REG - Mosman Oil & Gas Ltd - Coyote Wash Prospective Helium Resource 1,072 MMcf

Mosman Oil and GasAnnouncement

13/10/2025 07:05

For best results when printing this announcement, please click on link below:
https://newsfile.refinitiv.com/getnewsfile/v1/story?guid=urn:newsml:reuters.com:20251013:nRSM0785Da&default-theme=true

RNS Number : 0785D  Mosman Oil and Gas Limited  13 October 2025

13 October 2025

 

Mosman Oil and Gas Limited

("Mosman" or the "Company")

 

 

Coyote Wash Project - Prospective Gross Helium Resources of 1,072 MMcf

Mosman Oil and Gas Limited (AIM: MSMN), the helium, hydrogen and hydrocarbon
exploration, development and production company, which holds a 100% working
interest in the Coyote Wash Project in Colorado, USA ("Coyote Wash Project"),
is pleased to announce the first internal estimate of prospective helium
resources for the project.

Highlights

·   Best estimate 2U gross prospective helium resources of 1,072 MMcf
(million cubic feet) calculated across six identified prospects at Coyote
Wash, using parameters consistent with the recent independent evaluation of
the nearby Sagebrush Project prepared by Sproule ERCE and announced on 18
September 2025.

·     Resource model incorporates known reservoir properties from the
Coyote Wash 30-12 well and helium concentration data of 2.7% He measured at
Mosman's Sagebrush-1 well, located 5 miles to the southwest.

·  Coyote Wash lies in an established helium-producing region with proven
reservoir deliverability in the Middle and Lower Leadville formations.

Coyote Wash Project

The Coyote Wash Project is located in the Four Corners region of Colorado and
lies within an area of established helium production from the Leadville
Formation carbonates, including the Doe Creek field approximately 50 miles to
the north.

Technical evaluations by Mosman and its partner Four Corners Helium (FCH) have
focused on reinterpretation of vintage well data and reprocessed 3D seismic to
understand the resource potential within the project area. The Coyote Wash
30-12 well, drilled by Wintershall in 1985, encountered 258 feet of Leadville
carbonates within the Coyote Wash North closure. Three DST's were performed in
the middle and lower Leadville flowing non-flammable gas. Test data indicates
the well flowed 173mcf/d from 14ft of stacked dolomite units in the middle
Leadville. Although the gas composition was not analysed at the time, the well
confirmed good reservoir properties and deliverability from the Leadville
sequence before being plugged and abandoned.

A detailed petrophysical interpretation of Coyote Wash 30-12 and nearby offset
wells was subsequently undertaken by FCH to determine key reservoir parameters
for resource calculations. Interpretation of the reprocessed 3D seismic has
defined six individual prospects at the Leadville level within the project
area. Coyote Wash North (CN-1) is located in the upthrown fault block, while
the remaining five prospects lie in the southern downthrown block. These
structures have been mapped from high-quality seismic data and form the basis
of Mosman's initial prospective resource estimates.

Helium was confirmed at Mosman's Sagebrush-1 well, located five miles
southwest of Coyote Wash 30-12, with measured concentrations of 2.7% He.
Regional gas and production data indicate that similar commercial helium
concentrations are likely to be present at Coyote Wash, and this value has
been used to calculate the prospective helium resources across the six defined
structures.

In determining reservoir parameters, Mosman adopted a 5% porosity value for
the southern Coyote Wash prospects, consistent with the conservative "most
likely" porosity used by Sproule ERCE in their recent independent analysis of
the Sagebrush resource. A higher 8% porosity was applied to the Coyote Wash
North prospect, reflecting its proximity to the Coyote Wash 30-12 well and the
high reservoir quality observed there.

Figure 1: Coyote Wash project area and Coyote Wash North location

Figure 2: Two-way time structure map and prospects, Leadville formation,
Coyote Wash Project Area (source FCH)

Next Steps

Mosman will now formally engage Sproule ERCE, the independent consultant who
recently verified helium prospective resources at Sagebrush, to conduct a
detailed assessment and certification of the Coyote Wash prospective
resources.

This work will provide a third-party validation of Mosman's internal estimates
and form the basis for future drilling and development planning.

Howard McLaughlin, Chief Executive Officer of Mosman, commented: Coyote Wash
represents another exciting step in Mosman's US helium growth strategy. With
six mapped Leadville prospects and best-estimate helium prospective resources
exceeding one billion cubic feet, the project has clear scale and upside
potential. The combination of strong reservoir characteristics, proven
regional helium charge, and proximity to our Sagebrush discovery provides
confidence that Coyote Wash could become a significant addition to Mosman's
portfolio. Following Sproule ERCE's successful independent verification at
Sagebrush, we look forward to engaging them again to confirm and refine these
results as we advance towards drilling and development."

