EN 15112:2006

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.External cathodic protection of well casingsProtection cathodique externe des cuvelages de puitsÄußerer kathodischer Korrosionsschutz von BohrlochverrohrungenTa slovenski standard je istoveten z:EN 15112:2006SIST EN 15112:2006en25.220.40Kovinske prevlekeMetallic coatingsICS:SLOVENSKI
STANDARDSIST EN 15112:200601-oktober-2006

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 15112July 2006ICS 23.040.99; 77.060 English VersionExternal cathodic protection of well casingsProtection cathodique externe des cuvelages de puitsÄußerer kathodischer Korrosionsschutz vonBohrlochverrohrungenThis European Standard was approved by CEN on 19 June 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2006 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15112:2006: E

Voltage drop profile.16 Annex B (informative)
Polarisation curve method applied to a well.23 Annex C (informative)
Determination by calculation of the potential shift at the bottom of the well and the well to soil resistance.26 Bibliography.36

1 Scope This European Standard specifies methods used to evaluate the external corrosion hazards of well casings, as well as cathodic protection means and devices to be implemented in order to prevent corrosion of the external part of these wells in contact with the soil. This European Standard applies to any gas, oil or water well with metallic casing, whether cemented or not. However, in special conditions (shallow casing: e.g. 50 m, and homogeneous soil), EN 12954 can be used to achieve the cathodic protection and assess its efficiency. This European Standard also describes techniques allowing determination of the current required for protection and ensuring correct operation of the cathodic protection devices installed. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 12954:2001, Cathodic protection of buried or immersed metallic structures — General principles and application for pipelines EN 60079-10, Electrical apparatus for explosive gas atmospheres — Part 10: Classification of hazardous areas (IEC 60079-10:2002) 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 12954 and the following apply (see also Figure 1). 3.1 casing (or well casing) heavy steel pipe string used to line a borehole from the ground surface, and secured in the formations generally by cementing NOTE Casing is generally externally cemented over its total depth or over a length sufficient to obtain anchoring and stability between the production or storage zone and the ground surface or other intermediate layers. This pipe string allows: - to prevent the ingress of fluid from upper strata; - to keep the hole from collapsing due to the pressure of the geological layers crossed; - to isolate the inside part of the well from the surrounding soil; - to continue drilling to the production or storage zone; - to drive down the tubing string from the surface to the production or storage zone. There may be two or more strings of casing, one inside the other, in a single well:

surface casing: casing that extends from the surface to a depth sufficient to avoid any entering of surface waters or earth into the well; - intermediate casing: casing set from the ground surface down to an intermediate depth. This intermediate depth is situated between the surface casing shoe and the production or storage zone; - production casing: casing that extends through the surface casing and intermediate casing to the production or storage zone. The extremity of the production casing can be at the top or bottom of this zone. 3.2 cellar excavation at ground surface, intended for housing the wellhead and safety shut-off devices. EXAMPLE safety valves 3.3 cementation process, and its result, which ensures the anchoring of well casing in the borehole and the tightness between different geological levels.
NOTE In the same time, this cementation can mitigate corrosion 3.4 centralizer device constituted by a set of metallic blades which are fitted around the pipes of a string to keep them centred, either in the open hole (hole drilled in the ground), or inside pipes of larger diameter in which the considered string is installed. This device can also be used to ensure electrical continuity between the two concentric pipe strings 3.5 completion process, and its result, which consists of fitting a well with the tubing to allow well operation in accordance with the applicable codes of practice and safety rules 3.6 flow-line pipe connecting a well to a station 3.7 liner (bottom hole) pipe having the same function as the casing but hung inside a casing (or another liner) and not at the wellhead like a conventional casing 3.8 packer (production) device ensuring tightness of a pipe annulus. The production packer seals the annulus between the tubing and the production casing or liner 3.9 shoe cylindrical element attached to the lower part of the casing, and allowing to place the casing in the borehole (guide shoe). If equipped with a valve, it makes easier the borehole cementation (cementing shoe) 3.10 tubing (production tubing) pipe string, with its additional equipment, inside the production casing to allow the flow of oil, gas or water between the production or storage zone and the ground surface

12453 1210635789
Key 1
ground surface 2 surface casing 3
cementation 4
production casing 5
shoe 6
production annulus 7
tubing 8
liner (bottomhole) 9
packer (production) 10 intermediate casing Figure 1 — Typical well completion equipment
...