Heavy rainfall recently has meant several wells have had to be shut-in on both the Welch Permian basin project and the Strawn project.
This shut-in has not only halted production but has also delayed repairs that need to be regularly made.
Further, oil collection has been hampered as the roads are impassable due to the rain.
Mosman said the effect will be lower production, but conversely, given they are not operating, costs fall significantly.
Chairman John Barr said: "The rainfall has caused some disruption, but we are not aware of any damage to production facilities, and therefore once the rain abaits normal production should be quickly restored."
On the Stanley-1 and Stanley-2 wells, which are elsewhere in Texas, Mosman has ended plans to install further gas infrastructure at Stanley-1.
Mosman said: "The consultant's interpretation is that the data indicates a small gas cap is being depleted, and that once gas flow no longer has to be restricted, the well can then be opened up and optimised for oil production.
"As a result the initial proposal to install additional gas infrastructure has not proceeded."
On Stanley-2, drilling is on schedule to start in November, targeting the Yegua sands.
Barr commented: "Stanley-1 continues to generate revenue from gas and oil sales, however, the hope is that the oil will become the dominate revenue stream shortly."
"The board is keen to move forward to Stanley-2 well being drilled soon."
Mosman shares were 0.5% lower on Thursday at a price of 0.50 pence each.
