Winters-2 Drilling Update

22 October 2021

Mosman Oil and Gas Limited

("Mosman" or the "Company")

Winters-2 Drilling Update

Mosman Oil and Gas Limited (AIM: MSMN) the oil exploration, development, and production company, announces an update on the Winters-2 well in Polk County, Texas.

Further to the announcement made on 11 October, Mosman advises that Winters-2 was drilled to the target depth of 7,011 feet. Wireline logs, and side wall cores, and formation pressure tests were completed.

The report from on-site is that based on this data, the Winters-2 well has encountered potential pay in the Yegua and Wilcox sands. The well is being completed in the Third Wilcox which has a gross thickness of 54 feet (6,770-6,824 feet).

Information on flow rates will be made available when known, which will not be until after production facilities are installed.

The drilling rig will move to Stanley-5 location and that well is anticipated to commence drilling next week.

Qualified Person's Statement

The information contained in this announcement has been reviewed and approved by Andy Carroll, Technical Director for Mosman, who has over 35 years of relevant experience in the oil industry. Mr. Carroll is a member of the Society of Petroleum Engineers.

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 the publication of this announcement via Regulatory Information Service ('RIS'), this inside is now considered to be in the public domain.

Enquiries:

Updates on the Company's activities are regularly posted on its website:

www.mosmanoilandgas.com