Jonathan Ennis-King

• The Commonwealth Scientific and Industrial Research Organisation

The capture and geological storage of CO 2 is essential for net zero. Large volumes of secure subsurface storage will be required, much in unexplored saline aquifers. At the Otway International Test Centre we have executed a series of storage tests, including geophysical surveys, geochemical and petrophysical characterisation, drilling and instrume...

In this study, we conduct a comprehensive history matching study for the FluidFlower benchmark model. This benchmark was prepared and organized by the University of Bergen, the University of Stuttgart, and Massachusetts Institute of Technology, for promoting understanding of the complex physics of geological carbon storage (GCS) through in-house ex...

Underground Hydrogen Storage (UHS) is an emerging technology which aims to store terawatt-scale energy in the subsurface to alleviate daily and seasonal fluctuations in the ever-increasing renewable energy market. Depleted gas reservoirs and aquifers will be the main targets of storage which requires an understanding of the interaction between form...

Successful deployment of geological carbon storage (GCS) requires an extensive use of reservoir simulators for screening, ranking and optimization of storage sites. However, the time scales of GCS are such that no sufficient long-term data is available yet to validate the simulators against. As a consequence, there is currently no solid basis for a...

Physisorption can contribute to hydrogen subsurface storage. However, hydrogen physisorption at the surface of geological samples is mostly unknown. We are unaware of previous studies that investigate H 2 Physisorption in wide range of pure inorganic and organic earth minerals. Knowledge about H 2 Physisorption is required to evaluate the suitabili...

Underground hydrogen storage in depleted gas reservoirs is a promising and economical option for large-scale renewable energy storage to achieve net-zero carbon emission. While caprock plays an important role in sealing capacity, current knowledge is still limited on the effect of H2-brine-rock geochemical interactions on caprock integrity, raising...

The FluidFlower International Benchmark Study is a unique chance to assess the uncertainties introduced by numerical modelling through comparison to high-quality experimental data. A complete description of how the experiment was modelled by CSIRO is presented here, from the simplified model of the tracer tests and subsequent inversion of the perme...

Successful deployment of geological carbon storage (GCS) requires an extensive use of reservoir simulators for screening, ranking and optimization of storage sites. However, the time scales of GCS are such that no sufficient long-term data is available yet to validate the simulators against. As a consequence, there is currently no solid basis for a...

If there is a significant adoption of hydrogen in Australia as an energy carrier, it will be necessary to have storage options to buffer the fluctuations in supply and demand, both for domestic use and for export. For large-scale storage in a single location, underground hydrogen storage (UHS) is the preferred option for reasons of both cost and sa...

For Australia to capitalise on the growing hydrogen (H2) economy, the current capability gap for large-scale, secure and cost-effective H2 storage must be addressed. Large-scale underground hydrogen storage (UHS) in porous reservoirs offers the required capacity to balance discrepancies between demand and supply over seasonal durations, and support...

CO2CRC has made a significant investment into establishing the feasibility of conducting a CO2 injection experiment into a shallow fault at the CO2CRC Otway International Test Centre. Two appraisal wells drilled and cored through Brumbys Fault indicate the fault extends to the base of the upper 2 m thick Hesse Clay layer, which forms a seal to the...

Hydrogen storage in subsurface aquifers or depleted gas reservoirs represents a viable long-term energy storage solution. There is currently a scarcity of subsurface petrophysical data for the hydrogen system. In this work, we determine the wettability and Interfacial Tension (IFT) of the hydrogen-brine-quartz system using captive bubble, pendant d...

Underground hydrogen storage in depleted gas reservoirs is a promising and economical option for large-scale renewable energy storage to achieve net-zero carbon emission. While caprock plays an important role in sealing capacity, current knowledge is still limited on the effect of H2 -brine-rock geochemical interactions on caprock integrity, raisin...

Underground hydrogen storage (UHS) is considered a long-term storage solution which allows excess energy developed from renewable energy sources to be stored in the subsurface and retrieved when energy demand increases. Petrophysical properties of hydrogen interacting with fluid and solid in subsurface porous media have emerged to provide a practic...

Hydrogen storage in subsurface aquifers or depleted gas reservoirs represents a viable seasonal and/or long-term energy storage solution. However, currently, there is a scarcity of subsurface petrophysical data for the hydrogen system, limiting modelling work and industrial rollout. In this work, we address the knowledge gap by determining the wett...

The geomechanical response of a porous reservoir due to injection of fluid can result from a complex interplay between the changes in porepressure and temperature near the wellbore. As a result, predictions are usually made using either simplified analytical models, which may apply unrealistic assumptions in order to produce a tractable model, or d...

