Cost Scoping Analysis of Future Carbon Capture and Storage in the Sable Sub-basin
| Technology necessary for carbon capture, transport, and storage (CCS) has been proven in recent decades - notably onshore North America (many EOR projects), and offshore Norway (to store CO2 associated with natural gas production, ~1 million tonnes per year per field). A test well drilled in 2015 in northern-onshore Nova Scotia, which was jointly funded by industry and government, failed to find reservoir. This was consistent with a 2009 report which concluded that reservoir quality is limited onshore. The offshore Scotian Margin is prioritized as one of the highest ranked sedimentary basins in the world in the 2005 IPCC Special Report on CCS. In Nova Scotia carbon neutrality would require storage of ~16 million tonnes of CO2 per year – ~8 million tonnes per year considering only NSPower emissions. In this presentation we complete a preliminary cost scoping analysis for offshore storage of CO2 in deep saline aquifers of the Scotian Basin. Our scoping model includes infrastructure, CO2 capture, transportation, and storage based CCS projects around the world, plus estimates from the IPCC. This cost scoping analysis is completed in conjunction with modeled geology and fluid flow of CCS in the Missisauga reservoir (aquifer) on the Scotian Margin. |
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Detecting Wellbore Shape and Cavities, and Cement Imperfections in Fiberglass Cased Wells
| Electrically resistive composite casing materials are being introduced to the industry. The non-corrosive, electrically resistive fiberglass casing materials may improve the economics of the geothermal and oil & gas field projects. Here we present a technique for the detection of the integrity of magnetic cement behind resistive casing that can be used in the low enthalpy geothermal wells. We demonstrate that an optimized induction logging tool can detect small changes in the magnetic permeability of cement through a non-conductive casing in a vertical (or horizontal) well. We can determine both the integrity and solidification state of the cement-filled annulus behind the casing. Changes in magnetic permeability influence mostly the real part of the vertical component of the magnetic field. The signal amplitude is more sensitive to a change in magnetic properties of the cement, rather than the signal phase. Our simulations show that optimum separation between the transmitter and receiver coils ranges from 0.25 to 0.6 meters, and the most suitable magnetic field frequencies vary from 0.1 to 10 kHz. A high-frequency induction probe operating at 200 MHz can measure the degree of solidification of cement. The proposed method can detect borehole cracks filled with cement, an incomplete lift of cement, casing eccentricity, and other borehole inhomogeneities. |
Heat Flow in Fractured Rocks
| Global geothermal energy reserves are three orders of magnitude larger than fission and fossil fuel reserves combined. We develop an apparatus that simultaneously measures local thermal contact resistance of fractures and the global conductivity of the bulk rock. We find that thermal contact resistance reduces bulk thermal conductivity and causes sensitivity to water saturation, normal stress, and gouge. Upscaling from thermal contact resistance measurements matches globally measured thermal conductivity with striking precision. |
East Coast Stratigraphy and Aquifer Properties
| The aim of this study is to review the principal aquifer units of eastern Saudi Arabia and their properties such as thickness, porosity, transmissibility and storage coefficient to assess their geothermal potential. A total of 19 distinct aquifer units from 6 different locations are studied which comprise 7 Paleozoic, 6 Mesozoic and 6 Tertiary aquifer units. Based on a transmissivity cutoff the aquifers are categorized as high, moderate and low potential aquifers. The high potential aquifer units are Saq, Tabuk and Wajid in Paleozoic strata; Wasiya Biyadh, Dhruma, Arab D and Sakaka in Mesozoic strata and Dam and Hadrukh in Tertiary sequences. For example, the thermal maps of Paleozoic aquifer units indicate temperatures in excess of 150oC near the Ghawar field. Assuming a considerable increase in burial depth along the flanks of the Ghawar anticline the aquifers in adjacent synclines will have even high temperatures. The current study gives an overview of all the aquifer units and categorizes them based on their aquifer potential which will help in targeting high quality aquifer units for future geothermal projects in the eastern provinces of Saudi Arabia. |
Temperature-dependent Properties of Intact Rocks  | Geothermal energy can be a cost effective and sustainable. The accurate characterization of rock properties and behavior are critical to the engineering and management of geothermal reservoirs. We compiled thermal property data for intact rocks from published studies. The dataset includes sedimentary, metamorphic and igneous rocks subjected to various stress and temperature regimes. We propose new physics-inspired and asymptotically correct models for specific heat, thermal conductivity and thermal diffusivity of intact rocks. |
Nubia Resource: A multidisciplinary investigation for implementing CPG in the Gulf of Suez (Egypt)
