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The CNOOC operated Glengorm gas condensate discovery announced today (Tuesday, 29th January 2019) is the biggest in the UKCS since 2008, reported by partner Total to be 250 mmboe of recoverable resources.  The discovery is significant for the UKCS and will reignite interest in the HPHT play. 
Alyson Harding, Technical Manager for North West Europe E&P at Westwood Global Energy, explains:

“Today operator CNOOC (formerly Nexen CNOOC) with 50% equity and Joint Venture (JV) partners Total (25%) and Edison (25%) have announced the results of their 22/21c-13 Glengorm well in 28th Round licence P2215.  The well encountered gas condensate in a 37.6m (123ft) net pay in a Jurassic reservoir with excellent reservoir properties, understood to be Upper Jurassic Heather Formation turbidites.

“Total has reported recoverable resources of 250 mmboe, which makes this the largest discovery on the UKCS since the 22/25a-9Z Culzean discovery made in 2008 with resources of 250 mmboe.  The only larger discoveries made in the last 20 years”, added Alyson Harding, “is the 1.1 billion-barrel 20/6-3 Buzzard field in the North Sea discovered in 2001 and the 292 mmboe 213/27-1Z Rosebank discovery in 2004, West of Shetlands.  So, this is a significant discovery for the UKCS.

“The result is at the extreme upper end of the pre-drill expectations which were estimated by partner Maersk in 2016 (before the Total takeover) to have a P90-P50-P10 pre-drill range of 11 – 59 – 195 mmboe for the Heather and Fulmar targets combined.  The Upper Jurassic Heather formation is highly variable in terms of both thickness and quality across the Central North Sea.  There are few commercial Heather accumulations within the CNS to date.

“Clearly, the discovery well has provided a pleasant surprise to the JV.  The JV will now appraise the structure which is compartmentalised like many HPHT fields in the Central Graben which will confirm the potentially developable resources.  There are follow up Upper Jurassic prospects mapped on the block to test.

“Glengorm lies 24 km northwest of Elgin-Franklin and 44 km west of Culzean, so we believe that there could be long subsea tie-backs to either installation.  Total holds 25% equity in Glengorm and operates both installations.  The timing of a development could align with capacity availability at Culzean, due to start production this year, which Westwood estimate to come off plateau around 2023.

“The other option would be a subsea tie-back to the BP-operated ETAP infrastructure, which lies 35 km NW of Glengorm.  CNOOC may prefer a standalone development.  If the discovery be confirmed as c. 250 mmboe following appraisal, this should be an economic option given current development costs.

“Edison E&P, a subsidiary of EDF, and a 25% partner in Glengorm, is currently up for sale, including assets in Italy, Egypt, Croatia, Greece, Norway, Denmark as well as the UK. EDF made a strategic decision to pull out of upstream oil and gas, as have many other utility companies recently, to pursue a low carbon policy.  The Glengorm discovery will therefore not have any impact on Edison in the UK, other than increasing the value of the company for a potential buyer.

“Glengorm shows that high impact discoveries are possible in the UK North Sea, but not necessarily by drilling prospects deemed high impact pre-drill.  The unexpected upside can happen.”