Overview of produced water in Oilfield

Oil and gas reservoirs can contain water as a reservoir fluid. The water precentage ranges from a few (%) to almost total water saturation. The waters found in the oil and gas reservoirs are genetically related to oil origin and represent mixture of organic and inorganic materials. These waters are of marine origin and contain mineral salts such as Na+, K+, Ca2+, Mg2+, Cl-, HCO3, SO4. Produced water must be subjected to a particular treatment before the deposal so as not to contaminate the environment, primarly watercourses. The mineral composition of these waters can cause the occurence of limescale, which in turn result in damage of the equipment such as injection pumps, corrosion of metal parts etc. The paper presents an overview of the hydrochemical characteristics of the groundwaters of oil and gas reservoirs and produced water into the bargain. Produced or wastewater can be used among other things to inject into the aquifers of the oilfield to increase the production of crude oil as well as their treatment.