An oil company operating in a mature offshore field faced increasing intervention and completion challenges in deviated wells. The use of Electric Submersible Pumps (ESP) was necessary to maintain production, but the high deviation and rough wellbore conditions were damaging ESP cables, leading to costly failures and production downtime.
Objective
To protect downhole cables (ESP power cable, control lines, and fiber optics) during deployment and operation, ensuring:
- Safe installation
- Protection from mechanical damage
- Proper centralization of tubulars
Solution Components
1. Cross Coupling Cable Protectors (CCCPs)
- Purpose : Securely route cables across tubing couplings, which are stress concentration zones prone to damage.
- Design : Clamp-on style, made from corrosion-resistant alloy with a contoured shape matching the coupling profile.
- Benefit : Ensures that cables are flush with the tubing OD, reducing the risk of snagging or crushing during run-in.
2. Mid-Span Cable Protectors
- Purpose : Protect cable sections between couplings, particularly in long horizontal runs.
- Design : Slip-on or clamp-on designs, available with grooves for multiple lines (power, fiber, capillary).
- Benefit : Maintains cable integrity, especially in deviated or horizontal sections where tubing contacts the wellbore.
3. Centralizers
- Purpose : Ensure the tubing string remains centered in the wellbore, reducing side loads and friction.
- Design : Bow-spring or rigid body types, depending on application.
- Benefit : Minimizes casing/tubing wear and prevents differential sticking; enhances cementing quality in some cases.
Implementation
- Installed CCCPs at every tubing joint to route ESP cables across couplings.
- Used mid-span protectors every 30 ft in deviated and horizontal sections.
- Deployed rigid centralizers every 90 ft to keep the ESP string centralized and reduce bending stress on cables.
Results
- Cable Failures : Reduced to zero over a 12-month observation period.
- Installation Time : Decreased by 15% due to simplified cable handling.
- Production Downtime : Reduced by 22% compared to the previous year.
- ROI : The cost of protectors and centralizers was recovered within 3 months of continuous production without ESP failures.
Conclusion
The integration of Cross Coupling Cable Protectors, Mid-Span Cable Protectors, and Centralizers significantly enhanced well integrity and cable protection in challenging wellbore conditions. These tools have become standard in all new ESP well designs for the operator.
