US: Pantheon Resources Dubhe-1 appraisal well exceeds pre-drill estimates in target reservoir

Pantheon Resources, the oil and gas company developing the Kodiak and Ahpun oil fields near pipeline and transportation infrastructure on Alaska's North Slope, has announced results from the Dubhe-1 appraisal well.

The primary target of Dubhe-1 was the topset horizon (SMD-B), appraising the already discovered resource. Additionally, the well was designed to encounter three further exploration horizons (Prince Creek, SMD-C and the Slope Fan System), none of which have previously had any resource estimate attributed to them. Logs confirm additional prospective resource upside in these horizons.

Key Points

• The Dubhe-1 pilot hole was successfully drilled, logged and cored to a total measured depth ("MD") of 12,833 ft, equivalent to 8,699 ft true vertical depth ("TVD")
• Analysis of the thickness and quality of the primary target topset confirms that the SMD-B has exceeded the upside pre-drill expectations. The gross thickness of the hydrocarbon column in this interval was measured at 565 ft true vertical thickness ("TVT"); exceeding pre-drill expectations by 26%
• Dubhe-1 also encountered additional hydrocarbon bearing horizons in two of the exploration targets; the SMD-C and two Slope Fans
• The Company intends to drill, and subsequently flow test the planned sidetrack lateral in the SMD-B horizon to refine the production well type curve 

Dubhe-1 Well: Phase 1 Outcome

The first phase of the Dubhe-1 well programme consisted of a deviated pilot hole to gather cores and logs to select the optimum landing zone for a subsequent lateral sidetrack in the primary SMD-B zone. The well successfully reached the planned TVD and achieved all planned target reservoir penetrations - both primary and exploration objectives.

Dubhe-1 has confirmed a gross 565 ft TVT hydrocarbon bearing column in the SMD-B primary target horizon. This exceeds the pre-drill estimate (450 ft TVT based on Pipeline State#1 offset) by 26% and the upper end of pre-drill estimates (up to 500 ft TVT) by 13%. Reservoir properties are consistent with the nearby Pipeline State #1 discovery well. The hydrocarbon mix between oil, NGLs and gas will be determined after flow testing

Additional hydrocarbon bearing zones were encountered in the SMD-C and two Slope Fans.  These horizons were not included in the Ahpun estimated contingent resources of 282 million barrels and 804 billion cubic feet, prepared by Cawley Gillespie & Associates and therefore these resources represent material upside potential as co-development opportunities alongside the established Ahpun SMD-B primary reservoir. 

Source: Pantheon Resources

Details of Appraisal Analysis

Preliminary analysis indicates that Dubhe-1 has intersected multiple hydrocarbon bearing horizons over approximately 2,143 ft MD (1,085 ft TVT). In addition to the primary SMD-B objective of the well, multiple reservoirs were penetrated in this overall section consisting of interbedded sands and shales.

All intervals were logged with a full suite of Logging While Drilling ('LWD') tools and Volatiles Analysis Service ("VAS") of both sealed and unsealed cuttings samples. A 90 ft core, with 100% recovery, was taken from 11,732 - 11,823 ft MD (8,142 - 8,187 ft TVD) within SMD-B interval. In addition, sidewall cores were gathered to aid with log calibration.

Integrated analysis indicates the following hydrocarbon bearing zones within the Campanian interval:

In addition to these results, hydrocarbons were also identified in the Maastrichtian interval (Prince Creek and Upper Schrader Bluff Topsets 1 and 3) with a gross thickness of 1,158 ft TVT, in line with those same horizons encountered in Megrez-1. Preliminary analysis indicates similar reservoir properties and the results will be combined with the data from Megrez-1 for further technical evaluation and potential associated long term development planning if warranted.

Forward Plans

The Company is presently finalising the optimum location to position the lateral section of the well within this thick 565ft TVT section of SMD-B horizon. Drilling of this lateral is expected to commence over the coming days.  In addition to the logs, cores, cuttings and other data collected in the pilot hole, data gathered from the drilling of this horizontal lateral will be further integrated into the analysis.

At the same time, the Company is analysing data to optimise the design of hydraulic stimulation plans in the lateral. The Company is also tendering several service providers for these operations and a decision is expected to be made on these matters during the next two months. The Company will issue further guidance on this plan of operations when available.

The Company will be evaluating the large data set gathered from this well and previous wells penetrating these horizons that includes whole core and sidewall cores, VAS analysis of cuttings, LWD and wireline logs, seismic check shots to calibrate the proprietary 3D survey and reservoir fluid analysis ('PVT'). These analyses will be used to refine the dynamic reservoir model and design permanent production facilities as the Company's capital programme transitions to Ahpun field development. The Company will host a webinar on 9th September, 2025 to share the results of the Dubhe-1 drilling operation and preliminary insights into the scale of additional prospective resources encountered in the SMD-C and the Slope Fans.

Erich Krumanocker, Chief Development Officer, said:

'We are delighted to announce the Dubhe-1 pilot hole results as a success. The well confirms the presence and quality of the oil and gas reservoirs in the Ahpun field, exceeding our pre-drill expectations. We are now transitioning toward field development planning in support of capital efficient commercial production. The upside presented by the SMD-C and Slope Fan zones highlights the enormous potential in our portfolio.'

Original announcement link

Source: Pantheon Resources