Oil/Water Separation Experience From a Large Oil Field

Abstract

Summary This paper discusses challenges related to emulsions that have been encountered in a large Saudi Arabian field. The field produces from several different reservoirs with a range of fluid properties. These properties provide an interesting case of operational challenges in oil/water separation, including increased incidents of shorting in the separator, tripping of equipment, and increased demulsifier consumption. This paper presents the results of a comprehensive study that was initiated to understand the main causes of emulsion formation in the field and ways to optimize oil/water separation. The effects of several recommendations that were implemented by operations engineering in the field were evaluated. These include the conversion of a two-phase separator into a three-phase separator, splitting of the demulsifier injection between offshore producing platforms and onshore wet-crude handling facilities, and field trials with promising chemicals. The demulsifier costs have been reduced by more than 50% by the implementation of retrofitting and proper demulsifier-injection strategies. The results presented in the paper provide invaluable operational experience, and many lessons learned are applicable to any crude-oil-treating facility.