CGA Initial Resource Estimate for Ahpun Topsets

Cawley Gillespie & Associates Initial Resource Estimate for Ahpun Field Topsets at 280 Million Barrels Recoverable ANS Crude

Pantheon Resources plc (AIM: PANR) ("Pantheon" or "the Company"), owner of 100% working interest in the Kodiak and Ahpun oil fields, is pleased to announce the results of the recent Independent Expert Report ("IER") by Cawley Gillespie & Associates, Inc. ("CGA"). This completes the independent estimates for the Company's aggregate resources from the Kodiak field, Ahpun western topsets and Alkaid horizon resulting in totals exceeding 1.5 billion barrels ("Bbbl") of ANS Crude and 6.5 trillion cubic feet ("Tcf") of associated gas.

Highlights

CGA has completed its initial IER for the western topset horizons in the Ahpun oil and gas field (formerly named the SMD), located in the North Slope Alaska, and estimate the 2C contingent recoverable resources to be:

[1] At the time of CGA's engagement there was no recognised commercial market for the natural gas production, accordingly CGA attributed zero revenues to natural gas production in this analysis and therefore zero net resource is recognised until such time as the gas sales agreement is executed.

As was the case with Lee Keeling & Associates ("LKA") which recently updated its IER on the Alkaid horizon of the Ahpun field, CGA has evaluated the economics of the best estimate or 2C case. Based on an ANS Crude price of $80 per barrel delivered to the US West Coast, CGA estimates the net present value of the total contingent resources in the western topsets in the Ahpun field (using a real discount rate of 10%) at $1.74 billion.

This report extends the independent assessments of all the Company's contingent resources discovered, appraised and for which development approvals are being prepared. As previously announced, the Company is targeting Final Investment Decision ("FID") at the earliest possible date subject to regulatory consents, but in any case, to allow first production no later than 2028.

Pantheon commissioned CGA to prepare the independent report on the Ahpun field as it progresses funding options for its projects. This IER incorporates data obtained from the successful completion and test of the shallower topset horizon in the vertical section of the Alkaid-2 well in Q4 2023. For that test, Pantheon utilised a revised frac design with success, including using finer mesh sand and at a lower concentration in a slick water stimulation. This resulted in a materially improved frac efficiency compared to the completion in the horizontal section of Alkaid-2 and will be the starting point for all future frac designs. Pantheon was also able to obtain down hole pressure data and fluid samples consisting of oil, gas and condensates/NGLs. This allowed analysis of reservoir pressure and permeability leading to a better understanding of the western topsets reservoir parameters and potential development economics. These estimates can only be upgraded from the contingent resource to the reserves classification following FID.

This initial IER is based on Pantheon's base case development plan for Ahpun, but does not yet incorporate the benefits of planned infill drilling (or "wine-racking") in the southern portion of the topsets, where they are thickest. Analysis of the interference between "parent" and "child" wells in such a scenario is more complex and time consuming and will only be required later in the process of achieving FID. Preliminary management estimates indicate that "wine-racking" the wells in this area would add an additional c. 80 million barrels ("mmbbl") of high value recoverable resources. When combined with CGA's estimate, this would bring the total expected ultimate recovery from the Ahpun western topsets to c. 360 mmbbl as compared with the previously released management estimates (based on in-place quantities and a generalised recovery factor assumption) of 404 mmbbl.

Jay Cheatham, Pantheon Chief Executive, commented: "Cawley Gillespie & Associates have validated Pantheon's assessment that the Ahpun topsets on the west side of the Dalton Highway can be economically developed, even after excluding the potential market offtake for natural gas. The best estimate of 282 mmbbl of contingent recoverable resources of ANS crude and 803 billion cubic feet ("bcf") of natural gas underscore our ability to support the in-State phase of the Alaska LNG project, initially with Ahpun volumes and, in due course, Kodiak field resources."

David Hobbs, Pantheon Executive Chairman, commented: "We now have independent validation of all the contingent resources we are working to develop, including support for the commerciality of the Ahpun development, which will be first onstream given its immediate proximity to the established pipeline and road infrastructure. Validation of Pantheon's natural gas resources, in particular, is of great value as these resources enabled us to develop a strategic relationship with the State of Alaska resulting in the Gas Sales Precedent Agreement that we expect has the potential to lead to a long term take or pay agreement that could be used to support the funding of our post-FID capital costs.

"We will update the independent assessment of the Kodiak field to evaluate the economics of that development after we drill and test the planned appraisal wells up dip in the new acreage secured at the last two lease sales, subject to funding."

The Company plans to conduct a webinar at the end of June 2024 to discuss the results of the independent resource estimates, the recently concluded Gas Sales Precedent Agreement and its funding strategy for funding the development of Ahpun.

The estimates in the CGA IER have been prepared in accordance with definitions and guidelines set forth in the 2018 Petroleum Resource Management System ("PRMS") approved by the Society of Petroleum Engineers (SPE). The full report will be available at:

Glossary

Bbls: Barrels

Bbbl: Billion barrels

Bcf: Billion cubic feet

For Contingent Resources, the general cumulative terms low/best/high estimates are used to estimate the resulting 1C/2C/3C quantities, respectively. The terms C1, C2, and C3 are defined for incremental quantities of Contingent Resources:

• C1: Denotes low estimate of Contingent Resources. C1 is equal to 1C.
• C2: Denotes Contingent Resources of same technical confidence as Probable, but not commercially matured to Reserves.
• C3: Denotes Contingent Resources of same technical confidence as Possible, but not commercially matured to Reserves.

When the range of uncertainty is represented by a probability distribution, a low, best, and high estimate shall be provided such that:

• There should be at least a 90% probability (P90) that the quantities actually recovered will equal or exceed the low estimate.
• There should be at least a 50% probability (P50) that the quantities actually recovered will equal or exceed the best estimate.
• There should be at least a 10% probability (P10) that the quantities actually recovered will equal or exceed the high estimate.

Mmbbl: Million barrels

Overriding Royalty Interest (ORRI): A royalty granted to a third party other than the royalty payable to the State of Alaska.

Tcf: Trillion cubic feet

Working Interest: The legal ownership of the leases awarded by the State of Alaska. Pantheon's Net Revenue Interest (NRI) in the leases is less than 100% by virtue of royalties payable to the State and any ORRI. In the case of the Kodiak project, the State royalties vary between 12.5% and 16.67%. Management estimates that the average NRI is approximately 85%.