Biscathorpe & WN Reserves10 Jul 2020 16:08
There have been a few comments here recently about Biscathorpe being the largest un-appraised UK onshore discovery. Rather than assuming that’s the case, I looked at what’s been published about both Bisc and WN and I thought I'd share my conclusions if you're interested. I’m not comparing them with Saltfleetby or Wytch Farm, although I worked on both for a while in the 1990’s. Even the onshore portion of WF’s original reserves went way beyond any of them. Regarding the actual figures, it’s worth pointing out that we only have oil and gas IN PLACE figures for WN to compare with Bisc’s prospective resources. I’m pretty sure that the term “resource” for Bisc means they are talking about potentially recoverable oil, so we aren’t yet comparing like with like. The numbers for Biscathorpe were given in Egdon’s 30 March ’20 RNS, and for WN they were in Rathlin’s 11 Nov ’19 RNS. Please note: I used the operators’ more optimistic upside cases for both discoveries.
For Biscathorpe the upside case prospective resource for the Westphalian reservoir was estimated by Egdon to be 6.69 mm bbls. In addition, the upside case Dinantian oil in place was estimated to be 36 mm bbl. I’ve no idea what the Dinantian oil recovery factor might be, but it probably won’t be very large as the Dinantian reservoir isn’t usually very porous. So let’s say that Biscathorpe is 6.7 mm bbl x UJO’s 30.0%. This comes to about 2.0 mm bbl net recoverable for UJO, plus whatever they can get out of the Dinantian.
Rathlin have published a WN upside case of 283.0 mm bbl of liquids, plus 265.9 Bcf of gas. Both are in place figures. What about the likely recovery factor, you may well ask. Unfortunately we don’t yet know, but we can probably make an educated guess. Let’s say that it might be 25% for the liquids and 75% for the gas. These may seem a bit low, but the oil and gas at WN are in a Zechstein carbonate (limestone and / or dolomite) reservoir, rather than in a sandstone as at Biscathorpe. So if you use 25% and 75% you get 70.75 mm bbl of recoverable liquids plus 199.4 Bcf of recoverable gas. The gas is equivalent to 33.24 mm barrels of oil equivalent (boe) which you get when you divide the 199.4 Bcf of potentially recoverable gas by 6,000. The oil and gas come to a total of 103.99 mm boe. Let’s call it 104 million. So, if you multiply that by UJO’s 16.665% it comes to 17.33 MM boe net for UJO.
So Biscathorpe is certainly very interesting at 2.0 mm bbl net recoverable for UJO, but it’s a lot less than the 17.33 MM boe net that UJO might have in WN. I certainly know which of them I would rather have. This is even more the case when you remember that we already have two apparently successful wells at WN, but we'll need a side-tracked well at Biscathorpe to prove up the resource. Any constructive thoughts on my amateur calculations will be appreciated. Thanks, GP