Addressing Casing Pressure Challenges with wel-lok™ Technology

BiSN CRT Onshore AustraliaBiSN CRT Onshore Australia

wel-lok™ Cement Repair Tool (CRT)

Utilizing BiSN’s wel-lok™ Cement Repair Tool (CRT) to stop the gas flow in the annulus across multiple wells.

See Tool Specification
July 12, 2024

An Australian operator faced challenges with poor cement quality within the 7.00” x 9-5/8” annulus of several wells, resulting in the formation of leak paths and sustained casing pressure at the surface. The operator sought to isolate the lower coal formations from the aquifers above. Despite employing traditional remediation methods multiple times, they achieved limited success. To solve this issue the operator chose BiSN’s wel-lok™ CRT technology to set through perforations in the annulus above the leaking zone.

  • Statistics
  • Challenges
  • Solution
  • Results
  • Business Value
Statistics

wel-lok™ CRT Case Study Australiawel-lok™ CRT Case Study Australia
Challenges

Cement Quality and Isolation

Cement Quality Issue: Poor cement quality leading to leak paths and casing pressure problems.

Limited Success with Traditional Methods: Existing approaches haven’t effectively solved the cement quality issue.

Isolation Challenges: Difficulty isolating lower coal formations from aquifers to maintain well integrity.

BiSN CRT Onshore AustraliaBiSN CRT Onshore Australia
Solution

wel-lok™ Cement Repair Tool (CRT)

As each well in the campaign had differing work histories and configurations, a flexible approach was required from BiSN engineers to ensure the wells were permanently abandoned.

BiSN engineers used both alloy-on-heater casted tools deployed via e-line through perforations and bismuth beads technology deployed via drill pipe in a section-milled window, adapting to the different well conditions as required by the operator. In both deployment scenarios, the bismuth alloy was melted by a chemical reaction heater and allowed to flow with the viscosity of water through the flow paths and seal behind the 7″ casing.

All wells in the campaign successfully passed a 600 psi pressure test to confirm the presence of a full cross-section gas-tight bismuth alloy seal and a permanent abandonment.

Results

Seal Off Gas Migration to Surface

wel-lok™ CRT tools were successfully utilized to seal off gas migration to surface across several wells.

  • Faulty cement remediated with bismuth alloy.
  • Elimination of the requirement for unreliable
    cement squeezes.
  • Substantial cost savings realized by the operator.
  • Tool adaptability optimized to match
    diverse well conditions.
Business Value

Rigless Solution for P&A Applications

BiSN delivered a dependable solution to the customer for permanent well abandonment, mitigating the risk associated with ineffective cement squeezes while ensuring the enduring reliability of bismuth alloy. By leveraging the unique sealing properties of bismuth alloy, which require shorter plug lengths, the necessity to section mill an extensive window for a replacement cement plug was eliminated, resulting in notable cost savings for the operator. In partnering with BiSN, the operator effectively reduced HSE risks, operational time, and overall expenditure, demonstrating the tangible benefits of innovative solutions in well intervention and abandonment processes.

About the application

The wel-lok™ CRT (Cement Repair Tool) was developed to eliminate sustained casing pressure, or casing vent flow, in cemented annuli. Unlike traditional methods of perf and squeeze or perf and wash, this tool does not require any surface pumping pressure to squeeze or circulate the sealing material into place. The tool is also run rigless on electric line, sealing through casing perforations, so section milling is not required. The bismuth-based alloy has no porosity and solidifies to create a seal in minutes as opposed to hours with traditional cement and resins, eliminating the possibility of a micro-annulus being formed to allow future gas migration. If full bore access is required, it can be milled out and still maintain a gas tight seal in the annulus.

Cement Repair Tool - BiSN
Cement Repair Tool - BiSN
Cement Repair Tool - BiSN
Cement Repair Tool - BiSN

How it works…

The wel-lok™ CRT (Cement Repair Tool) was developed to eliminate sustained casing pressure, or casing vent flow, in cemented annuli.

How it works…

More wel-lok™ Case Studies

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