ConocoPhillips is proposing to acquire three dimensional marine seismic data in an area of the Timor Sea, 300 km north of Darwin, Northern Territory.
 
Data will be acquired in Retention Lease Permits NT/RL5 and NT/RL6, known as the Barossa and Caldita fields, as well as some adjacent open acreage. The permit areas are in Commonwealth waters of the Bonaparte Basin. The data acquisition area is approximately 3,186 km2 within a larger operational area of 10,448 km2 which allows for most contingencies and for line run‐outs, line turns and line run‐ins. Water depths in the operational area range from approximately 75 m to 550 m.
 
Data will be collected using a purpose‐built seismic vessel towing dual acoustic source arrays and hydrophone cables (streamers). Acoustic emissions from the source arrays are detected by the hydrophone cables and recorded on the vessel. The vessel will tow 16 hydrophone cables, at a length of 6 km at depths of 20 m. The distance between the hydrophone cables will be an average 50 m. The total volume of the seismic source proposed for the survey is 4,130 cubic inches. This source size was selected to meet several criteria regarding operational stability, predictable behaviour and fit‐for‐purpose subsurface seismic imaging (vertical focus). The vessel will collect data along a series of pre‐determined sail lines at an average speed of 8‐9 km/hour. There are a total of 109 sail lines in the acquisition area, with a total length of 8,384 km and a separation distance of 400 m. The seismic source will be discharged at a nominal interval of 8 seconds along each sail line. The seismic source will produce peak at source (i.e. within a few metres of the airgun array) sound pulses of zero‐to‐peak sound pressure level of approximately 246 dB re 1 μPa @ 1 m, and sound exposure levels of approximately 223 dB re 1 μPa2.s @ 1 m across a frequency range of 10 Hz to 2 kHz. The seismic vessel will be accompanied by a support vessel and a chase vessel that ensures other vessels do not come in close proximity. The survey is planned to occur from 1 July to 30 September 2016. Commencement of the survey is subject to gaining the required regulatory approvals and availability of the seismic vessel for conducting the survey.
 
NOPSEMA Note:  NOPSEMA is assessing this EP solely for petroleum activities that are planned to occur within the administrative boundaries of the Commonwealth of Australia.