Waterflood Strategy – Challenges and Innovations

Abstract More than thirty years ago, Gulf of Suez Petroleum Company (Gupco) - Egypt, initiated the first waterflood project for El Morgan oil field. The company now operating 14 different waterflood reservoirs. These reservoirs have produced a cumulative oil representing 40% of their original oil-in-place. On average, the projected waterflood recovery factor is 54% of OOIP. Due to non-uniform lithology and non-uniform pattern of existing well locations in most reservoirs, peripheral waterflood was found to be the most suitable and economic waterflood pattern at project startup. Peripheral waterflooding has the advantage that it minimizes the number of injection wells by converting the watered-out producers. As these reservoirs become more mature, the line-drive pattern (peripheral + internal injection) was found to be more effective. Since most of the reservoirs are currently in the mature stage, good managing and close monitoring for each waterflood project is extremely important. This paper presents major strategies in managing the different waterflood projects to maximize both the oil production rate and oil recovery in optimum manners. This is being achieved through several common and familiar waterflood issues including in-fill drilling, zonal injection improvement, injection pattern modification, injection below formation parting pressure, pressure maintenance, workovers for production and injection wells, continuous data collection, and water quality monitoring. The paper also addresses the waterflood side effects such as scale buildup, reservoir souring and facilities corrosion. In addition, the paper discusses some of the innovative techniques that have been used to maximize waterflood recovery and enable waterflooding of marginal fields at a cost effective manner. Examples for these techniques are gas-cap water barrier injection, heavy oil waterflooding, coiled-tube water injection lines, slim-tube dual completions, and satellite waterflooding for pilot and marginal fields waterflooding.