EN 1918-2:2016

• Abstract:

  This European Standard 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 1918-5 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 (this includes natural gas, compressed natural gas (CNG) and liquefied petroleum gas (LPG). 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 European Standard specifies common basic principles for underground gas storage facilities. Users of this European Standard should be aware that more detailed standards and/or codes of practice exist. A non-exhaustive list of relevant standards can be found in Annex A.; This European Standard 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 European Standard, 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.

• Status: Published
• Publication Date: 22-Mar-2016
• Withdrawal Date: 29-Sep-2016
• ICS: 75.200 - Petroleum products and natural gas handling equipment
• Technical Committee: CEN/TC 234 - Gas infrastructure
• Drafting Committee: CEN/TC 234/WG 4 - Gas underground storage
• Current Stage: 9092 - Decision on results of review/2YR ENQ - revise - Review Enquiry
• Start Date: 20-Dec-2022
• Completion Date: 17-Sep-2026
• Mandate: M/017 - Standardization mandate to CEN in the field of equipment and installation for the transmission and distribution of gas
• Ref Project: SIST EN 1918-2:2016 - Gas infrastructure - Underground gas storage - Part 2: Functional recommendations for storage in oil and gas fields

• Replaces: EN 1918-2:1998 - Gas supply systems - Underground gas storage - Part 2: Functional recommendations for storage in oil and gas fields
• Effective Date: 30-Mar-2016
• Refers: EN 1918-5:2016 - Gas infrastructure - Underground gas storage - Part 5: Functional recommendations for surface facilities
• Effective Date: 28-Jan-2026
• Revised: FprEN 1918-2 - Gas infrastructure - Underground gas storage - Part 2: Functional recommendations for storage in oil and gas fields
• Effective Date: 18-Jan-2023

Overview

EN 1918-2:2016 is the CEN European Standard that gives functional recommendations for underground gas storage (UGS) in oil and gas fields, covering design, construction, testing, commissioning, operation, maintenance and abandonment up to and including the wellhead. The standard applies to hydrocarbon gases that are gaseous at 15 °C and 0,1 MPa (for example natural gas, CNG and LPG) and addresses requirements needed to maintain storage integrity, performance and environmental compatibility. EN 1918-2:2016 is Part 2 of the EN 1918 series on underground gas storage and is intended to be used alongside national standards and codes of practice; national legislation takes precedence where more restrictive.

Key Topics

• Scope and definitions: common terminology for UGS in oil and gas fields (wells, casings, annuli, cushion gas, working gas, etc.).
• Design principles: field description, geological modelling, reservoir behaviour, determination of maximum operating pressure (MOP) and minimum operating limits.
• Well design and completion: drilling, casing, cementing, liners, completions and wellhead arrangements up to the master valve.
• Construction and commissioning: recommended practices for safe build-up, testing and initial commissioning of wells and subsurface systems.
• Operation and monitoring: injection/withdrawal procedures, inventory management (working vs cushion gas), continuous monitoring systems, monitoring wells and surveillance programmes.
• Safety and environment: practices to ensure safe operation and environmental protection, HSE considerations and handling of gas quality requirements.
• Abandonment and decommissioning: withdrawal, plugging and permanent abandonment of wells, removal or management of surface facilities and post‑closure monitoring.
• Interfaces and neighbouring activities: coordination with other subsurface uses and surface facilities (EN 1918-5 for surface facilities).

Applications

EN 1918-2:2016 is practical for:

• UGS project owners and asset operators planning storage in depleted oil and gas fields.
• Reservoir and well engineers defining MOP, cushion gas and completion designs.
• Design consultants and EPC contractors preparing engineering specifications and commissioning plans.
• HSE and environmental managers developing monitoring, testing and abandonment strategies.
• Regulators and permitting authorities assessing compliance with functional recommendations for safety and environmental protection.

Keywords: EN 1918-2:2016, underground gas storage, UGS, oil and gas fields, well design, maximum operating pressure, monitoring, decommissioning.

Related Standards

• EN 1918-1, -3, -4, -5 (other parts of the UGS series; Part 5 covers surface facilities)
• CEN/TR 13737 (clarifies national legislation/regulatory precedence)
• Annex A of EN 1918-2:2016 lists a non-exhaustive set of further relevant standards and codes of practice.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.NFLRQDOQDGasinfrastruktur - Untertagespeicherung von Gas - Teil 2: Funktionale Empfehlungen für die Speicherung in Öl- und GasfeldernInfrastructures gazières - Stockage souterrain de gaz - Partie 2: Recommandations fonctionnelles pour le stockage en gisements de pétrole et de gazGas infrastructure - Underground gas storage - Part 2: Functional recommendations for storage in oil and gas fields75.200Petroleum products and natural gas handling equipmentICS:Ta slovenski standard je istoveten z:EN 1918-2:2016SIST EN 1918-2:2016en,fr,de01-november-2016SIST EN 1918-2:2016SLOVENSKI
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EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 1918-2
March
t r s x ICS
y wä t r r Supersedes EN
s { s zæ tã s { { zEnglish Version
Gas infrastructure æ Underground gas storage æ Part
tã Functional recommendations for storage in oil and gas fields Infrastructures gazières æ Stockage souterrain de gaz æ Partie
tã Recommandations fonctionnelles pour le stockage en gisements de pétrole et de gaz
Gasinfrastruktur æ Untertagespeicherung von Gas æ Teil
tã Funktionale Empfehlungen für die Speicherung in Ölæ und Gasfeldern This European Standard was approved by CEN on
s r January
t r s xä
egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä
translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä
CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä
EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels
t r s x CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN
s { s zæ tã t r s x ESIST EN 1918-2:2016

