塔河油田及塔北碳酸盐岩油藏特征与成藏主控因素

Features and main controlling factors of carbonate reservoirs in Tahe Oilfield and northern Tarim Basin

塔河油田奥陶系油气藏为缝洞储集为主、多期成藏改造的复杂油气藏。塔河油田及塔北奥陶系油气藏具有以下共同特征:(1)多期岩溶,特别是加里东古构造格局及岩溶古地貌为油气运移提供了运移通道和储层发育条件,储层相对发育区成为油气运移优势通道和富集有利部位;(2)奥陶系自身储盖组合是奥陶系油气藏最主要储盖组合之一;(3)岩溶不整合形成区域性通道,并通过断裂、裂隙与输导层连接,构成输导体系;(4)成藏后的保存条件制约了古油气藏分布范围,后期成藏油气在构造高部位相对富集;(5)成藏始于加里东晚期,经历多期充注调整改造。

Ordovician reservoirs in the Tahe Oilfield are dominated by fracture and vug,and have experienced stages of deformation.They have the same features as those in the northern Tarim Basin.1） Periods of karst effect.Caledonian paleostructure and karst palaeogeomorphology provided pathways for hydrocarbon migration and room for reservoir formation.2） The reservoir and cap combination in Ordovician itself worked as the most important combination for Ordovician reservoir.3） Karst unconformities offered ways for regional migration,and formed migration system together with fractures and fissures.4） Reserve conditions after accumulation controlled the distribution of ancient reservoir.Petroleum accumulated in the late stage mainly enriched in the higher locations.5） Accumulation started in the late Caledonian,and came across stages of filling adjustment.