Occurrence and distribution of formation water in the Ordovician reservoirs of the Tahe Oilfield
Zhu Rong1, Lou Zhanghua1, Yun Lu2, Li Mei1, Jin Aimin1, Zhang Huiting1
1. Institute of Hydrology and Water Resource Engineering, Zhejiang University, Hangzhou 310028; 2. Research Institute of Exploration and Development, Northwest Branch, China Petroleum & Chemical Corporation, Urumqi 830011
According to the occurrence of formation water, three types of water were identified in the Ordovician reservoirs of the Tahe Oilfield in the Tarim Basin: 1) residual water in bottom of cave after oil and gas displacement, 2) residual water in fracture/pore around cave after oil and gas displacement, and 3) interlayer water below reservoirs. The chemical and dynamical characteristics of each type mentioned-above of groundwater were analyzed. Due to strong heterogeneity of the Ordovician carbonate reservoirs in Tahe, pore structures and oil-water distributions were very complicated. Because of the differences in the development of background reservoirs, displacement percentage of oil and gas, and the size of reservoirs, variations in the corresponding oil-water distribution, development performance and water cut behaviors were observed, which was summed up and their oil-gas exploration significance was discussed.