Frequently Asked Questions

Mitsui E&P Australia (MEPAU) are committed to communicating clearly with the Mid West community. We operate openly, transparently and in good faith with everyone we deal with.

MEPAU in the community

MEPAU in the Community - Guests at Long Table Lunch, Land & Lobster Festival, Dongara Western Australia

What activities are you planning and doing in the Mid West?

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

How long have you been in the Mid West?

Since MEPAU was founded in 2004, the company has grown to become one of Australia’s largest oil and gas producers. MEPAU has seven producing oil and gas assets in Australia and is Operator of four facilities in the Mid West of Western Australia. The company also has interests in 30 projects that are in exploration and development stages.

In 2018 MEPAU took over AWE Limited, which had been operating in the northern Perth Basin for a decade. MEPAU employs approximately 100 full-time employees and contractors in Western Australia, of which approximately 11 are located in the Mid West. During exploration programs and development activities, this number increases.

What does MEPAU contribute to the community?

In a purely financial sense MEPAU contributes more than $7 million a year to the Mid West economy. We pay wages and enter into contracts with local businesses. We also partner with the community to undertake local community investment projects.

Almost all of our Mid West staff are part of the regional community rather than flying in and out. As a company we are active in the community to ensure the Mid West remains a great place to live.

The gas we produce helps fuel the Western Australian economy and provides heating and cooking to Western Australian homes.

What community consultation have you undertaken?

MEPAU engages extensively with the local community of each project. We routinely host community roundtable meetings, place advertisements in the local newsletter and direct mail local residents.  In 2016, we established the independently facilitated Shire of Irwin Community Roundtable, which was set up in response to interest by local residents in our activities.

In addition, we hold discussions with the local shires where we operate so that community leaders are aware of our plans and can provide feedback.

We’ve established this dedicated Mid West website so that people can access relevant local information.

Further engagement is planned as MEPAU develops its forward exploration and development plans and we welcome people getting in touch directly if they have a query or suggestion.

MEPAU Community Consultation

Can onshore gas development and tourism/agriculture co-exist?

Yes, and the Mid West is a good example of this. Since the 1960s, more than 200 oil and gas wells have been drilled in the Perth Basin and gas has been produced from six fields, while agriculture and tourism have flourished.



MEPAU works closely with local landowners and farmers

Does MEPAU compensate landowners for drilling on their land?

Yes. MEPAU negotiates voluntary land access agreements with landowners on whose property we will be drilling.

We acknowledge we are using their property and seek to fairly compensate landowners for the disruption to their cropping and grazing programs.

How does MEPAU rehabilitate cleared land after drilling and activities?

 MEPAU treats landowners and their land with a high level of respect.

Prior to any clearing or site activities the project specific Environment Plan, which addresses rehabilitation requirements, is reviewed and assessed by the Department of Mines, Industry Regulation and Safety (DMIRS). The rehabilitation requirements are based on results of environmental studies undertaken to establish baseline conditions.

The land is rehabilitated under strict regulations established by DMIRS and in consultation with the landowner until completion criteria is achieved.

What is the area of ground disturbance and clearance used to drill a well?

Most of MEPAU’s drilling and facility locations in the Mid West are located on already cleared agricultural land, which means we are not clearing any native vegetation for our operations.

In most cases, the site work will include an access road, water bore access and the well pad. The ground disturbance typically covers anywhere from 3-5 hectares.

Engineering and Technical

Engineering & Technical - New compressor for Xyris Production Facility

What is the structure of a well bore?

Well bores are made up of multiple layers of steel casing and cement, which forms a multi-stage barrier to separate the well bore and the subsurface geology. This approach ensures there are multiple layers between the well bore and the subsurface aquifers.

To ensure and assess the well bore’s structural integrity during operations, we continually monitor pressure in the well bore and in the space between steel casings to ensure the well integrity is maintained.

Is there any likelihood that a well becomes over pressured and fails?

That is extremely unlikely. MEPAU pressure tests the well bore at each stage of the casing and cementing process to ensure the well bore is stable and safe.

In addition, the well is monitored 24/7 during drilling, so we know exactly what is occurring subsurface and can react accordingly to any potential issues.

Every well MEPAU plans is specifically designed to suit the local geological environment of that well bore position. If the studies showed that a well posed any unmanageable risk, we would not propose to drill it.

Why are some wells drilled vertically and others drilled horizontally?

That largely depends on the nature and geological setting of the formation we are targeting. Both techniques have been used safely for decades.

Chemical Disclosure

Drilling at Senecio

What chemicals are used during drilling?

State regulation since 2012 requires operators to fully disclose all chemicals used down-hole during drilling operations. The chemicals we use are assessed and approved by DMIRS for use and then made publicly available on their website.