Numerical-simulation studies of transport and flow in porous media are essential in many practical fields of research. Including the coupling of different physical processes allows accurate modelling of the effects of fluid flow and temperature changes on the subsurface reservoir structure, and conversely, the effects of reservoir-structure changes...

CO2CRC has made a significant investment into establishing the feasibility of conducting a CO2 injection experiment into a shallow fault. This world-leading experiment, located at the CO2CRC Otway International Test Centre in Victoria, Australia, would seek to improve our understanding of the conditions necessary for CO2 to move vertically up fault...

The inversion of cross-well time-lapse pressure tests is investigated as a monitoring technique for locating CO2 plumes in the subsurface. Fast inversion methods are possible which treat the gas plume as either a constant-pressure or reduced diffusivity region. However, neither constant-pressure nor diffusivity-barrier approaches are adequate for m...

Proper site characterisation is vital in the planning stages of a CO2 storage project; but we can also learn a good deal about the reservoir once the injection is underway or has been completed. During CO2CRC Otway Project Stage 2C, sources of valuable information about storage performance have been generated as a consequence of the staged injectio...

We studied the influence of the diffusion contrast between species on the dynamics of Rayleigh-Bénard (RB) convection in porous media. The onset time of buoyancy-driven instabilities and convective dissolution flux was quantified using linear stability analysis and direct numerical simulations. The parametric analysis indicates eight distinct insta...

To meet the Paris Agreement target of limiting global warming to 2 °C or below it is widely accepted that Carbon Capture and Storage (CCS) will have to be deployed at scale. For the first time, experiments have been undertaken over six cycles of water and supercritical CO2 injection using a state of the art high flow rig recreating in-situ conditio...

CO2CRC and its partners are undertaking a feasibility study for a planned CO2 controlled release and monitoring experiment on a shallow fault at the CO2CRC Otway Research Facility. In this project we plan to image, using a diverse range of geophysical and geochemical CO2 monitoring techniques, the migration of CO2 up a fault from a controlled relea...

CO2CRC is undertaking a feasibility study for a planned CO2 controlled release and monitoring experiment on a shallow fault at the CO2CRC Otway Research Facility. In the first phase of the project, a series of geophysical surveys and groundwater permeability assessments were conducted at the Otway Research Facility to characterise the prospective e...

A dynamic modelling study was undertaken to assess the feasibility of a planned CO2 injection experiment into a shallow fault at the CO2CRC's Otway Research Facility. The aim was to identify key physical properties that strongly influence migration behaviour but are presently unmeasured. Two different simulators (CMG-GEM and TOUGH2) were used to mo...

Density-driven convective mixing in porous media can be influenced by the spatial heterogeneity of the medium. Previous studies using two-dimensional models have shown that while the initial flow regimes are sensitive to local permeability variation, the later steady flux regime (where the dissolution flux is relatively constant) can be approximate...

To meet the Paris Agreement target of limiting global warming to 2ºC or below it is widely accepted that Carbon Capture and Storage (CCS) will have to be deployed at scale. The influence of residual trapping on CO2 well injectivity and its response over time has a major impact on the injection efficiency and storage capacity of CO2 storage sites. F...

A single well characterisation test was conducted at the CO2CRC Otway storage site in Victoria, Australia, in 2011 and repeated in 2014. The near-well permeability was found to have declined nearly 60% since the 2011 test, while the residual saturation inferred from a variety of techniques was lower in 2014. There was a significant change in water...

Future CO2 storage projects will require Monitoring and Verification (M&V) operations at the CO2 storage site to understand the behavior of the CO2 plume, including the assurance that leakage of the CO2 has not occurred. Current surface based monitoring technologies may be unable to yield sufficient resolution or accuracy. CO2CRC, in conjunction wi...

The measurement of pressure in a permeable zone overlying a CO2 injection zone has been tested as a useful technique for monitoring CO2 plume evolution and detecting potential leakage. From Nov 2015 to April 2016 15,000 t of CO2-rich gas were injected at the CO2CRC Otway site in Victoria, Australia, and pressure was monitored with multiple gauges b...

Understanding the near surface migration patterns and rates of efflux of CO2 is important for developing effective monitoring and verification programs for the geological storage of CO2. Soil flux surveys are a well-established technique for characterisingsurface CO2 emission sources from controlled release sites, CO2 storage sites or natural CO2 s...

Permanent downhole gauges for measuring pressure and temperature are very useful for reservoir surveillance. Whereas most applications have used a single downhole gauge, here we discuss experience using multiple downhole gauges simultaneously in a single well. At the CO2CRC Otway site four permanent gauges were installed in the CRC-2 well in 2011 w...

In this paper, we present the methodology and results of the various fault modelling that was conducted so that the project could confidently proceed from the safety and integrity perspective. The work is broadly divided into two components. The first component is to assess the likely pressures generated by CO2 injection and to assess whether or no...

