塔河油田奥陶系油藏古岩溶表生作用期次划分

Stages of Paleokarstic Hypergenesis in Ordovician Reservoir,Tahe Oilfield

岩溶缝洞型碳酸盐岩储层是塔河油田奥陶系最重要的储层类型,深入研究古岩溶类型、发育期次和发育模式对认识储层的发育规律具有重要意义。根据岩溶水的特点,可分为大气水和非大气水岩溶两类,大气水岩溶主要发育在表生条件下。结合塔河油田奥陶系古岩溶发育的地质特点,可以将其表生作用过程大致分为5个阶段,分别是加里东中期Ⅰ幕、Ⅱ幕、Ⅲ幕,海西早期和海西晚期。针对各个阶段的岩溶发育特点,建立了相应的岩溶发育模式。

Karstic fractured-vuggy carbonate reservoir is the most important type of Ordovician reservoirs in Tahe Oilfield. While the types, stages and models of paleokarst are important in the study of the laws of reservoir development. According to its features , the karst water is divided into two types, atmospheric water and non-atmospheric water. Usually, the former occurs in hypergenesis condition. Based on the geologic characteristics of Ordovician paleokarst in Tahe Oilfield, hypergenesis can be divided into Episode Ⅰ , Episode Ⅱ, Episode Ⅲ in mid-Caledonian, early-Hercynian, later-Hercynian. Furthermore, in view of karstic characteristics in every stage, relevant karstic models have been set up. They will play a significant role in revealing the development laws of Ordovician reservoir in Tahe Oilfield, and forecasting beneficial reservoir lines.