ACTive PTC
CT real-time pressure, temperature, and casing collar locator tool
Improve job efficiency and subsequent well performance with real-time downhole measurements.
Saltel Expandable Steel Patches
For oil and gas casing leak repair, perforation shutoff, tubing repair, and geothermal well integrity restoration
Casing and Tubing Repair
Why choose a Schlumberger casing patch as your restorative well integrity technology of choice?
Saltel expandable steel patches are a permanent solution, capable of molding to irregular geometries to create 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.
Made of high-quality stainless steel, the patch uses a profiled sealing system that 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. Our engineered system provides a resilient and reliable seal that is capable of withstanding significant differential pressures and thermal cycling, which can compromise the integrity of alternative 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.
Perforation shutoff
How does the time required to install a casing patch compare with the time to conduct a cement squeeze?
A casing patch using our field-proven Saltel Xpandable expandable steel technology requires less time to accurately position and install across unwanted perforations compared with conducting a cement squeeze. It does not significantly restrict wellbore access and only requires water to activate the inflatable packer used for controlled expansion of the patch against the casing—even a corroded or ovalized casing. Perforation shutoff can be completed in as little as two days.
In contrast, traditional methods for sealing unwanted perforations by squeezing cement into them are lengthy, multistep operations.
- Cement slurry is prepared and pumped down the wellbore into a squeeze target.
- Slurry is forced into all voids via pressure applied from surface.
- Cement milling assembly is subsequently run to remove the excess cement from across the perforations.
- Squeezed zones are evaluated via a pressure test, cement evaluation log, or both.
A cement squeeze may require four or more rig days; if it is unsuccessful, the operation can extend beyond a week, increasing costs and emissions. Moreover, designing the cement slurry must take into account the type of void to be filled and the rate of cement dehydration; a suboptimal slurry may not provide a complete fill and proper seal.
Using a Saltel expandable steel patch to shut off perforations is a simpler and faster operation than a cement squeeze, which comprises multiple steps and may require four or more rig days. If the cement squeeze is unsuccessful, the operation can extend beyond a week, increasing costs and emissions. Moreover, designing the cement slurry must take into account the type of void to be filled and the rate of cement dehydration; a suboptimal slurry may not provide a complete fill and proper seal.
Why is a Schlumberger expandable casing patch a more resilient long-term solution for perforation shutoff?
Saltel expandable steel patches are a permanent solution, creating a high-pressure inner lining that seals off a perforated zone without restricting production from neighboring perforations. The large ID enables nearly unrestricted access to the wellbore below, so that wireline- or tubing-conveyed perforating guns can pass through to add new perforations for production, injection, or postperforating treatment.
Made of high-quality stainless steel, the patch uses a profiled sealing system that 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. Our engineered system provides a resilient and reliable seal that is capable of withstanding significant differential pressures, which can compromise the integrity of squeezed cement over time. The profiled external seals are also inherently more resilient than third-party resin-based solutions to the thermal cycling induced by high-rate injection, suspension, and resumption of injection that are common during operations.
Casing patch procedure for installation
The downhole expansion tool is positioned inside the patch and the 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.
In addition to standard patches, several custom patches are available to withstand H2S, chlorides, strong acids and alkalis, nitrogen, aromatic hydrocarbons, and other aggressive chemicals and to provide V0-rated gas-tight seals.
High-temperature patches
HT patches are suitable for thermal wells up to 446 degF [230 degC]. They have short-term resistance to 482 degF [250 degC] and are ISO 14310–qualified up to that temperature.
Extreme-high-temperature patches
Extreme-high-temperature patches are rated up to 662 degF and especially designed for heavy oil production techniques—including steam-assisted gravity drainage (SAGD) and cyclic steam stimulation (CSS)—as well as geothermal wells. They seal effectively even through thermal cycling.
Prefracturing patches
Prefracturing patches seal off frac ports (e.g., ports that opened prematurely) and withstand hydraulic fracturing pressures up to 10,000 psi [69 MPa]. These patches have a special design to ensure sealing against the irregular profile of frac ports.
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