Old wells – New wells Challenges

in Underground Gas Storage (UGS) Environment

Xavier Herve

Business Development Manager,

Continental Europe , April 16, 2008

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Gas storage capacity vs. consumption 2005

2005 consumption was 535 bcm

– UGS capacity is 20% of this

2020 consumption will be 745 bcm

Gas demand will grow by 1.9% in

per year

Deficit in gas was 256 Bcm in

2005, will be 520 Bcm in 2020 if

nothing is done

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UGS Type

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Challenges in Old wells

The main problems and few numbers: (Wells = 30Years)

Cement Isolation : 60%

Perforation plugged : 20%

Corrosion : 12%

Damaged or not suitable Completion : 8%

Source SLB Intouch

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Topics of the presentation

Formation Evaluation in CH and OH

In situ stress measurement for cap rock Evaluation

Corrosion and Cement Evaluation new techniques

Well Services in CH and OH

Well repair (channeling)

New Cementing techniques

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Wireline Service Offering for UGS

Construction:

New

infrastructure

Rehabilitation

Existing sites Monitoring

Neutron RST

Corrosion &

Cement

EMIT/SCMT

Production

Logs PSP

Cement Evaluation

IBC

MDT Stress Test in

Cased hole

Cement Evaluation

IBC

Mechanical

Properties

through casing

(SScan)

OH Formation

Evaluation

Advanced

Evaluation: • MDT Stress Test

• Mechanical Prop- Sonic Scanner

(Anisotropy) • NMR •Imaging (FMI-OBMI)

CAPEX OPEX

Cap Rock 3D stresses evaluation over time

ABC Formation

Eval

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The micro-hydraulic fracturing with MDT packers

+ images

Pressure record during a micro-hydraulic fracturing test

Fracture

initiation

Closure pressure of the induced fracture

(Detail of the first hydraulic fracturing cycle)

Closure pressure

Breakdown pressure

Closure pressure determined from

the square root of the shut-in time

Closure pressure

Induced fractures detected

and oriented on FMI image

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Stress Test with MDT – Example 1

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Stress Test with MDT – Example 2

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Stress Test Data Acquisition in Cased Hole

Data acquisition with MDT Dual Packer with packers positioned across the perforated interval

Perforation of 1 ft interval zones with Wire-line Gun (HSD) with deep penetrating charges, 12 spf, Multiphasing (in all azimuths)

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In Situ Stress measurements Experience

Successful MDT Stress Tests in Cased Hole:

-Lussagnet UGS (France) , operated by Total

-Lacq Field (france), operated by Total

-San Salvo UGS (Italy), operated by STOGIT

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Cased Hole Formation Evaluation

Sub Group Service Platform / Scanner Family

Cement Evaluation

Acoustic CBL-VDL

Ultrasonic USIT Isolation Scanner

Corrosion Evaluation

Mechanical PMIT

Ultrasonic USIT UCI

Electromagnetic EMIT / METT

ABC

Analysis Behind Casing

Gamma Ray Total GR SGR PEX, RST

Spectral GR HNGS IPLT

Saturation CHFR

RST Sigma/Carbon

Oxygen

Density / PEF TLD PEX

Neutron

CNL-PE , APS RST

Spectroscopy ECS RST

Sonic Dipole Shear Imager Sonic Scanner

Formation testing CHDT

Borehole Seismic VSI VSI

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Cased Hole: ABC – Resistivity CHFR

Telemetry

Electronics

Insulating joint

Top current electrode

Arm section

Hydraulics

Bottom current

electrode 0.0m

13.0m

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Cased Hole: Corrosion Evaluation

Mechanical

measurement of the

inner diameter of the

pipe using a set of

caliper fingers for

azimuthal coverage.

Measurement of:

Inner Diameter,

Thikness,

Internal Wall rugosity.

Measurement of

Electromagnetic Thickness.

Detection of metal losses in the

inner and outer pipes – For the

inner pipe the measurement is

Azimuthal.

