When the BBC’s energy correspondence John Moylan, announced at 7.03 am on April 9 last year, that there could be 100 billion barrels of oil in the Weald Basin south of London there was uproar.
Not celebration. Not thanks. A kind of un-British scorn, cynicism and disbelief.
The BBC came up with the 100 billion barrel headline for the whole Weald by chatting with Steve Sanderson, and thumbnail sketched the ultimate potential of the Basin by using the Horse Hill numbers extending over a much bigger area.
Wells in the Weald have been producing oil for decades (you’ve probably put some of it in your car). But you’d be forgiven for not noticing – the nodding donkeys are so well hidden it’s like keyhole surgery.
What was different was that our advisers Nutech, the world’s leading reservoir analysts, had conducted state of the art drilling, electronic logging, and detailed analysis using techniques that had simply not been available a generation ago. Nutech are leaders in their field, and one of a handful of authorised companies to hold all the UK onshore drilling data for Her Majesty’s Government.
But Steve Sanderson (The CEO and now Chairman of UK Oil and Gas Investments) and I faced dilemma.
We had already been briefed by our technical advisors that there may indeed be over 100 billion barrels of oil in the Weald, so we couldn’t actually deny the news. To do so would have been to knowingly underplay our knowledge of what was coming and could be considered later on as misleading the market.
The media was unable to grasp this news, and in the interests of ‘balance’ insisted on dredging up unheard of technical experts who also had absolutely no knowledge of the new science to cast serious doubt on our news.
But as scientists, both Steve Sanderson and myself decided to stick to our guns. It was the right thing to do.
Now let’s analyse a very clear statement made by UKOG in media releases on April 9 and April 15.
“The oil in place hydrocarbon volumes estimated should not be considered as either contingent or prospective resources or reserves.”
Much hinged on whether this oil was recoverable. And we made that clear. At no point has UKOG ever said in any written or verbal communication that all the oil in place was recoverable. At best we gave estimates that between 3-15% might be recoverable, based on comparisons with major fields in the US and Siberia. As Nutech advised us:
“With the help of Nutech’s considerable global knowledge base and play library, we have identified that the Horse Hill Upper Jurassic rock sequence is analogous to known oil productive hybrid reservoir sections of the Bakken of the US Williston Basin, the Wolfcamp, Bone Springs, Clearfork, Spraberry, and Dean Formations in the US Permian Basin and the Bazhenov Formation of West Siberia. The US analogues have estimated recovery factors of between 3% and 15% of Oil in Place.”
But the media ignored all of this.
So, as scientists, what did we do? We got a second opinion.
We hired Schlumberger, in fact their global ‘A’ team, who work for national governments and the major oil companies. And Schlumberger came up with an even bigger number – 271.4 million barrels oil in place per square mile.
We then had to calculate the oil in place potential for the entire Weald basin.
First we assessed the potential of the 55 square miles of the Horse Hill Licences. Nutech came up with 9.245 billion barrels (P50) and Schlumberger came up with 10.993 billion barrels (mean oil in place). (Mean and P50 are almost the same thing).
The volumes were derived from a 3D geological and petrophysical static model analysing 85 UK Government (DECC/OGA) released wells and one proprietary well over the wider Weald Basin.
And finally Nutech calculated that the Weald Basin’s 1,261 square mile contained a gross best estimate P50 oil in place of 124 billion barrels of oil, numbers as defined by the Society of Petroleum Engineer’s Petroleum Resource Management System of resource reporting,
Yes, folks, 124 billion barrels. Even bigger than the 100 billion barrels announced by John Moylan on April 9 last year.
But still the press continued to doubt our findings despite the word of Nutech and Schlumberger.
Which brings us to this fantabulous week’s news. Can you actually get the oil out?
The first of threes zones to be flow tested at Horse Hill gushed with over 450 barrels of Britain’s finest 40 API oil, through a half inch choke. Over a two-day period with no drop off in rates.
We didn’t think the lower limestone oil would actually flow to surface. I thought the Portland sandstone zone might, but not the limestones. At best we would try to prove the concept that moveable oil existed there and not just a lump of damn bitumen.
50-100 barrels a day initial recovery by pumping from the tight limestones would have made me more than happy. 450 barrels a day gushing to surface without a pump probably hasn’t happened onshore UK for decades. Maybe the limestones are not as tight as we first thought? Remember, 60% of the world’s oil production does actually come from limestones.
This flow rate means that these limestones under Gatwick are highly fractured already. Good old mother nature did that without us knowing and she has already pre-fractured the ground allowing the oil to move freely to the well.
The job isn’t done yet. Our experts have another few weeks to wrap this up – roll on for the next two zones to test!
Will Horse Hill be commercial? In my opinion – heck yeah. 450 barrels of oil per day and two more zones still to test. I’ll take that any day.
The next step to transform this oil find in to a monster find is to drill a horizontal well and really up the oil output. Maybe even 18-20 horizontals from the same site. This is what the world is doing these days. Check it out on Google – It’s called Octopus drilling.
Is the Horse Hill site a 450 barrel a day, 5,000 barrel a day, or even 20,000 barrel a day producer? Only time will tell.
Then there are another 1,200 square miles to properly assess.
The UK Government needs to step up to the plate now to help companies like UKOG drill wells as quickly and cheaply as possible.
But one thing is now beyond any doubt – there really is recoverable oil in the Weald Basin. No one ever thought there would be but it’s there. And this is great news for the UK.