Fundamental study of migration of supercritical carbon dioxide in porous media under conditions of saline aquifers

Lead Research Organisation: University of Sheffield
Department Name: Mechanical Engineering

Abstract

Both Chinese and UK governments are committed to reducing emissions of greenhouse gases and have recognised carbon capture and storage (CCS) as an essential step towards this goal. The two countries have collaborated extensively and encourage new initiatives. This proposal is a response to the joint Call for Proposals from EPSRC and NSFC of China on CCS and will address a key fundamental issue under the priority theme 'Predicting and monitoring reservoir response' identified in the Call.Among the various CO2 storage options conceived, geological storage has achieved the best development, reaching a stage at which large deployments are foreseeable. There are three potential locations for geological storage, i.e. saline aquifers, depleted hydrocarbon reservoirs and un-mineable coal seams. The first of these is mostly favoured because it offers the greatest potential capabilities and is widely available. Over the past 10 years there have been over 10 saline aquifers injection operations conducted worldwide, and many more are being planned.A vast amount of work has been conducted recently studying a wide range of topics of CCS, from site section, environmental impact, public perception, economic viability, to technicality of injections and reservoir behaviours. In contrast, there are very limited studies addressing the underlying fundamentals of the trapping mechanisms and the multi-phase flow processes in porous media under complex thermodynamic conditions. The reason is that local measurement of flow in porous media at high pressure and elevated temperature is extremely difficult, and also there are no well-developed and efficient computational schemes for resolving two-phase flow in a large domain of complex geometries of porous media. The proposed research will make use of the latest development in measurement technology such as Magnetic Resonance Imaging (MRI) and numerical methods including for example Lattice Boltzmann Method (LBM). Detailed investigation will generate the much needed quantitative description of CO2 migration in porous media at extreme conditions relevant to saline aquifers encountered in carbon sequestration. and hence improve our understanding of the underlying physical processes. Experimental investigations on flow behaviour will be conducted at Tsinghua using a purposely-built supercritical CO2 test facility operating at conditions typical of deep saline aquifers with online measurement using a custom-built MRI. Both porous media made of sintered glass beads of constant diameter and real rock samples will be studied. Further experiments will be conducted at Leeds studying the geochemistry behaviours of the reactions of these rocks, as well as alternative reservoir lithologies and formation water chemistries. The computational studies will be led by Aberdeen and conducted at three levels: i) a finite-element solver of the fundamental equations governing the basic flow phenomena will be developed based on first principles. ii) An efficient two-phase flow LBM model for application of modelling CO2 migration in brine will be developed. It will be optimised for the particular fluid properties and thermodynamic conditions. Both of the above solvers will then be used to study the physical problems and generate further detailed information which is not available from experiments. iii) Exercises using CFD simulations with commercial software will also be continued. They will produce complementary data to compare with our new methods. Finally theoretical studies making use of the new results will be carried out by the whole multidisciplinary team. All experimental and computational results will be further processed to produce correlations/relationships for use with large scale simulations and will be studied comprehensively to develop further fundamental understanding of the phenomena of CO2/brine two-phase flow in porous media.

Planned Impact

The immediate beneficiaries of this project are researchers and academics who develop large-scale models and those who use those modelling tools for CO2 injection strategy and capacity studies. They will make use of the new data and improved understanding to test and improve the basic formulations used in the large-scale simulation models, and to find and correct any inappropriate assumption built into these models. Furthermore, new experimental techniques and numerical algorithms which emerge from the proposed research will benefit researchers working on broader applications such as groundwater utilisation and protection, fuel cells and chemical reactors. The next-level beneficiaries are major gas and coal fired power plants and other concentrated sources of CO2 and oil and gas production companies, who are interested in either capturing and storing CO2 they generate, or, using CO2 for enhanced oil recovery (EOR). They will benefit from the advance of CCS technology. Clearly, the ultimate beneficiaries are the general public and plants/animals on the planet, all will benefit from a benign climate. We will work towards maximising the impact through the following measures: Publications - This is the basic but probably most important step to maximise the impact of this fundamental research as the immediate beneficiaries are researchers and academics. Publication plan will be on the agenda of each project progress video conference (biannual). We will normally expect each PhD student to produce two journal publications and make two conference presentations. We expect four major publications from the first two themes, i.e., experiments on flow and computations, and two from the mineral-fluid interactions theme. We will also regularly attend workshops and seminars to communicate our results quickly and effectively to our peers and a wide public and have made explicit budget request for such activities. Specialised networks - These always produce a fast and efficient route for disseminating project results and receiving feedbacks. Currently the BY and RX are members/participants of several CCS related networks and international collaborative projects, e.g, CRIUS consortium, UKCCSC, and GeoCapacity, NZEC, COACH projects. It is expected that the present collaboration will also provide opportunity for other members of this team to be involved in activities organised by these networks and to expand their network in CCS. UK and China collaboration - Solid plans for the exchange of visits by investigators and students will be made at early stage of the project according to the outlines given in Justification of Resources. These visits together with the biannual progress meetings (video) will ensure that all the information/knowledge generated is promptly shared by all the team members. The team will explore further research collaboration opportunities in China and the UK. Collaboration and direct communication with the company - The industry project partner CO2DeepStore, an UK based company specifically focused on the commercialisation of geological storage of CO2 deep within the earth, has expressed keen interest in collaborating with the team in and outwith the proposed project. We will also actively seek further collaborations with industry. Further research - All Investigators have strong interest either in applying the results form this project to other areas or in applying the new data/knowledge in further studies in CCS applications. Training of personnel - An important impact of the proposed project is training a number of researchers both in the UK and in China, who will eventually make important impact to the society. In addition to the basic scientific training, they will be exposed to this large multi-disciplinary team. They will have opportunity to spend a period of time in partners' laboratory and frequently exchange ideas with them.

