Review on Downhole Oil-Water Separation Technology

Down-hole separation technology emerged in the 1990s through which a stream of gas and oil is produced at surface, while a stream of water is injected into the bottom formations and is never transported to the surface, and if needed, it is produced, separately. These systems are known as downhole oil-water and gas-water separation technologies. Hydro cyclones are one of the main components of this separation system. In this study, a comprehensive study has been presented on downhole separation technologies as well as the benefits, requirements and limitations of this technology. This study also provides useful data for the researchers on a number of fields and operational areas and companies owning this technology. According to the results of the present study, successful installations of DOWS system is technically and economically feasible while all the required parameters are accurately evaluated, leading to reducing the costs of water control, production and treatment, and limited surface facilities which is suitable for offshore fields. In addition, application of DOWS system is difficult for separating heavy oil because of the high density difference between water and oil. The water oil ratio should be high so that the dominant phase is water. Manufacturers of hydrocyclone separators recommend water fraction of more than 75%.