Vintage Energy has recorded commercial flow rates and mid to high gas volumes at Nangwarry-1 discovery, following production testing for the onshore Otway Basin well, South Australia.
Nangwarry-1 was perforated across the Top Pretty Hill Formation and produced gas at higher than anticipated flow rates of 10.5-10.8 million standard cubic feet per day (MMscfd) through a 48/46-inch chock at a flowing wellhead pressure of 1416 psi over a 46-hour period.
The company advised that this flow measured through a 3-inch orifice plate and chocked back to analyse the well over the extended flow period with stable conditions.
The current gross recoverable estimates for Nangwarry-1 carbon dioxide have been recorded at: low of 7.8 Bcf, best of 25.1 Bcf, and a high of 82.1 Bcf, according to ERC Equipoise (ERCE).
ERCE estimates were made prior to the production test, using a gas column of 98 metres, but reciting that the column could be greater.
The joint venture has reported they are pleased that the latest testing confirmed a gas column of at least 120m, which should result in increased recoverable estimates.
Following analysis of the main flow test data, and pressure build-up data after an extended shut in of the flow, Vintage has interpreted that there was no significant pressure drop in the reservoir as a result of the flow.
“As the flow test has negligible impact on the reservoir pressure, this indicates a sizeable volume of CO2 is present in the field,” Vintage outlined.
Based on the interpretation of the data, and the volume of gas produced during the test, it is considered that Nangwarry-1 has accessed a volume of CO2 created than the low estimate and falls in the mid or higher end of the pre-test volumetric estimates.