Re-Access Oil Reserves of Watered Out Shut-In Well in Mature Field; Case Study in the Gulf of Suez

Abstract

Abstract Hilal field is a mature brown field in Gulf of Suez. The field was discovered in 1982 and started production in July 1984 from five reservoirs. The platform was damaged due to ship collision shut down in 2007. A new platform was installed and restarted production in 2014. This paper showed the integrated dynamic and static study conducted to define and restore the remaining reserves of old P&A watered out producer. The study included reviewing wells/ reservoir production and pressure performance and all saturation and production logs to monitor water movement across the field and compare wells production performance in different reservoir compartments. New structure maps were built based on new seismic and geological interpretation and to match the dynamic information got the study. Review of the completion fluid during workovers was done to judge its effect on wells production performance. Water oil ration versus cumulative oil production curve was studied for all Nubia reservoir to define the general WOR trend and define remaining reserves of old wells. Wells production performance and production logs showed that despite being in down dip location, WELL-5 was the only well Nubia reservoir producer when old platform was, while up dip wells were completely watered out. Structure map was updated based on information and new fault was added to isolate Well-5 block. Focusing on Well-5 as possible oil potential location, the well was completed as Nubia producer in 1985 became a commingle producer from Nubia and Nukhul S. St in 2000. The well was producing with 85% WC when P&A. Production logs run in 2002 showed that Nukhul was producing with 90% water cut and 60% of liquid rates. Well workovers history showed that Nubia reservoir was damaged due to completion fluid during workover in 1994 and productivity was decreased. This justifies the domination of Nukhul S. St on Nubia. WOR versus cum oil curves suggested that Hilal-A5 was producing 60-70 % WC from Nubia when the well was P&A and Nukhul S. St was watered out. Based on the study, Hilal-B6 well was drilled targeting Well-5 location. The well penetrated +250 ft oil column in Nubia. By selective perforation, the well started production with traces water cut from Nubia. This paper showed the value of detailed integrated dynamic and static study. It showed workflow of studying the re-development of mature fields and finding sweet spot that can raise the field production.