Integrity of UGS

Committee: Storage Fabien FAVRET (EDF, France)

Mail: fabien.favret@edf.fr Mob: +33 (0) 607798125

Existing codes, norms and standards for safe UGS

Best practices for UGS safe operations EDF/Géostock case study in UK

FUELING THE FUTURE WITH GAS 2

Topics

Introduction to UGS safe operations • World-wide existing codes, norms and standards for UGS

– From design, construction, operation & maintenance and even abandonment

– Which has been established by experts of the domain: operators, notified bodies

(DNV, …) , gas associations, government executives, … mostly since the 90’s

– Some examples:

• EU : EN 1918-1/5:1998, 1918-2: 2014, ISO/TS 16530-2:2014, NORSOK D-010

(2004) and various others from/for specific countries as an ex: BSOR in UK, …

• USA: API 1170 & API 1171 established in 2015

• Russian Federation: Safety rules in oil and gas industry, Gazprom standards 2-3.5-

770-2013 or 2-2.3-696-2013, Rules of UGS safety, Federal standard

123.13330.2012, …

Norms, standards and codes • These norms/standards provide:

– Guidelines and/or philosophy for insuring mainly:

• Risks assessments and management (QRA approaches to include

HAZID, HAZCON & HAZOP [process] as a base to mitigate risks)

• Subsurface integrity management

• To be implemented using a case by case approach

Norms, standards and codes • API 1170 (US) main content: salt caverns

– Geological Evaluations

– Well Design

– Drilling

– Solution Mining

– Operations

– Integrity Monitoring not detailed

– Abandonment

Norms, standards and codes • API 1171 (US) main content: porous reservoirs

– General Principles

– Functional Integrity in Reservoir Design

– Functional Integrity in Well Design and Construction

– Risk Management for Storage Operations’

– Integrity Demonstration, Verification and Monitoring not detailed

– Safety, Security and Emergency Response

– Procedures and Training

Norms, standards and codes • Russian (CIS) main requirements for wells:

– General Principles: well architecture, cementing job in annulus, SSSV, …

– Functional Integrity of wells:

• MAOP for casing, tubing, annulus, reservoirs,

• Annulus pressure measurement and follow-up

• Wells testing by gas-hydrodynamic & geophysical investigations

• Well testing and productivity analysis & interpretation:

– Defects

– Casing leak

– …

– Safety distance between wells and other infrastructures (buildings, forests, …)

– …

Norms, standards and codes • ISO EN 1918/1-5:2014 (EU) main content:

– General Principles for Design, Construction, Testing, Commissioning,

Operation and Maintenance of UGS

– Wells:

• Recommended design & completion: packer/tubing, landing nipples

• SSSV

• 2x barrier philosophy

– Wells integrity management via peridodic inspections such as check of

annulus pressures, corrosion/erosion checks via casing inspections,

integrity of barriers (SSSV, wellhead, …) not exhaustively detailed

Norms, standards and codes • ISO EN 16530-2 (Well Integrity):2014 (EU) main content:

– Well integrity management system definition: Well operator shall have well integrity management system (WIMS) for all wells

– Each Well Operator shall ensure that sufficient resources in their organizations are available to manage well integrity effectively during the operational life cycle of the well Operator entire well inventory

– Well barrier envelope: Combination of one or several well barrier elements that together constitute a method of containment of fluids within a well that prevent uncontrolled flow of fluids within, or out of a well

– Well operator shall by able to demonstrate the status of the well barriers envelopes for each well &type

– The general sphere of well integrity monitoring are: well operating and components limits, well components status, annular pressure management, …

Norms, standards and codes • NORSOK standard D010:2004 main content:

– Well integrity definition: Application of technical, operational and organizational solutions to reduce risk of uncontrolled release of formation fluids throughout the life cycle of a well

– Management of well integrity has to be implemented during all the phases of well life; it starts from well design, continues during its construction, is constantly implemented during the production phase, and is part of the final abandonment

– Well barrier: Envelope of one or several dependent barrier elements preventing fluids or gases from flowing unintentionally from the formation into another formation or surface

UGS safe operations • These norms/standards provide:

– In most of the countries even if these norms/standards can be mandatory, it

is the responsibility of operators to define how to implement them

– In most of the countries, it is also the responsibility of the operator to

(annually) declare to the local/national administration what is going on for

each UGS site: O&M activities, incidents, accidents, heavy maintenance or

repair, …

– In addition, in most of the countries selective inspections are usually led on

site by notified bodies or administrations to control this declaration in-situ

UGS safe operations • These norms/standards:

– Are usually mandatory for new UGS projects and the 2 safety barriers

philosophy is more and more developed and/or imposed (ex: in EU)

– But not for existing ones (no retroactive application)

– Usually it is the solely operators decision to decide to apply or not new

codes/norms on its existing assets and if necessary to implement

action plans

UGS safe operations • These norms/standards are necessary to develop framework

guidelines for safe UGS operations

• Even if it is the operators responsibility to implement them

• But a (strong & efficient) control loop should be also in place (by

local/national administrations) for checking periodically:

– the implementation of the rules/norms/standards by UGS operators

– the technical expertise/skills & organization of UGS operators when they

are applying for a UGS license but also all along the UGS life-time

Case study EDF/Geostock cooperation in UK on salt caverns • In conjunction with:

– Wells Monitoring

– Subsidence monitoring

– Micro-seismic monitoring

• And based on the PVT model, EdF is developing methods, and then will program a specific module to be in position to check the integrity of a cavern (and in future a porous reservoir) with:

– Leak detection

– Structural abnormal behavior (high creep, shape disorder, ...)

• All these techniques are used in Hill-Top and Hole-House facilities to guarantee the integrity of wells and caverns Any abnormal situation to be tracked, checked and explained through the subsurface monitoring system, to lead to specific recommendations:

– To continue normal gas operations (green light)

– To implement careful gas operations (orange light) limited ranges of pressure and flow-rates

– To stop immediately gas operations (red light) further investigations to be done such as P/T logs, sonars, ...

Well Integrity Management System ?

WIMS Typical Workflow

The 2 main pillars for WIMS

WIMS – Monitoring Integrity

Microseismic monitoring

Advanced microseismic monitoring

Matching and using a PVT model in UK

Leak detection using a PVT model in UK

• Setting the scene from cavern tightness test criterias:

• Equivalent (density @ 0.7 kg/m3) gas leak test “acceptable” rates:

– SMRI = 50 kg/d 70 m3(n)/d = 3 m3(n)/h

– Germany = 30 kg/d 40 m3(n)/d = 1.8 m3(n)/h

– Experience 7 kg/d 10 m3(n)/d = 0.4 m3(n)/h

Simulation of a leak on April 1st @ 3 m3(n)/h

No leak

With leak

Sign of leak after 1 month

Obvious leak after 3 months

PVT tool for asset integrity management

• Subsurface monitoring using PVT simplified tool is proven @ wellhead

– In Germany with this model, range of pressures has been increased in 2014

from 60/203 bar to 50/208 bar by mining authority

• Subsurface integrity management seems also theoretically feasible:

– No risk of confusion with mismatch (no pattern)

– Different signatures for different events

– Ex: creep signature ≠ leak signature

• But:

– Technical, mathematical & IT developments to be done

– And then, in-situ tests to be achieved (on going in UK)

THANK YOU

QUESTIONS?