Shale found at the Horse Hill well in Surrey is a world class source rock for oil, according to the new chief executive of the UK Oil and Gas, the company behind the operation.
Steve Sanderson told a group of investors last night the shale was “super rich” in organic material and was at least as good, if not better, than that in the North Sea.
He said the findings challenged current thinking about oil and gas development across southern England and meant that last year’s British Geological Survey’s report on shale in the Weald needed to be updated.
Mr Sanderson said the Horse Hill well near Horley had discovered a depth of 1,500ft of Kimmeridge Clay. About 1,300ft of this was organic-rich shale.
“The big thing that we find from Horse Hill is the fact that the Kimmeridge Clay is not just fully mature but it’s actually within the peak oil generation window. So you’ve got significant generation of oil, at least in the Horse Hill area”.
Mr Sanderson said people thought the Kimmeridge Clay in the Weald was not as rich as the Wessex basin and not quite as rich as in the North Sea.
“Super rich, world class”
He said 2% total organic carbon (TOC) made a good oil source rock. “What we have seen in Horse Hill is that it is extremely rich”.
For intervals that had been analysed, the company saw the TOC as “being over 5-9.5%”, he added.
“That is super rich, that is world class, that is as good, if not better, than stuff in the North Sea”.
Investors heard that the BGS had said Kimmeridge Clay in the Weald was either immature for oil or only slightly within the oil window. Its report had said there was not much potential or source rock at Horse Hill.
“That model needs to be changed”, Mr Sanderson said. UKOG regarded the Kimmeridge Clay at Horse Hill as a Type 1 source rock, like those found in west Africa and Brazil. It was not regarded as a Type 2 source rock, like that found in the North Sea, which the BGS had used as the basis of its modelling in the Weald report. Type 1 source rocks can generate oil earlier and shallower and at lower temperatures, Mr Sanderson said.
The Horse Hill well found two layers of limestone, each about 100ft thick, encased in the organically-rich, thermally-mature source rocks. Mr Sanderson said the results revealed oil shows in the upper limestone.
The meeting heard that the Horse Hill results were similar to those from Cuadrilla’s well at Balcombe, about 15km further south in West Sussex. Mr Sanderson said there was evidence from both wells that the Kimmeridge had generated the oil found in layers of limestone. “Everyone said it [oil from shale] had been generated locally and it’s only just Balcombe. Well I think we have some evidence to show that’s not the case”.
UKOG’s company chairman, David Lenigas, told the meeting: “All those people who said that Horse Hill was a disaster, I’d like to say go screw you [holds up 2nd finger of right hand], right, and you can put that on record, because you were wrong”.
Conventional or unconventional?
The company frequently said Horse Hill was a conventional well and yesterday Steve Sanderson said it would not be fracked. He said the oil could be extracted from the limestone, which was naturally fractured.
But there were hints in the presentation that UKOG is interested in some unconventional operations. Steve Sanderson said: “Big bits of interest for the future for us in UKOG and for the rest of the UK is really in the centre of the [Weald] basin in hybrid plays, which are a combination of conventional and unconventional and also maybe unconventional but we’re not really planning to talk about that at the moment. That’s kind of in the future”.
He described the operation at Horse Hill as a hybrid. The company has contracted the US company, NUTECH, to analyse the results of the well. Mr Sanderson described NUTECH as “the world leader in looking at things from an unconventional perspective, ie looking at shale”.
He added that “a hell of a lot more log analysis” was needed to evaluate Horse Hill. “There’s a hell of a lot more steps you need to go through on the technical analysis that you would need to do for a conventional”.
Isle of Wight and Markwell’s Wood
The presentation heard that UKOG has an offshore licences around the Isle of Wight. It also bid for a licence on the island itself in the government’s 14th onshore round.
Mr Lenigas, said: “We see the Kimmeridge in the Isle of Wight as good, if not better than Horse Hill.”
He said because of the low oil price “this is the time to go shopping”. He said UKOG had just bought Markwell’s Wood, another well in West Sussex. “We love UK and we’re buying and we’ve got cash”, he said.