Polymeric and Alkali-Surfactant Polymer Enhanced Oil Recovery Chemical Treatment: Chemistry and Strategies Required After Breakthrough into the Process

摘要

The use of polymer flooding and alkali surfactant polymer (ASP) flooding techniques is becoming commonplace in the oil industry, particularly in projects where heavier and more viscous crude oil is produced. While the efficacy of these enhanced oil recovery (EOR) techniques cannot be disputed, as recovery factors (RF) can be doubled, often there is little consideration given to the implications of these EOR chemicals breaking through into producer wells. The impact caused by EOR chemical breakthrough can be varied, but most commonly the efficacy of oil/water separation is seriously affected. The contribution that EOR chemicals can have on reservoir souring is often underestimated, as is the effect they can have upon standard production chemicals such as scale and corrosion inhibitors. This paper draws upon the experience of several different EOR operations from around the world and demonstrates the different range of challenges that EOR chemical breakthrough has upon the production chemical strategy. Examples include the effect on separation, scale inhibition and on integrity management - three essential components of any flow assurance strategy. Two case histories are taken from Canada where the effect on separation was profound. A case history is also provided where a scale inhibition / solids mitigation strategy had to be significantly amended in order to accommodate the breakthrough of an ASP EOR flood. The paper details several lessons learned that can be used to assist the front end engineering and design (FEED) considerations of EOR strategies, including future-proofing facilities and production chemistry strategies for planned and retrospective EOR flooding projects.