Patagonia Lithium finds high free-fluid storage in Cilon Well 8
Patagonia Lithium has reported 15% total porosity and substantial free-fluid storage from Cilon Well 8, strengthening its interpretation of the aquifer’s pumping potential. The evidence is encouraging but remains incomplete, with four core results, further BMR Gamma data and a 72-hour pump test still outstanding.
- 15% total porosity and 5.9% drainable specific yield from one core result
- 11.97% specific yield reported at 220.6 metres
- Well 8 showed 60% free fluid in a key gravel zone
- Packer data points to transmissivity-driven flow rather than storage alone
- Four additional cores and a 72-hour pump test remain pending
Well 8 records strong porosity and free-fluid results
Patagonia Lithium Ltd (ASX:PL3) has found a potentially important distinction in Cilon Well 8: the well appears to contain not just sizeable pore spaces, but a high proportion of mobile brine within its gravel aquifers. One core sample returned 15% total porosity and 5.9% drainable specific yield, while the announcement also reports a specific yield of 11.97% at 220.6 metres.
The BMR Gamma survey indicates that the lower section of the well contains clay gravel with 60% pore space. In the designated comparison zone, Well 8 recorded 60% free fluid, compared with 21% in the corresponding zone of Well 7. Capillary water accounted for 30% of pore space in Well 8, while clay-bound water represented 10%.
Flow data favours transmissivity over simple storage
The result matters because high porosity does not automatically translate into a productive brine well. Pores must also be connected well enough for fluid to move. Patagonia says the packer results show no direct relationship between specific yield and flow rate, with recorded rates ranging from 347.8 litres per hour to 705.9 litres per hour across the tested intervals.
That pattern has led the company to favour a “transmissivity-controlled interpretation rather than a storage-controlled one”. In practical terms, the company’s reading is that the aquifer’s ability to transmit brine may be more important for production than the absolute volume of water held in its pore spaces. Executive Chairman Phillip Thomas said the well appeared capable of pumping brine because of its large capillary capacity, while also pointing to strong visual porosity, a 232ppm lithium result in the main aquifer and the observed pumping rates.
Additional testing will determine how repeatable the result is
The technical picture is not uniform through the hole. Patagonia describes a complex porosity profile that changes with depth and lithology, including upper clean sands where large pores may be partly blocked by fine sand and clay. That could leave substantial water in storage without equivalent hydraulic conductivity in every interval.
Only one core porosity result has been received so far. DBS&A is processing four more cores that can be correlated with the BMR results, while additional BMR data is also pending. A 72-hour pump test is currently underway, making its eventual sustained flow performance the clearest next test of whether the encouraging porosity and packer observations translate into a coherent production response.
Resource implications remain dependent on pump-test evidence
Patagonia’s existing mineral resource is stated at 551,400 tonnes of lithium carbonate equivalent at 294mg/L, comprising indicated and inferred material. The Well 8 results may provide more information for an updated resource assessment, but this announcement does not report a new resource, recovery estimate or production rate.
The key question now is whether the remaining core and gamma results confirm the same relationship between pore structure, brine mobility and lithium concentration across the wider well. Until the pump test is complete, the strongest numbers describe the geology and aquifer behaviour rather than a demonstrated commercial output.
Bottom Line?
The Well 8 data improves the geological case for productive brine extraction, but the 72-hour pump test must convert promising pore characteristics into sustained, measurable flow.
Questions in the middle?
- Will the completed 72-hour pump test confirm sustained flow across the most promising aquifer intervals?
- Do the four additional core samples support the 15% porosity and reported specific-yield results?
- Will the new Well 8 data materially change Patagonia’s next mineral resource estimate?