| NubiaResource is an integrated subsurface CO2 project, where CO2 is geologically stored during CO2 Capture and Storage (CCS) operations and simultaneously used to extract energy from hydrocarbon-depleted formations during so-called CO2-Plume Geothermal (CPG) operations. However, the poorly-understood geologic properties of the Nubian sandstone reservoir result in significant uncertainties concerning CO2 storage security and the potential to use the stored CO2 to produce geothermal energy during CPG. Therefore, during the first phase of the NubiaResource project, we are investigating if Nubian sandstone (a common rock type found in the Gulf of Suez's reservoirs at depths of 2.5-4.4 km, 35.7 °C/km geothermal gradient, confined by multiple aquitards) can serve as a CCS/CPG subsurface target. Using a compartmentalized oil reservoir within the Nubian Sandstone, with 810 m as an accumulative dip-slip fault displacement, we estimate the reservoir impedance [kPa.s/kg] for each fault block, following a 1D analytical Darcy solution, developed for a single-phase fluid in an inverted 5-spot well-pattern configuration. We determine a potential net electric power of 1137 kWe for the deepest fault block (depth: 4.0 km, surface area: 1.0 km2, pressure: 40 MPa, well diameter: 0.41 m). |
Study 1D Basin Modelling of Western Arabia Shield, Rifting IfalBasin Based on Satellite Gravity Data for Geothermal Low to Medium Enthalpy Exploration
| Geothermal research in the Kingdom of Saudi Arabia has been carried out since the eighties by Aramco. The study was conducted on Harrat or volcanic active areas that are in the Arabian Shield ridge to look for high enthalpy geothermal potential. However, the problem arises that the lack of water sources as heat-carrying agents, so it needs to do an enhanced geothermal system which is uneconomic at this time, causing geothermal energy not so attractive in Saudi Arabia. Along with the environmental issues arise globally and the unsustainable resources of fossil fuel. The Arab government began to think to diversify energy in the Kingdom, the government starts the energy diversification projects through KA-CARE by utilizing solar energy (solar PV), wind energy (wind turbine) and potentially geothermal energy, particularly low to medium enthalpy on specific space heating and cooling, and water desalination. Low and Medium enthalpy geothermal in the kingdom is more easily found on the banks of the red sea which has a relatively high geothermal gradient, but the problem is how to identify the right location to extract the heat. |
Dynamic Modeling of Buoyant Fluids: Implications for Hydrocarbon Distribution and Potential Carbon Capture and StorageDarragh O'Connor | In this study, well data, seismic data, and regional structure maps were accessed through the GSC, CNSOPB, and industry partners. These data were used to evaluate CCS potential in representative structures and regional aquifers in the subsurface Sable region through static and dynamic geocellular modeling. We conclude that CCS in depleted gas fields with hydrostatic aquifers carriesthe least risk of geologic leakage but haslimited potential because of the small size and low relief of the gas fields. In contrast, regional aquifers have massive storage potential, however serious concerns remain regarding leakage of injected carbon dioxide through the updip subcrop of these reservoirs near the seabed and the impact of displaced formation water into the ocean. |
Staying Cool in A Warming Climate: Temperature, Electricity and Air Conditioning in Saudi Arabia.png) .png?sfvrsn=12725d13_1) | As global temperatures warm and populations and incomes rise, the demand for cooling will soar, creating a positive feedback loop between global warming and electricity-related carbon dioxide (CO2) emissions. This study explores the relationship between temperature, electricity and air conditioning (AC), and the sustainability of cooling in the Kingdom of Saudi Arabia. With the highest share of AC in household electricity consumption in the world and its already very hot summers warming by 3 °C in many areas over the last 40 years, Saudi Arabia provides an important case study of how the cooling challenge can be managed. Data from the European Centre for Medium-Range Weather Forecasts (ECMWF ERA5) is used to illustrate local warming trends (1979–2018) and show the relationship between temperature and power generation within a typical year using hourly data (2011–2015). |
Physics-based Modeling on Seismic Hazard in Enhanced Geothermal System: the 2017 Mw 5.5 Pohang Earthquake  | The Pohang earthquake was recently confirmed to have occurred due to the injection activity of an Enhanced Geothermal System (EGS), making this the largest induced event associated with EGS. Based on moment tensor solutions, the Pohang earthquake features both strike-slip and thrust faulting as well as a pronounced non-double couple component. Grigoli et al. (2018) proposed the non-double couple solution as a combination of two possible fault planes. In this study, we investigate the Pohang earthquake using high-resolution 3D dynamic rupture simulations which coupled seismic wave propagation and frictional shear failure across predefined complex fault system. We use the open-source software SeisSol (www.seissol.org). We account for high-resolution topography, off-fault plasticity, and use a laboratory-based friction law (rate-and-state with strong velocity weakening), and additionally for locally inferred fault strength, friction coefficients, and distributed pore pressure across the faults. We test two configurations, one consisting of a single fault plane and another consisting of two simultaneously breaking fault planes intersecting at a small angle. Numerical experiments show that by resolving the regional tectonic stress field on both fault geometries leads to pure strike-slip faulting as only mechanical viable solution. On the other hand, a local stress orientation constrained by well breakouts leads to mixed strike-slip and thrust faulting for both the single and multiple fault geometries with moment release close to the observations. The moment tensor solution of the two fault-plane-model additionally exhibits a non-double couple component and fits the observations (regional waveform fit and ground deformation). This dynamic rupture simulation shows spatio-temporal of rupture processes to understand better the Pohang (induced) earthquake and its potential to seismic hazard map based on spatial shaking level. |
