RE: possibilities.....?9 Feb 2019 09:28
Dickupham
I’ve been wondering why a company the size of Shell would want to explore relatively small prospects in P2252 unless, of course, it fitted into a much bigger picture which could be revealed by broadband 3D seismic.
For 80 years geologists have been trying to develop gas in Zechstein reef carbonates – mainly around the Cleveland Anticline and its offshore extension in Q41, The reef trend crosses P2252 where 41/10-1 found fractured Zechstein with gas and almost blew out. The trend continues across the northern edge of Q42 with the Ossian and associated reef prospects. It is effectively a new play fairway neglected by North Sea explorers until now.
Exploration in North Yorkshire started in 1937, targeting Triassic and Permian reservoirs – same as P2252. D’Arcy (BP) drilled Eskdale-2, the first gas discovery in the Zechstein carbonates in the UK. Since then ~ 100exploration/appraisal wells have been drilled in the basin with exploration success relatively high. Out of the 25 pure exploration wells in the region, 13 have found hydrocarbon accumulations (flowed gas) and eight of the discoveries have been developed to date with some e.g. Lockton still producing,. The primary reservoir is the Permian-aged Zechstein carbonate sequence and, more specifically, the Z2 cycle, which is a tight carbonate reservoir overprinted by a high permeability fracture system. Despite considerable investment and effort over the years, the historical development story of these fields has been very much one of technical and investment failure. Amoco did try a near-horizontal well offshore Cleveland which flowed >20 mmscfd but gave up..
Meanwhile, onshore Netherlands, NAM (Shell) has developed several gas fields in the Coevorden area in Netherlands, which are more or less same Zechstein play, by using underbalanced horizontal drilling. So it seems a combination of broadband 3D seismic and horizontal drilling might open a new, multi-tcf play fairway. This is all described in CNRL’s 2016 CPR. I’d be interested to know is CNRL and Shell have also agreed to co-operate in forthcoming licencing rounds or farm ins to chase this play.
Now that would be really exciting if CNRL were involved in a huge new gas play 50 years after the first UKCS discoveries.