A Critical Evaluation of Water Coning Correlations in Vertical Wells

Abstract

In oil and gas production, developing bottom-water reservoirs with active aquifer requires production strategy that can handle production-rate-sensitive phenomenon – water coning. The coned water that moves into the completion interval results in production related problems: excessive water production, surface water handling, low oil productivity, among others. To this end, several correlations: critical rate, breakthrough time and water-cut performance after breakthrough have been developed based on analytical, empirical and numerical approach to evaluate water coning tendencies in petroleum reservoirs. Some of the developed correlations have gained field application. However, limited literatures are available that have evaluated the prediction of these water coning correlations. Thus, the various water coning correlations for vertical well were evaluated and the obtained results show that most correlations have the same prediction profile. Conversely, these correlations predicted different coning parameters’ value. Further analysis of the results depicts that critical production rate and breakthrough time in vertical wells are indirectly dependent on fractional well penetration. In addition, the correlations developed from water-cut data for the prediction of water-cut performance after breakthrough indicate more realistic predictions in the water-cut profile than the correlations developed from water-oil ratio. Therefore, to delay water coning tendency in bottom-water reservoirs, fractional well penetration is a consideration in vertical wells to establish optimum critical oil rate and breakthrough time during oil and gas production.