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Delineation of the 16/1-12 oil discovery

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Oilfield Technology,



The well was initially classified as a wildcat well, but will now be reclassified as an appraisal well.

The well was drilled about six km south of the Edvard Grieg field in the central part of the North Sea, about three km south of the 16/1-12 discovery, 190 km west of Stavanger. The discovery was proven in basement rocks in 2009. After drilling the discovery well, the operator's resource estimate for the discovery was between three and eight million m3 of recoverable oil.

The objective of the well was to prove oil in thin sandstone layers in Upper Jurassic / Lower Cretaceous reservoir rocks, and in the underlying jointed, porous granitic basement rock.

Upper Jurassic/Lower Cretaceous reservoir rocks were not present. The well encountered an oil column of about 30 m in jointed, porous basement rock, with reservoir quality varying from poor to moderate, depending on the degree of fracturing. The oil/water contact was encountered at 1927 m below the sea surface. Collected pressure data shows communication with the 16/1-12 oil discovery, with approximately the same oil/water contact. Preliminary estimates place the size of the discovery between two and seven million Sm3 of recoverable oil. The licensees will assess the discovery with a view towards a tie-in to the Edvard Grieg field.

Extensive data acquisition and sampling have been carried out. Several formation tests (a DST, 5 mini-DSTs and a fracture/injection test) have been conducted. The production rate from DST was 42 m3 of oil per flow day through a 36/64 in. nozzle opening. The oil is under-saturated with a gas/oil ratio of 180 Sm3/Sm3. The formation tests (DST and mini-DST) mainly revealed moderate production and flow properties. Due to poor communication from the well to the porous, fractured basement rock, paraffin was injected in a minor fracturing and injection test, which yielded stable rates of 1000 m3 per day.

This is the second exploration well to be drilled in production licence 338 C, which was carved out of production licence 338 and awarded on 16 December 2014.

Well 16/1-25 S was drilled to respective vertical and measured depths of 2096 and 2185 m below the sea surface, and was terminated in granitic basement rock. The well will be permanently plugged and abandoned. Water depth at the site is 106 m.

The well was drilled by the Bredford Dolphin drilling facility.


Adapted from a press release by Louise Mulhall

Read the article online at: https://www.oilfieldtechnology.com/offshore-and-subsea/23122015/delineation-of-the-16-1-12-oil-discovery/

 

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