Geological and Geophysical Study of an Hydrocarbon Storage in Salt Caverns in Manosque (France)

The creation of an underground storage facility in salt leached caverns in Manosque for liquid hydrocarbons was decided in the mid-60s by the oil companies to meet regulatory obligations in terms of strategic reserve, imposed following the Suez crisis. The Salt of Manosque is of Oligocene age and was deposited after the Pyrenean orogenic phase. The origin of the salt is Triassic (Keuper) and results of dissolution of outcrops uplifted by orogeny tectonic movements, then evaporites, were deformed due to the tilting of the block inducing the sliding of the salt mass, and increasing locally the thickness of the salt depending on its initial deposit and structural location. The resulting thickness of the salt formation ranges between 200 to 1000 m. The average proportion of insoluble minerals is in the order of 15%. This study allows a better understanding of the mineralogical composition of the Manosque salt. It explains the occurrence of potassium detected in the leaching brine. The structural map indicates the salt thickness distribution and can be used for locating new caverns. A clear relationship is established between seismic activity and halokinetic phenomena.