understanding and mitigating well-integrity challenges...
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Understanding and Mitigating
Well-Integrity Challenges in a
Mature Basin
David Hardie, Anita Lewis
Senior Advisors
September 29, 2015
AER
2
Surface Casing Vent Flow (SCVF) & Gas Migration (GM)
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Outline
Well demographics
Well-integrity challenges
Life cycle approach to mitigate
challenges
3
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Wells: Stages
of the Life
Cycle
4
Western Canada British Columbia, Alberta, and Saskatchewan
By year-end 2015, there will be 600 000 wells
drilled in western Canada
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Well Integrity
Issues:
What Are We
Seeing?
5
Types of wellbore leakage:
• SCVF and GM (8 per cent)
• Casing failures (2 per cent)
• Abandonment plug failures
(2 per cent)
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Factors
Influencing
SCVF/GM
6
Geography and geology
Primary cementing
Well deviation
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Wells with Reported SCVF/GM
7
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Influence of
Cement Top
8
Cement at Surface
Total SCVF/GM
12.1%
SCVF
11.5%
GM
0.5%
SCVF & GM
0.1%
Total SCVF/GM
4.5%
SCVF
3.9%
GM
0.5%
SCVF & GM
0.1%
Low Cement Top Cement top below surface casing shoe
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Assessing
Risk
9
0
10
20
30
40
50
60
70
<1 1-9.9 10-99.9 100-299 300-1000 >1000
Pe
rce
nta
ge (
%)
Flow Rates (m3/d)
Alberta British Columbia
Non-Serious Serious
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Alberta: Evolving Well Designs
10
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
1995 1997 1999 2001 2003 2005 2007 2009 2011 2013
Per
cen
t o
f w
ells
dri
lled
Year
Deviated % Slant % Horizontal % Vertical %
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Influence of
Deviation on
Well Integrity
11
Active & Inactive Wells
All wells had reported cement returns to surface during
drilling of the well.
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Alberta:
Leakage in
Abandoned
Wells
12
Prior SCVF/GM
Regulatory requirements
Age of well
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Alberta:
Leakage in
Abandoned
Wells
13
16%
6% 6%
Historic leak No historic leak Not likelytested/reported
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Alberta:
Leakage in
Abandoned
Wells
14
Impact of Regulatory Requirements
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Alberta:
Leakage in
Abandoned
Wells
15
Leaking Abandoned Wells by Age
44%
6%
27%
9%
14%
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
Pre 1966 1966 -1975 1976 -1985 1986 -1997 After 1997
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What are the
Risks?
16
Fugitive emissions
Groundwater contamination
Spills
Public safety
Credibility of regulator
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Well Integrity:
How Are We
Addressing
the Issue?
17
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Well Integrity:
How Are We
Addressing the
Issue?
Directive 079: Surface
Development in Proximity to
Abandoned Wells
• Management versus repair
Draft IRP # 25: Primary and
Remedial Cementing
• Improving well construction
practices
Assessing risks through pilot
projects and data-driven
modelling
18
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Well-
Integrity Risk
Assessment
Model
19
Well Risk
Well Integrity & Operations
Consequence
Well Construction
& Design
Mitigating Well Integrity Risks
20
Directive 020:
Well Abandonment
Directive 079: Surface
Development in Proximity to
Abandoned Wells
Abandoned Well Integrity
Assessment Project
DACC IRP 25 – Cementing
CSA – New well standard
AER Rules & Directives
IRP24: Hyd. Fracturing
AER URF Initiative
Frac Focus
Well Information Management System
SPE: Various Initiatives
Mitigating Well Integrity Risks
Assessment of leakage risk
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Building a
Healthy and
Sustainable
Energy Sector
21
Liability
Management
Long-Term
Public
Protection
Regulatory
Initiatives
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