Potential Storage Capacity Research Articles

Sparse fulleryne structures enhance potential hydrogen storage and mobility

We propose a novel fullerene-like molecule—a so-called fulleryne—to increase potential hydrogen storage capacity of carbon-based systems, assessed via full atomistic molecular dynamics.

Thermochemical performance of carbon nanotubes based hybrid materials for MgO/H2O/Mg(OH)2 chemical heat pumps

Newly developed hybrid materials made of magnesium hydroxide and carbon nanotubes were proposed as heat storage medium for MgO/H2O/Mg(OH)2 chemical heat pumps. Samples were synthesized by deposition-precipitation method varying the Mg(OH)2 load (32–52wt.%) and the type of carbon nanotubes, pristine or functionalized. The performances of the synthesized materials were evaluated by thermogravimetric analysis, which simulates the chemical heat pump cycle. The presence of the carbonaceous material positively affected the reaction performances, so that the hybrid materials showed improved heat storage/output capacity and faster heat output rate compared to pure Mg(OH)2. The functionalization treatment and a proper Mg(OH)2 load were fundamental to better the dispersibility of Mg(OH)2 into the carbon nanotubes bundles which in turn enhanced the thermochemical performance of the active material, fully exploiting for the first time its maximum potential heat storage capacity, that is ∼1300kJ/kgMg(OH)2, thus bringing the development of this technology to a level closer to its industrial application.

Mapping of the CO2 storage potential in the Nordic region

The concept of utilising available pore space in deep saline sandstone aquifers for storage of CO2 was recognised in the late 1980s. In 1996, the first commercial CO2 storage project began with injection into sandstones of the Utsira Formation in Norway. The formation is located above the Sleipner Formation from where the Sleipner field produces natural gas. The project was initiated due to a high CO2 content of the natural gas, which was subjected to a Norwegian offshore carbon tax. The natural gas is produced on the Sleipner platform where the CO2 is separated, captured and reinjected from a neighbouring platform. The potential for using the technology to reduce CO2 emissions from large stationary point sources initiated many research projects aimed at mapping areas with potential CO2 storage capacity around the world.

No Significant Effect of Phosphorous Doping on the Electrochemical Performance of Silicon-Carbon Composite Anodes for Li-ion Batteries

SUMMARY Using an industry-relevant method of production we have demonstrated production of doped silicon nanoparticles for Li-ion batteries. The particles have been characterized and tested in Li-ion battery half-cells for demonstration of the performance as Li ion storage material in the anode. In this presentation we will show the results regarding the characterization of the particles as well as the performance results of the material in Li-ion half cells. BACKGROUND The use of silicon as part of the anode in Li-ion batteries enhances the potential storage capacity greatly. While the graphite anode used in standard Li-ion batteries has a theoretical capacity of 372 mAh/g, the theoretical capacity for Si is 3,572 mAh/g [1]. However, to be able to absorb the sufficient amount of Li ions reversibly, the silicon material needs to be nanostructured [2]. EXPERIMENTAL IFE has earlier demonstrated production of silicon particles prepared using a silane-based free-space reactor, which allows control of particle size distribution and crystallinity and a high production capacity [3]. In this work, the setup was modified to allow for introduction of phosphine gas in the production process. The intention was to introduce phosphorous dopant atoms to modify the electrical conductivity of the silicon material. The current particles were produced with a silane flow rate of 5 slm, and 5 slm of 3% phosphine diluted in He. Thus, the P concentration in the process gases was 3% with respect to Si. The production rate at 100% yield would be about 400 g/h, while the product recovered from the process typically was between 100 and 200 g/h. The processing temperature was varied from 475 °C to 600 °C to produce particles with different properties. All electrochemical tests were performed in a crimped 2032 coin cell with lithium metal used as a counter electrode, with a polymer separator (Celgard 3401) and 1 M LiPF6 in 1:1 EC/DMC electrolyte (LP30, BASF). For some experiments, 10 wt% fluoroethylene carbonate (FEC) was used as electrolyte additive. The cells were cycled at 25 °C between 0.05 and 1.0 V with a constant C-rate of C/10 (after initial 3 cycles at C/20) using an Arbin Battery cycler (Arbin Instruments). RESULTS AND CONCLUSIONS The phosphorus content of the particles was by inductively coupled plasma mass spectrometry (ICP-MS) and energy-dispersive x-ray spectroscopy (EDS) measured to be in the range of 1.7-1.8% with respect to silicon. Thus, it seems that the utilization of the phosphine is not complete, or phosphorous binds to materials which are not recovered from the production process. The particle size distribution was centered around 600 nm as measured by laser scattering in a Malvern Mastersizer 2000. SEM and TEM revealed that the particles consisted of aggregates of spherical silicon particles with a primary particle size of 50-400 nm. X-ray diffraction showed that we could produce amorphous or crystalline particles depending on the temperature of the process. Cycling of the particles in lithium battery half cells showed a life time of about 300 cycles for doped and undoped particles. Some measurements indicate a better conductivity of the doped material but the results were not conclusive. The cells were cycled with a limited capacity regime where the capacity was set to 1000 mAh/g(Si) and thus the end-voltage could vary. The most pronounced difference in the cycling performance between doped and undoped silicon particles was a shift in the increase in end voltage for the doped particles: While end-voltage increased from 0.4 V to 0.6 V over the first 25 cycles, this development is stretched out over the first 50 cycles or more for doped particles. See the attached figure for further details.

