Extreme-HT expandable steel patches
For remedial operations in geothermal and thermal recovery heavy oil wells
Our extreme-high-temperature (extreme-HT) remedial patches use field-proven Saltel Xpandable™ expandable steel technology and are rated up to 662 degF [350 degC]. They are available for casing sizes from 7 in to 13 3/8 in. Download the datasheet for detailed specifications.
- Repair a zone of damaged tubing or casing
- Shut off unwanted perforations
- Perform other remedial operations
- Steam-assisted gravity drainage (SAGD) wells
- Cyclic steam stimulation (CSS) wells
- Geothermal wells.
Saltel expandable steel patches are a permanent solution, capable of molding to irregular geometries. Expanded with an inflatable packer downhole, the patch creates a high-pressure inner lining that seals off and protects damaged casing or tubing from further loss of integrity. Overlapping patches can be used across long breaches. The large ID enables nearly unrestricted access to the wellbore below, so drilling, completion, or well intervention operations can continue and most bottomhole assemblies can pass through as required. Using these patches to seal off unwanted perforations can save multiple days of rig time—hence reducing cost and emissions—and significantly improve the likelihood of success compared with cement squeezes.
Our engineered system provides a resilient and reliable seal that is able to withstand significant differential pressures and thermal cycling, which can compromise the integrity of alternative sealing technologies over time. In addition to the profiled external seals, the patches can be secured with anchoring strips to mitigate slippage risks due to axial loads and withstand the lateral forces and wear encountered if drilling ahead. The patch can be run on tubing, drillpipe, or coiled tubing.
The patch is made of high-quality stainless steel to resist severe temperature and corrosion. The steel is covered with an expandable packing seal made of graphite and high-temperature PTFE. This material selection enables the patch to seal effectively at low and high temperatures (i.e., through thermal cycling) and in different mediums, such as water, vapor, and nitrogen. The profiled sealing system conforms to varying IDs and is applied and cured in a controlled environment during manufacturing, employing different materials based on the application requirements—unlike the field-applied epoxy resin used by some providers.
How is the patch installed?
The downhole expansion tool is positioned inside the patch and its packer section is inflated enough to grip the inside of the patch. The assembly is run in hole, and once it is at depth, the packer is further inflated using pressure from surface. The top of the patch expands and is pushed against the casing or tubing being repaired to activate the outer seals and anchor the patch in place. The packer is subsequently deflated, run in another 3 ft [1 m], and reinflated. The process is repeated until the full length of the steel patch has been expanded. By expanding the patch from the top down, the risk of a stuck setting tool is minimized.
