Miscible Gas EOR Pilot Design Decisions Driven by Linking EOR Performance Parameters to Uncertainties - A Kuwait Field Example

Abstract

Abstract Many decisions in enhanced oil recovery (EOR) pilot design are required to plan an EOR pilot that, if executed successfully, gives a reliable data set and sufficient information to make full field EOR development decisions in the future. A miscible gas EOR pilot was designed for the formation "X" in the field "Y" of Kuwait using an uncertainty driven approach. The method presented in this is paper is a qualitative way of linking key miscible gas EOR performance parameters of the formation to the intrinsic uncertainties of the properties impacting them. An assessment of the impact of the uncertainty itself, likelihood of impact and the acceptance, or required uncertainty reduction, provided the direct link to the selection of the pilot concept, the pilot type, the pilot location and the operational sequence of executing the pilot. The key miscible EOR performance drivers for the formation in, with unacceptable high uncertainty, are vertical sweep efficiency (Ev) and remaining oil saturation (ROS). Hence it was decided a non-producing pilot with a single injection well and with observation well(s), is the EOR pilot concept and type enabling data gathering to address the above key uncertainties. The pilot area and pilot location was assessed via a semi-quantitative assessment of more than 10 parameters impacting miscible gas injection EOR, for example remaining oil, recovery factor, and pilot location distance to producers. While the final goal of the miscible gas EOR development for the formation is a miscible CO2 flood, it was decided to use produced hydrocarbon (HC) gas as a pilot injectant. This addresses the key objectives of the pilot with sufficient accuracy, while avoiding costly and timeline infrastructure changes at this early stage of understanding the chances of a successful EOR development. The additive information to the audience is the consistent approach of using an uncertainty based assessment of key EOR performance drivers throughout the entire pilot planning steps and defining pilot objectives, pilot concept and type as well as pilot location.