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Time (ms)

Arrival times Fluid Velocity,

Flexural Velocity

Amplitudes Flexural

Attenuation

50

mm

Am

plitu

de

Cased Hole: IBC - Imaging Behind Casing Tool

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Cased Hole: Isolation Scanner

Robust Evaluation of all types of Cement

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Cased Hole: Isolation Scanner

1st &2nd interface (csg)

3rd interface cmt/2nd

sting

or formation wall

3D View

Cement detected (brown)

With some debonding

Borehole

Wall

IBC

Liquid

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Well Services

Well Isolation repair in CH

New Cement product in OH

Remedial Solution for Establishment of zonal isolation and correction of channeling behind pipe

•Applications of SqueezeCRETE

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Problem in near wellbore

Poor cement

Cave due to sanding

Channel in formation

Solution specific case

Cement

Gel

Resin

Stimulation

Near-Wellbore Flow

Oil

Water

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Squeezing in Narrow Gaps

SqueezeCRETE solution

Density: ~ 14.0 ppg (1.68 sg)

Temperature: 40º - 320ºF (4 º - 160 º C)

Compressive Strength > 2000 Psi

For gaps as small as 120 microns

Particle Size Avg. ~5 microns

Squeeze Slurry

Considerations: • Particle Size - Maximum particle size must

be 3-5 times smaller than the gap for good

penetration

• Viscosity - Low viscosity required for low

placement pressures

• Fluid Loss - Excellent fluid loss control to

avoid slurry dehydration

Set cement must have:

• Sufficient compressive strength

• High shear bond strength

• Low permeability

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SqueezeCRETE Applications

Casing leaks

Liner tops

Old perforations

Channels behind casing

Fractures

Permeable matrices

Squeezing a gravel pack

SqueezeCRETE repairs well problems

when cement won’t

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SqueezeCRETE Penetration

Well dispersed Micro-cement

SqueezeCRETE technology

Injection points

0

50

100

150

200

250

300

160 320

Gap width (microns)

Penetr

ati

on (

mm

)

Conventional microcement

SqueezeCRETE

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What our clients tell the press about SqueezeCRETE

“We had already tried several methods to abandon the reservoir

section, all had been unsuccessful.

The SqueezeCRETE application

provided an immediate result and

caused minimal disruption to our

operations”

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Life-of-project UGS solutions

Zonal isolation

Design studies

Advanced cementing solutions

– FlexSTONE technology

– FUTUR active set cement

Cement evaluation

Isolation Scanner tool

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FUTUR active set cement technology

Blend placed during primary

cementing – surface operations remain unchanged

– focus on isolation above reservoir

Presence of hydrocarbons triggers the

self-healing effect

Matrix swells to re-establish hydraulic

seal

Prevents – surface casing leaks

– sustained casing pressure (SCP) at the

wellhead

– accidental, uncontrolled hydrocarbon

release

Restores integrity without intervention

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Months Years

Long-Term

Gas Migration

Post-set

Minutes

Immediate

Gas Migration

Placement

FUTUR is designed to protect against long-term gas migration

– It does not replace good cementing practices and proper slurry design before the cement sets

FUTUR - Protection against Gas Migration

HoursDays

Short-Term

Gas Migration

During Set

Centralization –

good stand-off

Fluid displacement

Hydrostatic pressure

during placement

Analysis with

GasMigrationAdvisor

Gas migration control

additives

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FUTUR Case History – Italy UGS

Challenge – isolation across gas injection zones – provide long-term ‘active’ seal to prevent gas

leakage in UGS facilities near urban centers – leaks common in these types of wells over the

last four decades

Solution – 1.7 sg gas-tight FUTUR system – 14 m3 slurry placed

Result – successful cementation of Cortomaggiore 155dir

well completed Q1 2007 – no leaks detected – perforation and gravel pack operations

completed Q1 2007 – effective cement bond across injection zone – well monitoring vs. time is planned

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FUTUR Case History – Italy UGS SPE110523

Customer responses

– Eni

• First job of its kind posted on Eni Knowledge

Management Technical website

– Stogit

• Q1 Earning Highlights Review: The applied

technique resulted in achieving very effective zonal

isolation and will be used within the three year

cementing campaign awarded by Stogit to develop

gas storage wells.

Future prospects for FUTUR are strong for UGS

applications in Italy

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In Old wells we can still do more :

Completion with Microseismic detectors and Fiber optic

for Real Time monitoring

Thru Tubing Rotating Drilling for side tracking

Patch zones , or leaks or Corrosion points

Cross Well Resistivity Measurement

Coiled tubing drilling,

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You see the

possibility – the

only certainty

is that there’ll be uncertainty.

In the event of

change, it’s the time between

receiving the

information,

fully

understanding

it’s consequences

and taking

action that has

a critical

significance.

Having control

is the key to

realization.

The Opportunity is Out There !

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Thanks