Publications

Oil fields in Southern Oman are characterized by medium to high oil viscosity and low salinity which is excellent candidate for chemical EOR application. With the rise of oil price in recent years, EOR development in Oman is deemed to be viable for many operators. To seize this opportunity, Medco LLC has initiated EOR study and screening since 2006, and has completed laboratory study for 4 fields in 2012. In this study, a mature field with more than 2 decades of production has been considered as main target for chemical EOR application. Polymer flood and Surfactant Polymer (SP) flood process were studied in laboratory scale and simulation work. A novel ultra-high molecular weight (MW) polymer was used in the process and the result show promising incremental recovery factor of around 8-13% with good injectivity based on coreflood. More than 50 surfactants were screened and 2 amphoteric surfactants with Interfacial Tension (IFT) lower than 0.001 mN/m were selected as main candidate for SP process. During laboratory work, organic salt was introduced in the SP system to reduce adsorption created by surfactant. Incremental recovery factor by SP process is around 18% with water cut reduction of 15%. Simulation study covering core scale, pilot and full field scale was conducted to assess validity of the laboratory work as well as sensitivity on several development scenarios. This paper present detail polymer and SP selection as well as coreflood matching including several sensitivities on ultra-high polymer characteristics. Pilot area selection method and surveillance technique to acquire important data are also discussed alongside full field simulation to determine the most feasible chemical flooding strategy with several economic constraints.