Western Surat gas project (withdrawn)

Senex Energy Limited (Senex), on behalf of its wholly-owned subsidiary Stuart Petroleum Cooper Basin Gas Pty Ltd (Stuart Petroleum), proposes to develop the Western Surat Gas Project within an area of approximately 993km² located approximately 30km northeast of Roma, in southern-central Queensland. The proposed project area includes authority to prospect (ATP) 889 (only north of the Warrego Highway), 795 and 767, held in the name Stuart Petroleum.

Project summary

The project area is located within the Maranoa and Western Downs local government areas (LGAs). The proposed project would involve the staged drilling of up to 1000 wells and the construction and operation of supporting infrastructure over a period of approximately 30 years. The targeted production throughput rate would be approximately 35–50 terajoules per day. The proposed project would comprise development of a gasfield only and would not require the development of a liquefied natural gas (LNG) processing facility or export pipeline connecting the gasfield to an LNG facility.

The number of operating wells at any time would be determined progressively over the life of the project, dependent on matters such as the location, size and quality of reserves, along with environmental, land access and cultural heritage constraints. The predicted maximum number of wells actively producing gas on the tenure would be between 100 and 300 wells in the first five years. Where practical and commercially viable, existing infrastructure from other nearby approved developments would be utilised and gas field facilities co-located.

Wells proposed to be drilled in the project area comprise mainly production wells. Some exploration and appraisal wells may be drilled in areas on tenure proposed to be developed later in the project life to assist in understanding the reservoir characteristics ahead of production drilling. In addition, water monitoring bores may be drilled to provide data to assist in ongoing field development planning. Wells no longer in production would be progressively decommissioned and rehabilitated throughout the project life.

Gathering flowlines would transfer low pressure gas from the wells to small scale nodal compressors or larger scale field compressor facilities for initial compression before being transferred via trunklines to a central processing facility for further compression and dehydration processing into sales gas. A high-pressure steel pipeline would be required to transfer the sales gas from the central processing facility to its destination. It is anticipated that only one central processing facility is required to support producing wells.

Depending on the management option employed, drilling and other project activities such as dust suppression and construction would primarily source groundwater derived from coal seam depressurisation activities. This produced water may require treatment through a facility with capacity of up to 12 megalitres per day prior to beneficial use.

Power required on-site for initial start-up of wells, would be supplied using diesel generators. The generators would thereafter be powered by gas. The central processing facility, field compressor facilities, nodal compressors, accommodation and workshop infrastructure would also be powered using gas generators with diesel powered back-up generators.

Employees required to support construction and ongoing operations would generally be accommodated in Roma and on-site temporary drilling and construction camps. It is anticipated that the proposed project would require approximately 100 employees during construction and approximately 20 employees during operation, although better estimates would be provided in the environmental impact statement (EIS).

Environmental Protection Act 1994 (Queensland)

On 31 March 2015, Senex applied under sections 70 and 71 of the Environmental Protection Act 1994 (EP Act) for approval to voluntarily prepare an EIS. Under section 72 of the EP Act, the department approved the application on 6 May 2015.

Environment Protection and Biodiversity Conservation Act 1999 (Commonwealth)

The proposed project was referred on 24 April 2015 to the Australian Department of the Environment (EPBC 2015/7469). On 21 May 2015, the Department of the Environment determined the proposed project to be a controlled action under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). The controlling provisions are sections 16 and 17B (wetlands of international importance), sections 18 and 18A (listed threatened species and communities), sections 20 and 20A (listed migratory species) and sections 24D and 24E (water resource, in relation to coal seam gas development and large coal mining development). The EIS process will assess potential impacts of the project on the controlling provisions consistent with the bilateral agreement (section 45 of the EPBC Act) between the Australian and Queensland governments for the purposes of the Australian Government’s assessment under part 8 of the EPBC Act.