Evaluating New Chemical Treatments to Decrease Water Soluble Organic (WSO) Content from Produced Water Discharge

Abstract

Abstract During the offshore disposal of produced water, an oil sheen is sometimes visible at the surface, even when the oil content is within acceptable limits. Water Soluble Organics (WSO) are well known as one of the main causes of the appearance of sheen. The most common approach to inhibiting sheening is the acidification of oil, where some organic acid is added prior the oil treatment system. However, high acid volumes (3–5 tons/day at 500-ppm dosage) raise asset integrity concerns. This work investigates a cost-effective and sustainable alternative to acidification for sheen control. Two products were tested: Product A, an advanced emulsion breaker with integrated WSO removal properties for treatment of crude oils, and Product B, a flocculant agent with integrated WSO removal properties for treatment of produced water. With Product A, the results showed a 55% WSO reduction compared to the blank, compared with a 40% reduction with the emulsion breaker upon acidification. With Product B, the results showed a 98% WSO reduction against 71% with a reference flocculant only. Combined, these new products can potentially decrease WSO levels of the disposed produced water and inhibit the appearance of sheen. This is an alternative protocol to the acidification method currently used in offshore platforms to avoid sheen appearance. The far lower dosages (80 and 40 ppm for Products A and B, respectively) compared to the acid treatment (around 500 ppm) could reduce the overall integrity management risk, the chemical demand by 83%, and the Scope 3 CO2 emissions by up to 90%.