Generalized empirical correlations have been developed to predict, (1) critical oil rate, and (2) water breakthrough time in vertical and horizontal wells. Water coning is a serious problem in many producer wells, which increases the cost of producing operations, and reduces the efficiency of the depletion mechanism and the overall recovery.
A numerical simulation was used to analyze the most relevant fluid and reservoir parameters that affect water coning using a 3-D radial vertical well model and a 3-D Cartesian horizontal well model. The method of determining the average oil column height below perforations at breakthrough (hwb), was developed from a stepwise procedure. First, a number of simulation runs was made to investigate the coning performance at different reservoir and fluid properties for both vertical and horizontal wells. Then, for each simulation run, water oil ratio (WOR) was plotted against of average oil column height below perforations (hbp), on a semi-log scale, from which (hwb) was determined. Once the (hwb) data was obtained for all the simulation runs, regression analysis was then used to define the relationship between (hwb) and various reservoir and fluid properties.
An extensive parametric sensitivity analysis of water coning was made to provide data for developing a predictive correlation of calculating breakthrough time and breakthrough height as a function of various reservoir and fluid properties. The simulation outputs are used to develop empirical water coning correlations to predict critical oil rate, and water breakthrough time for vertical and horizontal wells. The parameters were grouped together based on the basic flow equations and the grouping was confirmed by regression analysis. Several field examples from CTH1 area of Hassi R’mel field in Algeria will be discussed.