Desalination of Produced Water of Asab Oil Field Abu-Dhabi to Enhance its Oil Recovery and Water Injectivity

摘要

Produced water is the largest waste stream generated in oil and gas industries. It is a mixture of different organic and inorganic compounds. Global produced water production is estimated at around 280 million barrels per day compared with around 97 million barrels per day of oil. As a result, water to oil ratio is around 3:1 that is to say; water cut is 70%. Due to the increasing volume of waste all over the world in the current decade, the outcome and effect of discharging produced water on the environment has lately become a significant issue of concern. In certain fields like Asab oil field Abu Dhabi UAE, the produced water is re-injected in the field through injection wells. However, it is found that the concentration of salt in injected formation water in Asab field is 150,000-262,000 ppm and this high saline water is injected in the reservoir. Where it may cause severe formation damage: pore plugging, water injectivity and oil productivity problems. Our objective is to develop a cost effective technique to reduce the salinity of this produced water to control formation damage. We used a couple of chemicals/reagents to reduce the salinity of injected water in Asab field, to increase oil recovery and minimize formation damage such physico-chemical and/or pore blockage. This research examines the sources, characteristics, and extent of different chemicals specially fatty acids and different other techniques that can be used to reduce the salinity of water because no single technology can meet suitable effluent characteristics, thus two or more treatment systems might be used in series operation. However, we were successful to reduce the salinity of brine to approximately 64-74%, where it can be re- injected into the reservoir with minimum formation damage and maximum injectivity.