Integrating ASP Flooding into Mature Polymer Flooding in Marmul Field in Southern Oman

Abstract

Abstract The Marmul field is a medium-large mature oil field situated in the Southern part of Oman. Due to the relatively high viscosity of Marmul crude (~90 cP at reservoir conditions), polymer and ASP flooding were selected as the technology to improve the oil recovery beyond that of waterflooding. The commercial-scale polymer flooding in Marmul has been ongoing since 2010 and recently further expansions plans were announced. ASP flooding was extensively studies through the laboratory tests and field trials. Two field trials (Pilot and Phase-1A) with different ASP formulations and targeting different target reservoir intervals indicated a potential of 20-30% incremental oil recovery due to ASP injection after the water flooding. In the ongoing ASP field trial (Phase-1B project), the ASP solution is being injected in the quaternary mode to test the post-polymer performance of ASP flooding under field conditions. Post the technical success of the ASP Phase-1B project, the task was to identify the optimal concept for the ASP flooding in the Marmul field. A hybrid approach based on numerical modeling and data-driven capacitance-resistance modeling was proposed to calculate the incremental oil recovery due to ASP flooding for the well patterns. Moreover, this publication presents the approach to integrating the ASP flooding into the mature polymer flooding in the Marmul oil covering both subsurface and surface aspects. Marmul well patterns are both water and polymer flooded; hence an attempt was made to evaluate the efficiency of ASP flooding for both post-polymer and post-water injection conditions. Data from core flooding experiments and field trials were used to forecast the efficiency of ASP flooding post-water and post-polymer flooding. Moreover, to take into account the properties variation across the field a set of field parameters such as reservoir heterogeneity and mineralogy, remaining oil saturation and its distribution, well performance, etc., was used to forecast the performance of ASP flooding in different well patterns. Resulting pattern-specific oil recovery was used in an economic evaluation to select the optimal concept for the commercial-scale ASP flooding project in Marmul.