1. Aviat: a Lower Pleistocene shallow gas hazard developed as a fuel gas supply for the Forties Field
- Author
-
Phil Rose, Brice R. Rea, Stuart G. Archer, Matteo Spagnolo, Grant Byerley, John Cater, and Owen Vaughan
- Subjects
Rock flour ,Horizon (geology) ,geography ,geography.geographical_feature_category ,Early Pleistocene ,Pleistocene ,020209 energy ,Front (oceanography) ,Energy Engineering and Power Technology ,Geology ,02 engineering and technology ,010502 geochemistry & geophysics ,01 natural sciences ,Paleontology ,Fuel Technology ,Fuel gas ,Geochemistry and Petrology ,Outwash plain ,0202 electrical engineering, electronic engineering, information engineering ,Ice sheet ,Geomorphology ,0105 earth and related environmental sciences - Abstract
The search for a gas source near to Apache9s Forties Field in the North Sea was motivated by the prediction of an ever-increasing fuel gas shortfall as the field oil rate declined. The Central North Sea is well known for a large number of shallow gas hazards in the Pleistocene section that have historically caused blowouts during exploration and development. These gas accumulations typically show up as small bright anomalies on seismic data. In 2009, a large gas anomaly was identified to the east of Forties, and the Aviat Field was discovered in 2010 when exploration well 22/7-5 was drilled. The Aviat Field reservoir is interpreted to be a subaqueous glacial outwash fan, consisting of silt-grade, rock flour material, deposited in front of a grounded ice sheet in some 400 m of water. Aviat sits on an overcompacted silty mudstone that was deformed by this ice sheet – the Crenulate Marker. The distribution of this horizon implies that the Early Pleistocene ice sheet covered at least the northern half of the UK North Sea. Although the Aviat reservoir is thin (2–9 m thick), the well tests, pressure profiles and geophysical response demonstrate that the reservoir is well connected, extensive (over 35 km 2 ) with high deliverability (up to 18 MMscfd achieved). Aviat was sanctioned in 2014 for development as a fuel gas supply for the Forties Field, with first gas achieved in July 2016.
- Published
- 2017