Integrated CCS aspect into CO2 EOR Project under wide range of reservoir properties and operating conditions

Carbon Capture and Storage (CCS) aspects can be combined with enhanced oil recovery (EOR) aspects for environmental responsibility and project economics. Oil Field in Pattani Basin, Gulf of Thailand is one candidate for this process integration. However, because of unique field characteristics like the number of reservoirs, and lack of data on fluid composition, and rock properties, full detailed reservoir simulations are hard to accomplish. Hence, this study proposes the use of numerical simulations with generalized field parameters to briefly quantify the potential for integrating CCS and EOR in Pattani Basin oil reservoirs. GEM composition reservoir simulator was used for comparison of six operating conditions: 1) Natural Production, 2) Waterflooding, 3) Gasflooding, 4) Single Cycling Water Alternated Gas (WAG), 5) Double Cycling WAG, and 6) Simultaneous Water Alternated Gas (SWAG). Two levels fractional factorial experimental design techniques were applied to reduce the number of required simulation runs. Central composite design was utilized additionally if assumptions in the fractional factorial design were violated. By using statistical analysis, important input parameters called factors were determined. Regression analyses of important factors to responses of interests (incremental recovery factor, required gas injection volume and gas storability) were used to establish a metamodel. Our results suggest that for general Pattani Basin oil reservoirs the most preferable technique is SWAG method with CO2 injection because it provides highest recovery factor and gas storage volume. Using a higher CO2 portion in SWAG injection stream can further increase recovery factors. When using natural gas as the injection gas, the most preferable method in terms of recovery factor is the double cycling WAG method followed by the single cycling WAG method. (C) 2013 The Authors. Published by Elsevier Ltd.