银根-额济纳旗盆地苏红图坳陷西区构造特征与演化

Tectonics and Evolution of the West Suhongtu Depression in Yingen-Ejinaqi Basin

苏红图坳陷西区位于银根-额济纳旗盆地的北部,该区勘探程度较低,地层格架尚不明确,特别是对于古生界地层的沉积特征存在较大争议,严重制约着该区的油气资源评价进程。在前人研究成果的基础上,基于研究区最新的钻井和地震资料,结合区域调查成果,深入剖析了苏红图坳陷西区的构造-地层发育特征及其演化规律。研究认为,古生界地层在白垩纪沉积之前经历裂谷、裂陷构造演化、挤压隆升、初期断陷改造等多个演化阶段,遭受长时期的隆升与剥蚀;自下而上主要发育石炭系阿木山组、二叠系埋汗哈达组、阿其德组和哈尔苏海组四套地层。中生界地层经历断陷期、扩张期、断坳转换期等多个大的构造演化阶段形成众多具有相似构造沉积发育史、相似断裂发育特征的小型中生界凹陷(如哈日凹陷、巴北凹陷、乌南凹陷等),自下而上均发育巴音戈壁组、苏宏图组、银根组、乌兰苏海组、新生代地层,易于整体评价与认识。

Suhongtu depression is in the northern part of the Yingen - Ejinaqi basin. Stratigraphic framework in here is still unclear because of the low degree of exploration, especially, there is a big controversy on the upper Paleozoic strata sedimentary characteristics. These seriously restricts the evaluation process of oil and gas resource in this area. On the basis of the previous research results, we deeply analyze the tectonic - formation development features and evolution regularity of the west Suhongtu depression, based on the latest drilling, seismic data and combined with the survey results of regional in the study area. Based on studies, we get some opinions. The upper paleozoic strata experienced multiple evolutionary stages, the rift valley, chasmic, compressional uplifting and early fault, before the cretaceous deposits. They suffered a long period of uplift and denudation. These are four sets of horizon eventually to keep , which include amushan formation of the carboniferous and maihanhada formation, aqide formation, haersuhai formation of the permian from the bottom up. There are many small mesozoic sag in the upper part of the superimposed basins by fault depression stage, expansion period, fault - depressed diversionary period. They have similar evolutionary history of tectonic sedimentary and characteristics of fracture. From the bottom up, the formations of bayingebi, suhongtu,yingen,wulansuhai and cenozoic are development in all small mesozoic sag（ such as Hari sag, Babei sag, Wunan sag） of the Suhongtu depression. They are very easy to evaluating and understanding as a whole.