Any chemicals stored on-site are stored in accordance with regulations, inside lined bunds and fenced areas.

How would you know if the chemicals used during drilling have entered the water systems?

Before drilling operations begin, MEPAU undertakes baseline water quality studies and then conducts water quality monitoring during and after drilling operations and reports the results to regulatory authorities.

The monitoring program, including the proposed sampling method and location, is developed with advice from the Department of Water and Environmental Regulation. The sampling procedure is conducted by a qualified independent technician with sign off from the landowner and company at the time of acquisition.

The samples are comprehensively analysed by a NATA certified laboratory and copies of the analysis are provided to the landowners and appropriate regulatory body.

What happens to the water bores when you stop drilling?

When MEPAU negotiates its land access agreements with the local landowner, part of that process is deciding what will happen to the infrastructure such as water bores.

In the majority of cases, landowners request that the water bore remains for their future use and benefit.

Water management – above and below ground

CSIRO UWA Monitoring Project

How are surface aquifers protected during drilling operations?

Aquifers are protected by both natural and mechanical barriers. Our own mechanical barrier is the multiple layers of steel casing plus cement, providing multiple barriers between the well and the aquifer.

Natural barriers exist in the sub-surface structural formation of impermeable rock layers, which prevent the migration of any hydrocarbons to surface aquifers.

In addition, MEPAU has introduced baseline water quality studies and measures and reports the results of post-drilling water quality studies to the regulators. This monitoring provides MEPAU and regulators with early indicators should any leakage occur. We are confident there will be no leakage due to the safety measures in place; however the monitoring shows these measures are working.

What is the long-term method for aquifer protection?

During the production phase of a well, which could last 10 to 40 years, we maintain well integrity with production tubing casing and packer systems, which isolate hydrocarbon production from the subsurface.

The internals of well casing are protected by various means including being maintained by cathodic protection and corrosion inhibitor treatments. Any decommissioned wells are plugged with cement to prevent leakage.

How much water is used to drill a well?

MEPAU typically plans to use approximately 4,000-6,000kL for drilling a traditional vertical well. This amount includes the water for the camp and drilling operations.

To put this into perspective that is the equivalent of two-and-a-half Olympic-sized swimming pools. For example, the drilling and hydraulic fracture of the Woodada Deep-01 well used 0.04 per cent of the total allocation for water extraction from the Lesueur Aquifer.

Where does MEPAU source the water for drilling operations?

Water for all drilling operations is obtained from a local existing water bore if available; otherwise a new bore will be constructed.

Water extraction and water bore construction is licensed by the Department of Water and Environmental Regulation (DWER). MEPAU establishes monitoring or observation bores within proximity of operations following consultation with DWER.

Waitsia Field Specific Questions

Waitzia acuminata photograph by Gail Reed

What is your forward plan for the Waitsia field?

Initially, our focus was on Waitsia Stage 1A, which was refurbishing the Xyris Production Facility (XPF), laying pipeline infrastructure from two wells to XPF and conducting an extended production test. Waitsia Stage 1A has been producing since August 2016.

Since then, additional appraisal activities have been conducted and the data has been valuable in assisting the Waitsia Gas Project development process. These activities include drilling appraisal wells Waitsia-03 and Waitsia-04 and also conducting diagnostic tests at the Irwin-01, Waitsia-02, Waitsia-03 and Waitsia-04 wells.  These helped the planning and design phase of the Waitsia Stage 1 Expansion Project, which was completed in 2020, as well as the Waitsia Stage 2 project, which includes building a new production facility, that is scheduled to begin construction in mid-2021.

Have you engaged with the local community about your plans?

Yes, there has been considerable engagement with community immediate to our operations as well as the Dongara and Mid West community. This has ranged from a number of community information exchange sessions, direct engagement, site tours, electronic updates, direct mailouts, newspaper advertisements and media exposure.

We are pleased to sponsor the independently facilitated Shire of Irwin Community Roundtable that is facilitating even greater communication between MEPAU and the local community, which was established in 2016.

What is your local employment policy?

Part of our commitment to being a good neighbour is to support local businesses. We awarded more than $10 million in contracts to Mid West businesses during the Stage 1A development. This is in addition to the more than $7 million the company spent annually in the Mid West through wages, sponsorship and ongoing contracts.

MEPAU sets high standards for its operations. Furthermore, the oil and gas industry in Western Australia demands the very best in quality, safety and efficiency. The fact that we’ve awarded large value contracts locally is a reflection of the technical capability, competitiveness and cost efficiency of Mid West service providers.

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Mitsui E&P Australia (MEPAU) supplies gas to Western Australian customers

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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 energy industries.