Evaluating Different CO2-EOR Methods for Coupled Emission Reduction in the Oropouche Field, Trinidad

Abstract

Declining petroleum reserves and issues relating to climate change are receiving national attention in Trinidad and Tobago (T&T). Different CO2 enhanced oil recovery (CO2-EOR) techniques were evaluated to determine its feasibility to act as a sink and to boost oil production in the EOR44 reserve in the Oropouche Field in southwest Trinidad. The Computer Modelling Group (CMG) software was used to evaluate the EOR injection methods of CO2, CO2+N2, and WAG injections. The findings showed that WAG was the best injection method, producing the most oil (3.5 MMBBL) at 200 MScf/day of CO2 injection, with the greatest recovery factor of the scenarios at 40% and the maximum storage efficiency of 38%, storing roughly 100,000 tCO2. The environmental performance utilized a CCUS system characterized by a cradle to grave boundary which represented CO2 capture, CO2 compression, CO2 transportation by truck, and the EOR operation as well as injection possibilities for the EOR process. The results indicated that the CO2 capture facility unit generating between 33,000 and 37,000 Mt of CO2, has higher emission output than the compression and transportation units. The scenario performing the least in terms of storage performance was CO2-N2, with just 8% of CO2 being stored. The WAG injection had the largest sequestration capability with a projection of 35%. This study demonstrated the feasibility of the use of CO2-EOR as a net sink in the EOR 44 area, an appropriate step to aid in T&T's efforts to mitigate climate change and improve oil production.