Feasibility and Simulation of CO2 Storage in Offshore Lebanon: Saline Aquifers Case Study

This paper presents a case study of offshore Lebanon to evaluate the influence of key geological parameters, namely porosity, permeability, and salinity, on the performance of CO2 sequestration in marine saline aquifers. Through numerical simulations, this study investigates the long-term storage capacity of local formations, supported by a comprehensive feasibility and economic analysis. The objective is to assess the viability of implementing a CCUS project in the region, with the ultimate goal of formulating a technically sound and cost-effective storage strategy tailored to Lebanon's offshore context.

This study simulated CO2 injection into saline aquifers across various geological settings. A representative cross-section from offshore Lebanon was utilized as the foundation for the modeling scenarios, incorporating salinity values between 35,000 and 100,000 ppm, permeability ranging from 100 to 1000 mD, and porosity between 20% and 30%. Each scenario was run over a 5,000-year timespan to evaluate CO2 behavior with respect to sequestration mechanisms and dissolution rates. The model accounts for realistic subsurface conditions, integrating rock–fluid interactions, hydrostatic pressure equilibrium, and well design parameters for both injection and monitoring. Geological analysis, coupled with detailed calculations and sensitivity studies, was conducted to guide the optimal site selection and inform key technical decisions for offshore implementation. In addition, a feasibility study was conducted to evaluate the integration of major CO2 emission sources along Lebanon's coastal zone with the proposed offshore storage site and to assess the technical and economic viability of transport infrastructure and pipeline routing. The simulation results revealed a strong correlation between the formation properties and overall storage efficiency. High permeability was found to compromise retention and increase the risk of upward migration, whereas higher porosity enhanced CO2 solubility and storage potential. Given the inverse relationship between salinity and CO2 solubility, formations with lower salinity were more favorable for long-term storage. Among the evaluated cases, the scenario characterized by 20% porosity, 100 mD permeability, and 35,000 ppm salinity offered the most balanced performance, combining effective retention with efficient convective dissolution. In contrast, the scenario with 30% porosity, 1,000 mD permeability, and 100,000 ppm salinity yielded the highest initial storage capacity, but raised concerns regarding solubility limitations and potential leakage over extended timescales.

Block 4 in Lebanon's offshore domain was identified as a promising site, owing to its favorable geological characteristics, overlain by a thick evaporitic seal, and its proximity to major CO2-emitting power plants. The total project cost was estimated at approximately ±$740 million, incorporating expenditures related to pipeline infrastructure, labor, and ancillary services. The feasibility analysis confirmed that under appropriate assumptions for CO2 credit pricing, CAPEX, and OPEX, the project can achieve economic viability. Thus, the proposed initiative offers a scalable and strategic framework for advancing Lebanon's climate-mitigation efforts through CCUS deployment.

This study represents the first integrated long-term CCUS modeling effort targeting the Lebanese offshore environment by simulating the representative geological conditions of the Levantine Basin and conducting a comprehensive cost assessment. It delivers a cost-benefit implementation roadmap, while pinpointing the optimal combinations of formation properties required for effective CO2 sequestration. The findings not only provide a replicable framework but also offer valuable regional insights for developing countries exploring CCUS technologies as part of their carbon mitigation strategies.