Saltel Expandable Steel Patches | Schlumberger

Saltel Expandable Steel Patches

For oil and gas casing leak repair, perforation shutoff, tubing repair, and geothermal well integrity restoration

Flexible option for restoring well integrity

Saltel expandable steel patches are a permanent solution to repair a zone of damaged tubing or casing, shut off unwanted perforations, seal a leaking sliding sleeve, or perform other remedial operations. Expanded with an inflatable packer downhole, the patch creates a high-pressure inner lining with minimal loss of diameter. Saltel Xpandable expandable steel technology uses high-quality stainless steel and application- and downhole-condition-specific sealing and anchoring systems. The patch can be run on tubing, drillpipe, or coiled tubing.

Rated up to 14,500 psi [100 MPa]
Rated up to 662 degF [350 degC]
Casing and Tubing Repair

Reliable and resilient tubing and casing leak repair

Casing and tubing damage are often considered issues for mature wells, suffered only after years or decades of corrosion, erosion, or wear fatigue. However, they are increasingly occurring in newer wells because of the stresses and loads experienced while installing initial casing and tubing in long horizontal and tortuous wellbores. These forces can cause casing buckling, leaks at casing connections, or worse—casing breaches.

Casing and tubing repair options depend on the size and condition of the pipe, the depth and extent of the leak or damage, and the productivity (economics) of the well. For example, from an economic perspective, leaks toward the toe of a long lateral may not merit remediation other than plugging above and abandoning the lost clusters. Leaks toward the heel, however, merit remediation, but a casing patch with the ability to withstand high pumping pressures and a sufficiently large ID to enable passage of reduced-OD high-expansion frac plugs is required.

Saltel expandable steel patch.
Resilient and reliable profiled sealing system used by Saltel expandable steel patches.

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
Energy Consumption Reduction
Lowers diesel consumption by more than 60%
Emissions Reduction
Decreases CO2e emissions by 65%
Waste Reduction
Reduces waste by 94%

† Typical reduction for a land workover rig, principally by lowering consumption of the diesel used to power the rig and avoiding the embodied carbon in cement
Mainly by eliminating disposal of excess cement, which can be as much as 70% of the total mixed, but accounting for the impact of disposing of the patch-setting packer element

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.
Multiple steps of cement squeeze operation vs. simpler, faster internal casing patch installation.
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.
Multiple steps of cement squeeze operation vs. simpler, faster internal casing patch installation.
Resilient and reliable profiled sealing system used by Saltel expandable steel patches.

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.

Saltel placing some patches during an intervention.
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