塔里木盆地阿瓦提坳陷油气资源潜力分析

阿瓦提坳陷是目前塔里木盆地勘探程度最低的地区,区内及周缘已发现乌鲁桥油苗、志留系沥青砂岩等油气显示。通过对区域构造背景及其演化、主要烃源岩沉积背景及其地球化学特征的研究,明确阿瓦提坳陷及周缘发育潟湖相、陆棚—斜坡相2类沉积背景不同、地球化学特征有别的主力烃源岩。下寒武统玉尔吐斯组、中上奥陶统萨尔干组、印干组烃源岩以斜坡相为主,是与上升洋流有关的特高丰度烃源岩;中下寒武统则发育以潟湖相为主的较高丰度烃源岩。并提出了本区优质烃源岩的沉积发育模式及其沉积环境的判别指标。通过层序地层、地震相、沉积相研究,开展了层序地层格架下地震相、沉积相约束的烃源岩识别与预测。在典型油藏解剖、油气成藏条件综合分析的基础上,明确了阿瓦提坳陷及邻区有利勘探领域。 

Analysis of hydrocarbon resource potential in Awati Depression of Tarim Basin

The degree of petroleum prospecting in the Awati Depression is the lowest comparing with that in platform depression areas of the Tarim Basin. Some oil and gas shows such as the Wuluqiao oil show and the Silurian asphaltic sandstone were found in the depression and its surroundings. Based on the studies of regional tectonic setting and its evolution, depositional environments and geochemical characteristics of the main source rocks, two different kinds of principle source rocks with different sedimentary backgrounds and geochemical features, deve-loped in lagoonal facies and continental shelf and slope facies respectively, were determined. Source rocks deve-loped in the Lower Cambrian Yuertusi Formation, the Middle and Upper Ordovician Saergan Formation and Yingan Formation were dominated by slope facies and showed extra-high organic content which was related to ascending current. And the Middle and Lower Cambrian source rocks with relative high organic content were developed in lagoonal facies. The sedimentary models for the formation of quality source rocks and the identification marks for depositional environments were proposed. According to the studies of sequence stratigraphy, seismic facies and depositional facies, the identification and prediction of source rocks confined by seismic and depositional facies under sequence stratigraphic framework were carried out. On the basis of dissecting of typical reservoir and synthetic analysis of hydrocarbon accumulation, the potential targets for petroleum exploration were indicated in the Awati Depression and its surrounding areas.