BiSN Wel-Lok Bismuth Alloy Plug System Enhances Well Integrity, Cuts Costs, and Supports Abandonment Operations
Oilfield services company KAESO Energy Services showcased the BiSN Wel-Lok sealing technology, which utilizes a bismuth-based alloy, during the Angola Oil & Gas 2025 conference and exhibition.
The technology was highlighted at a pre-conference workshop—sponsored by KAESO Energy Services—on September 2 in Luanda. Jorge de Morais, General Manager of KAESO Energy Services, explained that the system creates a gas-tight, metal-to-metal seal using a bismuth alloy.
“This material is durable and resistant to H₂S and CO₂,” he stated, adding: “It has the density of lead—imagine a fluid, like water, but as dense as lead.”
Designed for complex well conditions—including damaged casings, sand screens, and gravel packs—the system has already been successfully deployed in Angola for water shut-off operations, enabling increased oil production and reducing the need for costly corrective interventions.
According to KAESO Energy Services, the solution is being positioned as an alternative to conventional plugging technologies, with applications in both well integrity management and permanent abandonment operations.
Landry Pouna, Operations Director of KAESO Energy Services, detailed the process: “The Wel-Lok technology involves deploying the bismuth alloy to the desired depth, where heat is applied via thermite heaters to melt the alloy. Once molten, it flows around the tubing, casing, or into the annulus and, upon cooling, solidifies and expands slightly, creating a gas-tight, metal-to-metal seal that bonds to both steel and rock.”
