Different types of underground geological storage facilities exist. It can be either a natural geological formed cavern (depleted fields, salt caverns, aquifers) or it can be a man made cavern (abandoned mine).
Gas Storage is mainly onshore due to the costs of development and constraint to transport natural gas from storage facility to the transportation network (and vice versa)
The number of wells and well design depend on the type of underground reservoir:
Depleted fields are attractive because their geological and physical characteristics have already been studied and are usually well known. This kind of reservoir generally allows to re-use part of existing wells with suitable modification. Aquifer reservoir and salt cavern require installation of new wells (about 8-10 wells per site).
Drilling operations are realized using the classic oil & gas drilling technique and well architecture is based on standard well design.
Salt cavern reservoir is generally the most critical case due to the two-stage process with a first long (can last several years), and expensive "leaching operation" to create the cavity. This operation can generate corrosion problems and crystallization associated with the brine. Structurally, and due to heterogeneity of the rock types, cavern created within bedded salt formation is also more unstable and the creep of rock salt resulting can generate external pressure to the completion casing.
In all cases, the casings must have the quality required to ensure a longer service life and are generally being tested for tightness. For completion, production casings and liners require premium connections gas tight.
For all these different cases, from standard application to more severe environments, Vallourec offers a full range of premium connections and proprietary grades.
Vallourec Global Solution can help you selecting the most appropriate connection and material for your application based on field experience gained thru years of services for Oil and gas industry including gas storage application.
The worldwide network of VAM® Field Service provides the best in class services and expertise for VAM® connections running supervision, supporting our clients for make-up and inspection services.