The Types of Reservoirs Encountered by the Wells in the Halahatang Oilfield and Water Flooding Effects

In the fracture-vug reservoirs of Halahatang Oilfield, water flooding effects are quite different in different production wells. In order to solve this problem, a reservoir type discrimination method based on geophysical methods, logging response features, and dynamic analysis systems was established by analyzing dynamic and static characteristics of production wells in the process of water flooding. The reservoirs encountered by the wells in Halahatang Oilfield were divided into four types, i.e., isolated cavern+weak bottom water, isolated cavern+strong bottom water, fracture-vug and fracture-vug+bottom cavern. The water flooding effects in different types of fracture-vug reservoirs were analyzed by means of water flooding mechanism research and field test. This method was applied on site for water flooding operation at 60 wells in Halahatang Oilfield. And it was shown that the waterflooding method was suitable for isolated cavern+weak bottom water type and fracture-vug+bottom cavern type reservoirs instead of fracture-vug type and isolated cavern-strong bottom water type reservoirs. It was an important guidance for optimizing development modes of fracture-vug reservoirs and improving single-well water flooding effects in Halahatang Oilfield.