New Economic Concept of Synergy of CO2 Geological Storage and Enhanced Oil Recovery in E6 Structure Offshore Latvia

n the current study, we proposed new economic concept of synergy of CO2 geological storage (CGS) in Cambrian Deimena Formation and CO2-EOR/EOR+ in Upper Ordovician Saldus Formation in E6 structure offshore Latvia. Compared to recently proposed two scenarios, we updated CO2 injection technics and proposed more economic and feasible scenario of CO2 injection. Profits of the synergy and possible risks were analysed for two possible cases of CO2 storage (upward CO2 leakage by faults from Deimena to Saldus Formation, and no-leakage case) in the new scenario. Reducing overall costs common injection well of the new scenario, increased oil production (in contrast with conventional CO2-EOR), increased CO2 storage capacity are advantages of this concept. Opportunity of testing the integrity of the Deimena Formation storage reservoir and monitoring of behaviour of CO2 within the storage site are additional surpluses.

For the first time, we estimated theoretical storage capacity of the Saldus Formation at the end of CO2-EOR cycle (65–144 Mt, average: 110 Mt). Total capacity of the E6 structure in the Deimena and Saldus formations at the end of CO2-EOR cycle by optimistic (320–745 Mt, average: 490 Mt) and conservative approaches (170–385 Mt, average: 265 Mt) were evaluated.