2D Seismic Survey WA-532-P, WA-533-P and WA-50-L
|Activity type||Seismic survey|
|Submitted by||INPEX Browse E&P Pty Ltd|
|Submission date||30 July, 2019|
|Status||Under assessment (with titleholder)|
|Link to previously accepted EP|
INPEX is proposing to undertake a two-dimensional (2D) seismic survey of Exploration Permits WA-532-P and WA-533-P in the Browse and Offshore Canning Basins. The 2D seismic survey will also include the acquisition of seismic data in Production Licence WA-50-L, also within the Browse Basin
The permit areas are located wholly within Commonwealth waters. At the closest point, the survey activity will be undertaken over 87 km west of Broome and 42 km offshore from the Dampier Peninsula. Seismic data acquisition will mainly take place in water depths between approximately 50 m and 600 m below mean sea level. However, some seismic data acquisition may occur in shallower areas located at Lynher Bank in the southern part of WA-532-P where the shallowest water depth is approximately 30 m, and east of WA-533-P where the shallowest water depth is approximately 37 m.=
The survey will be undertaken by a seismic survey vessel towing an underwater seismic source and a single streamer behind it. The seismic source will be towed behind the vessel at water depths of approximately 5-10 m. The seismic source will use compressed air to emit regular pulses of sound which reflect off the seabed and underlying geological rock formations and structure boundary. The reflected sound will be received by the streamer, which may be up to 6-10 km in length and will be towed behind the survey vessel at a water depth of approximately 5-15 m.
During the survey, the seismic survey vessel will sail along the pre-determined acquisition lines at a speed of approximately 4.5 knots (approximately 8 km/hr), discharging the seismic source approximately every 18.75 m (approximately every 8 seconds). Data will be acquired along a grid of broadly-spaced, approximately orthogonal lines (spaced approximately three to six kilometres apart) within the ‘Acquisition Area’ with associated vessel movements and support activities undertaken within the ‘Operational Area’.
The 2D seismic survey is proposed to take place in waters that overlap with the Kimberley Australian Marine Park. Consistent with the management arrangements prescribed in the Australian Government’s North-west Marine Parks Network Management Plan, the seismic data acquisition is proposed to take place in the Multiple Use Zone of the marine park. Operation of the seismic source will not occur in areas that are designated as a National Park Zone and Habitat Protection Zone of the marine park, although survey vessels may transit through these zones.
Based on the environmental risk assessments presented in the Environment Plan (EP), an acceptable window of opportunity was determined to be from 1 November to 31 May in either calendar year that the EP applies (2020 or 2021). Therefore, no seismic acquisition will occur during the period 1 June to 31 October in either year, to prevent any potential disturbance during the time of year when humpback whales aggregate in waters off the Kimberley coast.
INPEX consulted widely to develop an EP that details the processes involved in assessing the potential risks and impacts to the different receptors within the receiving environment and stakeholders that utilise the area. Included within this assessment are the proposed control measures and operational procedures that will be implemented in order to reduce the potential environmental impacts from the planned operational activities, and risks from unplanned events, to As Low As Reasonably Practicable and to Acceptable Levels.
INPEX is concurrently engaging with stakeholder representatives develop a claim process, for financial loss, if impact is attributed to this Activity.