Assessment of the Potential for CO2 Storage and Utilization in the Fractured and Porous Reservoir of the Cambrian Sandstones in West Lithuania’s Baltic Basin

Abstract

Cambrian sandstones comprise a large and saline-only aquifer that can be utilized for CO2 geological storage in the Baltic basin, including Lithuania. The two prospective storage sites with the most potential are located in west Lithuania. Despite the larger area of the Gargždai elevation (233 km2), the Syderiai uplift (62 km2) is characterized by the largest storage volume. The most significant difference between the studied structures is primarily related to the much higher reservoir quality of the Cambrian sandstones at the Syderiai site. The sandstones’ average porosity is 16% and their permeability measures 310 mD, while the Gargždai site is characterized by poor reservoir quality (average porosity of 7% and permeability as low as 10 mD in the sandstone). The main controlling parameter for the sandstones is authigenic quartz cementation. The reservoir type is classified as the porous sandstone type for the Syderiai site and as the fractured reservoir type for the Gargždai site. The storage volumes of CO2 of the sites were assessed as 56.7 Mt and 31.3 Mt, respectively. The present study determined that the Syderiai uplift was the prospective site with the most potential for the geological storage trapping of CO2, owing to its high reservoir quality, while the Gargždai elevation is characterized as a potential alternative for CO2 storage combined with EOR technology for oil exploitation, despite its poor reservoir quality.