Standards Development

Scope

This document covers the functional recommendations for design, construction, testing, commissioning, operation, maintenance and abandonment of underground gas storage facilities in oil and gas fields up to and including the wellhead.

It specifies practices which are safe and environmentally acceptable.

For necessary surface facilities for underground gas storage, FprEN 1918­5 applies. In this context "gas" is any hydrocarbon fuel: ­

- which is in a gaseous state at a temperature of 15 °C and under a pressure of 0,1 MPa. (The stored product is also named fluid); ­

- which meets specific quality requirements in order to maintain underground storage integrity, performance, environmental compatibility and fulfils contractual requirements.

This comprises:

• Methane­rich gases: o Compressed Natural Gas o Biomethane o Synthetic methane

• Other hydrocarbon gases such as: o Ethylene o LPG (Liquified Petroleum Gas)

• Hydrogen of various purities

• Any mixtures of the gases above

NOTE Correspondingly, this document can be considered where applicable for underground storage of any other fluid e.g. helium, carbon dioxide, compressed air, rDME (renewable Dimethylether) and hydrogen transport fluids (such as ammonia and LOHC) This document specifies common basic principles for underground gas storage facilities. Users of this document should be aware that more detailed standards and/or codes of practice exist on national level. A non­exhaustive list of relevant standards can be found in Annex A.

This document is intended to be applied in association with these national standards and/or codes of practice and does not replace them. In the event of conflicts in terms of more restrictive requirements in the national legislation/regulation with the requirements of this document, the national legislation/regulation takes precedence as illustrated in CEN/TR 13737 (all parts).

NOTE CEN/TR 13737 (all parts) contains:

-  clarification of relevant legislation/regulations applicable in a country; ­

- if appropriate, more restrictive national requirements; ­

- national contact point for the latest information.

This European Standard is not intended to be applied retrospectively to existing facilities. NOTE Correspondingly this document can be considered for major conversions in case of significant change of gas composition.

Purpose

EN 1918­2 was published in 2016.

A revision is needed to answer the standardization request M/526 of the European Commission on adaptation of infrastructures to climate change.

A revision will also anticipate the standardization request expected on hydrogen and address the storage of mixtures of hydrogen with natural gas up to 100%. The storage of mixtures of hydrogen with natural gas will be addressed in all parts of EN 1918. But the knowledge and feasibility are higher for salt caverns and surface facilities.

A revision will also anticipate and answer the draft regulation on methane emissions reduction. The revision will also improve the chapter on abandonment.