Biodegradation of Crude Oil as Potential Source of Organic Acids in Produced Water

Abstract

The concentrations of organic acids in produced water are highly variable. Because of the information shown in others chapters of this book about the toxic effects of organic acids, it is of major interest to understand the mechanisms controlling the occurrence of this compound group in produced water. This chapter focuses on in-reservoir biogeochemical processes which may produce organic acids as products or by-products. The biodegradation processes inside reservoirs decrease the hydrocarbon content of petroleum. Additionally, an increase in oil acidity as measured by total acid number (TAN) is frequently observed. Since the formation waters of reservoirs are in close contact with these processes, the production of smaller, more polar petroleum constituents will also have an effect on the composition of organic molecules in the produced water. This manuscript reviews the literature with respect to acids production of petroleum biodegradation and the effects of water re-injection on such processes.