Using underground gas storage to replace the swing capacity of the giant natural gas field of Groningen in the Netherlands. A reservoir performance feasibility study

In this study we probe the ultimate potential Underground Gas Storage (UGS) capacity of the Netherlands by carrying out a detailed feasibility study on inflow performances of all onshore natural gas reservoirs. The Netherlands is one of the largest natural gas producers in Western Europe. The current decline of its national production and looming production restrictions on its largest field of Groningen -owing to its induced seismicity- have recently made necessary to upgrade the two largest UGS of Norg and Grijpskerk. The joined working volume of these two UGS is expected to replace the swing capacity of the Groningen field to continue guaranteeing the security of supply of low calorific natural gas. The question is whether this UGS configuration will provide the expected working storage capacity unrestricted by issues on reservoir performances and/or induced seismicity. This matter will be of paramount importance in the near future when production restrictions and/or the advance state of depletion of the Groningen field will turn the Netherlands into a net importer of high calorific natural gas. By then, the question will be whether the available UGSs will still be economically attractive to continue operating, or if additional or alternative UGSs will be needed?. Hence the characterization and ranking of the best potential reservoirs available today is of paramount importance for future UGS developments.We built an in-house automated module based on the application of the traditional inflow performance relationship analysis to screen the performances of natural gas reservoirs in onshore Netherlands. Results enable identifying the 72 best candidates with an ultimate total working volume capacity of 122±30 billion Sm3. A detailed sensitivity analysis shows the impact of variations in the reservoir properties or wellbore/tubing configurations on withdrawal performances and storage capacity. We validate our predictions by comparing them to performances of the UGSs currently operating in the Netherlands. Our results show that although Norg and Grijpskerk stand midst the best candidates, their working:cushion gas volume (wv:cv) ratios appear amongst the lowest. We found many other reservoir candidates with higher wv:cv ratios (>1) and working volumes between 3 and 10 billion Sm3 geographically distributed across the Netherlands. Any of the current and future UGSs will have to compete with economically more attractive means of gas import via pipelines and liquefied natural gas. We suggest that only the strategic development of a network of efficient underground gas storages with wv:cv ratios >1, could increase its economical attractiveness. This can reduce future dependence on foreign gas supply for cases of import disruption or shortages during peak demand in winter periods. Future political and economic decisions and societal acceptance will determine the role that UGS will play in the security of supply of natural gas in the Netherlands and Western Europe.

