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Fourth Sustainable Earth Sciences Conference
- Conference date: September 3-7, 2017
- Location: Malmö, Sweden
- Published: 03 September 2017
1 - 20 of 23 results
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Geothermal Reservoir Quality of Upper Triassic – Lower Jurassic Paralic Sandstones in Copenhagen
Authors M. Olivarius, H. Vosgerau, U. Gregersen, L. Kristensen, R. Weibel, M.L. Hjuler, A. Mathiesen and L.H. NielsenSummaryLow-enthalpy geothermal energy is exploited from deep sandstones in Copenhagen in eastern Denmark, and the possibility of exploit the shallower sandstones of the Gassum Formation and the Karlebo Member is considered here. Petrography, porosity, permeability and provenance data from core and cutting samples on Zealand are compared in order to investigate the sediment composition and the reservoir properties across the area. Sandstones from central Zealand are on average coarser grained and better sorted than sandstones from the Copenhagen area, and this trend is found both within the Gassum Formation and the Karlebo Member. The sandstones from these units have a comparable and very mature mineralogy where quartz is the dominant component. Zircon age dating reveals that this is most likely caused by reworking of older sediments from the Ringkøbing–Fyn High. Good reservoir quality is presumably present in the vast majority of the sandstones in the Copenhagen area. Differences in maximum burial depth and associated diagenesis must be taken into account when estimating the reservoir properties of sandstones in the Copenhagen area. The high mineralogical maturity documents that these sandstone reservoirs would be optimal for geothermal exploitation since the water will be reinjected into almost inert sandstones.
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Three Component Seismic Acquisition Implemented for Deep Geothermal Exploration in Vienna
Authors M.G. Schreilechner, P. Keglovic, M.F. Jud, C.G. Eichkitz and E. LüschenSummaryVarious national studies (e.g. GeoEnergie 2050) predict a realistic application capacity of deep geothermal energy in Austria between 450 MW and 700 MW. The Vienna region possesses 40% to 60% of these capacity values. At the same time, the metropolitan area of Vienna has one of the largest district heating systems in Europe. This is why the use of hydrothermal geothermal energy plays a key role in the supply strategy of the Vienna metropolitan area (see Climate Protection Program of the City of Vienna and Vienna Urban Development Plan (STEP 2025)).
However, the future use of this heat source depends on efficient exploration and implementation concepts that do not yet exist. A new scientific project will overcome these conceptual gaps. Based on research results in the wider Vienna area, a “Flagship Region for geothermal energy exploration” will be developed for other Austrian regions. Three-dimensional subsurface properties will be characterized using geophysical methods. Together with geological and reservoir data, these will be pooled and visualized within a 3D data cube. These data will be evaluated in terms of geological parameters, existing resources and possible technical, economic and geological risks.
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Coupled Geomechanical Study for the Evaluation of Fault Stability and Microseismic Events of the ECOGI Geothermal Field
Authors A. Mandiuc, Ch. Spyrou, G. Sosio and C. BaujardSummaryIn the framework of the ECOGI geothermal project in Alsace, eastern France ( Baujard et al. 2017 ), an integrated geological, fluid flow, and geomechanical model of the Rittershoffen site was built ( Sosio et al. 2016 ). This paper completes that study by improving the coupled geomechanical simulation, notably by reviewing the previous discrete fracture network model and incorporating it in the simulation, and demonstrates a workflow to predict the fault reactivation and microseismic event generation induced by geothermal operations. This prediction, based on finite-element simulations of the stress and plastic deformations linked to the changes in pressure and temperature, is matched with the observed microseismic events ( Lengline et al. 2017 ) to validate the mechanical model.
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S-wave Seismic Experiments for Geothermal Exploration of the Upper Jurassic Carbonate Platform in the Bavarian Molasse Basin
Authors B. Wawerzinek, H. Buness and R. ThomasSummaryThe Upper Jurassic carbonate platform is the most utilized geothermal reservoir in Germany. To exploit its full potential, a large 3D seismic survey was conducted in the city of Munich. We used 3C MEMS sensors along several 2D lines to (1) record the shots of the regular survey and (2) to test a direct excitation of S-waves using the SHOVER technique. The Z-component of the single sensor MEMS recordings gave a comparable quality of the stack as a geophone group recording, although the noise level of single shot gathers was raised slightly. The passive recording of the 3D-survey shots gave clear converted wave signals as well from the top and from the inside of the platform. The application of the SHOVER technique was affected by practical issues in this urban environment, only single shots could be analyzed. They show reflections from the top of the carbonate platform on the radial and transversal components, however the suppression of P-waves turned out to be imperfect.
