Oil Formation Environment and Water-Injection Development of Chang-2 Oil Bed in Ordos Basin, Central China

Guang Cheng Xie and Rong Xi Li
Chang'An University, Xi'An, China

The discovery and research to authigenic glauconite in Chang-2 Oil bed of Ordos Basin, Central China, shows that the sedimentary environment of Chang-2 Oil bed is marsh-river-lake. Organic matter, which were deposited and protected in an environment that changed from oxidation to reduction, had a certain oil formation potential to form the reservoir with lower oil saturation. In the development, the oil production of this kind reservoir usually high at the early stage but it has a lower recovery because of water flooded in a short time. Some oil field had to close because of low production. The author estimate that the proved oil reserve of Chang-2 Oil bed of Ordos Basin is at least about 2x10⁸t. The author proposed that oil could be produced and the oil recovery could be increased by two-fold using water-injection at the base of the oil bed.

Key words: Ordos Basin, Chang-2 Oil bed, Authigenic glauconite Environment of marsh-river-lake, Oil reservoir of lower saturation, water-injection at the base of the oil bed