2021 offshore greenhouse gas storage acreage release: nominated areas for comment

GHG21-1 and GHG21-2 are within the North Australia Exercise Area (NAXA), the Darwin Air Weapons Range (Central & West) and Restricted Airspace.

Offshore activities may impact the safety of air navigation due to the risk of collision with low-flying aircraft below 500 feet. The calculation of lowest safe flying altitudes depends on the height of obstructions within a certain area, however, accurate infrastructure height and location data is needed to treat potential risks. Notification of these risks to aviation can be achieved via release of a Notice to Airmen (NOTAM) and notification to Airservices Australia of the new Vertical Obstruction data.

Offshore activities may impact military flying training areas. The Civil Aviation Safety Authority (CASA) has declared numerous Restricted and Danger Areas to protect military operations from any non-compatible aviation activities. These areas often extend down to the surface of the land or ocean, and any obstruction into these airspace volumes may impact Defence usage of Training Areas. Additionally, increased sea or air activity to/from the offshore areas may cause Defence to lose access to Defence Practice Areas or flying training areas that are located offshore. Coordination between all stakeholders is needed to ensure any competing needs are facilitated. If the military activity is unable to move to another area, it may result in the loss or diminished use of a military flying training area and adversely impact Defence capability.

Proponents are advised that they may be ordered to evacuate Restricted Airspace or any gazetted Defence Practice Area (DPA) at short notice and unauthorised access to the area will be prohibited.

Proponents should also be aware of the risk of Unexploded Ordinance (UXO) in the area and assess if any risk mitigation actions are required. Defence provides no guarantee or indemnity regarding the safety or whereabouts of UXO.

Proponents should liaise with Defence (using the contact details provided in the General Comments) early in the project planning phase in order to facilitate deconfliction with Defence activities. Additionally, at least five weeks prior to commencement of activities, Defence should be notified regarding:

• the nature of planned infrastructure development (permanent or temporary);
• the positions and dimensions (lateral and vertical) of abovementioned infrastructure;
• any planned aviation activities;
• any planned seismic survey activities; and/or
• whether any wells are to be left suspended or plugged and abandoned.

Proponents should also follow all procedures and restrictions relating to Notices to Mariners (NOTMAR) and Notice to Airmen (NOTAM). Further information is available from the Australian Hydrographic Service and Airservices Australia.

Proponents are advised that low level flying activities may be undertaken by Defence within the Restricted Airspace areas detailed above. Proponents should ensure that they adhere to the NOTAM restrictions, publish a NOTAM notification and notify Defence as per above advice.

Defence requires the following safety operating conditions to be satisfied by the Proponent, Operator or License/Permit holder of GHG21-1 and GHG21-2:

• Operation of the licensed capacity of the GHG field to be no greater than a demonstrable volume where the Regulator accepts that over pressurisation of the field cannot reasonably occur.
• Abnormal operating conditions are monitored and notified within an agreed response and protocol with Defence to alert enhanced risk potential to vessels and aircraft operating in the NAXA.
• Seismic activities such as earthquakes are monitored and notified to the same protocols as above
• Defence (Australian Government) is indemnified for UXO events or disturbances through UXO.

Please read the further information provided in the General Comments.

Proponents should follow all procedures and restrictions relating to Notices to Mariners (NOTMAR) and Notice to Airmen (NOTAM). Further information is available from the Australian Hydrographic Service and Airservices Australia.

Please read the further information provided in the General Comments.

Certain areas in the 2021 Offshore Petroleum Acreage Release coincide with military restricted airspace. Non-Defence flying operations in these areas are required to be conducted in accordance with Notice to Airmen (NOTAM) restrictions.

Proponents are advised that the Minister for Defence has the authority, under the Defence Force Regulations 1952, to gazette any area of sea or airspace as a Defence Practice Area (DPA) for carrying out Defence operations or practices. Operations in these areas are required to be conducted in accordance with Notice to Mariners (NOTMAR) restrictions. A deed of access may be required by Defence when operating within a DPA.

There is potential for unexploded ordnance (UXO) on or in the sea floor in areas where Defence operates and especially in Air Weapons Range Areas. Therefore, proponents should be aware of the risks involved in conducting offshore exploration and development activities. The potential presence of UXO carries with it an associated risk of detonation. Defence takes no responsibility for:

• reporting the location and type of ordnance dropped in the areas of interest to the permit holders;
• identification of or removal of any UXO; or
• any loss or damage suffered or incurred by the company or any third party arising out of, or directly related to, UXO.

As a consequence, the Australian Government provides no guarantee or indemnity regarding the safety or whereabouts of UXO.

Contact Details - All notifications and liaison:
Offshore Petroleum,
Property Management Branch
E-mail: Offshore.Petroleum@defence.gov.au
Post: PO BOX 7925, CANBERRA BC, ACT 2600