THE PROJECT

One of Europe’s leading geothermal developers is exploring the potential of a poorly developed geothermal reservoir that is also targeted for public water supply in France. The context is not dissimilar to the Yarragadee aquifer in Perth which is used to provide 25% of the public water supply and is also targeted by 26 geothermal and injection wells.

To assess the impact of injection of geothermally cooled water on the aquifer, Rockwater constructed a comprehensive geological model of the target aquifer in France. The geological model incorporated a major fault displacing the porous sandstone intervals.

Numerical groundwater flow and heat transport modelling was used to estimate the likely impact of injection on nearby production bores used for potable water supply. To provide a probabilistic the numerical model was run multiple time using a Monte-Carlo approach.

Another aspect of the study included geochemical modelling using the PHREEQC code of precipitation/dissolution reactions caused by the cooling of the geothermal water down to very low temperatures after circulation through a heat pump.

The Rockwater study was used to estimate the optimum injection temperature and ensure no detrimental impact on the nearby bores used for water supply. The study was completed in line with the local regulatory framework and produced in French to be included in a public tender.

Rockwater is leading in geothermal modelling.

• Geothermal modelling study
• Geochemical modelling study
• Monte-Carlo predictive uncertainty analyses

• Leapfrog Geo
• PHREEQC modelling
• Geothermal modelling

THE PROJECT

One of Australia’s largest companies is actively exploring the potential for green ammonia production in Western Australia. Geothermal electricity generation from onshore hot sedimentary aquifers is attractive because geothermal energy is available 24/7 unlike other renewables. It can also provide desalinated water using waste-heat from the geothermal process.

Rockwater used its proprietary code PyGeo to conduct a basin-wide analysis of the Levelised Cost of Electricity (LCOE) of geothermal electricity generation in one of Western Australia’s foremost onshore sedimentary basin.

Unlike simple temperature mapping analyses, the code combined temperature information with Monte-Carlo porosity and permeability values to produce probabilistic estimates of the achievable geothermal power versus depth.

The results of the basin-wide assessment were used to identify sub-areas within the basin with high potential. For these areas, the PyGeo code used reservoir specific porosity and permeability trends combined with seismic horizon grids and temperature grids to generate spatial LCOE maps.

The Rockwater workflow was highly successful and contributed to the identification of two areas with a 20 MW+ potential and competitive LCOE.

Rockwater is the leader in developing geothermal resources in Australia.

• Geothermal feasibility study
• Financial modelling (LCOE, IRR, NPV)

• Python scripts
• Leapfrog Geo
• Seismic interpretation (DUG Insight)

THE PROJECT

Montgomery House is an historic Perth landmark that has been transformed into an 80-bed aged care facility. The challenges of providing air conditioning for such a large and heritage-sensitive site were matched by the challenges of its location – it borders a former rubbish disposal site and is surrounded by residences (and so is sensitive to drilling and testing operations).

An open-loop geothermal energy system was established by Rockwater at Montgomery House to accesses aquifers within the Kings Park Formation.

Two production bores deliver 24 °C water to a heat exchanger.  The water is injected back in the same aquifer using another bore located as far as possible from the pumping bores to avoid thermal breakthrough.  The thermal energy is used to heat and cool Montgomery House via an automated heating, ventilating, and air conditioning (HVAC) system.

The Montgomery House project has delivered considerable long-term energy savings.

Similar HVAC projects have been conducted by Rockwater at the Shoreline project in North Coogee, and several other mid- to large- sized facilities.

• Geological and geophysical interpretation
• Groundwater modelling (including thermal breakthrough assessment)
• Field investigation reporting
• Compliance reporting

• Down-hole geophysics surveys
• Mud-rotary bores
• Pumping tests
• Injection tests
• Temperature profiling
• Injection bore development

THE PROJECT

Geothermal hot springs are becoming increasingly popular for health, leisure and tourism.  Peninsula Hot Springs is the leading commercial hot spring facility in Australia, with over half a million visitors per year.

Rockwater has been providing hydrogeological services to Peninsula Hot Springs since 2018.  Our work has involved the construction and testing of two new injection bores to a cumulative drilling depth of 1,130 m.

A down-hole drilling motor, commonly used in the oil and gas industry, was used to steer the trajectory of one injection bore away from the other, to maximise bore separation and exposure to the aquifer.

Gyro surveys were performed to keep track of the bore trajectory. Other innovative technologies implemented on the project included pre-pack screens and flush-jointed stainless-steel casing.

Rockwater also contributed to the selection and testing of advanced water filters to control clogging, which is particularly prevalent in this application of geothermal technology.

Rockwater is involved in several other similar projects for geothermal hot springs in Western Australia, Victoria and New South Wales.

