The growing popularity of water-based Enhanced Oil Recovery (EOR) techniques, such as Low Salinity Injection (LSI), Chemical EOR (CEOR), and steam-flooding, impacts the water footprint of the oil and gas industry. It also affects the water treatment industry by creating new opportunities as a function of the requirements of equipment and systems in EOR projects. In some cases, the needed technologies have little to no history of application in the upstream oil and gas industry, therefore impacting EOR project budgets and schedules. These issues become particularly acute in offshore applications that are generally limited by footprint and weight, thereby further reducing suitable water treatment options. The issues are further confounded by the lack of communication between oil companies on equipment successes and failures in these new applications. EOR projects are often kept as low profile, particularly by smaller oil companies, to strengthen competitive advantages in the marketplace.
One of the best treatment options for the environment is the reuse of produced water for re-injection in EOR applications. This is particularly attractive in CEOR where residual polymer and surfactant may deem the produced water unacceptable for discharge. But injection additives may stabilize emulsions and render the produced water and oil mixture challenging to separate. Ideally, water treatment technologies are used that both enable good separation and maximize potential reuse of produced water.
As a first step in disseminating the current body of knowledge of water usage and treatment in EOR applications, a survey was conducted in 2012 of water-based EOR projects to ascertain their water source and background information on the water treatment technologies employed. The survey was co-sponsored by the Produced Water Society. Specific information on the source water salinity and temperature was obtained, in addition to the type of EOR used, the project location, and details of the existing treatment system(s). The survey results were then augmented with exhaustive literature searches of both full-scale EOR applications and emerging technology solutions currently being piloted.
This paper describes the survey results which detail water-based data from more than fifty EOR projects around the world, along with a critique of the emerging technologies being piloted in global EOR field sites.