Wel-lok M2MTM

Provide a permanent seal for well abandonment, through tubing applications, wells of restrictions & large diameter casing

Wel-lok M2M™ – An Overview of the Technology

The Wel-lok M2M™ technology consists of utilizing a modified thermite chemical reaction heater to melt bismuth-based alloys downhole. The melted alloys have a viscosity similar to water, and a specific gravity 10 times that of water, allowing them to flow into the smallest areas of a wellbore without the need of any surface pumping equipment. As the alloys cool and solidify, they expand to provide a seamless gas tight seal that is non-corrosive and not affected by H2S or C02.

Application Technology

This Wel-lok M2M TS™ application was the first use of this new technology. It was developed to overcome the shortcomings of traditional methods of bridge plugs using cement. It quickly became apparent that this innovative technology is superior to the standard methods both when compared by speed and cost. It can be run on a wire line or a slick line and can pass through small restrictions such as damaged or crushed casing, yet still set the gas tight plug due to the larger drift than conventional bridge plugs.


In an effort to increase the expansion ratio beyond even that of the original TS without compromising pressure differential and gas tight sealing capabilities, BiSN developed the Wel-lok M2M MXD™ tool. The use of a bailer to carry the bismuth based alloy downhole in shot form allows for a smaller diameter tool to be run in hole while increasing the expansion ratio of the tool up to 3 times the tool OD.

Summary of Wel-lok M2M™ Features

Creates a metal to metal seal without using elastomers

Ready for pressure testing in one hour

V0 ISO 14310 tested

No mechanical parts

Electronically activated

One trip operation

Differential pressure ratings up to 10,000 psi

Available in a range of sizes to suit API & non API tubings

Benefits of Wel-lok M2M™ for Permanent Abandonment

Can be used even in damaged or corroded casing

Retrievable without milling

Non-corrosive and not affected by H2S or CO2

Reduced corporate liability

Reduced intervention costs

Reduced environmental impact

Larger expansion than traditional plugs

Temperature ranges up to 160 °C


The Wel-lok M2M TS™ (Tubing Seal) was developed to overcome the shortcomings of traditional methods, using bridge plugs and cement during well abandonment. It is typically run on electric line but can be deployed on a slick line or coil tubing as well. It can pass through small restrictions such as damaged or crushed tubing, yet still create the gas tight seal. It has a higher expansion ratio than conventional plugs, higher pressure ratings than inflatable packers and gas blocking abilities that cement cannot match.

Flow prior to tool setting

Flow prior to tool setting

Flow after tool setting

Flow after tool setting

(in) (A)
(ft) (B)
3 1/2"2.5895
4 1/2" - 5”3.58180
5 1/2"4.58250
7” - 7 5/8"5.759.5610
9 5/8”89.5800
* custom sizes available

Additional Abandonment Tools

You can view or download a PDF data sheet of all our other tools by clicking the links below.