Establishment and potential snow storage capacity of willow (Salix spp.) living snow fences in south-central Minnesota, USA

Living snow fences (LSFs) are a cost-effective windbreak practice designed to mitigate blowing and drifting snow problems along transportation routes. Shrub-willows (Salix spp.) have been proposed as a LSF species to provide multiple benefits, given their potential to reach effective heights and densities soon after planting and provide a marketable biomass product. However, information regarding their establishment and snow storage capacity in LSF settings is limited. We investigated establishment and potential snow storage capacity of three shrub-willow varieties in LSF planting arrangements of two and four rows after one growing season post-coppice on a two-year-old root system in south-central Minnesota, USA. We found willows had an average survival of 89 %, an average height of approximately 1 m, and potential snow storage capacities ranging from 1 to 9 t m−1. Compared to the mean annual snow transport of the south-central region (39.9 t m−1), none of the willow LSF varieties and planting arrangements were able to trap all of the predicted blowing snow at the study site after two growing seasons post-coppice. However, using willow LSF models, we observed that willow LSFs could exceed local snow transport after 2–3 growing seasons post-coppice. Additionally, four-row willow LSF arrangements trapped approximately 20 % more snow than to two-row arrangements, and willow variety did not affect snow storage. These results add to the limited literature on shrub-willow LSFs and can guide the design of effective willow LSFs.

Case studies on the CO2 storage and EOR in heterogeneous, highly water-saturated, and extra-low permeability Chinese reservoirs

The CO2 storage and CO2 enhanced oil recovery (EOR) in reservoirs often face challenges due to a high heterogeneity, high levels of water saturation, or low permeability. Based on the evaluation method of the CO2 storage capacity and EOR, three typical reservoirs representing these challenges are introduced to study their effect on the CO2 EOR potentials and CO2 storage capacities. The properties of these reservoirs were analyzed in detail, and geological models were built. The reservoir simulation method is adopted to analyze and validate the CO2 injection process and the storage effect for different types of reservoirs. From the examples in this paper, the low permeability reservoirs appear to have a higher EOR potential and CO2 storage capacity than highly heterogeneous reservoirs. These results support the premise of injecting CO2 into reservoirs to decrease atmospheric greenhouse gas emissions while enhancing oil recovery.

Identification of oil reservoirs suitable for CO2-EOR and CO2 storage (CCUS) using reserves databases, with application to Alberta, Canada

Carbon capture and storage (CCS) is a key technology which could be utilized to stabilize CO2 concentrations in the atmosphere. While all the components of integrated CCS systems exist and are in use today in the fossil-fuel extraction and refining industries, very few large-scale integrated CCS projects are currently in operation, due mainly to the high cost of implementation. For this reason, in the last few years the concept of CO2 capture, utilization and storage (CCUS) has been advanced, based on the premise that utilizing CO2 captured from anthropogenic sources, particularly in CO2 enhanced oil recovery (EOR) operations, would provide revenue that will, accordingly, reduce costs and facilitate deployment. When a large number of oil reservoirs are found in a particular region or jurisdiction, it is very difficult to ascertain which oil reservoirs are suitable for CO2-EOR by using detailed reservoir analysis and numerical simulations. In such cases, reserves databases may contain sufficient information to allow a region- or jurisdiction-wide identification (screening) of oil reservoirs suitable for CO2-EOR. Based on industry's experience to date with CO2-EOR, a set of 14 criteria has been developed to screen oil reservoirs in terms of their suitability for CO2-EOR, including operational and reservoir characteristics, and reservoir size. Using the published statistical analysis of the performance of 31 CO2-EOR operations in Texas, it is possible to estimate the incremental oil recovery factor and the net CO2 utilization factor for a given oil reservoir suitable for CO2-EOR, hence the incremental oil recovery and associated CO2 storage for that reservoir. In terms of CCUS, two additional screening criteria are introduced, which relate the size and location of large CO2 sources with respect to the location and potential CO2 storage capacity of a given oil reservoir suitable for CO2-EOR. If more than one oil reservoir meets these conditions for a particular large CO2 source, the reservoirs could be ranked using a weighted normalized parametric procedure that takes into account reservoir storage capacity in relation to the size of CO2 emissions from that particular source, the distance between the source and the reservoirs, and the depth of the reservoirs.The screening and ranking procedures for identifying oil reservoirs suitable for CO2-EOR and CO2 storage has been applied to Alberta, Canada, where there are close to 13,000 oil reservoirs recorded in the reserves database of the oil and gas regulatory agency. Application of the screening criteria identified 136 oil reservoirs in 85 oil fields that are suitable for CO2-EOR. The criteria that have the greatest impact on screening are oil gravity, minimum miscibility pressure and reservoir size. Second-order criteria in terms of impact are reservoir temperature and oil viscosity. Porosity and initial oil saturation have almost no effect, mostly because most reservoirs would normally satisfy these criteria. The cumulative incremental oil production at 2 HCPV injected CO2 in these 136 oil reservoirs is estimated to be 759, 1742 and 2858 MMSTB at P10, P50 and P90, respectively, with corresponding cumulative CO2 storage capacity of 213, 868 and 1742Mt CO2. Considering a maximum straight distance of 300km between any of the 38 large CO2 sources in Alberta and oil fields with reservoirs suitable for CO2-EOR, and a minimum storage capacity equivalent to 5 years of emissions leads to the identification of 29 oil fields that are suitable for both CO2-EOR and CO2 storage (i.e., CCUS).The methodology presented herein for screening oil reservoirs for CO2-EOR and CO2 storage can be applied to any region or jurisdiction in the world, possibly with some adjustments regarding some threshold values and weighting coefficients for reservoir ranking.