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Exploration for Deep Enhanced Geothermal Systems with Riksriggen and the LTU Downhole Stress Measurement System
Authors M. Ask, D. Ask and J.-E. RosbergSummaryRecent developments in drilling technology have resulted in about five to ten times faster penetration rates compared to penetration rates of conventional diamond drilling. The increased penetration rates open up for affordable drilling of deep boreholes in regions with cold crust, such as in Scandinavia, allowing for geothermal energy generation in enhanced geothermal systems. We present two infrastructures for downhole sampling and testing, Riksriggen and the LTU downhole stress measurement system. Riksriggen produces a borehole that allows in-situ sampling and testing to 2.5 km depth. Furthermore, highly relevant data for geothermal energy production is produced, for example fracture geometries and frequencies, as well as depth of zones with elevated transmissivity zones and their in-situ hydraulic conductivities. The LTU downhole stress measurement system allows determination of the three-dimensional stress tensor and its spatial variation with depth in a scientific unambiguously way. Thus, Riksriggen and the LTU downhole stress measurement system provide data needed for planning most stable borehole trajectory with depth and to determine optimal pattern of production and injection wells (e.g. hydraulic stimulation by fraccing), as well as for assessing the risk of induced seismicity.
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Feasibility of Using Plasma Assisted Drilling in Geothermal Wells
Authors M. Bazargan, A. Gudmundsson and P.I. MeredithSummaryMain reason that prevent companies from investing in geothermal resources is the cost of deep drilling. Also, making fractures in candidate medium to increase permeability to make the heat production operation more profitable. Reducing cost of drilling can reduce the cost of this operation. To achieve this goal, plasma arc can bring heat flux induced and cause some advantages such as rock weakening and increasing the rate of penetration during the operation. This paper investigates the effects of plasma on the rock properties on optical parameters such as expansion coefficient during plasma arc assists drilling and fracturing operations. In this work, an interaction of plasma and rock texture has been investigated experimentally. Limestone sample interacts with a temperature that generated from plasma torch or arc with initiating and propagation fractures. Although, as running experiments for big scales are way too expensive and in some cases impossible with current technology, a numerical model is a suitable option that can be utilized to test different cases before experiment and operations. In this paper, using finite difference and finite element methods, two thermal models have been created for each type of plasma interaction with rock which can suggest some possible results.
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Optimal Budget Allocation of R&D Programs for Sustainable Development - A Case Study of Construction and Transportation
By H. SongSummaryIn many countries, various R&D programs have been pursued to increase national competitiveness and to improve the quality of public life and sustainable Development (SD) has become a primary objective for R&D activities, especially in the area of Construction and Transportation(C&T) technology. Optimal budget allocation in line with the strategic objectives of SD is one of the major tasks for policy makers but guidelines for developing the content and a decision-making system for budget allocation have not been appropriately established. In this study, the capability of the genetic algorithm (GA) to suggest an optimal budget layout is investigated using the R&D data from Korea. First, a relationship the C&T technology classification to SD indicators is investigated. Then, the GA is applied for the optimal allocation of the R&D budget. The case study shows the potential to provide decision-making information for R&D budget allocation according to the strategic objectives of SD.
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Precipitation of Calcium Compounds on Rock Kept in Calcium Hydroxide Solution
More LessSummaryIt is important to consider the closure of cracks and pores in rock for radioactive waste disposal and carbon capture and storage to maintain or decrease the permeability of rock. In this study, we investigated the precipitation of calcium compounds on the rock surface in calcium hydroxide solution to consider whether sealing of pores and cracks is possible and accelerated or not. It was found that the precipitation of calcium compounds occurred on rock surfaces. Additionally, we found that the closure of cracks and pores in rock occurred from the P-wave velocity measurement and observation by the scanning electron microscope. Since the closure of cracks and pores can decrease the permeability in rock, it is concluded that the precipitation of calcium compounds on rock is useful for the geological disposal of radioactive wastes and carbon capture and storage.
