Hampshire, Portsmouth and Southampton
Minerals and Waste
5.11 The presence of oil and gas in commercial quantities depends upon the existence of the right geological circumstances for it to accumulate. Oil and gas 'reservoirs' occur in Hampshire at depths of up to 2,000 metres within limestones and sandstones of Triassic and Jurassic age. Geophysical, particularly seismic, surveys are carried out in order to locate possible reservoir structures, prior to exploratory drilling. Survey work has been carried out across large parts of Hampshire and many exploratory boreholes have now been drilled. However, oil and gas has only been discovered in commercial quantities in three locations, at Humbly Grove (near Alton), Stockbridge and Horndean. These three oilfields are now in production.
5.12 The Humbly Grove oilfield has eight production well sites collecting oil and gas from three separate reservoirs. The oil is transported from a gathering station by underground pipeline to a rail connected export terminal at Alton. The gas is used at the site for the generation of electricity. The Stockbridge and Horndean oilfields are much smaller and oil is collected from the well sites by road tanker and sent to the Alton terminal.