Flow Assurance Study for Waxy Crude Oils

In subsea environments, wax-phase separation, deposition, and gelling constitute an important concern in production operation/activities. Understanding the crude oil wax-phase behavior can help to avoid the high costs resulting from production reduction or stoppage in the field operations to mitigate these effects. Conversely, expenses arising from production system overdesign may also be prevented. In this context, two waxy crude oils from different Brazilian fields were selected to be characterized according to Petrobras technical specification for flow assurance requirements. These light crude oils A and B have similar chemical characteristics of saturates, aromatics, resins, and asphaltenes (SARA) analysis, but crude oil A has a wax appearance temperature 15 degrees C higher than crude oil B. Despite having a density around 29 degrees American Petroleum Institute (API), for a rheological point of view, crude oil B has a viscosity about half that of crude oil A at 20 degrees C. In addition, crude oil B dehydrated exhibits Newtonian behavior, in the range evaluated for the shear rate and temperature, while crude oil A features a shear thinning behavior, which increases with the increase of the water content and temperature reduction.