Identification of potential soil water retention using hydric numerical model at arid regions by land-use changes

Assessment of soil water retention in arid region is an input required parameter in precision water management at large scale. Investigations were carried out in Tanta catchment in the middle Nile Delta, Egypt (30° 45 N, 30° 55 E), where collecting soil samples covered different hydrological soil groups and land-uses. Based on the natural resource conservation service curve number model (NRCS-CN), CN approach was used to investigate the effect of spatio-temporal variations of different land-uses on soil water retention. Potential soil water retention from 1990 to 2015 was reduced by 118.1m3 per hectare with decreasing cropland area. Urbanization encroachment from 1990 to 2015 was increased by 2.13% by decreasing cropland with 15.3% (5300ha in 2015). This resulted in losing the potential soil water retention by 625,968.42m3 water for the whole catchment area. Impact of land degradation was pronounced, where 2.65%, 29.35%, and 1.11% of the initial crop land-use in 1990 were converted to bare soil, fallow, and urban area, respectively in 2015. Implementation of (S) value of the NRCS-CN model with GIS technique provides useful measure to identify land-use changes of potential water storage capacity at catchment scale.

Impact of Maximum Allowable Cost on CO2 Storage Capacity in Saline Formations.

Injecting CO2 into deep saline formations represents an important component of many greenhouse-gas-reduction strategies for the future. A number of authors have posed concern over the thousands of injection wells likely to be needed. However, a more important criterion than the number of wells is whether the total cost of storing the CO2 is market-bearable. Previous studies have sought to determine the number of injection wells required to achieve a specified storage target. Here an alternative methodology is presented whereby we specify a maximum allowable cost (MAC) per ton of CO2 stored, a priori, and determine the corresponding potential operational storage capacity. The methodology takes advantage of an analytical solution for pressure build-up during CO2 injection into a cylindrical saline formation, accounting for two-phase flow, brine evaporation, and salt precipitation around the injection well. The methodology is applied to 375 saline formations from the U.K. Continental Shelf. Parameter uncertainty is propagated using Monte Carlo simulation with 10 000 realizations for each formation. The results show that MAC affects both the magnitude and spatial distribution of potential operational storage capacity on a national scale. Different storage prospects can appear more or less attractive depending on the MAC scenario considered. It is also shown that, under high well-injection rate scenarios with relatively low cost, there is adequate operational storage capacity for the equivalent of 40 years of U.K. CO2 emissions.

Dynamic Thermal Performance of a PCM Window System: Characterization Using Large Scale Measurements

