Encapsulated Polymer Technology for Enhanced Oil Recovery in Offshore Subsea Wells

Summary Polymer flooding involves injecting water-soluble polymers into oil reservoirs to increase the viscosity of the injected water, improving oil displacement. This method typically enhances oil recovery by 10% in tertiary mode, i.e., after prolonged water injection, and by up to 20% when polymer injection is applied earlier, in secondary mode. It accelerates oil production while reducing the carbon footprint, water usage, and handling. In subsea environments, the injection of polymers through valves presents significant mechanical challenges. High shear forces in subsea manifolds can cause polymer degradation, reducing their effectiveness in improving oil recovery and potentially compromising the overall efficiency of the polymer flooding process. To address the issue of mechanical degradation associated with polymer injection in subsea environments, a novel solution has been developed: encapsulated polymer technology. This technology involves enclosing polymer molecules within a protective shell, allowing them to withstand the high shear forces encountered in subsea manifolds. Encapsulation not only preserves the integrity of the polymers but also ensures controlled release in the reservoir, optimizing their performance for enhanced oil recovery. By fine-tuning the chemistry of the protective shell, the release of linear polymer chains can be adjusted to occur between 12 and 48 hours after entering the reservoir. Once released, the polymer solution develops the same viscosity as its non-encapsulated equivalent. Yard tests and field trials have demonstrated the effectiveness of encapsulated polymer technology in real conditions. These encapsulated polymers have shown remarkable resistance to mechanical degradation, maintaining their performance over extended periods and exhibiting excellent injectivity across a wide range of rock permeabilities. The successful deployment of encapsulated polymer technology opens new opportunities for offshore reservoir development with subsea wells. By mitigating the challenges associated with polymer injection in subsea environments, this innovative technology enables the efficient and sustainable application of polymer flooding to enhance oil recovery. As the industry seeks environmentally conscious solutions, encapsulated polymer technology stands out as a key enabler, contributing to both increased oil production and a reduced carbon footprint in offshore operations.