A key objective of stage 2 of the Cooperative Research Centre for Greenhouse Gas Technologies Otway Project is to evaluate the seismic detection limit of greenhouse gas injected into a saline aquifer. For this purpose, injection of a small amount of CO2-rich gas into the Paaratte Formation, a saline aquifer located at a depth of approximately 1.5 k...

Reservoir cooling at the injection interval is expected if CO2 is used as a heat carrier fluid in multi-well enhanced geothermal systems. Cooling the reservoir near the well alters the stress field. The tensile fracture pressure is reduced at the injection well perforations when the temperature difference between injected fluid and the reservoir is...

The dissolution of carbon dioxide (CO2) in deep saline aquifer water is recognized as one of the fundamental mechanisms in the subsurface for storing significant quantities of CO2. One fundamental physical effect of CO2 dissolution is the slight increase in water density in the layer in contact with the buoyant free-phase CO2 plume. Under specific...

We study the effect of background flow on the dissolution and transport of carbon dioxide (CO2) during geological storage in saline aquifers, and include the processes of diffusion, advection, and free convection. We develop a semi-analytical model that captures the evolution of the dissolution in the absence of free convection. Using the semi-anal...

The experience from CO2 injection at pilot projects (Frio, Ketzin, Nagaoka, US Regional Partnerships) and existing commercial operations (Sleipner, Snøhvit, In Salah, acid-gas injection) demonstrates that CO2 geological storage in saline aquifers is technologically feasible. Monitoring and verification technologies have been tested and demonstrated...

Enhanced dissolution of CO2 into a saline aquifer due to convective mixing is an important physical process for the secure long-term storage of significant quantities of CO2. Numerical simulations have previously shown that the dissolution rate of CO2 into reservoir brine will stabilise after a certain time period, with only small oscillations abou...

In this work semi-analytical solutions for saturation, temperature, pressure and in situ reservoir stress are found for immiscible nonisothermal injection into a radial porous medium. A model for advection-dominated, nonisothermal, two-phase flow from a previous work is used to estimate the reservoir pressure and stress that result from injection o...

Structural and geomechanical models of the CO2CRC Otway Project's Paaratte Formation are presented in advance of the proposed Otway Project time-lapse seismic monitoring of plume stabilisation test. The main goal of this experiment is to detect and monitor a CO2 plume in a saline aquifer using 4D seismic techniques and subsequently confirm plume st...

This work introduces the derivation and solution of the conservation laws for nonisothermal immiscible two-phase flow in one dimension (1D) with heat loss to surrounding strata. Purely advective flow is assumed so that the method of characteristics can be applied to the fluid flow and thermal equations with an arbitrary relative permeability model....

This paper presents the results of a partitioning tracer test using noble gases to measure residual CO2 saturation in the field as one part of the CO2CRC residual saturation and dissolution test sequence. Noble gas tracers were used in a sequential partitioning tracer test. The first tracer test was performed prior to CO2 injection to characterise...

The rate of buoyant migration of CO \(_2\) is of fundamental importance in storage in deep saline formations, and is known to be strongly affected by local heterogeneity. Using a simple model of heterogeneity consisting of a random distribution of impermeable barriers to represent a reservoir containing shale barriers, theoretical predictions of th...

As part of the CO2CRC Otway Residual Saturation and Dissolution Test, a series of field tests were conducted at their project site in Victoria, Australia, with the primary goal of developing and assessing methods for quantifying residual CO2 saturation in a saline aquifer. This paper reports the outcome of one of these tests, a single-well “push-pu...

Injecting carbon dioxide for storage can lead to substantial cooling of the reservoir that lasts for many years. This paper compares temperature data from the first stage of the CO2CRC Otway Project with theoretical results. Solutions are given for one-dimensional models of vertical and spherical heat diffusion and a radial model of lateral heat tr...

Residual and dissolution trapping are important mechanisms for secure geological storage of carbon dioxide. When appraising a potential site, it is desirable to have accurate field-scale estimates of the proportion of trapping by these mechanisms. For this purpose a short single-well test has been conceived that could be implemented before large- s...

Residual CO2 trapping (Sgr-CO2) is a key mechanism for geological CO2 storage. The CO2CRC undertook a sequence of field tests with the aim of comparing different ways of determining Sgr-CO2 including a dissolution test. Dissolution test results show an unexpectedly early breakthrough and low maximum CO2 concentrations in the back- produced water ma...

The presence of impermeable barriers in a reservoir can significantly impede the buoyant migration of $\mathrm{CO}_2$ injected deep into a heterogeneous geological formation. An important consequence of the presence of these impermeable barriers in terms of the long-term storage of $\mathrm{CO}_2$ is the residual trapping that takes place benea...