Introdution of more dynamic building envelope components have been done throughout the last decades in order to try to increase indoor thermal comfort and reduce energy need in buildings for both temperature and light control. One of these promising technologies is phase change materials (PCM), where, the latent heat storage potential of the transition between solid and liquid state of a material is utilized as thermal mass. A PCM layer incorporated in a transparent component can increase the possibilities to harvest energy from solar radiation by reducing the heating/cooling demand and still allowing the utilization of daylight. The introduction of dynamic components in the building envelope makes the characterization of conventional static performance indices insufficient in giving a clear picture of the performance of the component in question.Measurements have been performed on a state-of-the-art window that integrates PCM using a large scale climate simulator. The glazing unit consists of a four-pane glazing with an integrated layer that dynamically controls the solar transmittance (prismatic glass) in the outer glazing cavity. The innermost cavity is filled with a phase change material.This article presents and assesses the series of measurements and the related methodologies with the aim of investigating the thermal behavior and thermal mass activation of the PCM-filled window. The experiments have been carried out using several static and dynamic test cycles comprised of temperature and solar radiation cycling. A conventional double-pane window has also been experimental investigated using the same test cycles for reference purpose.It was found that even for temperatures similar to a warm day in Nordic climate, the potential latent heat storage capacity of the PCM was fully activated, but relatively long periods of sun combined with high exterior temperatures are needed.

Response of Vertisols, Andosols, and Alisols to paddy management

Interchanging submergence and drainage in paddy soils induce alternating redox conditions. It is known that this causes changes in organic carbon stocks, in amounts and crystallinity of Fe oxides as well as transformation of clay minerals and subsequent changes in cation exchange capacity (CEC). However, the influence of the initial soil type on the extent of these changes is not yet well understood. Therefore, we studied paddy soils that derived from three different soil types (Vertisols, Andosols, Alisols) on volcanic parent material in Java (Indonesia). To account for the variability in parent materials, we additionally sampled sandstone-derived Alisols in China. Adjacent non-paddy soils were sampled as references. Samples were analyzed for texture, bulk density, clay mineral composition, total element content, pH, CEC, phosphorus retention, organic carbon (OC), and acid oxalate- (Feox) and dithionite–citrate–bicarbonate-extractable Fe (FeDCB).Only the Alisol-derived paddy soil in China showed textural changes, compared to the non-paddy soil. Evidence for paddy management induced ferrolysis was not found. The smaller topsoil clay content in the paddy soil is most probable caused by clay migration. Only minor differences in clay minerals were found; topsoils of Andosol-derived paddy soils, however, tend to be less desilicated, indicating phytolith accumulation. Except for Vertisols, paddy management caused significant depletion in Fe oxides in the topsoils (puddled layer and plow pan) due to redox processes. The extent to which the reduced Fe was leached or re-oxidized as short range-ordered Fe oxides depended on the soil texture. Andosols and sandy Alisols facilitated leaching, clayey Alisols re-oxidation. In either case, the stocks of crystalline Fe oxides diminished, causing increased proportions of short range-ordered Fe oxides. Retention of phosphorus was directly related to changes in the absolute amounts of short range-ordered Fe oxides. An accumulation of Fe oxides in paddy subsoils was not found. Lateral transport with drainage water might be a reason. In highly permeable soils with large vertical water fluxes (e.g., Andosols under paddy management), colloidal transport might also play a role. Despite losses in potential OC storage capacity (i.e., Fe oxides, clay minerals, allophane), paddy soils derived from Andosols and sandy Alisols in China had larger OC concentrations in the puddled topsoil, whereby the other soils showed no increase in OC under paddy management. Therefore, paddy management does not necessarily enhance carbon sequestration. Rather, differences in organic matter input between non-paddy and paddy soils seem to determine whether OC is accumulated under paddy management or not. Effects of paddy management on CEC were little and mainly due to OC accumulation and Fe oxide coating removal from clay minerals.Overall, paddy management-induced changes were partly influenced by the original soil and the parent material. In turn, the main characteristics of the initial soil type were preserved and not overridden by paddy management.

Carbon sequestration potential of the Habanero reservoir when carbon dioxide is used as the heat exchange fluid

The use of sequestered carbon dioxide (CO2) as the heat exchange fluid in enhanced geothermal system (EGS) has significant potential to increase their productivity, contribute further to reducing carbon emissions and increase the economic viability of geothermal power generation. Coupled CO2 sequestration and geothermal energy production from hot dry rock (HDR) EGS were first proposed 15 years ago but have yet to be practically implemented. This paper reviews some of the issues in assessing these systems with particular focus on the power generation and CO2 sequestration capacity. The Habanero geothermal field in the Cooper Basin of South Australia is assessed for its potential CO2 storage capacity if supercritical CO2 is used as the working fluid for heat extraction. The analysis suggests that the major CO2 sequestration mechanisms are the storage in the fracture-stimulation damaged zone followed by diffusion into the pores within the rock matrix. The assessment indicates that 5% of working fluid loss commonly suggested as the storage capacity might be an over-estimate of the long-term CO2 sequestration capacity of EGS in which supercritical CO2 is used as the circulation fluid.

