Seismic Surveys

Companies use seismic surveys to produce detailed images of local subsurface geology to determine the location and size of possible oil and gas reservoirs.

Explorers generate seismic (sound) waves and measure the time taken for the waves to travel from the source, reflect off subsurface features and be detected by receivers at the surface. This can help build an image of the subsurface.

Information in the seismic signal can also be used to indicate features such as rock density and the likely presence of fluids or gases.

  • Onshore operations usually use specialised trucks that carry a heavy plate that is vibrated to generate a seismic signal and a series of geophones laid out on the ground to record the returning sound waves for later analysis.

In offshore operations, a specialised vessel tows a collection of cables or “streamers”.  One set with seismic sources that use compressed air to produce acoustic energy and another set with hydrophones attached that  capture the returning sound waves for later analysis.

Onshore Seismic

Offshore Seismic

Environmental impact of seismic surveys

Seismic information is used to accurately plan locations for wells, reducing the need for further exploration and minimising environmental impact.

Onshore seismic has been used in sensitive locations without damaging buildings or the environment. Seismic surveys have even been conducted in sensitive urban environments, such as central Paris.

More than four decades of seismic surveying and numerous research projects have shown no evidence that offshore seismic surveys harm marine environments.

All Australian whale populations are increasing. For example, humpback whale populations are increasing at close to their biological maximum – more than 10 per cent a year. There is much more offshore oil and gas activity on Australia’s west coast than on its east coast, but the rates of increase are almost identical.

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