塔里木盆地英买力凸起南部寒武系褶皱的地质属性及其油气成藏条件分析

传统上,塔北隆起英买力凸起南部多个寒武系大型异常体被认为是中寒武统盐构造的反映。笔者研究发现这些大型异常体的解译有一定的多解性。分析认为,构造的主体存在碳酸盐岩生物建隆块体的可能,后期被断裂复杂化形成大型叠置复合褶皱。寒武系褶皱内幕的断层和裂缝极其发育,大大改善了寒武系白云岩储层物性,有利于油气聚集;基底断裂发育,能有效沟通油源;中寒武统泥岩或含膏泥岩形成良好的盖层,封闭条件良好;综合分析认为英买力南部寒武系大型构造具备优越的油气成藏和保存条件,有利于形成大中型油气田,是塔里木盆地潜在的油气勘探新领域。

Geological attributes and conditions of hydrocarbon accumulation of Cambrian folds in the southern Yingmaili swell,Tarim basin

Traditionally,the Cambrian abnormal bodies in the southern Yingmaili swell were considered to be the reflections of Middle-Cambrian salt tectonics.However,we found that there are multiple options to explain these large anomalous bodies.It is possible that the carbonate build-ups exist in the main part of the folded structures and were thickened by the latter faults and formed large overlying composite folds.Faults and cracks are extremely developed inside the Cambrian folds and can greatly improve Cambrian dolomitite reservoir properties.They are very conducive to the oil and gas accumulation.The basement rifts can connect effectively with oil source,and the Middle-Cambrian shale or mudstone can form good capping formations that are well closed.A comprehensive analysis on the southern Yingmaili area indicates that the Cambrian large-scale fold structures possess favorable conditions for hydrocarbon accumulation and storage,and are favorable for forming large and medium-scale oil and gas fields.The Cambrian carbonatite build-up will be one of the new hydrocarbon exploration potential fields in the Tarim basin.