Casing Wear | Sub-Surface Equipment | Materials And Corrosion Control
| Damage Mechanism | Casing Wear |
Damage Description |
· Metal loss on casing occurs due to rotary contact of drill pipe with casing, riser, and other down-hole elements. Excessive metal loss could result in collapse during operation. |
Affected Materials |
· Carbon steel and low alloy steels |
Critical factors |
· Rotating hours
· Dogleg severity · Side load |
Affected Units or Equipment |
· Casing, riser and other down-hole rotating elements |
Appearance or Morphology of Damage |
· Uniform or uneven metal loss |
Prevention/Mitigation |
· Limit the rotating hours (to how many? what is the norm, design?)
· Employ CWEAR software to provide a timely warning of possible catastrophic hazards caused by wear in casing, riser, or flex joint |
Inspection and Monitoring |
· Employ the CWEAR software for calculating and monitoring the progression of wear due to rotary contact of drill pipe with casing, riser, and other down-hole elements.
· Run a log (?) to determine the amount of metal loss on casing. The extent, magnitude, and location of wear can be calculated as well as its effect on burst and collapse pressures (how?). |
Inspection Frequency |
● Before completion (once?) |
Key Performance Indicators (KPIs) |
● # MTBF due to casing wear ● # Casing wear failures per year ● # Logs undertaken per year ● # CWEAR calculations per year ● #Casing wear failures averted as a result of use of CWEAR |
Plant Integrity Windows (PIWs) |
● Wall loss <12.5% per API 5CT |
Competencies and Training |
|
Reference Resources (Standards/GIs/BPs) |
● http://www.petris.com/DrillingSoftware/Programs&Features/cwear.asp “CWEAR – Casing and Riser Wear Model calculates casing and riser casing wear for onshore and offshore operations including drilling, re-drilling, reaming upward, and rotating off bottom.” |
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