Hydraulic Fracturing in Pre-Fractured Media
| Fluid injection in highly fractured rocks often reopens preexisting discontinuities without initiating new tensile fractures through the rock matrix. By using a unique silicone fluid at relatively low injection pressures, this paper investigates the competing influences of triaxial state-of-stress and fracture network geometry on viscous fluid flow densely fractured media. |
Modelling of Optimum Well Spacing for Multiple Subsurface Scenarios
| Geothermal energy is promising for fulfilling future energy demand since it is clean, environmentally-friendly, and sustainable. One key challenge in developing geothermal resources is in the reservoir characterization, related to complex reservoir system, sparse exploration data, and non-isothermal behavior. Therefore, future predictions should account for these uncertainties. The tricky part in performing uncertainty quantification (UQ) is in recognizing the distribution of the uncertain parameters. Insufficient data may lead to an incomplete reconstruction of the distributions, therefore, reducing the reliability of the prediction. Within this study, we emphasize the importance of building a comprehensive database for assisting the UQ processes and introduce a robust workflow to incorporate big data in the UQ, so-called data-driven UQ. We asses rock properties, fluid properties, and operational parameters, which are classified into three groups: flow-controlled properties, thermal-controlled properties, and operational parameters. We explore the correlation among parameters and explain the physics derived from data analysis. |
Proxy-model for Flow and Transport in Geothermal Reservoirs
| In this project, a physics-based proxy model is developed to predict flow and heat transport in low-enthalpy reservoirs. Streamlines that describe flow in a system and mostly controlled by steady-state pressure distribution are traced using Pollock's method and the reservoir is divided into streamtubes. Rock-heat depletion is modeled by semi-analytic model along streamlines. The objective is to predict geothermal doublet breakthrough time using only a limited number of streamtubes, thus minimizing simulation time and CPU resources. |
Usage of shallow-marine carbonates as thermal energy storage for solar cooling. A case study from Northern Oman
| In this study, we analysed different controlling parameters of a daily aquifer thermal energy storage (ATES) with a storage temperature of 100 °C within the carbonate dominated Seeb formation in Muscat, Oman. The storage is designed as a daily thermal energy storage to cover the cooling demand of an institute building. During the day, solar surplus heat is stored and used as energy source during night-time. We designed three model scenarios to study the effect of different well-screen distances, aquifer thicknesses and the impact of hydraulic heterogeneities due to changes of the main lithofacies on the storage efficiency. In our simulation the highest efficiency with 88 per cent after one year of operation is reached with a 10 m screen-to-screen distance within a 20 m thick aquifer. The reduction of the screen-to screen distance from 30 m to 10 m increases the efficiency by 7 per cent. A further reduction decreases the efficiency again through hydraulic interference. The reduction of the aquifer thickness from 40 m to 20 m has only a minor effect (2 per cent efficiency increase). The occurrence of hydraulic heterogeneities results in a significant changes of the flow regime and thus to a reduction of the efficiency by 7 per cent due to higher heat losses within the aquifer. |
A Systematic Workflow for Geothermal Exploration in Carbonates: Lessons from the Upper Jurassic of the Molasse Basin/Germany
| During the Upper Jurassic, South Germany was part of an epicontinental shelf sea, as large parts of the continental edges were flooded. Most carbonates formed in a relatively deep carbonate ramp/platform, situated below-average storm wave base. These carbonates are mainly comprised of sponges, thrombolites and microbial crusts and characterized as bioherms or mounds. Towards the top of the Upper Jurassic interval, the sponges as a main-bioherm builder are replaced by corals, ooids, peloids, and reef debris indicating a shallower environment of deposition. This change from an M-factory to a T-factory is most likely related to a regression and sea-level fall at the end of the Upper Jurassic which has a significant impact on geothermal sweet spot distribution. This study links core-based facies with the borehole image facies and uses a systematic workflow to identify geothermal reservoir types involving: borehole image facies and sequence analysis, integration with seismic data, and integration with dynamic data. |
