Showcased during a preconference workshop – sponsored by KAESO Energy Services – on September 2 in Luanda Jorge de Morais, General Manager, KAESO Energy Services stated that the technology creates a gas-tight, metal-to-metal seal using a bismuth-based alloy.

“This material is durable, and it can resist H2S and CO2,” he said, adding, “It has the density of lead – imagine it as a fluid, as water, and as dense as lead.”

Designed for complex well conditions – including damaged casings, sand screens and gravel packs – the system has been successfully deployed in Angola for water shut-off operations, increasing oil production while reducing the need for costly remedial interventions.

According to KAESO Energy Services, the system is designed for challenging well conditions such as damaged casings, sand screens and gravel packs. It is being positioned as an alternative to conventional plug technologies, with applications in both well integrity management and permanent abandonment operations.

“The wel-lok technology involves running the bismuth alloy to the desired depth, wherein heat is applied using thermite heaters to melt the alloy. The molten alloy then flows around tubing, casing or into the annulus and, once it cools, the allow solidifies and expands slightly, creating a gas-tight, metal-to-metal seal that bonds to steel and rock,” stated Landry Pouna, Operations Director, KAESO Energy Services.