Publications

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Lamy-Chappuis B (2016) The effect of CO 2 -enriched brine injection on the mechanical properties of calcite-bearing sandstone in International Journal of Greenhouse Gas Control

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Zu YQ (2013) Phase-field-based lattice Boltzmann model for incompressible binary fluid systems with density and viscosity contrasts. in Physical review. E, Statistical, nonlinear, and soft matter physics

 
Description The overall aim of our research is to develop fundamental understanding and quantitative description of CO2 migration in porous media at extreme conditions relevant to saline aquifers encountered in carbon sequestration.
(1) We have discovered that CO2-saturated brine is effective at dissolving calcite from sandstone, resulting in markedly increased rock porosity. Depending on the specific geological setting, enhanced permeability through calcite dissolution could be a threat to the integrity of injection schemes or could be managed to make them more effective.
(2) We have developed a new two-phase flow Lattice Boltzmann Method (LBM) model for incompressible binary fluids with density and viscosity contrasts with various improvements in comparison with existing models including significantly reduced spurious interfacial forces, and hence providing a better tool for the prediction of CO2 injection and storage. We have conducted simulations with systematically varied conditions using the new model to develop a better understanding of the CO2 migration process.
(3) It is known that the predicted permeability of single phase flow using LBM is dependent on the chosen fluid viscosity, but we have for the first time established that the predicted relative permeability of two-phase flow using LBM is independent of the viscosities of the fluids.
(4) MRI has been used to characterise and quantify the behaviours of the migration of supercritical CO2 in sintered glass beads of constant diameter and in realistic heterogeneous porous media and new reliable data are now available for model validation.
Exploitation Route A number of journal and conference papers have been published/are in preparation. These systematically report our new data, computing models, and new understanding, which are likely to benefit other researchers and modelers. For example, Phys. Rev. E 87, 043301, which was published in 2013, has already attracted some 10 citations demonstrating its impact.
Sectors Energy,Environment

URL http://www.sheffield.ac.uk/heft/co2flip
 
Description This research is fundamental in nature and its immediate beneficiaries of this project are researchers and academics who develop large-scale models and those who use those modelling tools for CO2 injection strategy and capacity studies.
First Year Of Impact 2004
Sector Education,Energy,Environment
Impact Types Economic

 
Title CO2FLIP_Stokes 
Description The model simulates pore-scale creeping two-phase flow in porous media. The fundamental mass and momentum balance equations for two fluid phases are solved within a domain of a true representation of the pore geometry. The contribution of inertial effects to the fluid motion is neglected so the movement of each fluid is described by conventional Stokes equations. The three-dimensional pore space is split into a large number of cube-shaped computational cells. The equations are solved using the volume-of-fluid method combined with an interface-tracking algorithm and a sharp surface tension model with smoothing of the interface-normal vectors at the contact line. For real world applications the pore geometry is usually obtained by 3D Computed Tomography. Simulation results can be up-scaled to obtain flow properties relevant for two-phase flows such as CO2 migration in brine aquifers. 
Type Of Material Computer model/algorithm 
Provided To Others? No  
Impact The model will be used to improve understanding of the processes occurring during migration of CO2 through brine aquifers and to generate a database of digital rock models and the corresponding field-scale flow properties for a series of rock samples. These in turn will the efficiency of CO2 injection schemes. 
 
Description Visiting Professor (University of Texas at Austin) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Presented a lecture to the CCS research group in Austin and engaged in extended discussions with members. Also gave related but more general lectures in the geology department
Year(s) Of Engagement Activity 2012
 
Description Workshop Presentation (California) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Co-presented an invited contribution to a workshop on Geochemistry of Geologic CO2 Sequestration. This workshop was organised and led by many of the leading figures in the field and provided an outstanding opportunity to introduce work carried out in the UK. It led to increased interest in our work and an increase in reading and citations of it.
Year(s) Of Engagement Activity 2013