Potential evaluation of CO2 EOR and sequestration in Yanchang oilfield

CO2 storage in oil reservoirs is not only an effective method for reducing CO2 emissions and greenhouse effect, but also a superior choice by enhancing oil recovery economically. This option, which lowers CO2 sequestration cost by recovering incremental oil, is particularly attractive in mature oil fields, such as Yanchang oilfield in China where many oil pools are near depletion and where most of the needed infrastructure is already in place. Using screening criterion, MMP determination and capacity evaluation methods, the feasibility of CO2 flooding, potential CO2 EOR and CO2 storage capacity of twenty-seven reservoirs in Yanchang Oilfield were evaluated. Results show that of all the 27 reservoirs only 8 are suitable for implementing CO2 EOR and sequestration project with average CO2 storage coefficient of 0.185, demonstrated the CO2.sequestration potential in Yanchang oilfield is very limited.

South West Hub Project: appraising a carbon storage resource in Western Australia

The South West Hub Carbon Capture and Storage Project (SWH), managed by the WA Department of Mines and Petroleum (WA DMP), is evaluating the potential for a commercial-scale carbon storage site near major emissions sites in southwest WA. The area under investigation is in the southern Perth Basin, focusing on a 150 km2 area in the shires of Harvey and Waroona. WA DMP is conducting a major feasibility study and collecting pre-competitive data in partnership with the local community. The activities are done in a stage-gate model to obtain relevant information on the potential storage capacity, containment security and injectivity of the geology. Following a smaller 2D seismic survey and the drilling of the Harvey–1 stratigraphic well, a more complex 3D seismic survey was undertaken in February to March, 2014. These activities have confirmed the potential for commercial-scale CO2 storage. A new work package has been initiated with the drilling of three wells (Harvey–2, –3 and –4) underway and plans to drill a fifth well in the next 12 months. The stage-gate approach has been cost-effective, resulting in a carefully planned data acquisition and research program. The approach allows new results, information and potential future activities to be rolled out to stakeholders and the community in the area.

CO2 storage capacity estimation for a deep saline formation by static reservoir modelling: the Cretaceous Paaratte Formation, offshore Otway Basin, Victoria

This study used stochastic simulation to estimate the CO2 storage capacity of the Cretaceous Paaratte Formation within the Casino 3D seismic survey area of the offshore Otway Basin, Victoria. Besides interpretation results from primary hard data (well data), relative acoustic impedance was used as secondary soft (proxy) data to model the distribution of the volume fraction of shale (V-Shale). The V-Shale model provided an equivalent model of lithofacies for the clastic reservoir. V-Shale correlated well with the net-to-gross and effective porosity parameters in well log interpretation results. Collocated co-kriging was then used to model the distributions of net-to-gross and effective porosity from well profiles by stochastic co-simulation processes. Using the total pore volume (TPV) obtained from this 3D modelling and storage efficiency factors defined by US DOE-NETL (2012), the potential CO2 storage capacity of the Paaratte reservoir is estimated to be between 11.94 million tonnes (P90) and 128.75 million tonnes (P10) within the geographic footprint of the Casino 3D seismic survey area. The expected TPV storage capacity (P50 confidence interval) is 46.82 million tonnes.

Carbon dioxide sequestration in saline formations: Part I—Review of the modeling of solubility trapping

Abstract Sequestration of carbon dioxide in saline aquifers has emerged as the preferred method of permanently storing CO2 in subsurface formations because of the abundance and potential storage capacity of such sites. The key to the successful design and implementation of a sequestration operation is the ability to predict the spread of CO2 within the aquifer. This requires an understanding of the fundamental flow processes within a complex geologic environment that depend on the interaction of the trapping mechanisms related to capillarity, dissolution and mineralization. Due to the complex nature of this interaction, previous studies have dealt with the modeling of each of the trapping mechanisms individually, under idealized conditions. These studies have focused on the spread of the gravity current of supercritical CO2, enhanced dissolution due to natural convection and the process of mineralization involving the formation of carbonate precipitates. The objective of the current two part review is to provide a perspective on the progress made thus far towards the modeling of solubility trapping in part I and aspects of multiphase flow modeling related to CO2 sequestration in part II. The reviews are an attempt to facilitate the development of an integrated model for the prediction of practical problems as well as the identification of areas that need attention.

