The Wel-lok M2M™ technology consists of utilising 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.
This Wel-lok M2M™ 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.
Slim tool profile design to negotiate restrictions
High expansion ratio capability for sealing in large diameters
Utilises modified thermite chemical reaction heater to quickly melt bismuth based alloys
Gas tight seal in large diameter casings without the use of elastomers
Easy and quick to deploy in a single trip intervention
Reduced intervention costs
Long lasting reliable sealing solution despite restricted access
Extends the production life of the well
Non-corrosive and not affected by H2S or CO2
Reduced environmental impact
Temperature ranges up to 160 °C
Available in a range of sizes to suit API & non API tubing casings
The Wel-lok M2M MXD™ (Maximum Drift) has been specifically developed for rigless through tubing applications. This tool has a smaller OD and higher expansion ratio than some of the other Wel-lok M2M™ tools but uses the same technology to create metal to metal (M2M™) seals. Unlike conventional through tubing tools utilising a petal basket and cement or inflatable packers, the MXD™ offers a gas tight seal with up to a 10,000 psi differential pressure rating and can be deployed in a single trip. Utilising bismuth alloy pellets, deployed inside a bailer, eliminating any restrictions on the volume of alloy that can used to create a seal.
|BiSN WEL-LOK M2M MXDTM DIMENSIONS|
|CASING RANGES||TOOL OD|
|LEFT IN HOLE|
|*3 1/2" - 7"||2.125||12.5||28||600|
|4 1/2" - 7 5/8"||2.875||12.5||28||750|
|*5" - 9 5/8"||3.5||12.5||28||950|
|* currently in development|