Non-exhaustive list of relevant standards . 28 Annex B (informative)
Significant technical changes between this European Standard and the previous version EN 1918-2:1998 . 30
MOP maximum pressure of the storage reservoir or cavern, normally at maximum inventory of gas in storage, which has not to be exceeded in order to ensure the integrity of the UGS and is based on the outcome of geological/technical engineering and is approved by authorities Note 1 to entry: The maximum operating pressure is related to a datum depth and in caverns usually to the casing shoe of the last cemented casing. 3.1.26 minimum operating pressure minimum pressure of the storage reservoir or cavern, normally reached at the end of the decline phase of the withdrawal profile and for caverns is based on geomechanical investigations to ensure stability and to limit the effect of subsidence and normally has to be approved by authorities and has not to be underrun Note 1 to entry: The minimum pressure is related to a datum depth. 3.1.27 monitoring well observation well well for purposes of monitoring the storage horizon and/or overlying or underlying horizons for subsurface phenomena such as pressure fluctuation, fluid flow and qualities, temperature, etc. 3.1.28 operating well well used for gas withdrawal and/or injection 3.1.29 overburden all sediments or rock that overlie a geological formation SIST EN 1918-2:2016

It contains fluids which are internally in pressure communication. 3.1.33 saturation percentages of pore space occupied by fluids 3.1.34 seismic technology technology to characterize the subsurface image with respect to extent, geometry, fault pattern and fluid content applying acoustic waves, impressed by sources near to surface in the subsurface strata, which pass through strata with different seismic responses and filtering effects back to surface, where they are recorded and analysed 3.1.35 string entity of casing or tubing plus additional equipment, screwed or welded together as parts of a well respectively completion 3.1.36 subsurface safety valve valve installed in casing and/or tubing beneath the wellhead or the lower end of the tubing for the purpose of stopping the flow of gas in case of emergency 3.1.37 tubing pipe or set of pipes that are screwed or welded together to form a string, through which fluids are injected or withdrawn or which can be used for monitoring 3.1.38 well borehole and its technical equipment including the wellhead 3.1.39 well integrity well condition without uncontrolled release of fluids throughout the life cycle SIST EN 1918-2:2016

Key 1 operating wells 2 monitoring wells 3 indicator horizon 4 caprock 5 storage reservoir and stored gas 6 salt dome 7 cavern Figure 1 — Storage in aquifers, oil and gas fields, solution mined salt caverns For LPG storage only salt or rock caverns can be applied. The UGS type applied is dependent on the geological conditions and prerequisites as well on the designed capacity layout. 4.2.3 General characterization of UGS UGS are naturally or artificially developed reservoirs respectively artifically developed caverns in subsurface geological formations used for the storage of natural gas (or LPG). A UGS consists of all subsurface and surface facilities required for the storage and for the withdrawal and injection of natural gas (or storage of LPG). Several subsurface storage reservoirs or caverns may be connected to one or several common surface facilities. The suitability of subsurface geological formations have to be investigated individually for each location, in order to operate the storage facilities in an efficient, safe and environmentally compatible manner. In order to construct a storage facility wells are used to establish a controlled connection between the reservoir or cavern and the surface facilities at the well head. The wells used for cycling the storage gas are called operating wells. In addition to the operating wells specially assigned observation wells may be used to monitor SIST EN 1918-2:2016

Key 1 storage wells 2 monitoring wells 3 indicator horizon 4 caprock 5 storage reservoir and stored gas Figure 2 — Storage in oil and gas fields 4.3 Long-term containment of stored gas The storage facility shall be designed, constructed and operated to ensure the continuing long-term containment of the stored gas. This presupposes: — adequate prior knowledge of the geological formation, in which the storage is to be developed and of its geological environment; — acquisition of all relevant information needed for specifying parameter limits for construction and operation; — demonstration that the storage is capable of ensuring long-term containment of the stored gas through its hydraulic and mechanical integrity. SIST EN 1918-2:2016

Key 1 wellhead 10 production packer with snap-latch seal assembly 2 wing valve 11 landing nipple 3 master valve 12 sand screen 4 casing 13 gravel pack 5 control line for subsurface safety valve 14 underreamed storage horizon 6 subsurface safety valve 15 perforation 7 tubing 16 sump 8 sliding side door 17 cement head 9 production gravel pack packer – safety joint 18 storage reservoir Figure 3 — Examples for well completions – gravel pack completion (left) and perforated cased hole completion (right) SIST EN 1918-2:2016
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