Total Strikes It Rich in the North Sea

Total’s phenomenal long run of luck in the North Sea continued with the discovery, announced just this month, of a new gas condensate in the Alwyn Area of the Northern North Sea. The field, now named Islay, lies in block 3/15 of the UK sector, some 440 kilometers north-east of Aberdeen in a water depth of 120 meters.

What has made the latest discovery possible is the huge strides made in seismic technology.
“The technology has moved on fantastically since the days of two-dimensional (2D) line-based seismic reports,” says Paul Mason, new business manager at Total E&P UK. No-one at that time thought that 3D seismic would be possible because of the huge computing power it would require to drive it.” However, 3D has now come along and Total has been able to revisit its massive data sets and look at old and new seismic material with eyes that could give it a much higher degree of resoution and detail.

“We can now see structures at 4,000 meters beneath the surface. Jura, the field we announced first gas from on 20 May this year, is located at around 100 meters from the surface and so we found it rather more readily. However, when we applied the 3D technology, our geologists could see a nice big structure, like a stack of dominoes, which is exactly what you are looking for, and our well on Islay proved positive at 4,000 meters” .

Islay will be another high-temperature, high-pressure field (HTHP) and the initial worry for Total was whether it would be able to retain its reservoir properties, with the right porosity, despite the high pressures involved. “Basically, at that sort of depth, you get a lot of pressure on the rock and, in the race for space, with cements and pressure trying to close up the porosity, you can lose out,” Mason says. “In fact, the test well answered this question positively, showing that the reservoir was able to maintain its good characteristics at that depth.”

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