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Well Integrity Overview
Well Integrity – what does it all mean!
Definition of Well Integrity
Well Integrity is the Design, Installation, Operation and Maintenance of all Well Equipment to a standard that ensures the Safe Containment of
Produced Well Fluids & Injectants for the Life of the well.
Keep the hydrocarbons in the pipe !
Why is Well Integrity Important?
It’s about the safety of people, our equipment and our business
This is what we want to avoid!Why is Well Integrity Important?
It can help to prevent incidents like this
Integrity Drivers & Implementation
• Safety • Statutory regulations • Internal Policy &
Standards • Production • Reputation
• Technical & Performance Standards
• Procedures • Industry Standards • Vendors Procedures • Knowledge , Training
& Competency
Well Integrity Minimum Standards Standard / Element No What , Where & How ?
1) Accountable Person Wells Technical Authority
2) Well Operating Procedures Well Handover Process & Operate Wells
3) Well Intervention Procedures Field Specific Procedures
4) Tubing / Casing Integrity Management Field Specific Procedures
5) Xmas Tree Maintenance & Testing Policy
Field Specific Procedures & Planned maintenance routines (PMR’s)
6) DHSV / ASV Integrity Management Field Specific Procedures & Planned maintenance routines (PMR’s
7) Knowledge Management Drilling & Well Operations Policy
Well Construction Principles • Generally a well will consist of conductor, casing,
tubing, wellhead and Christmas tree.• The conductor protects the casing from seabed to
platform surface, and provides a stable support for the wellhead and Christmas tree.
• Three or four strings of casing will be run inside the conductor, with diminishing I.D’s
• Typically 30” conductor.• 20” Surface Casing • 13.3/8” Intermediate Casing• 9.5/8” Production Casing • 7” Liner
Casing Design : Basic Construction
12
3
67
9
11
10
1. 30” conductor
2. Conductor setting depth
3. 20” surface casing
4. 20” shoe
5. Cement
6. Formation open to C annulus
7. 13 3/8” casing
8. Formation open to B annulus
9. 9 5/8” production casing
10. Liner hanger
11. 7” Liner
12. TD – Total Depth
12
4
5
8
Completion Components – What’s installed
1
2
4
7
9 10
1112
6
1. Tubing hanger (Upper annulus barrier)2. SC-SSSV (Sub-surface barrier)3. Control line4. Tubing (Vertical barrier)5. A annulus (tubing-casing)6. Gas lift valves (in SPMs)7. Expansion joint: Tubing Seal Receptacle8. Anchor seal assembly9. Production packer10. Packer sealing element (Lower barrier)11. Tailpipe12. WEG
5
3
9 5/8”Production
Casing
8
Completion Components – Why?
Function : 1
2
4
7
9 10
1112
6
1. Upper annulus barrier & supports tubing2. Protects the surface installation 3. Hydraulically operates the SC-SSSV4. Conveys hydrocarbons to surface5. Protects production casing from attack6. Permit entry of lift gas annulus to tubing7. Accommodates expansion / contraction8. Ties & seals tubing string to packer9. Anchors tubing string to production csg10. Forms lower barrier of the A annulus11. Allows installation of instrumentation12. Easy entry of production logging tools
back into tailpipe
5
3
9 5/8”Production
Casing
8
Annular Safety Valve - Gas Lift
The ASV contains large amounts of pressurised gas in the tubing-casing annulus – should the well-head become damaged
An 8,500 ft annulus contains large quantities of lift gas when pressured up to 1800 psi
Provides annular by-pass via a hydraulically operated valve array
Lift Gas
Annular Safety Valve - Closed
Lift gas above ASV escaped to surface following loss of surface systems integrity
Evacuated Lift GasASV in Closed Position
Lift gas retained in A annulus below ASV
Integrity DriversIntegrity Drivers
The Well Integrity Envelope
DHSVs - Regular integrity & function testing
Xmas Trees - Regular Maintenance and Testing
Annuli – Regular monitoring & reporting
Report and Action if set criteria do not meet expectations.
Why monitor annuli pressures ?
• The annular voids form the principal barriers between the produced fluids and the atmosphere.
• By monitoring the annulus pressures we are able to assess the condition and integrity of the well tubulars.
• Anomalous annulus pressures may give the first indication of down hole problems although it does not automatically mean there is a leak
• Thermal expansion or ingress of formation fluid could also cause an increase in annulus pressure, regular sampling of annulus fluids may also be undertaken
• Annulus temperatures should also be considered
Definition :
“the area between two concentric circles” “a ring shaped part , figure or space”
Annulus Monitoring - Well Start-up
Tbg A B C Formn
Increasing distance from tubing
Depth
Tubing, Annulus & Formation Temperature
Hot Cool
ABCABC
Formation
Cuttings Re-Injection
Recommended Annuli Naming Convention
Example of Collapsed Tubing