Experimental Modeling of Gas Channeling for Water-Alternating-Gas Flooding in High-Temperature and High-Pressure Reservoirs

The objective of this study was to investigate gas channeling behavior and its governing factors during water-alternating-gas (WAG) flooding in high-temperature and high-pressure reservoirs. According to the geological characteristics and development conditions of the target carbonate reservoir, various core models were fabricated and the relevant experimental method was designed based on the similarity criterion of physical simulation. A series of experiments were performed to discussed the production performance of WAG flooding, and the effect of core heterogeneity and injection rate on oil displacement efficiency was investigated. Experimental results showed that WAG flooding presented great potential of enhanced oil recovery and good effect on delaying water and gas production. The severer the core heterogeneity, the smaller the fluctuation range and the less the fluctuation frequency of water cut and gas-oil ratio. The effect of WAG flooding on water and gas production control became worse with an increase in core heterogeneity. The injection rate presented less significant effect on oil recovery compared to core heterogeneity. Water and gas breakthrough occurred earlier at a higher injection rate. This experimental study could provide guiding suggestions for reasonable implementation of WAG flooding in the oilfield.

Keywords: WAG flooding; gas channeling; enhanced oil recovery; high-temperature and-high pressure reservoir; physical simulation