Geostock is a private company active in designing, supervising the construction and operating underground storage of liquids or gases in mined caverns, salt caverns and porous media. It works with energy companies as well as with academic and government bodies and has been involved in several European CO2 storage projects including: the Géodénergies MISS-CO2 seismicity modelling project; ENOS, the Horizon 2020 onshore CO2 storage project; and Géodénergies’ CO2-DISSOLVED industrial pilot project.

It has overseen the engineering and/or construction of many underground natural gas storage facilities at depleted oil and gas fields including in Spain, Italy, Georgia, China and Hungary. It also has considerable experience with salt caverns and aquifers. As of 2021, it was involved in six collaborative public/private French projects to support CCUS including ROSTOCK-H and STOPHIL-H2, both examining hydrogen storage in salt caverns.