Collapse | Sub-surface Equipment | Materials And Corrosion Control
| Damage Mechanism | Collapse (Production Tubing/Casing/Drill Pipe) |
Damage Description |
· Downhole production tubing/casing or drill pipe collapses when the differential pressure between the outside and the inside exceeds the nominal collapse resistance of the tubing. Pipe suffers collapse at localized areas which have lost their nominal material properties due to localized heating, fabrication defects or corrosion. Burst is just the reverse of collapse with the pressure on the inside of the tubing causing to split open. |
Affected Materials |
· Carbon steel and low alloy steels. |
Critical factors |
· Differential pressure
· Localized inhomogeneities in microstructure, chemistry or mechanical properties · Corrosion · Manufacturing defects |
Affected Units or Equipment |
· Production: Hanger subs, R & X nipples, flow couplings, production tubing, casing, production liner, tail pipe, PBR seal and packer assemblies, sand screens, and other downhole accessories
· Drilling: Drill pipe · Workover: Coiled tubing |
Appearance or Morphology of Damage |
· Collapse (denting or folding) or rupture (burst) |
Prevention/Mitigation |
· Run downhole equipment with the safe remaining wall thickness
· Avoid excessive differential pressure · Screen out pipe with excessive corrosion, manufacturing defects or heat checking |
Inspection & Monitoring |
· Visual inspection before commissioning · VT, UT and RT inspection techniques should focus on general and local loss in thickness due to corrosion, fabrication defects or heat checking |
Inspection Frequency |
· After each job |
Key Performance Indicators (KPIs) |
· # Collapse failures per year |
Plant Integrity Windows (PIWs) |
· Not Applicable |
Competencies and Training |
· Corrosion Courses
o e-COE 101 Corrosion Basics o e-COE 701 Corrosion & Corrosion Prevention o PEW 407 Corrosion Technology o COE 104 Chemical Treatment for Producing Operations |
Reference Resources (Standards/GIs/BPs) |
· B. D. Craig “Practical Oilfield Metallurgy and Corrosion” by Pennwell, 1993 · Handling and Running Procedure for Chrome OCTG by Drilling & Workover Engineering Department, May 2003 · Field Inspection Guidelines for Sumitomo Metal’s CRA Material- Saudi Aramco – Karan, Sumitomo Metal, 2008 · Offshore Running and Handling Guidelines for Sumitomo Metal’s CRA Material, Saudi Aramco-Karan, 2008 · API 5C1 Recommended Practice for Care and Use of Casing and Tubing |
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