Offshore Polymer EOR Injection Philosophies, Constrains and Solutions

Abstract

Abstract In the past decade, the number of polymer injection projects has greatly increased worldwide, with more and more full field implementations. More recently, the focus has shifted toward the deployment of such technologies offshore which presents very specific constraints in terms of facilities, logistics and produced water treatment. One restraint is related to the surface facilities and the footprint available to install the required equipment. This can have a great impact on the choice of the chemical form; two forms are usually considered (powder or emulsion) which dictate the type of equipment necessary and the complexity of the injection process. Other factors come into play when choosing the product form, including weather conditions, available storage, logistics and the existing infrastructure. Many projects are being constrained by the presence of subsea chokes, which can degrade the polymer solution and compromise the economics if not dealt with adequately. In this paper we will review the existing projects and discuss the offshore deployment philosophies for polymer injection. Then, the focus will be on brown fields and the differences between polymer emulsion and powder forms and how both can be processed in the field. Specific highlights will be on polymer design and selection, equipment and logistics for a real field case. Recent developments will be presented in relation to viscosity preservation during injection even in the presence of subsea chokes. Different approaches will be proposed including the deployment of non-degrading chokes or the use of Delayed Viscosity Polymer.