Simplified shape factor analysis as applied to an unconfined peripheral waterflooding system

Unconfined peripheral waterflood systems have been studied in which the last production well was located at the mid-point of a fluid mapper. This study was made by using 4 wells with constant injection pressure. By locating the last production well in the center of the fluid mapper, it was found that an area beyond the last well was swept which would not be accounted for in the confined peripheral flood systems. By applying the complete channel, circling- in technique, shape factors were determined and are tabulated. Using this set of shape factors and those obtained for a confined system with the same basic data, it was found that a greater cumulative recovery will be predicted using the shape factors of an unconfined system. A mathematical analysis has been made to facilitate the determination of these shape factors. Based on this analysis, a simplified procedure was developed whereby shape factors can be graphically determined with a minimum amount of manual labor.