ASP Journey, from Pilot to Full Field Implementation in South of the Sultanate of Oman

Abstract

The Marmul inverted five-spot pilot was successfully completed in 2016, demonstrating the effectiveness of Alkaline Surfactant Polymer (ASP) flooding in improving oil recovery from Al khalata reservoir. Earlier studies including core flood experiments, single well chemical tracer tests and small scale models indicated a potential of >10% of ASP incremental recovery over polymer flood and >20% over water flood. The pilot included a custom-built ASP facility, a first of its kind of scale squeeze treatment for high pH, state-of-the-art nuclear magnetic resonance (NMR) technology for vertical saturation estimates and very extensive sampling and surveillance programme. Overall, the pilot operation was very smooth and stable, achieving high facility uptime, good injectivity, accurate chemical dosing and met the surveillance target. The estimated ASP incremental recovery from the pilot was over 30%, which increased the interest in a field-wide ASP injection. The acquired pilot results and operation experience were used to scale up the facilities design and assess the impact of key uncertainties observed in the field and the lab. Major factors influencing the recovery factor and project efficiency were analysed including chemicals formulation, facilities design and water treatment technologies. A mind-shift on the formulation cocktail and facilities design was proposed to improve the economic attractiveness of the process on large scale implementations. A phased development is proposed to de-risk subsurface and surface concepts which are different from those in the pilot. This paper discusses in brief the pilot operation & performance, scaling up the results to full field implementation and key design considerations for a cost effective ASP project.