Prospex Energy PLC - Production Restarts at Viura Field

Prospex Energy plc / Index: AIM / Epic: PXEN / Sector: Oil and Gas

20 October 2025

Prospex Energy plc

("Prospex" or the "Company")

Production Restarts at Viura Field

Prospex Energy plc (AIM: PXEN), the AIM quoted investing company focused on European gas and power projects, is very pleased to inform shareholders that gas production has resumed from the Viura‑1B well in the Viura gas field in northern Spain.  The operator of the Viura field, HEYCO Energía Iberia S.L. ("HEI" or the "Operator") brought the well back into production on Friday 17 October 2025.  The well was started with a reduced choke setting and ramped up in stages to reach 120,000 cubic metres per day with 7 cubic metres per day of water by Sunday 20 October 2025.  Start-up is ongoing with the target of reaching 180,000 cubic metres per day plateau production this week.

Prospex owns 7.24% of the Viura field through its ownership of 7.5% of HEI.  Prospex is accruing 14.47% of the production income from the Viura gas field until payback of its initial capital investment (expected to be ≈£8 million) plus the accrued 10% p.a. interest thereon.

During the well tests performed in August with wireline downhole pressure and flowrate monitoring, a failure in the pressure control equipment required the safe and controlled cutting of the associated cable while still inside the well.  Operations to retrieve equipment from the well, using equipment mobilised from Aberdeen UK have been completed safely and without incident and the well is now back in  production.

Mark Routh, Prospex's CEO, commented:

"The resumption of production from the Viura field is very welcome news.  The operator safely removed the severed wireline cable from the well with no injuries or safety incidents, enabling recommencement of gas production from the well.  Prospex' share of production from Viura represents the largest contribution to the Company's portfolio of net production with the associated reinstatement of cashflow being particularly welcome news."

Background

The Viura-1B well was shut in during April-2025 owing to the detection of a leak in the completion tubing which required a rig intervention to reinstate production.  A rig was mobilised and the production tubing was replaced in July.  Operations to re-instate continuous production in August encountered an unforeseen issue whilst preparing to monitor the pressures and flow rates from the well using specialised downhole wireline logging tools.  To ensure well and site safety the wireline cable had to be cut and left in the well when equipment failure resulted in a potential well control issue.

Total natural gas produced from the Viura-1B well from start-up in December 2024 to the end of Q1-2025 was 30.2 MMscm = 1.1 Bcf (which is ≈ 4.4 MMscm = 154 MMscf net to Prospex).

The Viura acquisition significantly increased Prospex's estimated reserves by 6.5 Bcf (0.18 Bcm) net to Prospex.  The Operator's best estimate of recoverable gross remaining reserves at the Viura field is 90 Bcf (2.5 Bcm) and is expected to increase upon further evaluation of the newly drilled horizons.  Once the newly reprocessed 3D seismic is reinterpreted it is the Operator's intention to update the reservoir model, gas in place and the reserves for the Viura field.

The information contained within this announcement is deemed by the Company to constitute inside information as stipulated under the Market Abuse Regulation (EU) No. 596/2014 as it forms part of United Kingdom domestic law by virtue of the European Union (Withdrawal) Act 2018, as amended by virtue of the Market Abuse (Amendment) (EU Exit) Regulations 2019.

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For further information visit www.prospex.energy or contact the following:

Notes

Prospex Energy PLC is an AIM quoted investment company focussed on high impact onshore and shallow offshore European opportunities with short timelines to production.  The Company's strategy is to acquire undervalued projects with multiple, tangible value trigger points that can be realised within 12 months of acquisition and then applying low-cost re-evaluation techniques to identify and de-risk prospects.  The Company will rapidly scale up gas production in the short term to generate internal revenues that can then be deployed to develop the asset base and increase production further.