• Well LSC-3a is the first to re-inject brine into the sandstone reservoir matrix, with a measured surface injection rate of about 35 standard litres per second.
  • Vulcan interprets an injection capacity of about 64 standard litres per second under planned operating conditions, compared with the Field Development Plan assumption of about 40.
  • Results will guide the next two reinjection wells, LSC-4 and LSC-5.

Vulcan Energy Resources Limited (ASX:VUL) has reported results from well LSC-3a, the seventh well drilled for its planned 28-well Lionheart Field Development Plan (FDP). According to the company, the well is its first to re-inject brine into the sandstone reservoir matrix, rather than into the fault zone where earlier reinjection took place. Vulcan says the test supports the injection assumptions used in the FDP.

What the company drilled and tested

Project Lionheart sits in the Upper Rhine Valley Brine Field, which straddles the German and French border. Vulcan describes it as a lithium and renewable energy project, with a target of 24,000 tonnes of lithium hydroxide monohydrate a year, which the company says is enough for about 500,000 electric vehicle batteries. Vulcan also lists co-products of 275 GWh of renewable power for internal use and 560 GWh of heat a year for local consumers. The project life of 30 years is based on the company's 2023 Bridging Study.

LSC-3a was drilled in September 2026 by Vercana, Vulcan's in-house drilling company, and tested in early October 2026. It is a geo-steered Horizontal Well with a total measured depth of 3,743 metres. Its pilot hole, LSC-3, confirmed a higher-permeability reservoir interval that had previously been encountered in the LSC-1 and LSC-2 wells. Including LSC-3a, Vulcan has drilled seven wells for the FDP to date, made up of four existing wells and three new ones.

The measured and interpreted figures

The announcement separates what was measured from what was interpreted. During testing, Vulcan measured a surface injection rate of about 35 standard litres per second at a wellhead pressure of 69 barg and a temperature of 18 degrees Celsius.

The company then interpreted the well's capacity under the conditions it plans to use in operation, a wellhead pressure of 70 barg and a wellhead temperature of 65 degrees Celsius. On that basis, it interprets an injection capacity of about 64 standard litres per second. Vulcan states that this figure comes from test data, downhole measurements and wellbore modelling rather than from a direct measurement. For comparison, the FDP assumes a rate of about 40 standard litres per second for matrix injectors.

Why it matters for the development plan

Vulcan says the result is the first direct field validation of matrix injection within the FDP, and that it supports the planned mix of matrix and fault-zone injectors. The company attributes the reduced subsurface uncertainty to a combination of seismic reprocessing, drilling, logging, core analysis and injector testing. It says integrated analysis has confirmed a laterally persistent, higher-permeability reservoir interval across multiple wells, and that updated seismic imaging has improved its confidence in predicting the reservoir and placing wells.

The company also says the results give it flexibility for further optimisation of the FDP. It describes results to date as at or above expectations, while acknowledging that some variance is expected as the programme continues. Chief Executive Officer Cris Moreno called the outcome another strong result for Lionheart.

Limits and what comes next

The disclosure is a single-well test result and does not change the project's financial or production position. The 64 standard litres per second figure is an interpretation under planned operating conditions that were not the conditions of the test itself, and the announcement does not provide a development timetable, funding update or a new or revised production forecast arising from this well test. The 24,000 tonne target, the co-product volumes and the 30-year life are Vulcan's own targets and estimates, drawn from earlier company studies, and are not outcomes of this test.

The next confirmed steps relate to the wells themselves. Vulcan says the LSC-3a results will feed into its integrated geological and dynamic reservoir interpretation and will guide the design and execution of the next two reinjection wells, LSC-4 and LSC-5.

The earlier studies Vulcan references were not reviewed for this article.