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Feasibility of Using Pressurized Mud Cap Drilling for Geothermal Wells
Authors S. Chamankhah and M. BazarganSummaryMost expensive and cost effective part of geothermal reservoirs is their drilling operations. The use of Pressurized Mud Cap Drilling (PMCD) mode of MPD together with a Rotary Control device (RCD) and associated choke manifold, Annular Pressure While Drilling (AWPD) tool and possible surface mud/gas separation equipment provides annular pressure control of the well using a combination of surface backpressure and a typically lighter hydrostatic column provided by the drilling fluid for a combined bottom hole pressure in excess of pore pressure. the combination of this method with other advanced technologies in increase the safety of this operation. Managed pressure drilling (MPD), in the foundation concept of view is a magic package of drilling optimization methods That if correctly gathered and planned will improve the overall drilling performance, Moreover, MPD will eliminate the risks as well as break the operation costs via proactively managing the hydraulic pressure profile and removing the problems related to a high Non Productive Time (NPT) commonly encountered in drilling operations. This simple core concept could help in growing the technology in order to generate a new source of modification in conventional drilling shape in the near future.
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Buried Structure 3D Seismic Interpretation of Coal Mining District and Its Safety Influence on Coal Mine
More LessSummaryIn order to ascertain the buried structure distribution, the structural forms and faulted structure of major coal seams in the mining area has been obtained through full 3D horizon tracking and multi seismic attribute fault identification. A total of 817 faults in the whole area are interpreted, the faulted structures have a dominant NW-NWW strike and secondary NE strike, reverse faults are developed and those faults grow up to the surface and dip into coal seam floor. Based on the 3D seismic interpretation result as well as collapse depth and fractured extent, the buried structure zones are divided into normal zone, influence zone and fault depression zone. The buried structure zones have a broom-like distribution in map view, while in profile, they have large fault displacement in shallow formations and small fault displacement in deep formations, which has fault depression characteristics. Faults within the buried structure zones can connect through all aquifers from upper unconsolidated formations to lower karst fissure bearing limestone formations, each aquifer may have relation with one another, therefore, the buried structure zones lead to water bursting risks. As mining depth goes deeper and mining impact increases, water bursting risks of buried structure zones also increase.
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Feasibility Study of Operating Managed Pressure Drilling in Geothermal Well Using CBHP
Authors S. Chamankhah and M. BazarganSummaryDrilling in geothermal wells is always the most expensive part of operation. Also, we know when go deep in layers, we always can absorb more heat and energy. This case can make some part of operation more expensive to go from shallow geothermal reservoirs to deep geothermal reservoirs. Managed pressure drilling (MPD) is an effective solution to obviate the drilling problems of narrow drilling window between the pore and fracture pressure, such as well kick and loss and well collapse and stuck. The Constant Bottom Hole Pressure (CBHP) technique, one of the MPD variants, was selected to freeze bottom hole pressure in narrow area between pore and fracture pressure as a safe method to drill without loss and gain. In this paper tried to control the ECD in upper sections to be able to drill in narrow drilling margin. Drilling window between collapse and fracture pressure is normally closed due to geological reasons, which in turn leads to creation of a boundary at which the dynamic formation losses could not be properly controlled.
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Direct Prediction of Aquifer Thermal Energy Storage System Efficiency Using Short-term Push-pull Tests
Authors T. Hermans, N. Lesparre, T. Kremer, J. Caers, F. Nguyen and T. RobertSummaryAquifer thermal energy storage (ATES) systems are designed to recover in winter the heat stored in the aquifer during summer. In practice however, spatial heterogeneity or non-favorable hydrogeological conditions reduces the energy efficiency. In many cases, a deterministic approach is used to calibrate the subsurface component of those systems, neglecting the quantification of uncertainty. In this contribution, we propose to use the recently-developed prediction-focused approach to forecast the heat storage capacity of an alluvial aquifer. We compare the ability of two different push/pull tests to make this prediction. We first analyze the performance of the method using synthetic cases and validate the approach using field data. For both, we show that the method is able to forecast the posterior distribution with realistic uncertainty. We also identify the experiment which has the highest information content for the desired prediction. Then we forecast the long-term heat storage capacity of the aquifer and assess its uncertainty. This final result can be used to design properly the heat pump associated with the system.
