沙河子组地质结构和地层发育的构造背景,建立了沙河子组层序地层模式:双向多断阶层序模式、双箕状不对称层序模式。

The deep exploration of Northern Songliao Basin has got a series of breakthrough,such as Xujiaweizi,and so on.For the recognition of deep geology of Gulong-Changjiaweizi Fault Depression is lower,it is still at the early stage of deep exploration.The Shahezi Formation of the fault depression of Gulong-Changjiaweizi was filled by a suite of fan delta and lacustrine deposits,is the important reservoir bed and source bed.We utilized multipurposely the data of logging,drilling,seismic and so on,applied the theory of sequence stratigraphy to continental fault depression of lake basin deposit,identified the top and bottom surfaces of the third-order sequences of Shahezi Formation,devided it into 2 the third-order sequences,and distinguished from highland systems tract,transgression systems tracts,lowstand systems tracts,established the high precision isochronous sequence stratigraphic framework.Based on the geologic configuration of Shahezi Formation and the tectonic background of the strata development,author established the sequence stratigraphic modes of Shehezi Formation： two-way multistage fault terrace sequence stratigraphic model,double half-graben asymmetric sequence stratigraphic model.