• Examples of successful WAG (EOR) implementations in carbonate reservoirs
  An overall oil recovery factor for carbonate reservoirs is significantly lower than average and does not exceed 25%, as conducting an effective EOR process is quite challenging due to their heterogeneity. The combination of unfavourable wettability - which hinders the displacement of crude oil remaining in the rock matrix, and fracturing - which reduces the impact of viscosity forces on displacement efficiency and leads to a premature breakthrough of the injected fluids into the production wells, causes significant problems in production. Water-alternating-gas (WAG) injection is one of the most interesting EOR methods, which reduces the mobility of injected fluids. If properly designed and optimised, the WAG process can also be effective in difficult geological and reservoir conditions. The examples of successful implementation of the WAG method presented in the paper confirm the possibility of effective WAG process development in the carbonate reservoirs. ...more

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