Large-ID Straddle Restores Integrity While Maximising Through-Bore Access
When tubing damage halted production in a North Sea well, Interwell's large-bore straddle isolated the leak while preserving a 2.62" through-bore. The solution avoided costly workover and kept the well fully accessible for future intervention. Delivered in nine weeks, production recovered with minimal flow restriction.
Year
Region
Challenge
The operator identified a loss of well integrity in a mature North Sea well, with production tubing damage causing the well to shallow lift and ultimately preventing flow. A 40-finger Multi Finger Caliper (MFC) survey confirmed a hole in the tubing at 822 m, creating a leak path across the interval and impacting overall well performance.
The requirement was to isolate the damaged section and restore production without committing to a costly workover. At the same time, the operator needed to retain full access to the well for future intervention and Plug and Abandonment (P&A) activities. Conventional straddle solutions would typically address the integrity issue but introduce significant internal restrictions; limiting flow and restricting intervention capability. A solution was required that restored integrity while minimising impact on production and preserving operational flexibility.
Solution
Interwell deployed the 362–450 Internal Diameter Large (IDL) straddle to isolate the damaged section of production tubing and reinstate well integrity. The straddle was installed across the identified hole at 822 m, providing a reliable seal and restoring containment of the well.
The 362–450 IDL features a 3.62” OD for 4 1/2” tubing and delivers a marketleading 2.62” internal diameter for a mechanical retrievable straddle. While any straddle introduces some restriction, this design significantly reduces the impact compared to conventional alternatives; helping to preserve flow performance and minimise pressure losses. This is particularly important in gas lift wells, where additional restriction can further impact lifting efficiency.
Crucially, the large internal diameter ensures the well remains accessible for future intervention. Standard intervention tools can be deployed and retrieved through the straddle, and the selected High Expansion (HEX) Retrievable Bridge Plugs (RBPs) can be run and retrieved without removing the straddle.
The straddle was set across the target interval and pressure tested to confirm isolation. A full gas lift valve changeout was completed to optimise production. The full scope was delivered within nine weeks from order to installation.
Clik to view: Multi-Finger Caliper (MFC) Log showing hole in tubing
Value Created
The solution restored well integrity and eliminated the leak path in the production tubing, allowing the well to return to stable operation. By isolating the damaged section without introducing significant additional restriction, the operator was able to recover production without compromising lifting performance.
The large through-bore provides a clear operational advantage by keeping the well fully usable. Future intervention activities can be carried out through the straddle without additional recovery. Compatibility with the selected HEX RBPs enables barrier operations without removing the straddle.
This reduces future intervention time, cost, and complexity, while maintaining flexibility for both ongoing well management and eventual Plug and Abandonment (P&A).
By avoiding a full workover, the intervention reduced cost, minimised operational risk, and limited downtime. The result is a targeted solution which restores integrity, enables production recovery, and maintains full access to the well for future operations.
Benefits
→ Restores well integrity with reduced impact on production compared to conventional straddles
→ Minimises flow restriction compared to conventional straddles
→ Maintains access for intervention through a large through-bore
→ Enables deployment and retrieval of HEX RBPs without removing the straddle
→ Avoids straddle recovery to regain well access for future intervention
→ Reduces overall intervention time and cost
→ Maintains flexibility for future operations and P&A