Table 1: Prospective Resources at Coyote Wash

 

 Best Estimate 2U Prospective Resources (MMcf)
                      Total Gas                          Recoverable Helium
  Coyote Wash North   31,298                             509
 Coyote Wash South-1  15,878                             260
 Coyote Wash South-2  5,076                              82
 Coyote Wash South-3  5,101                              67
 Coyote Wash South-4  5,529                              90
 Coyote Wash South-5  3,959                              64
 Total                65,942                             1,072

                                54,072                         879

 Net of Royalty
                                54,072                         879

 Mosman % (net)
 Source: Mosman / FCH estimates
 Notes
 1. The estimated quantities of gas that may potentially be recovered by the
 application of a future development project relates to undeveloped
 accumulations. These estimates have a risk of development. Further appraisal
 and evaluation are required to determine the optimal development plan and
 commerciality.
 2. The natural gas resource estimates have been derived in accordance with
 the principles of the Petroleum Resources Management System (PRMS). The PRMS
 specifically applies to petroleum. However, the Oil and Gas Reserves Committee
 of the Society of Petroleum Engineers (SPE) advised in August 2022 that
 although the gaseous extraction of natural hydrogen and helium is outside of
 the scope of the PRMS, the principles can be applied given the similarities in
 exploration, evaluation and exploitation.
 3. The resource estimates are presented on a net entitlements basis and
 represent Mosman's net economic interest in the prospective recoverable
 hydrogen and helium volumes after deductions for an 14% royalty and the 100%
 working interest. Royalty rate escalates over an initial 12-year period from
 14% to 18%. Thereafter it remains at 18%.
 4. The Prospective Resources have been evaluated using deterministic methods
 and represent best estimates. A low case and high case were not estimated.
 5.  The estimates are for naturally occurring gas only. No adjustment has
 been made to the estimates to account for fuel and flare

Qualified Person Statement

The information contained in this announcement has been reviewed and approved
by Howard McLaughlin, Chief Executive Officer for Mosman, who has more than 45
years of experience in the oil and gas industry and is a member of the
American Association of Petroleum Geologists.

Market Abuse Regulation (MAR) Disclosure

The information contained within this announcement is deemed by the Company to
constitute inside information as stipulated under the Market Abuse Regulations
(EU) No. 596/2014 ('MAR') which has been incorporated into UK law by the
European Union (Withdrawal) Act 2018. Upon publication via Regulatory
Information Service ('RIS'), this information is now in the public domain

Enquiries:

 Mosman Oil & Gas Limited      NOMAD and Joint Broker

 Carl Dumbrell                 SP Angel Corporate Finance LLP

 Chairman                      Stuart Gledhill / Richard Hail / Adam Cowl

                               +44 (0) 20 3470 0470
 Brand Communications          Joint Broker

 Alan Green                    CMC Markets UK Plc

 Tel: +44 (0) 7976 431608      Douglas Crippen

                               +44 (0) 020 3003 8632

 

Updates on the Company's activities are regularly posted on its
website: www.mosmanoilandgas.com (http://www.mosmanoilandgas.com/)

 

Notes to editors

Mosman (AIM: MSMN) is a helium, hydrogen and hydrocarbon exploration,
development, and production company with projects in the US and Australia.
Mosman's strategic objectives remain consistent: to identify opportunities
which will provide operating cash flow and have development upside, in
conjunction with progressing exploration. The Company has several projects in
the US, in addition to royalty interests in Australia.

 

Proposed Change of Name and Ticker

At the forthcoming Annual General Meeting on 10 November 2025, shareholders
will be asked to approve the proposed change of the Company's name to Quantum
Helium Limited, with a proposed new AIM ticker QHE. The change, once approved
and registered with the Australian Securities and Investments Commission
(ASIC), will reflect Mosman's strategic focus on helium exploration and
development. A further announcement will be made regarding the timetable for
the proposed change in due course.

 

Glossary

 Term                   Definition
 1U / Low Estimate      At least a 90% probability that the quantities recovered will equal or exceed
                        this estimate.
 2U / Best Estimate     At least a 50% probability that the quantities recovered will equal or exceed
                        this estimate. Often considered the "most likely" case.
 3U / High Estimate     At least a 10% probability that the quantities recovered will equal or exceed
                        this estimate. Represents upside potential.
 DST (Drill Stem Test)  A temporary well test conducted to determine the presence and productivity of
                        hydrocarbons or helium in a formation.
 MMscf                  Million standard cubic feet of gas, measured at standard conditions of
                        temperature and pressure.
 Mscf                   Thousand standard cubic feet of gas, measured at standard conditions of
                        temperature and pressure.
 Porosity               The percentage of pore volume or void space, or that volume within rock that
                        can contain fluids. Porosity can be generated by the development of fractures,
                        in which case it is called fracture porosity. Effective porosity is the
                        interconnected pore volume in a rock that contributes to fluid flow in a
                        reservoir. It excludes isolated pores. Total porosity is the total void space
                        in the rock whether or not it contributes to fluid flow. Thus, effective
                        porosity is typically less than total porosity.
 PRMS                   Petroleum Resources Management System, the globally recognized framework
                        issued by the Society of Petroleum Engineers (SPE) and partners, used for
                        classifying petroleum and non-hydrocarbon resources.
 Prospective Resource   Those quantities of petroleum estimated, as of a given date, to be potentially
                        recoverable from undiscovered accumulations by application of future
                        development projects.

 

This information is provided by RNS, the news service of the London Stock Exchange. RNS is approved by the Financial Conduct Authority to act as a Primary Information Provider in the United Kingdom. Terms and conditions relating to the use and distribution of this information may apply. For further information, please contact
rns@lseg.com (mailto:rns@lseg.com)
 or visit
www.rns.com (http://www.rns.com/)
.

RNS may use your IP address to confirm compliance with the terms and conditions, to analyse how you engage with the information contained in this communication, and to share such analysis on an anonymised basis with others as part of our commercial services. For further information about how RNS and the London Stock Exchange use the personal data you provide us, please see our
Privacy Policy (https://www.lseg.com/privacy-and-cookie-policy)
.   END  UPDMJBATMTABMRA



            Copyright 2019 Regulatory News Service, all rights reserved