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High-resolution Seismic Investigations of a Geological Energy-storage Site - Dalby (Tornquist Zone), Southwest Sweden
Authors A. Malehmir, B. Bergman, B. Andersson, R. Sturk and M. JohanssonSummaryThree high-resolution refraction and reflection seismic profiles for the planning of a major underground thermal-energy-storage site within the Tornquist suture zone of Scania in southwest of Sweden were acquired during August 2015. Combined cabled- and wireless recorders were used to provide continuity on both side of a major road running in the middle of the study area. First arrivals are clear in most shot gathers allowing them to be used for traditional refraction seismic data analysis and also for more advanced traveltime tomography. Bedrock depressions are clearly observed in the tomograms suggesting the possibility of weakness zones, highly fractured and/or weathered, in the bedrock and confirmed in several places by boreholes. Signs of reflections in raw shot gathers were encouraging and motivated to process the reflection component of the data. Several steeply-dipping reflections were imaged down to 400 m depth. The origins of the reflections are unclear right now ranging from amphibolite sheets to diabase dykes as well as faults within the gneissic rocks, and each of this implies a different geological scenario at where the site will be developed. This study however illustrates the potential of the combined refraction and reflection imaging for underground energy-storage-site characterizations.
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H2 Storage Simulations Using Effective Hydraulic Properties – Comparison with Heterogeneous Cases
Authors W.T Pfeiffer and S. BauerSummaryIn this work 10 different methods to calculate an effective permeability are used to generate homogenous rock models based on a heterogeneous rock model of an existing geologic structure in Northern Germany. Subsequently, simulation results of a hypothetical H2 storage operation obtained for the various homogeneous models are compared to those of the heterogeneous ensemble to evaluate the applicability of the individual methods. It is shown that the upper bound of storage performance metrics such as storage flow rates or power output can be estimated for the given structure using simulations in which permeability is estimated by an arithmetic mean. Likewise, the lower bound of the results obtained for the heterogeneous ensemble can be estimated by simulations in which effective permeability is estimated using a geometric average of the vertical arithmetic averages. The overpressure signal induced by the storage operation are slightly underestimated in the far field of the storage wells, being within 0.5 bars of the median of the heterogeneous ensemble for most homogeneous cases.
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Seasonal Deep Aquifer Thermal Energy Storage in the Gassum Sandstone Formation
Authors H.D.H. Holmslykke, C. Kjøller and I.L. FabriciusSummarySeasonal storage of excess heat in hot deep aquifers is considered to optimise the usage of commonly available energy sources. The potential chemical reactions caused by heating the Gassum Sandstone Formation to up to 150°C is investigated by core flooding experiments combined with petrographic analysis and geochemical modelling. Synthetic formation water is injected into two sets of Gassum Formation samples at 25°C, 50°C (reservoir temperature), 100°C and 150°C with a velocity of 0.05 PV/hr and 0.1 PV/hr, respectively. A significant increase in the aqueous concentration of silicium and iron with increasing temperature is observed due to dissolution of silica and siderite. Increasing the reservoir temperature from 50°C to 100°C enhanced the naturally occurring weathering of Na-rich feldspar to kaolinite. Dissolution of quartz increased sharply above 100°C and was the dominating process at 150°C. At temperatures ≤100°C, the silicium concentration was controlled by a dynamic equilibrium between feldspar dissolution and kaolinite precipitation while the concentration was kinetically controlled by quartz dissolution at 150°C. The results imply that storage of excess heat in the Gassum Formation in the Stenlille area may be possible provided operational precautions are taken.
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Laboratory Experiments for Safe Underground Hydrogen/Energy Storage in Depleted Natural Gas Reservoirs
Authors S. Henkel, D. Pudlo and C. HeubeckSummaryFluctuating energy production by renewable sources increases the demand for energy storage capacities, especially caused by the ongoing installation of wind power plants and photovoltaic sites. Transforming electricity into hydrogen, which is used as an energy buffer, will help stabilize electrical grids and provide a safe and reliable energy supply. In this context the storage of large volumes of H2 and H2-bearing gas mixtures in sealed depleted gas fields is a possible option. Borehole casings, tubing and cements may, however, be affected by high temperature, pressure and formation fluid salinity in these heterogeneous sedimentary rocks in the presence of H2 and negatively affect secure hydrogen storage. Preliminary results from laboratory experiments with hydrogen under reservoir conditions indicate that high reservoir temperature (>100°C), pressure (>15 MPa) and formation fluid salinity (TDS >200 g/l) may indeed promote the surface alteration of borehole steel alloys and induce the dissolution of pore-filling mineral (anhydrite, barite, some carbonate species) in the reservoir due to physico-chemical variations in the formation fluids. No such reactions were observed at lower values, suggesting that safe hydrogen storage may be possible under less harsh conditions.
