Assessment of Trans-Boundary Effects at LBr-1 CO2 Storage Pilot Site and Regulatory Solutions

Abstract

The paper evaluates possible trans-boundary issues related to planned CO2 injection and storage at LBr-1, a candidate structure for a future geological storage pilot. LBr-1 is an abandoned hydrocarbon field situated in the Czech part of the Vienna Basin, close to the Czech-Slovak border. At first, currently valid national legislations relevant to CO2 geological storage in the Czech Republic and Slovakia were examined. In the second step, implications of the current legislation and regulatory regimes on the LBr-1 site itself were studied. The most important finding is that both the storage site and storage complex are located entirely on the territory of the Czech Republic. However, several trans-boundary issues were identified, especially those that are related to possible (even if unlikely) leakage of CO2 from the storage complex. Four possible types of trans-boundary issues were examined in detail – pressure build-up, possible leakage through boreholes, possible leakage through faults and possible migration of fluids out of the reservoir due to exceeding spill points for three scenarios – limited CO2 storage, full storage and CO2-EOR scenario. While pressure build-up and leakage through faults do not appear to cause trans-boundary issues, the other two phenomena need to be carefully considered. In case CO2 leakage appears either through abandoned wells or due to exceeding the southern spill point, the analysis of possible leakage pathways shows that the CO2 could migrate into the territory of Slovakia. These findings mean that a cooperation of regulatory authorities from both Czech and Slovak Republics will be necessary to prepare and operate the storage site. This is a significant complicating factor for possible injection of CO2 at LBr-1. Despite of this, the realization of a CO2 storage project on the site is considered viable, especially in the basic pilot storage scenario. This case avoids the spill-point related concerns (because of the limited extent of CO2 plume) and involves only a limited number of abandoned wells that need to be taken care of concerning their abandonment status.