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patch repairs casing, enabling acid frac operations

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Published on 9 June 2022

Saltel casing patch shuts off perforations, overcomes critical H₂S, severe doglegs, and restrictions, restores the casing integrity, and enables a major operator to resume acid frac operations.

Despite challenging operating conditions, a significant operator in Central Asia overcomes critical H₂S and resumes operations after the successful deployment and installation of a customized expandable steel casing patch.

The Distributed Temperature Sensing technology identified a leak in the 4.5in casing.

Schlumberger Reservoir Performance and Integrity Department had planned to perform acid stimulation of 5 compartments in the client’s well the year before. The client observed a sharp, unexpected downhole pressure drop during the well pressure test. The Distributed Temperature Sensing technology (DTS) identified a leak through the punched tubing. The acid stimulation job was canceled until a solution to shut off the perforations (casing patch) could be found, putting a hold on the customer operations and placing this issue as a priority for the client’s upper management.

Perforation shut off. Patch in H2S with high Dogleg severity

Saltel casing patch: a versatile alternative to cope with numerous downhole challenges.

Schlumberger needed to come up with a suitable perforation shut-off alternative within a limited time. This workover was challenging in many aspects, such as:

  • Identifying and providing a solution in a short period for the area.
  • Being compatible with high chemical content (critical H₂S).
  • Passing through a tubing restriction and severe dogleg.
  • Ensuring a Rigless deployment.
  • Securing both procurement and importation for the client, allowing to meet urgent requirements.
perfs shut off challenges - Patch in H2S with high DLS

Given that the customer’s emergency significantly impacted the production, Schlumberger (Reservoir Performance and integrity, and Completions) proposed a cross-segment fit-for-basin alternative with fast delivery and quick intervention, namely Saltel expandable steel patch. The patch had to shut off unsolicited perforations and overcome H₂S. Saltel casing patch, which had never been deployed in the GeoUnit before, was ticking all the boxes.
Saltel patch won the client for its extensive global track record. It was an excellent premium alternative to other technologies, such as chemical injection. (Cement or resin squeeze). Chemical injection alternatives would not have met the well’s integrity requirements regarding long-term isolation and guaranteed mechanical barrier.

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