塔河油田奥陶系碳酸盐岩缝洞型储层为该区最重要的油气生产层段.依据地质岩心(屑)、录井、钻井、测井、地震等多种资料,运用由点到线再到面的方法,探讨了塔河油田奥陶系碳酸盐岩油藏的溶洞发育规律.由区内溶洞充填砂泥岩的伊利石K-Ar同位素定年,得出其形成时间在369.33～451.90Ma,古溶洞的形成时间应该早于该时段或与该时段同时,即加里东中晚期-海西早期.溶洞的发育受控于古地貌,存在三个纵向溶洞带.岩溶水输入方式的不同,使得塔河地区溶洞的平面分布分区性较强.北部区奥陶系鹰山组和一间房组中的岩溶水为面状输入方式,南部有上奥陶统隔水层覆盖的区,鹰山组和一间房组中岩溶水为侧向输入方式,岩溶水的出口位置位于断裂带附近,尤其是断裂带与断裂带相交的部位.塔河油田北部和南部的岩洛水系统基本为一个统一的系统.建立了该区大气淡水岩溶模式.

Ordovician carbonate fissuring/cavernous reservoirs are the important oil pay beds in Tahe Oilfield. Based on the K-Ar isotopic dating for illite from sandstone and mudrock filling in the karstic caverns of the reservoirs, the formation time of cave-fillings is during 369.33-451.90 Ma and thus that of the paleocaverns should be earlier than orequal to the 369.33-451.90Ma, which is corresponding to the late Caledonian-early Hercynian periods. There are three vertical cavern zones in Tahe area. Paleocavern development was controlled by paleo-landform. Karstic water input in different ways which resulted in the divisional distribution of caverns in plane in this area. In northern area, the karst water behaved asa planar way of input into the Ordovician Yingshan and Yijianfang strata while in the southern area, the water did asa lateral way of input into the same strata that are covered by impermeable upper Ordovician rocks. Exit of karstic water was located near the fault zone, The karstic water basically belongs toa unified system in the northern and the southern parts of the oilfield. A local model of meteoric karst reservoir is established.