Review: Approaches to research on CO2/brine two-phase migration in saline aquifers

Understanding CO2/brine multiphase migration processes is critical for effectively evaluating potential storage capacity, ensuring storage security, and predicting the long-term fate of CO2 storage in saline aquifers. Success depends on the development and application of appropriate research methods. This paper accordingly reviews the progress made in research methods on CO2/brine two-phase migration. Due to intrinsic linkage between CO2 migration and trapping in saline aquifers, prediction of CO2/brine migration processes requires an accurate understanding of CO2 trapping mechanisms. Six recognized physical or geochemical mechanisms, including structural and stratigraphic trapping, residual gas trapping, hydrodynamic trapping, solubility trapping, local capillary trapping and mineral trapping, can impede or prevent CO2 migration according to different dominating variables, and consequently immobilize CO2 in brine formations at varying time and spatial scales. Laboratory experiments, field-scale monitoring and computational modeling are the main approaches in studies on CO2/brine multiphase migration. Different techniques have been designed and developed within each of these methods in terms of physical conditions and spatial scales of multiphase migration phenomena. Due to multi-scale characteristics of CO2/brine multiphase migration processes and complementary relationships among these methods and techniques, different research methods and techniques are often used in combination. Based on a systematic analysis of limitations and weaknesses, improvements are recommended which could potentially increase the accuracy, reliability and applicability of the approaches.

An overview of current status of carbon dioxide capture and storage technologies

Abstract Global warming and climate change concerns have triggered global efforts to reduce the concentration of atmospheric carbon dioxide (CO2). Carbon dioxide capture and storage (CCS) is considered a crucial strategy for meeting CO2 emission reduction targets. In this paper, various aspects of CCS are reviewed and discussed including the state of the art technologies for CO2 capture, separation, transport, storage, leakage, monitoring, and life cycle analysis. The selection of specific CO2 capture technology heavily depends on the type of CO2 generating plant and fuel used. Among those CO2 separation processes, absorption is the most mature and commonly adopted due to its higher efficiency and lower cost. Pipeline is considered to be the most viable solution for large volume of CO2 transport. Among those geological formations for CO2 storage, enhanced oil recovery is mature and has been practiced for many years but its economical viability for anthropogenic sources needs to be demonstrated. There are growing interests in CO2 storage in saline aquifers due to their enormous potential storage capacity and several projects are in the pipeline for demonstration of its viability. There are multiple hurdles to CCS deployment including the absence of a clear business case for CCS investment and the absence of robust economic incentives to support the additional high capital and operating costs of the whole CCS process.

Assessment of storage capacity for CO2in saline aquifers near hydrocarbon fields, northern Songliao Basin, China

Carbon dioxide capture and storage (CCS) is the only technology currently available that can significantly reduce carbon dioxide (CO2) emissions from conventional fossil fuel use. Depleted oil/gas fields, unmineable coal seams, and deep saline aquifers are generally considered to be the main storage options. In this paper, the authors consider opportunities presented by aquifers close to hydrocarbon fields in the northern Songliao Basin (China) for storage. Data obtained during exploration and production often delineates nearby structures filled with saline water which have not been charged with hydrocarbons but could offer an opportunity for CO2 storage. Based on published data and production data from hydrocarbon fields in the northern Songliao Basin, the potential for geological storage of CO2 in these hydrocarbon field saline aquifers (HFSA) has been assessed and in the northern Songliao Basin, the central and western regions offer great potential for CO2 storage in HFSA. Out of the 42 identified oil/gas fields, aquifers near 24 of the fields offer promising storage potential with an estimated potential storage capacity of 9.8 × 109 tonnes (t) CO2, which is more than 100 times the current annual emissions of large point sources in the Songliao Basin.