Perforation Shutoff with Expandable Steel Patch | SLB

Perforation shutoff using expandable internal casing patches

Field-proven, sustainable, and lower-cost alternative to cement squeezing using a drilling or workover rig, snubbing unit, or CT

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 because a suboptimal slurry may not provide a complete fill and proper seal.

Why is an SLB expandable casing patch a more resilient long-term solution for perforation shutoff?

Our 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.

Case Study: Using Expandable Steel Patches Instead of Cement Squeezes Saved 820 Hours of Rig Time

Avoiding cement squeezes saved an operator 820 hours of rig time

Using expandable steel patches to seal off open perforations in 10 depleted wells enabled water injection into lower zones, saved time, and reduced both cost and the carbon footprint.

Read case study

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