Wells team trial new technology for plug and abandonment work on Flounder

Bismuth, an alloy that has gained popularity in the oil and gas industry, is a type of material that stands out for their safety and reliability in the plugging and abandonment of wells.

Recently, our Wells team trialled the use of Bismuth plugs on our Flounder platform to create a seal across the surface casing. The casing in our wells is a steel pipe that lines the wellbore, sealing it off from geological formations.

This process involved the removal of a small 10-metre section of the production casing at 500 metres below the sea mudline and the installation of a packer in this section. Two tons of Bismuth alloy beads were then placed and heated to 270 degrees Celsius with a downhole heater, turning the beads into a molten alloy which formed a seal across this small section of the surface casing in the well.

This approach was used when the whole production casing cannot be removed from the well, variations of this technology can also beused in production wells to plug packer leaks, isolate water shut offs and other enhancement opportunities where a target isolation is required.

“The main benefit from this trial is knowing we can achieve the placement of the Bismuth plug in a specific location within a well, and with over 200 well abandonments remaining in Bass Strait, this method will likely be used on several of our wells in the future,” highlighted Michael Atkinson, Wells Engineer.

The plugging of the well was a collaborative effort led by Offshore team supervisors, Justin Horan and Ryan Zadow, Well Engineers, Michael Atkinson and Stephen Metz, BiSN offshore technicians, Alan McLelland and Oliver Carragher, support from Esso’s rig contractor, Superior Energy Services Australia, and other vendors including Baker Hughes and IPI who provided milling equipment and inflatable packers.

With careful planning and controlled offshore execution, the operation was executed smoothly with lessons learnt that will be applied to future plug and abandonment of other wells.

Andrew Miatello, Wells Engineering Supervisor, commented, “The successful first application of the Bismuth plug is a testament to our Wells Engineering and Offshore team’s commitment to innovation and continuous improvement. The safe and positive outcome provides another tool in the toolbox for the plug and abandonment journey we have ahead of us.”