Australian regulator accepts Inpex’s plan for offshore survey

Australia’s National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) has accepted a plan for a 2D seismic survey in the Browse and Offshore Canning basins submitted by Japan’s Inpex.

NOPSEMA said that the plan for the proposed survey was submitted by Inpex’s subsidiary Inpex Browse E&P in late July 2019 and that it was accepted last Thursday, April 9.

In the plan, Inpex proposed to carry out a 2D seismic survey of exploration permits WA-532-P and WA-533-P in the Browse and Offshore Canning Basins as well as the acquisition of seismic data in production license WA-50-L, also in the Browse Basin.

At the closest point, the survey activity will be undertaken over 87 kilometres west of Broome and 42 kilometres offshore from the Dampier Peninsula in water depths between 50 and 600 meters.

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 around 30 meters and east of WA-533-P where the shallowest water depth is some 37 meters.

NOPSEMA stated that 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 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 towed behind the survey vessel.

During the survey, data will be acquired along a grid of broadly spaced, approximately orthogonal lines some three to six kilometres apart within the acquisition area.

Also, the survey is proposed to take place in waters that overlap with the Kimberley Australian Marine Park. The data acquisition will 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 November 1 to May 31 in either calendar year that the EP applies – 2020 or 2021.

NOPSEMA further stated that, due to the unforeseen circumstances of the COVID-19 pandemic, Inpex might not be able to complete the survey within the proposed timeframe. If required, Inpex will submit an EP revision to accommodate the altered schedule.

Two exploration permits in this plan, WA-532-P and WA-533-P, were awarded to Inpex in Australia’s 2016 and 2017 offshore petroleum exploration acreage releases, respectively.