Western Surat Gas Project, Australia


western surat gas project

Western Surat Gas project involves the development of an area of coal seams covering 915km², located north of Roma, Queensland, Australia. Senex Energy owns and operates 100% of the project tenements.

The initial appraisal wells of the project came online towards the end of 2016 under a pilot programme.

The first phase of development activities commenced in October 2016, and Senex is currently moving the project towards full-phase development.

Western Surat Gas project location

The Western Surat Gas project is located in the Maranoa and Western Downs Local Government Areas, and includes 13 blocks within the Authority to Prospect (ATP) 795, ATP 767 and part of ATP 889.

Twelve of the total blocks are located 30km north-east of Roma, while the remaining block is located approximately 10km north of Wallumbilla.

Western Surat Gas project development and infrastructure

Western Surat gas project is estimated to contain net proven reserves of 8.3 million metric barrels of oil equivalent (Mmboe), and proven and probable reserves of 72.6Mmboe.

Exploration and appraisal works have already been undertaken to better understand the reservoir properties and de-risk the project.

The project will involve the drilling of up to 1,000 wells over a 30-year period, with a target gas production of up to 50 terajoules (TJ) a day.

The proposed wells will mainly include production wells, with certain exploration and appraisal wells also planned. Each well will include a well pad covering an area of one hectare.

The wells will be drilled to a depth between 150m and 800m, with the top sections being cased with steel and cement to prevent movement of water.

Most of the wells will be vertical wells, while deviated wells are also planned to be drilled in certain areas.

Power required for the drilling activities will initially be provided by diesel generators, which will be powered in later stages by gas.

Pilot and phase two development of the Western Surat Gas project

Senex commenced development of the project through the launch of a pilot programme at the Glenora block.

The programme was completed in November 2016 and included appraisal of the pilot wells in the block. Rehabilitation works on 47 legacy wells on the Eos block were also undertaken.

Senex announced the sanction of a $50m investment in a 30-well drilling programme in February 2017.

The investment will also focus on the development of associate infrastructure, as well as the commencement of appraisal activities on the Eos block.

The first wells from the programme are planned to come online in mid-2018, producing at the rate of 10TJ/day. The produced gas will be supplied to the Santos-operated Gladstone Liquefied Natural Gas (GLNG) plant, located on Curtis Island in Queensland.

Plans for the construction of a gas production facility in the Eos Block and parallel appraisal wells west of the block have also been outlined.

The next phase of development will include the drilling of additional 30-50 wells, subject to regulatory approvals. The activities will focus on optimising reservoir performance and maximising well recovery.

Processing and transport

The project is expected to require minimal compression and water handling facilities.

"The project will involve the drilling of up to 1,000 wells over a 30-year period, with a target gas production of up to 50 terajoules (TJ) a day."

Low-pressure gas from the wells will be transferred to three interconnected pods by gathering flowlines for initial compression.

The compressed gas will then be transferred to a central processing facility for further compression and conversion into sales gas. A high-pressure steel pipeline will be built to transfer the sales gas to its destination.

Supply contract for the Australian gas project

Senex has signed a 20-year gas sales agreement with GLNG, which includes the supply of 50TJ of gas a day to GLNG along with potential sharing of infrastructure facilities.

GLNG will also purchase a small portion of the project acreage (Maisey block) for $42m.