Case Study : Expandable steel Patch in a gas storage well

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Published on 28 February 2017

A custom casing patch reinforced was set successfully across cracked zone to fully restore well integrity


The client ran a caliper log to determine the condition of their 13-3/8in casing string in a Gas Storage well when they noticed there was a major restriction at 1,891ft/576m (275mm restriction). It was later decided to run a camera for a full visual of the breach. When doing so they noticed a crack across the restricted zone. A failed pressure test confirmed that well intervention was required to fully restore well integrity.
Originally the customer had 2 options:

  • Option 1: Swage out the casing to full ID (this would have required a custom built swage at a cost)
  • Option 2: Mill out the restricted zone then run a patch or squeeze cement.
  • Option 3: Keep the casing restriction and run a Saltel Patch over the restricted zone with a customized casing patch with a large expansion ratio, minimizing any risk of further damaging casing due to milling or swaging.

To minimize the costs associated with rig and personnel time + equipment rental fees, The client selected the first option (milling + swaging, prior to running Saltel Patch.)


A 8.0m x 13-3/8in x 6mm (customized) reinforced patch was set successfully across the restricted/cracked zone to fully restore well integrity. The patch had a customized 10.354in/263mm Run In Hole OD. The patch was set and drifted using our 254.00mm OD drift ring (or 10.0’’) which was what the customer wanted as a guaranteed minimum ID.

This enabled to guarantee a final ID which would allow for mechanical tools to pass the patch without risking damage or getting stuck. The patch was pressure tested @ 10 Kpsi. The test lasted 60min and the patch held solid.

Saltel and the customer have been on contact post job completion with 100% customer satisfaction, the Gas Storage well is now in full use and the customer did not have to pay a penalty for pipeline downtime.

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