Union Jack Oil PLC has published findings from an expert assessment of the reservoirs at the Wressle field, onshore UK, that indicate the potential for a significant upgrade to resources.
The company noted that consultant Gaffney, Cline & Associates saw potential for an extra 10.12mln barrels of oil-initially-in-place and 2.43mln barrels of potentially recoverable resources, based on its analysis of ‘speculative deeper oil-water contact’ for the Ashover Grit reservoir.
Wressle has been something of a revelation for Union Jack and its partners since it was brought back online in 2021, producing way above expectations in the past year. In August, Union Jack reported that the field had generated over US$9mln in net revenue since production recommenced amidst strong crude oil pricing.
Whilst it is proving lucrative for the clutch of small-cap oil and gas firms that developed Wressle, the field retains quite modest reserves - presently it has some 670,000 barrels of proved and probable (2P) reserves across its producing Ashover Grit and Wingfield Flags oil reservoirs.
If the potential resource upside indicated by GaffneyCline can be confirmed in the future, it would substantially extend the life of the field.
"The GaffneyCline Report reflects a serious technical effort over a prolonged period and its content is highly encouraging for the future of the Wressle development,” said David Bramhill, Union Jack executive chair in a statement.
"GaffneyCline's findings, observations and technical work in respect of the potential upside in respect of the Ashover Grit reservoir have gone a long way in answering our questions regarding future potential upside and prolonged productivity," he added.
The GaffneyCline report provided an ‘illustrative production scenario’ which showed Wressle operated under a constrained plateau production rate of 800 barrels of oil per day for approximately five years.
Additionally, the consultant indicated further hydrocarbon potential of the Santon Sandstone zone at Wressle adding to the Penistone Flags zone which has yet to be developed in the field – GaffneyCline attributed some 1.56mln barrels of gross contingent oil resources for Penistone and 60,000 barrels for Santon.
Union Jack noted that Wressle’s current field development plan anticipates continuing production from the Ashover Grit and Wingfield Flags, alongside the development of the Penistone Flags resource through the drilling of two or three additional wells.
It is noted that the illustrative production scenario, in which Wressle produces 800 bopd (barrels of oil per day) for five years, is based on the development plan and includes volumes from the Penistone.
Moreover, it comes with the caveat that there remains ‘significant uncertainty on the initial flow rate that will be obtained from the Penistone Flags reservoir’ and that the ‘illustrative production scenario does not necessarily reflect the operator's or the other partner's views’.
David Bramhill, meanwhile, said: "The Illustrative Production Profile indicates robust and material productivity for at least five years and beyond. Should the Deeper Oil-Water Contact potential of the Ashover Grit reservoir become proven, the incremental value of Wressle as a development would be transformational for the Wressle partners."
"Union Jack thanks GaffneyCline for their diligence in compiling this excellent, informative, and value-adding report," the Union Jack executive chair concluded.