Rockhopper completes seismic and mapping surveys

Marzo de 2006

 

Rockhopper Exploration which holds hydrocarbons exploration and production licences offshore the Falkland Islands completed in mid February seismic and electro magnetic imaging surveys over their acreage.

According to the latest release from the Falklands Department of Mineral Resources, Geophysical Surveys Incorporated, GSI undertook the collection of 900 kilometres of 2D seismic survey in the North Falklands Basin acreage of Rockhopper.


The vessel GSI Pacific managed to conclude the job last February 17 just before seismic surveying restrictions become effective in the north basin because of the Illex squid season.

Rockhopper Exploration also contracted Offshore Hydrocarbon Mapping, OHM, from Bremen, to undertake a Controlled Source Electro Magnetic Imaging (CSEMI), the first time such a survey has been undertaken in the Designated Area.
 

The survey was done by MV Aurelia

The CSEMI begins with a grid of sensors anchored to the sea bed and then an electromagnetic source is towed behind the surveying vessel. The source transmits an electromagnetic field into the earth, which is modified by the presence of subsurface resistive layers. These changes in the field are measured and the resulting data is processed to provide information on the resistive structures of the subsurface.

Because hydrocarbon accumulations are generally very resistive, this method can indicate the presence of oil and gas in water depths of as little as 50 metres in certain circumstances, and can detect and map the edges of such accumulations.

This has the advantage of reducing the risk of drilling non-commercial exploration wells and the number of wells needed for appraisal drilling, thereby creating considerable savings for oil explorers. Once the survey is completed the sensors are recovered from the sea bed and the ship moves to the next target.

The survey started on 9 January and was completed on 13 February.

For OHM it was also a new experience since the company has undertaken a number of surveys in deep waters but this one was in shallow water. OHM formally launched its shallow water CSEM service in November.
 

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