• Geological and geophysical interpretation
• Field investigation reporting
• Groundwater modelling
• Thermal breakthrough modelling
• Visualisation with Leapfrog modelling software
• Clogging risk assessments
• Filtration design
• Aquifer storage and recovery injection valve

• Mud-rotary bores
• Directional drilling
• Nuclear magnetic resonance surveys
• Gyro surveys
• Pumping tests
• Injection tests
• Membrane Filtration Index tests

THE PROJECT

The Gippsland Regional Aquatic Centre (GRAC) at Traralgon was developed by the Latrobe City Council and the Victoria Government.  It is a major showcase facility for competitive swimming, leisure, community use and major regional events.

GRAC has a significant energy load, with pool heating representing the bulk of the energy consumption.

Rockwater was extensively involved in the Taralgon project, from initial stages to project-commissioning.  Our work involved a feasibility assessment, developing RFQ documentation, reviewing contractor submissions, and supervising the drilling and testing of a 640 m deep production bore.

The production bore targeted hot water in a highly-permeable aquifer that is thermally insulated by overlying coal measures.

Rockwater also supervised the construction and testing of an injection bore to 620 m depth. The injection bore is used to dispose of the cooled water after it has passed through a heat exchanger.  

The system was successfully tested in early 2020 at a temperature of 68°C, exceeding all expectations.

• Geological and geophysical interpretation
• Groundwater modelling (including thermal breakthrough assessment)
• Field investigation reporting
• Compliance reporting
• Regulatory approvals applications
• Geochemical modelling (PHREEQC) of injection impacts

• Down-hole geophysics surveys 
• Mud-rotary bores
• Pumping tests
• Injection test
• Temperature profiling/logging
• Injection bore development
• CCTV and Televiewer surveys 
• Bore-development discharge control, including utilising cooling towers and receptor monitoring

THE PROJECT

In 2012, Australia and South Africa won the right to host the Square-Kilometre Array, which will be the world’s largest and most sensitive radio telescope.  A supercomputer was built at CSIRO’s Pawsey Centre for processing of the data, estimated to be in excess of 1017 floating point operations per second.

The energy requirements for cooling of the first stage of the Pawsey supercomputer were estimated to be 2,600 kW.  A large-scale geothermal cooling system has been implemented to provide this cooling power.

Rockwater designed and implemented the geothermal cooling system at Pawsey, starting with a hydrogeological assessment of a highly prospective, yet poorly-defined aquifer system, known as Mullaloo Aquifer. This highly-permeable aquifer is located at the top of the Tertiary-aged Kings Park Formation and cuts through older Cretaceous sediments beneath the Pawsey Centre.  

Two production bores and four injection bores were constructed and tested in the Mullaloo Aquifer under the supervision of Rockwater.  The production bores provide water of sufficient volume and temperature for cooling of the supercomputer.

Rockwater continues to oversee monitoring of the geothermal bores and periodically organises re-development of the bores to maintain their efficiency.

• Geological and geophysical interpretation
• Field investigation reporting
• Groundwater modelling (including thermal breakthrough modelling)
• Clogging risk assessments
• Filtration design
• Downhole packer injection valve

• Mud rotary bore drilling
• Pumping tests
• Rhodamine WT tracer tests
• Injection tests
• Membrane Filtration Index tests

THE PROJECT

A new swimming pool complex was constructed by the City of Stirling at Scarborough Beach in 2017-18, at a cost of $26m.  The pool employs the latest in technology, including a geothermal heating system, giving it Australia’s first six-star green rating.

Rockwater supervised the construction, testing and commissioning of an extraction-injection bore doublet in the Yarragadee Aquifer at the Scarborough swimming pool.

The production bore was drilled to 970 m depth to achieve a water temperature of 49.6°C, whereas the injection bore was drilled about 500 m shallower to avoid recirculation of the cooled water.  

Both bores are capable of producing 50 L/s, although the operational pumping rate is generally less than 25 L/s.

The Scarborough geothermal system provides over 4,500 MWh/year of low carbon heat to the pools, contributing to utility cost savings of several hundreds of thousands of dollars every year, and an CO2 abatement of more than 1,000 tons per year.

Twenty-six, deep geothermal bores have been constructed in the Perth Basin by Rockwater since 1998, mostly for the heating of large swimming pools, such as Scarborough.

Rockwater is the leader in developing geothermal resources for direct-use applications in Australia

• Geothermal feasibility study
• Geothermal bore design
• Geological and geophysical interpretation
• Groundwater modelling (including thermal breakthrough)
• Geochemical modelling using PHREEQC
• Field investigation reporting
• Annual compliance reporting

• Down-hole geophysical surveys
• Mud-rotary bores
• Temperature logging
• Verticality (gyro) surveys
• Downhole CCTV surveys
• Pumping tests
• Injection tests
• Injection bore redevelopment