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Quest CCS at Two Million Tonnes
Authors A. Halladay, V. Oropeza Bacci, S. O’Brien, J. Duer, L. Rock and S. KassamSummaryThe Quest Carbon Capture and Storage Project is located at the Scotford Upgrader, located in Alberta, Canada, and captures, transports and stores over one million tonnes of CO2 annually. Injection operations commenced in August, 2015 and reached the milestone of one million tonnes of CO2 injected after one year of operation in August, 2016. It is projected that Quest will reach two million tonnes injected in May 2017. The capture efficiency has been better than planned, and the storage reservoir had demonstrated more than sufficient injectivity for the volumes.
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Ranking and Risking Alternative CO2 Storage Sites Offshore Norway
Authors P.S. Ringrose, R. Thorsen, P. Zweigel, B. Nazarian, A.-K. Furre, B. Paasch, N. Thompson and P.I. KarstadSummaryAs a part of the Norwegian Government plan to develop a new full-scale CCS project, several industrial players were engaged to conduct feasibility studies on CO2 capture, transport and storage during 2016. This paper summarizes the storage site evaluation study. The overall concept is to capture CO2 from several industrial sources in the Oslo area and transport via ship to offshore storage on the Norwegian continental shelf. The design capacity requirement was to handle 1.5 million tonnes of CO2 per year over a period of 25 years. Three storage site were investigated: the Heimdal gas field, and two new sites named Smeaheia and Utsira South. All three sites were found to be technically feasible from a geological and reservoir engineering perspective. However, the Utsira site had insufficient capacity due to well-leakage risk and limited available area for storage licencing. Use of the depleted Heimdal gas field was found to be technically feasible but less attractive due to costs and operational issues at the site. In contrast, the Smeaheia site offered both operational and geological flexibility leading to its eventual selection for further maturation as a new offshore CO2 storage site in Norway.
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The Plains CO2 Reduction (PCOR) Partnership - Successes Leading to New Innovation
Authors C. Gorecki, S.C. Ayash, N. Wildgust, W.D. Peck, J.A. Hamling, L.J. Pekot, J.A. Sorensen, M.D. Jensen, D.J. Daly, R.J. Klapperich and L.V. HeebinkSummaryThe Energy & Environmental Research Center (EERC), through the Plains CO2 Reduction (PCOR) Partnership, has been working to demonstrate the secure geologic storage of CO2 for the past 14 years. This work is manifested in multiple field tests, including ongoing large-scale CO2 injection; characterization of regional CO2 sources and geologic storage resources; an adaptive management approach for CO2 storage project development; and numerous lessons learned and best practices. The knowledge gained through the success of the PCOR Partnership is being leveraged by several new projects at the EERC that continue to advance the science of CO2 storage through innovative monitoring techniques and technologies. Two of these projects involve tracking injected CO2 in the reservoir through novel applications of the seismic method, while a third is developing an intelligent monitoring system to integrate simulation and monitoring data in an automated fashion.
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Assessing the Potential of Passive Seismic Monitoring to Detect a CO2 Leak from the Aquistore Storage Site
Authors A.L. Stork, C. Allmark, A. Curtis, J.-M. Kendall, H.E. Huppert, D.J. White and K. WorthSummaryThis paper investigates the potential for passive seismic monitoring (PSM) to detect a CO2 leak for two possible scenarios, where a leak is seismic or aseismic. The Aquistore research project in Saskatchewan, Canada provides a suitable site to investigate this because the site is comprehensively monitored. To understand whether induced seismicity would occur following a hypothetical leak, we conduct modelling of fluid flow through a vertical fault. In the event of an aseismic leak, we assess the potential for ambient noise interferometry (ANI) and a tomographic inversion for Rayleigh wave group-velocity maps to provide a suitable CO2 leakage detection tool. A time-lapse ambient noise tomography survey of a CO2 storage site is possible for the first time because data is available preceding and following injection start-up. The fluid-flow modelling shows that a CO2 leak through a vertical fault would result in induced seismic events at depths <500 m. Predicted changes in seismic velocities with CO2 saturation at Aquistore are too small to resolve with the current precision of surface-wave velocity models. However, ANI may be useful to provide a cost-effective early warning system for leakage if uncertainties are reduced.
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