塔河奥陶系油藏断裂对古岩溶的控制作用

The control action of fault to paleokarst in view of Ordovician reservoir in Tahe area

通过对塔河地区奥陶系断裂特征的系统统计分析表明,塔河地区的大型溶洞或分布在T74界面以下较深的溶洞,多数明显受到中-大型断裂的控制作用。分析结果表明,这些断裂主要形成于海西早期,断裂带控制了海西早期溶洞的形成。根据断裂与溶洞发育之间关系,提出了"控洞断裂"、"洞控断层"的概念,并指出塔河地区中-大断裂主要为"控洞断裂",控制了深部岩溶洞穴分布,而小型不协调"毛毛断裂"多数为"洞控断层"。根据岩溶期次及断裂分布及"控洞断裂"的认识,建立了塔河地区奥陶系古岩溶作用时期深部洞穴形成的"断裂环"岩溶的模式。研究成果为塔河及外围地区奥陶系溶洞型油藏的勘探提供了重要依据。

The analysis of systematic statistics of Ordovician fault characteristics in Tahe in this article shows that the large karst caves most probably distributed in the caves which are below the boundary of T74 and mostly controlled by mid-large faults.Most of these faults were formed in the Early-Middle Hercynian and controlled the development of karst caves.According to the relationship between faults and the development of karst caves,the concepts of ＂fault which could control karst caves＂ and ＂fault which controlled by karst caves＂ have been proposed,and it is believed in this article that middle-large faults in Tahe are mainly ＂fault which could control karst caves＂,but the small fractures in this area are mostly ＂fault which controlled by karst caves＂.On the basis of the theory of ＂fault which could control karst caves＂,the mode of ＂fault-paleokarst＂ in Ordovician of Tahe area has been established.This understanding provides important theoretic basis for the exploration of cavern-type reservoirs in Tahe area and its surrounding regions.