‘Flow testing’ has started at the Horse Hill oil site, nicknamed the ‘Gatwick gusher’.

The operator, Horse Hill Developments Ltd (HHDL), is testing the potential flow of oil from three layers: the Portland Sandstone, Upper Kimmeridge Limestone and Lower Kimmeridge Limestone, using the well they drilled in late 2014.

The process involves perforating the well at each layer to test whether oil flows. If it doesn’t flow, or if the flow is weak, they will use a range of methods to encourage fluids to flow up the wellbore – including using acids, injecting diesel into the rock, and ‘swabbing’ to reduce the pressure in the wellbore.

Section 1 of this document gives more details of the processes involved.

The testing will lead to a range of fluids being extracted, including unspent hydrochloric acid, brine, diesel and water as well as the crude oil they are looking for. The Environment Agency Permit includes details of how all these materials are to be disposed of.

The company anticipates flow testing will take about 30 days.

Protectors at work

Protectors are at the site, recording and logging what enters and leaves the site and trying to ensure that planning conditions, such as the traffic route, are respected.

Experience shows that the operators and contractors don’t always meet the conditions imposed on them, and the regulators are not quick to spot or stop breaches. The protectors are playing a constructive and useful role for the good of all of us.

In this interview with BBC Surrey, one of the protectors, Dave, talks about what they are doing.

If you’d like to help, please go to the site: Horse Hill, Horley, Surrey, RH6 OHN

Please be aware that Horse Hill is a narrow road with fast traffic at times. Please be conscious of road safety issues at all times.

What could happen at Horse Hill?

Once testing is complete, the well will be resealed while HHDL examines the results.

If the results from the Kimmeridge (shale) layers are promising, the next step is likely to be applications for more wells.

In an interview in Shale Gas International Magazine, Chris Hughes, Commercial Director at NuTech, a consultancy which supports the oil industry, said,

“The next stage with Horse Hill and other prospective fields in the UK shale play basins… will require the drilling of new wells in order to get maximum information back…

“The proving of the play, and the process of getting it into production, will require the drilling of more boreholes, moving further away from where we currently are in the licence… If we moved a mile away from the Horse Hill site and drilled another well, would the rock look exactly the same as we saw in Horse Hill or is it thinner or thicker in terms of the actual target plays? Is it tighter? Is it less hydrocarbon-rich?”

The industry’s dream is for a large-scale shale gas industry in the Weald. This is completely incompatible with the need for a quick transition away from fossil fuels to avoid runaway climate change, not to mention the serious local environmental threats it poses.

Find out more about fracking, ‘tight oil’ and what you can do: Come to a meeting in Oxted on Saturday 6 February.