Drover-1 exploration well
- The Drover-1 exploration well site is located on agricultural land in the Shire of Coorow, adjacent to the Lesueur National Park and near the Mount Peron Water Reserve.
- The well was successfully drilled in mid-2014 without any significant health, safety or environmental incidents.
- Gas readings were observed while drilling and core samples and logs were taken over the target zones to evaluate their shale and tight gas potential.
- Initial results indicated that the Kockatea Shale at this location has good source potential for gas liquids and three intervals have been identified that could constitute targets for future operations or appraisal.
- A diagnostic test, Diagnostic Fracture Injection Test (DFIT), over one of the target zones was conducted in April 2015. This test, which used a mix of water and saline water, assessed reservoir pressure, permeability, natural fracturing and potential for hydraulic fracture stimulation.
- The results of the DFIT showed that the majority of the target formation at Drover-1 was unlikely to have sufficient natural fracturing or propensity for hydraulic fracturing to achieve a commercial flow rate of gas and the well has proceeded to be decommissioned.
Based on the exploration results at Drover-1, AWE concluded that sufficient technical information has been gathered to complete assessment of the shale gas potential at this location and that no further work is required at this location. AWE is now finalising rehabilitation at Drover-1 and planning further exploration work in the permit area.
- Rehabilitation of the site, to its previous agricultural use, will occur early in 2016.
- AWE has applied to the Department of Mines and Petroleum to renew the exploration permit, which would cover a smaller area.
- The technical information gathered at Drover-1 helped AWE prepare a new forward work program for the renewed permit area being sought.
Project fast facts
Mount Peron Water Reserve
The nearest drinking water source to Drover-1 exploration activity is the Mount Peron Water Reserve which supplies the towns of Greenhead and Leeman.
AWE acknowledges there is a genuine concern in some sections of the community about the potential impact of drilling operations on the drinking water supply.
However, we can assure the community that AWE’s exploration program was thoroughly assessed and subsequently approved by a number of regulatory bodies before we were allowed to proceed. The approvals include strict operating conditions including monitoring and reporting requirements.
Before Drover-1 exploration work commenced, AWE commissioned hydrogeological consultants who prepared a groundwater study of the area to gain a thorough understanding of the local hydrogeology.
AWE carefully assessed the potential risks associated with Drover-1 exploration and identified a plan to mitigate them. This plan was scrutinised by multiple regulators including the:
- Department of Mines and Petroleum (DMP);
- Environmental Protection Authority (EPA); and
- Department of Water (DoW).
EPA assess risk to be negligible
The EPA decided not to formally assess the proposal to drill and test the Drover-1 well based on its view that it posed little risk to the environment and the regulator was satisfied that the Department of Mines and Petroleum’s decision making process would manage any potential impacts. When the EPA’s decision not to assess the proposal was appealed, the appeal was rigorously assessed by the WA Appeals Convenor and then dismissed by the Minister for Environment.
Drover-1 exploration approvals process
The Department of Mines and Petroleum assessed and approved the Drover-1 drilling plans for health, safety and environment, applying a series of operating conditions to ensure potential risks would be properly managed.
The Department of Water reviewed and approved the required water licence, applying its own operating conditions.
The findings from the Department of Water included:
- Drinking water source for the supply to consumers in Greenhead and Leeman is not at risk from the Drover-1 exploration operations
- Any surface spills left unattended would take hundreds (up to 800) years to travel the distance to Mount Peron borefield approximately 4km away
- The vertical separation and presence of an aquitard (sediment or rock with such low permeability that cannot transfer water) between the overlying aquifer and the target zone, is sufficient to protect the water resource from potential contamination by chemicals or hydrocarbons.