FE270 Section 10 (NXPowerLite).ppt cathodic protection

cathodic protection

1. Haward Technology Middle East 1Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Section 10
Protection of Production and
Injection Well Casing

2. Haward Technology Middle East 2Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Well
Completion
SCVF:
Surface Casing Vent
Flow
Shallow area high risk
of SCVF
Deep area less risk of
SCVF

3. Haward Technology Middle East 3Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Well Construction
Cap rock
Reservoir
Corrosive stratum
Casing
Flowline

4. Haward Technology Middle East 4Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
CP Current to Casing
NACE RP-0285-2002, Corrosion Control of Underground
Storage Tank Systems by Cathodic Protection
NACE RP-0186-2007, Application of Cathodic Protection
for External Surfaces of Steel Well Casings

5. Haward Technology Middle East 5Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Factors Relevant to CP Design
Subsurface geology
Well completion details
Current requirements
Density and proximity of wells
Interference from foreign CP systems
Optimise anode bed location
Electrical isolation of flow lines
AC power availability
Alternative power supply – wind, thermal, solar

6. Haward Technology Middle East 6Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Quality
of Grouting

7. Haward Technology Middle East 7Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Well Logging Tool

8. Haward Technology Middle East 8Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Acoustic and
Gamma Log

9. Haward Technology Middle East 9Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Failure Mechanisms
Canadian data from
130,000 m in 142 wells
External corrosion and cement
quality from 10,500 m in 142 wells

10. Haward Technology Middle East 10Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Well Construction
Cap rock
Reservoir
Corrosive strata
Casing
Isolation flange
T/R
Groundbed

11. Haward Technology Middle East 11Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Limitations of CP
High resistance strata
Low resistance strata
Poor quality cement job
Salinity changing OH
-
/Cl
-
ratio in cement
Carbon dioxide reducing cement pH

12. Haward Technology Middle East 12Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Typical Casing CP System
ANODE
CHAINS
PVC-CASING PERFORATED
ANODE GROUNDBED
HEAD STRUCTURE
ANODE
JUNCTION BOX
T/R-UNIT
PVC-CASING
FLOWLINE
I-FLANGE
WELL HEAD
CATHODE
JUNCTION BOX

13. Haward Technology Middle East 13Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Deep Ground Bed
Use redundant well
Drill new hole
Location of hole fixed by
potential profile testing
Anodes located 75 - 100 m
below the surface

14. Haward Technology Middle East 14Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Power Sources
Wind Thermal Solar

15. Haward Technology Middle East 15Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Total Current Density
The current density required depends on the
environment and cement quality
A range of current densities are used to determine the
total current requirement and can range from 1 –
30mA/m².
As a rule of thumb:
Depth (m) Current (A)
900 2
1500 5
3000 30

16. Haward Technology Middle East 16Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Casing Potential Profiles
Surface equipment must be electrically isolated from
the well head.
Well head equipment ID must equal casing ID.
Rods and tubing must be removed from well.
Casing must be in contact with formation -not inside a
liner.
Area to be profiled must not contain conductive fluids.
Complete casing history with well completion data
should be available
Well must be cleaned of rust and wax

17. Haward Technology Middle East 17Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair

18. Haward Technology Middle East 18Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Cathodic
Protection
Profile

19. Haward Technology Middle East 19Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
CP Profile Outputs

20. Haward Technology Middle East 20Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
CP Profiles
Different
Currents
Zero
current
1 Amp
DEPTH
POTENTIAL

21. Haward Technology Middle East 21Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
Internal Corrosion
Caliper Tools

22. Haward Technology Middle East 22Section 10
Cathodic Protection Systems: Design,
Fabrication, Installation, Operation and Repair
End of This
Section