Numerical simulation is an essential component of many studies of geological storage of carbon dioxide, but care must be taken to ensure the accuracy of the results. Unlike several other possible sources of simulation errors, which have previously been considered in detail and have well-understood techniques for mitigating their effects, comparativ...

Carbon capture and storage (CCS) is vital to reduce CO(2) emissions to the atmosphere, potentially providing 20% of the needed reductions in global emissions. Research and demonstration projects are important to increase scientific understanding of CCS, and making processes and results widely available helps to reduce public concerns, which may oth...

Carbon capture and storage (CCS) is vital to reduce CO2 emissions to the atmosphere, potentially providing 20% of the needed reductions in global emissions. Research and demonstration projects are important to increase scientific understanding of CCS, and making processes and results widely available helps to reduce public concerns, which may other...

Carbon capture and storage (CCS) is vital to reduce CO2 emissions to the atmosphere, potentially providing 20% of the needed reductions in global emissions. Research and demonstration projects are important to increase scientific understanding of CCS, and making processes and results widely available helps to reduce public concerns, which may other...

The first stage of the CO2CRC Otway Project, located in south-eastern Australia, has stored 65,445 tonnes of CO2-rich gas in the depleted Naylor Gas Field. Comparisons have been made between simulations using the non-isothermal multi-phase flow simulator TOUGH2/EOS7C and the accumulated field data up to and beyond the end of injection. The geologic...

Existing pilot, demonstration and commercial storage projects have demonstrated that CO2 geological storage is technically feasible. However, these projects do not operate at a scale that is necessary to make a significant reduction in greenhouse gas emissions into the atmosphere. The infrastructure for injecting carbon dioxide will need to be an o...

Residual trapping is one of the four trapping mechanisms that have been identified for geological CO2 storage, a means to reduce atmospheric emissions and the related impacts as a result of continued use of fossil fuels. The objective of this research is to design a single-well injection-withdrawal test to estimate residual CO2 trapping (Sgr) in br...

The Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) Otway Project in Australia is the first heavily monitored pilot site for CO2 storage in a depleted natural gas reservoir. With the site characterisation and risk analysis complete, the new CRC-1 injection well was drilled in April 2007. An updated static and dynamic model fore...

The CO2CRC Otway Project in southwestern Victoria, Australia has injected over 17 months 65,445 tonnes of a mixed CO2–CH4 fluid into the water leg of a depleted natural gas reservoir at a depth of ∼2km. Pressurized sub-surface fluids were collected from the Naylor-1 observation well using a tri-level U-tube sampling system located near the crest of...

Carbon dioxide wells are different to oil, gas and water wells because large density changes due to transient thermal effects can decouple surface pressure from downhole pressure. This means, for instance, that wellhead pressure can decline while reservoir pressure is building after shut-in of a production reservoir. Similarly the opposite can occu...

A geomechanical assessment of the Naylor Field, Otway Basin, Australia has been undertaken to investigate the possible geomechanical effects of CO2 injection and storage. The study aims to evaluate the geomechanical behaviour of the caprock/reservoir system and to estimate the risk of fault reactivation. The stress regime in the onshore Victorian O...

The presence of impermeable horizontal barriers (such as shales) in a reservoir is known to have a significant effect on its vertical permeability. Since calculation of an effective vertical permeability of such a reservoir is important, approximation of the distribution of vertical permeability may also be useful for analysis of the two-phase vert...

The experience from CO2 injection at pilot projects (Frio, Ketzin, Nagaoka, US Regional Partnerships) and existing commercial operations (Sleipner, Snohvit, In Salah, acid-gas injection) demonstrates that CO2 geological storage in saline aquifers is technologically feasible. Monitoring and verification technologies have been tested and demonstrated...

The objective of our research is to design a single-well injection-withdrawal test to evaluate residual phase trapping at potential CO2 geological storage sites. Given the significant depths targeted for CO2 storage and the resulting high costs associated with drilling to those depths, it is attractive to develop a single-well test that can provide...

The Carnahan–Starling–Patel–Teja (CSPT) equation of state was revisited to improve the fitting accuracy of vapour–liquid equilibrium data of pure fluid substances. By setting the pseudo-critical compressibility factor and the correction coefficient in the attractive parameter as the temperature-dependent variables, the fitting accuracies of the vap...

This paper summarises the results of a benchmark study that compares a number of mathematical and numerical models applied to specific problems in the context of carbon dioxide (CO2) storage in geologic formations. The processes modelled comprise advective multi-phase flow, compositional effects due to dissolution of CO2 into the ambient brine and...

For deep injection of CO2 in thick saline formations, the movements of both the free gas phase and dissolved CO2 are sensitive to variations in vertical permeability. A simple model for vertical heterogeneity was studied, consisting of a random distribution of horizontal impermeable barriers with a given overall volume fraction and distribution of...