Official oil production at the Horse Hill site in Surrey has fallen to its lowest level so far, according to monthly data released today.
The site, operated by a subsidiary of UK Oil & Gas plc (UKOG), is the UK’s newest onshore oil production site. It was nicknamed the Gatwick Gusher four years ago when estimates claimed it could supply 25% of UK needs.
But data published by the Oil & Gas Authority showed that production has fallen by nearly two thirds since the first full month in April 2020.
The figures for September 2020, the most recent available, report that Horse Hill produced 376 tonnes of oil, or 93.30 barrels of oil per day (bopd).
This was down 30% on the August level (536 tonnes or 128.44 bopd). Horse Hill represents 0.6% of UK onshore oil production.
The September total is far short of the results of tests in 2016, which claimed aggregate flow of 1,688 barrels per day.
The data also reveals that Horse Hill has fallen to eighth place in the list of the UK’s largest onshore producing fields. In April, it was in fourth place, behind Wytch Farm, Welton and Singleton. It dropped to fifth in May, sixth in June and seventh in July and August.
These are the final monthly production figures for Horse Hill before work began to improve oil flows on 1 October 2020.
UK Oil & Gas announced it was reperforating the full Portland oil producing section of the Horse Hill-1 well, inserting a simplified production tubing string and setting the downhole pump deeper to increase pumping efficiency.
Water and gas
The total amount of formation water produced at Horse Hill fell in September from 226 tonnes in August to 180 tonnes in September. But the ratio of oil to water was 2.1, down from 2.4 in August.
Water production is usually lowest when a field begins production and increases as fields mature. Horse Hill has planning permission for a water reinjection well but has not yet drilled the well. The company has said water reinjection would cut the cost of disposing of waste water and could help to maintain reservoir pressure.
Production of waste gas at Horse Hill also fell in September to 15.5 tonnes, down from 20.75 in August. The ratio of gas to oil was down slightly. Gas at Horse Hill is currently flared.
Total UK onshore oil in September fell for a second consecutive month to 57,800 tonnes, from a 2020 high in January of 63,287 tonnes.
The biggest producing field, Wytch Farm, in Dorset, which supplies 84% of UK onshore oil, fell 4% in September to 48,558 tonnes. But production at other fields at Welton, Stockbridge, Humbly Grove, Horndean and Glentworth all increased in September.
Onshore production in September was 1.7% of total UK production.