D3 Energy Ltd (ASX:D3E, OTCQB:DNRGF) has confirmed a 38% increase in gas flow at its RBD10 well in the Free State, South Africa, following a 14-day production re-test. The well delivered an average flow rate of 264 thousand standard cubic feet per day (Mscfd), up from 191 Mscfd recorded in the previous year.
Combined with a 32% uplift recently recorded at nearby RBD03, the results indicate strong reservoir deliverability and suggest that wells can be spaced further apart. This would reduce the number of wells needed for full-field development, lowering capital expenditure and enhancing project economics.
Well location map.
“The mere fact that pressure continued to increase post initial testing to warrant retesting in the first place, is a testament to the unique source and reservoir characteristics that distinguishes this asset from virtually any other project, anywhere in the world,” D3 Energy managing director and CEO David Casey said.
“In a conventional reservoir as gas is produced reservoir pressure will drop and rates will decline accordingly during subsequent testing. The absence of that behaviour here can only imply that we are seeing continual generation and recharge of both helium and biogenic methane at depth.
“As I have said previously this is a genuine once in a career asset, and notwithstanding that there will ultimately be an equilibrium where recharge will match production, that would appear to be a long way off given the fact that we have evidence of boreholes drilled over 40 years ago still flowing at stabilised rates to this day.
“This notably in an area where thousands of boreholes have been previously drilled for gold exploration.”
Pressure behaviour signals continuous recharge
The decision to re-test RBD10 was based on a sustained increase in reservoir pressure, a phenomenon uncommon in conventional reservoirs. Normally, pressure declines following production. However, in RBD10 and RBD03, pressure not only held but increased, indicating active recharge of helium and biogenic methane from deeper source rocks through an extensive fault system.
The 14-day re-test at RBD10 yielded a total gas volume of 3,695 Mscf, with no choke applied, reaffirming the well’s productive potential. The company believes these results will allow for wider well spacing across the project, reducing drilling intensity while maintaining output levels.
The flow rate improvement at RBD10 mirrors the performance observed at RBD03, suggesting a more connected and higher-quality reservoir than initially interpreted. D3 Energy expects this will translate into fewer wells drilled, lower initial and sustaining capital costs, and improved long-term field performance.
Technical summary of RBD10 re-test
RBD10 is a vertical well located within permit ER315 and was drilled in February 2024 to a total depth of 546 metres. The target zones, between 420 and 546 metres, comprise fractured quartzite beneath dolerite within the Witwatersrand Formation.
The test recovered gas over a 14-day period, confirming an average stabilised flow rate of 264 Mscfd with a total volume of 3,695 Mscf. The well is now shut in again to monitor pressure build-up. The absence of a choke during testing supports the interpretation of a strong, self-recharging reservoir system.