energize oil & gas – issue 01-2013 - GL Group

offshore storage
Gas for Britain’s Winter Days
Storing natural gas in depleted subsea fields involves onshore equipment that operates
under enormous pressure. GL Noble Denton develops the required inspection regimen
Centrica Storage Limited (CSL) operates a large
natural gas storage facility about 18 miles (29
km) off the east coast of Yorkshire to meet seasonal
peak demands in the UK. The Rough facility, a partially
depleted gas field under the North Sea, is linked to the
onshore gas processing terminal at Easington, where CSL
has developed a reception facility to accommodate production
from the new offshore York field. The easington gas
terminal can inject more than 125 million cubic metres
per day into the subsea storage facility per day,
Energy. UK
gas storage
facilities and
receiving
terminals
operated
by CSL.
which represents over 70 per cent of UK’s storage
capacity and can meet approximately 10 per cent of
the nation’s peak daily demand.
As part of the development of the Easington
Caythorpe
facility, all the York onshore assets required Written
Schemes of Examination (WSoEs) to be in place prior
to first gas to ensure conformity with the applicable statutory
Bains Langeled
Easington
requirements, including the Gas Safety (Management)
Regulations 1996 and the Pressure Systems Safety Regulations
2000. CSL awarded a project to GL Noble Denton
to develop a suite of Written Schemes of Examination
for the Easington assets. The project included the
following activities:
Identification of the York assets that required a Written
Scheme of Examination
Obtaining and reviewing the relevant design documents
to develop corrosion risk assessments (CRA)
abstract
for each asset, highlighting the main degradation
mechanisms and priority areas for inspection
Reviewing the outputs from the corrosion risk
assessments to produce baseline inspection work
Pressure system inspections
must follow a Written
Scheme of Examination
Requirements for gas terminals
are especially strict
scopes and inspection reports to measure the original
key integrity data for each asset
Working with CSL’s engineers to develop a methodology
for risk-based Inspection (RBI), and a procedure compliant
with API 580/581 and CSL’s specific requirements
Completing a detailed RBI study for each of the assets in
accordance with the agreed RBI procedure
Producing Written Schemes of Examination based on
the RBI results
Expertise Provided
GL Noble Denton conducted a series of workshops that
resulted in the development of a risk-based inspection
(RBI) procedure in accordance with API
Rough 580/581 and CSL’s specific requirements. The
RBI procedure, which was used to define
Baird
and agree the Terms of Reference and methodology
for the RBI study, in addition to the
Written Schemes of Examination, included the
following:
Probability of failure calculation methods
Consequence of failure assessment methods
Methods for deriving consequence
Inspection strategy
GL Noble Denton tailored its Galiom TM RBI/
AIM software package and used the relevant
input data to ensure that the RBI study and
Written Schemes of Examination were generated
in accordance with the agreed RBI Procedure.
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