Decommissioning and Rehabilitation Project

Mitsui E&P Australia (MEPAU) is undertaking well site decommissioning activities throughout our Perth Basin permits as part of a campaign to rehabilitate well sites which are no longer in use. Decommissioning is an established industry practice undertaken at the end of a well’s life using a decommissioning plan approved by the government regulator.

Well decommissioning involves environmentally sound and safe isolation of the well. Typical steps of the process include removing any production tubing, isolating productive formations from other formations by installing cement plugs at several intervals, pressure testing of the cement plugs, cutting off the well head below ground level, removing remaining surface equipment and facilities and rehabilitating the site to an agreed end use.

Most of the well sites are on cleared agricultural land. MEPAU is using local services and supplies whenever practical.

Landowners and nearby residents are being consulted prior to activities starting at each well site.

See what we’re currently working on by consulting our Schedule of Activities for 2020/2021.

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Rig crew running in hole with the tubing

Old wells continue to be decommissioned

In 2019 MEPAU decommissioned three wells in the Woodada and the Dongara gas fields areas of the Mid West that were no longer being used.

Denison 3D Seismic Survey

Denison 3D Seismic Survey

The Denison 3D Seismic Survey was the most complicated survey ever done in Australia at the time. Find out more about what was involved in the Denison 3D Seismic Survey.

Care and Maintenance

Care and Maintenance

When a facility is not being used, it’s put into care and maintenance. Read more about Care and Maintenance.

What we do at Mitsui E&P Australia

What we do

We are actively exploring, appraising, developing and producing oil and gas in a number of locations in the northern Perth Basin. Read more about what we do


Before anything can happen we need to plan carefully. Read more about the planning process.


We look for gas, and when we find it we figure out if it’s worth pursuing further. Find out more about our exploration and appraisal process.


Once we’ve confirmed a well is commercially viable we get ready to put it into production. Read more about the development process.


During the production phase we produce gas from the well and sell it. Find out more about the production process.


The Northern Perth Basin

The northern Perth Basin is a prolific oil and gas producing area covering a large portion of the Mid West region of Western Australia. The town of Dongara, located approximately 360km north of Perth, is the regional economic hub for a number of industries, including oil and gas.