Prospex Eng Regulatory News (PXEN)

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

26 August 2025

Prospex Energy plc

("Prospex" or the "Company")

Viura Field Update

Initial flow tests confirm potential for high flow rates from the Viura-1B well

Prospex Energy plc (AIM: PXEN), the AIM quoted investing company focused on European gas and power projects, wishes to inform shareholders that it has been advised by the Operator of the Viura field, HEYCO Energia Iberia S.L. ("HEI" or the "Operator"), that the recompletion workover of the Viura‑1B well, in the Viura gas field in northern Spain, was achieved without the need for a coil tubing unit, resulting in significant cost savings.

In addition a short flow test carried out at the well confirmed that the well is operating successfully after the workover, demonstrating strong deliverability from both the well and the Viura reservoir.

During the short flow test the following rates were achieved:

· 100,000 scm/d (3.5 MMscfd) at a 10% choke setting.

· 200,000 scm/d (7.1 MMscfd) at a 25% choke setting.

· Both flow tests produced dry gas with no water from the topmost section of the main Utrillas‑A reservoir, fulfilling one of the main objectives of the workover intervention.

As advised in the RNS of 31 July 2025, the Operator successfully replaced the tubing in the Viura-1B well but now advises of a delay to the reinstatement of production from the Viura-1B well due to technical and equipment issues, both sourcing and implementation, which are delaying the resumption of production and which they are working urgently to address.

The Company is waiting for further information from the Operator, including the likely timing of the resumption of production, which is currently unknown, and will keep shareholders informed of the Operator's progress as appropriate.

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

Mark Routh, Prospex's CEO, commented:

"Initial production tests at the Viura-1B well have confirmed what we have always known and the reason we invested in Viura - the potential to deliver first class flow rates from this large onshore gas field. However, interventions in deep, deviated wells such as Viura-1B are technically complex and take time to execute and are not without challenges especially since the necessary equipment may not be immediately available in region. However, we are confident that the Operator is working urgently to bring the Viura field safely back into continuous production from the Viura-1B well and I look forward to updating shareholders on its progress in due course."

Background

The Viura-1B well is currently not in production and 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 and operations are ongoing to re-instate continuous production.

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. This 90 Bcf most likely recoverable reserve number is not an independently derived 2P reserve number but is based upon the operator's most recent tests and studies with best estimates of gas in place and recovery factors. 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.

Qualified Person Signoff

In accordance with the AIM note for Mining and Oil and Gas Companies, the Company discloses that Mark Routh, the CEO and a director of Prospex Energy plc has reviewed the technical information contained herein. Mark Routh has an MSc in Petroleum Engineering and has been a member of the Society of Petroleum Engineers since 1985. He has more than 40 years of operating experience in the upstream oil and gas industry. Mark Routh consents to the inclusion of the information in the form and context in which it appears.

Glossary:

Bcf Billion standard cubic feet

Bcm Billion standard cubic metres

Boe Barrels of Oil Equivalent (where 1 MMBoe = 5.8 Bcf)

MMBoe Million Barrels of Oil Equivalent

mcf Thousand standard cubic feet

MMscf Million standard cubic feet

MMscfd Million standard cubic feet per day

MMscm Million standard cubic metres

MMscm/d Million standard cubic metres per day

MWh Mega Watt hour

scm Standard cubic metres

scm/d Standard cubic metres per day

TTF The 'Title Transfer Facility' - a virtual trading point for natural gas in the Netherlands.