Vancouver, British Columbia--(Newsfile Corp. - August 11, 2026) - Dune Oil Corp. (CSE: DUNE) (OTCQB: TRLEF) (FSE: Z62) ("Dune" or the "Company") is pleased to advance its oil block discovery in the Gabar petroleum province of southeastern Türkiye, "the Gabar Block", which an independent evaluation under COGEH and 51-101 standards assigned a 2C contingent resource of 27.6 MMbbl. A tender for a 40-kilometre 2D seismic acquisition program is now underway ahead of further drilling, which is expected to be finalized by September 2026, to pave the way for additional drilling locations.

The Gabar Block covers approximately 450 km² of block M47 areas, c,d, where Dune has a right to earn up to a 29% working interest dated January 9, 2026, as amended. The Gabar Block is located approximately 11 km southeast of the Şehit Aybüke Yalçın field, Türkiye's largest onshore light oil discovery, which targets similar Beloka and Mardin Group carbonate reservoirs as M47. The Gabar region hosts significant established production, with over 100 analogue wells operating within a 2-to-12-kilometre radius.

Approximately seven new oil fields have been discovered in the Cudi-Gabar region over the past five years. According to public reports, Gabar regional oil fields currently produce a combined rate of over 80,000 bbl/d, against a state national target of 100,000 bbl/d. Approximately 40 rigs are working a 140-well location inventory in the surrounding area.

The Çetinkaya-1 ("C-1") well, drilled in 2025, encountered 32.4° API light oil with 38 metres of gross pay. Drilling was halted on lost circulation at 2,455 metres, leaving approximately 160 metres of potential reservoir unpenetrated. C-1 is anticipated to be re-entered later this year for further production testing.

An independent NI 51-101 resource evaluation by Chapman has assigned the North Prospect a 2C contingent resource of 27.6 MMbbl, with an unrisked NPV-10 of US$733.5 million and a risk-adjusted value of US$594.2 million. The evaluation assigned an 81% chance of commerciality. Total unrisked resource potential across the three prospects is 51.6 MMbbl net to Dune, with up to 80 vertical development wells on the North Prospect, subject to commerciality.

Dune is earning its interest by funding a US$15 million work program commitment in stages. US$800,000 m has been advanced year-to-date. Approximately US$4.35 million is due September 15, 2026, and further payments thereafter. Dune bears 60% and 80% of the cost of the next wells, respectively, from its contributions. Thereafter, all costs will be pro-rata to interest.

A high-resolution gravity study completed in May-June confirmed the presence of significant fault-related structures and identified priority leads across the licence. The new finalized program covers 40 kilometres of 2D seismic across three priority exploration areas, to be acquired over approximately six weeks using modern nodal recording technology. A field scouting program was completed on July 29-30 to verify the seismic lines and determine the excavation works in the field. Currently, only about 25% of the Block is covered by seismic, with new seismic expected to generate four to six additional drillable exploration locations. Upon completion, the Company expects to announce its next drilling locations.

Project Highlights

• 2C Contingent Resource of 27.6 MMbbl on the North Discovery, with an unrisked NPV-10 of US$733.5 million.

• Approximately 11 km from the Şehit Aybüke Yalçın oil field, Türkiye's largest onshore oil discovery.

• 38 metres of gross oil pay at C-1 discovery well.

• Total unrisked resource potential of 51.6 MMbbl net to Dune across three prospects, with a North Prospect 3C estimate at an unrisked NPV-10 of US$1.18 billion.

• Seven newly discovered analogue oil fields in the Gabar region over the past five years.

• Analogue Gabar regional fields produce a combined rate of over 80,000 bbl/d.

• 578,213 MSTB PIIP (100% interest) assessed by appraisal.

About Dune Oil Corp.

Dune Oil Corp. (formerly Trillion Energy International Inc.) is a Canadian oil exploration company focused on Türkiye. The Company has an agreement to earn up to a 29% working interest in the M47 oil exploration block (C3 and C4 licences) located in the Cudi-Gabar petroleum province of southeastern Türkiye. The earn-in includes funding a total of US$15 million for 2026 and 2027 work commitments. More information may be found on www.sedarplus.ca and on the Company's website at www.duneoil.ca.

Cautionary Statement Regarding Forward-Looking Information

This news release contains "forward-looking information" within the meaning of applicable Canadian securities laws, including statements regarding the planned 40-kilometre 2D seismic acquisition program and the timing and results thereof; the identification of new drilling locations and the anticipated drilling program; the Company's earn-in commitments and the timing of payments thereunder; and the contingent and prospective resource estimates and the associated net present values. This information reflects the Company's current expectations and is subject to risks and uncertainties, including exploration, drilling and operational risk; the risk that technical results differ from current interpretations; the uncertainty inherent in resource estimates; delays in the seismic program; the risk that funding milestones are not met or that required capital is not available; and Türkiye regulatory, JOC partner and currency risks. Readers should not place undue reliance on forward-looking information, which is made as of the date hereof; the Company disclaims any obligation to update it except as required by applicable securities law.

Oil and Gas Disclosure, COGEH / NI 51-101

This news release has been prepared in accordance with National Instrument 51-101, Standards of Disclosure for Oil and Gas Activities ("NI 51-101") and the Canadian Oil and Gas Evaluation Handbook ("COGEH").

The North Prospect contingent resources disclosed herein are estimates only. There is no certainty that it will be commercially viable to produce any portion of the contingent resources. They have been classified with a Project Maturity Sub-class of Development Unclarified and remain subject to the contingencies and development conditions set out in the Company's independent resource-evaluation news release dated April 16, 2026.

The Central and Findık (South) prospective resources included in the 51.6 MMbbl figure are estimates only. There is no certainty that any portion of the prospective resources will be discovered or, if discovered, that it will be commercially viable to produce any portion of the resources. The figures stated are unrisked and carry both a risk of discovery and a risk of development.

"Net oil pay" refers to the thickness of reservoir rock meeting the minimum porosity and maximum water saturation cut-offs applied by the evaluator from wireline log analysis, as described in the Company's news release dated April 16, 2026. "PIIP" is Petroleum Initially-In-Place on a 100% gross property basis before application of a recovery factor; it is not a resources or reserves estimate and only a portion is classified as resources.

All net present values ("NPV") disclosed herein are stated before tax and discounted at 10% ("NPV-10"), are derived from the independent resource evaluation prepared by Chapman Hydrogen and Petroleum Engineering Ltd. with an effective date of December 31, 2025, and reflect Chapman's January 1, 2026 forecast price assumptions after deduction of applicable royalties. Estimated NPVs do not represent fair market value. The full price-deck, royalty, capital and operating cost, discount-rate and risking-methodology assumptions are set out in the Company's independent resource-evaluation news release dated April 16, 2026, available on SEDAR+ at www.sedarplus.ca.

References to production at the Şehit Aybüke Yalçın field, to current Gabar production of approximately 80,000 barrels per day and the 100,000 barrels per day government target, and to regional field discoveries, rig counts and well location inventories, are based on publicly available information reported by Türkiye Petrolleri Anonim Ortaklığı ("TPAO"), Türkiye's Ministry of Energy and Natural Resources, and public media sources. These are third-party properties in the same geological trend; Dune has no direct knowledge of their subsurface or production data, and they are not necessarily indicative of results that may be achieved at Block M47C3,C4.

Neither the Canadian Securities Exchange nor its regulation services provider accepts responsibility for the adequacy or accuracy of this news release.

To view the source version of this press release, please visit https://www.newsfilecorp.com/release/309156