【摘要】 通过对大量岩心、录井和测井以及地震资料研究,在前人研究结果的基础上(南屯组分为南一段和南二段),将乌尔逊凹陷南屯组二段进一步划分为三个四级层序(SQ1、SQ2、SQ3)。研究得出工区内不同时期的沉积特征主要受构造演化及沉积物供应的控制:SQ1沉积时期,乌尔逊凹陷南部整体开始下沉,湖盆面积迅速扩大,主要发育扇三角洲、辫状河三角洲沉积体系,同时发育滨、浅湖相沉积,半深湖-深湖和湖底扇沉积;SQ2沉积时期湖平面进一步上升,沉积特征与SQ1沉积时期相似;SQ3沉积时期,控陷断层活动减弱,湖面减小,扇三角洲发育规模减小,辫状河三角洲沉积体系发育规模较大。更多还原

【Abstract】 Based on the results of previous studies(nantun formation is divided into the first member and the second member of nantun formation),combined core logging and logging data and seismic data,the second member of nantun formation can be divided into three 4th-order sequences(SQ1、SQ2、SQ3).The sedimentary characterristics in different periods are mainly controlled by tectonic evolution and sediment supply.In SQ1 period,the whole southern Urxun sag began to sink,and the area of the lake rapidely expanded,sedimentary facies mainly develop fan delta,braided river delta systems,while developing shore,coastal-shallow lacustrine,semi-deep lake-deep lake and the sublacustine.In SQ2 period the lake base level raise continuously,and sedimentary characteristics like the SQ1.In SQ3 period,controlling fault weakened,the lake decreased,reducing the scale of the fan delta devolopment,but the braided-river delta system still developed at a large scale.更多还原