Our Expertise

Geostock benefits from a whole range of skills, with over 50 years of know-how and expertise in underground storage technologies, for all techniques and all products.

Multidisciplinary skills

Our underground storage expertise is global and covers both Subsurface and Surface, but also Operation and Maintenance of  Storage Facilities

  • Subsurface Technologies
    Geology, Geophysics, Geomechanics, Hydrogeology, Reservoir Engineering, Civil Engineering, Mining, Leaching
  • Drilling and Well ServicesVertical as well as directional and horizontal drillings, Well completion, Work over, Maintenance, Plugging and abandoning of wells.
  • Logging and Testing Services
    Pressure, Temperature and flow rate measurements in underground storage wells, Level measurements and sampling of natural gas and liquid products, Tightness tests, Complex tests for reservoir performance assessment.
  • Surface Engineering
    General installation, Processes, Pipelines, Electricity/Instrumentation, Control Systems
  • Management, Operation and Maintenance
  • Closure and Abandonment of Storage sites

For all types of Underground Storage Techniques and a full range of Products

What is a salt-leached cavern?

What is a salt-leached cavern?

Salt cavern storage requires the presence of a significant salt deposit. The cavern is created by dissolving the salt in fresh water (leaching). Its shape and volume are established by sonar readings. The caverns are elongated in shape, several hundred meters high and several tens of meters in diameter. They are usually located at a depth of between 200 and 2,000 meters and can have a volume of several hundred thousand cubic meters.

The stability of the cavern is guaranteed by the right choice of geometry and continuous monitoring of the pressure, temperature and flow during operation. Its tightness results from the intrinsic properties of salt.

Stored products:

  • Liquid hydrocarbons
  • Liquefied hydrocarbons
  • Natural gas
  • Compressed air
  • Hydrogen
  • Effluents

Underground Storage in Salt-leached Caverns

 

What is a Mined Rock Cavern?

What is a Mined Rock Cavern?

A mined cavern consists of one or more tunnels carved out of the rock (limestone, chalk, granite, etc.). The tunnels are usually located at a depth of 50 to 200 meters. Generally unlined, their tightness is based on the principle of hydraulic containment, which defines the depth at which the cavern needs to be located to allow for the water naturally contained in the surrounding rocks to flow constantly towards the cavern at all points, thus containing the product inside the storage cavern.

The mined-cavern technique – both with and without a lining, as applicable – may also be applied to the cryogenic storage of gases having a liquefaction point below -10°C.

Stored products:

  • Liquid hydrocarbons
  • Liquefied hydrocarbons
  • Natural gas (compressed or liquefied)

 

  Underground Storage in Mined Rock Caverns

What are Aquifers & Depleted fields?

What are Aquifers and depleted fields?

A field of this type is a porous, permeable geological formation (the reservoir) – a depleted field or an aquifer – overlain with an impermeable stratum and structured so as to ensure lateral containment.

It is usually located at a depth of between 500 and 2,000 meters. During the storage phase, the gas is compressed and injected into the reservoir in gaseous state through a series of production wells. During recovery, the gas is withdrawn under the effect of its own pressure.

Equipment on the surface includes specifically compression, processing and metering facilities. Monitoring wells are used to check the position of the gas and the tightness of the reservoir.

Stored products:

  • Natural gas
  • Compressed air
  • Hydrogen
  • CO2
  • Effluents

 Underground Storage in Porous Media