West Salym ASP Pilot: Surveillance Results and Operational Challenges

Abstract

Abstract In the West Salym field, a mature waterflood is ongoing with increasing water cuts and declining oil production. To counter the decline a tertiary oil recovery technique called Alkaline-Surfactant-Polymer (ASP) flooding was selected. Earlier studies indicated 15-20% potential incremental oil recovery due to ASP injection. An injection/production pilot to demonstrate oil recovery potential of the ASP flooding and collect information to decide on the subsequent commercial ASP projects was started with the preflush injection in February 2016. ASP injection started in July 2016 and was followed by the injection of polymer slug in February 2017. By the end of 2017 polymer injection is to be followed by the injection of postflush till the end of the project. As the project is still ongoing the paper focuses on the pilot status, progress achieved, and plans for the remaining part of the project. To meet project objectives and collect data on the ASP flooding performance a dedicated surveillance program was developed and the results of the program are discussed below. Technical challenges encountered during the operation phase and the solutions applied to resolve those challenges are also the focus of this paper. Additional studies were performed to assess the performance of ongoing ASP flooding and their results are presented. Finally, laboratory data and field observations collected during the pilot operation phase are presented to support our conclusions.