Oil under Portsdown
There is no oil under Portsdown Hill - or at least, that was the conclusion from the 1936 exploratory drilling by the D'Arcy Exploration company.
The following section describes
Oil Exploration at Portsdown
Past
On March 30th, 1936, a rig began to drill into the chalk at the base of the southside of the hill.
The hole was 2 foot wide and ultimately reached 6,500 foot deep (~0.6 meters wide, ~2000 metres deep).
Detailed research had suggested oil would be found in good quantities, and with war looming, it was hoped that Portsdown would provide a vital supply.
However, no visible black oil was found, although there were reports of a strong petroleum smell around the rig. A second attempt in the 1950's, when a second bore was drilled close to that same site, was equally unsuccessful.
In 1985 exploratory drilling in Southwick, on the north side, east end of Portsdown Hill, found no oil, and in 1987, drilling near Wickham, on the north side, west end of Portsdown again found nothing.
Present
The nearest productive oil to Portsdown is Horndean, about 8km to the north of Portsdown. Oil was discovered here towards the end of 1982, and began producing in September 1988. Its peak production is 22,000 tonnes per year.
Future?
The licence for oil exploration under Portsdown is currently held by Northern Petroleum PC. They believe there is a good case for re-exploring the sites around Portsdown: The first had been drilled "when the oil industry was in its infancy", and the second (at Wickham, in 1987) was drilled across a fault.
"Work is now being undertaken to further study the well logs and reprocess and re-interpret the seismic data in order to better understand the structural context of the wells and determine the most favourable location for a new well and assess the risks."[1]
While they believe oil is trapped in the prospect, they don't think it is there in commercial quantities. However, they do plan additional analysis in the area, to consider if it would be worth while to drill an additional appraisal well.
The Geological case for Oil under Portsdown
The Portdsdown area is SSW and updip of the Horndean oil field which is known to be filled with oil to spill point. We are projecting one other structure between Horndean and Potwell and, with the large quantity of oil generated out of the Weald Basin, any trap updip of Horndean becomes interesting.For any comments, suggestions or contributions, please e-mail me at: portsdown@bbm.me.uk
References
[1] Northern Petroleum PLC, Report 2001, UK Onshore:
http://www.northpet.com/report2001/report-ops-uk.html#PEDL099