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17 October 2022

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Mosman Oil an Gas Limite

("Mosman" or the "Company")

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Cinnabar Well Successfully Drille an Moving to Prouction

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Mosman Oil an Gas Limite (AIM: MSMN) the oil exploration, evelopment, an prouction company, announces that the Cinnabar evelopment well in Tyler County, Texas has complete rilling.

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The well was rille to a epth of 9,900 feet. The mu-log confirme multiple oil-bearing Wilcox sans from 9,00 feet to 9,80 feet. The Wilcox sans are the primary targets which notably have a long prouction history in nearby wells (mainly oil with some associate gas). 160

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The next steps are to run wireline logs followe by run an cement prouction casing, an then procee to put the well on prouction. Flow tests are not require as the prouction capability is alreay emonstrate at the existing prouction wells in the lease area.160 Base on nearby well history, the anticipate prouction rate estimates remain at circa 120 boep (gross) although obviously actual prouction rates will not be known until hyrocarbons are flowe to surface.

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Once casing is run an cemente the rilling rig will be off contract an emobilize, which may take a week. After the rilling rig has left the well site, a service rig will be brought in to run the tubing an packer. The casing will then be perforate, an the well can be prouce once a flowline is lai from the Cinnabar well to the existing prouction facilities. The prouction zone epth will be avise once it is perforate, an flow rates will be announce in ue course.

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The Company is please with the successful rilling at Cinnabar with mulogs confirming Mosman's technical work, incluing 3D seismic reprocessing, inicating consierable potential for aitional evelopment wells at Cinnabar. Planning for aition wells will commence immeiately. The lease has an area of over 30 acres an the allowable Wilcox well spacing is 40 acres.

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Mosman owns a 7% working interest in the Cinnabar well an the Cinnabar lease. Mosman Operating LLC, a 100% owne subsiiary of Mosman, is the Operator of the lease.

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John W Barr, Chairman, sai: 160

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"Mosman is extremely please with this outcome, which reinforces the company's ecision to prioritise the reevelopment of the Cinnabar lease. At current oil prices, the economics of these wells is very attractive in both the short an long term.

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"This successful rilling again reinforces the investment case in South-Eastern Texas where Mosman has participate in multiple wells, an every one of these wells has been place on prouction. Mosman looks forwar to proviing further upates in ue course."

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Qualifie Person's Statement

The information containe in this announcement has been reviewe an approve by Any Carroll, Technical Director for Mosman, who has over 3 years of relevant experience in the oil inustry. Mr. Carroll is a member of the Society of Petroleum Engineers.

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Market Abuse Regulation (MAR) Disclosure

The information containe within this announcement is eeme by the Company to constitute insie information as stipulate uner the Market Abuse Regulations (EU) No. 96/2014 ('MAR') which has been incorporate into UK law by the European Union (Withrawal) Act 2018. Upon the publication of this announcement via Regulatory Information Service ('RIS'), this information is now consiere to be in the public omain.

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Enquiries:

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Upates on the Company's activities are regularly poste on its website:

www.mosmanoilangas.com

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Notes to eitors

Mosman (AIM:MSMN) is an oil exploration, evelopment, an prouction company with projects in the US an Australia. Mosman's strategic objectives remain consistent: to ientify opportunities which will provie operating cash flow an have evelopment upsie, in conjunction with progressing exploration of existing exploration permits. The Company has several projects in the US. In aition to exploration projects in the Amaeus Basin in Central Australia.

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Glossary:

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