Regional geothermal aquifer architecture of the fluvial Lower Cretaceous Nieuwerkerk Formation – a palynological analysis

The primary challenge for efficient geothermal doublet design and deployment is the adequate prediction of the size, shape, lateral extent and thickness (or aquifer architecture) of aquifers. In the West Netherlands Basin, fluvial Lower Cretaceous sandstone-rich successions form the main aquifers for geothermal heat exploitation. Large variations in the thickness of these successions are recognised in currently active doublet systems that cannot be explained. This creates an uncertainty in aquifer thickness prediction, which increases the uncertainty in doublet lifetime prediction as it has an impact on net aquifer volume. The goal of this study was to improve our understanding of the thickness variations and regional aquifer architecture of the Nieuwerkerk Formation geothermal aquifers. For this purpose, new palynological data were evaluated to correlate aquifers in currently active doublet systems based on their chronostratigraphic position and regional Maximum Flooding Surfaces. Based on the palynological cuttings analysis, the fluvial interval of the Nieuwerkerk Formation was subdivided into two successions: a Late Ryazanian to Early Valanginian succession and a Valanginian succession. Within these successions trends were identified in sandstone content. In combination with seismic interpretation, maps were constructed that predict aquifer thickness and their lateral extent in the basin. The study emphasises the value of palynological analyses to reduce the uncertainty of fluvial hot sedimentary aquifer exploitation

Public perception of geothermal energy at the local level in the UK

Successful development of a new renewable energy technology does not only rely on the success of pilot projects but also to a significant extent on the development of an adequate public engagement strategy. To be able to develop such a strategy a good understanding is required of the public perception of the new technology. Geothermal energy is still an emerging technology in the UK; in the absence of public debate on this topic, media reporting provides a suitable proxy for its public perception. Therefore, this study has gauged the public perception of geothermal energy in the UK by evaluating local news articles from 1980 to 2018. A coding scheme was developed to derive the main themes and to identify both the perceived advantages and hurdles for geothermal development. We focussed on local newspapers to be able to compare public perception in different regions in the UK. Results show a mainly positive perception of geothermal energy in all geographical regions across the UK. Only few articles mention risks, induced seismicity and environmental pollution. In contrast, advantages and positive aspects of geothermal energy, such as its carbon neutral footprint, the enormous amount of available geothermal heat and the potential contribution of geothermal development to the revival of local economies, are much more frequently mentioned. Perceived hurdles that are mostly described in the articles are: (1) the absence of geothermal legislation and subsidies in the UK; (2) the lack of available funding; and finally (3) technological and geological challenges or uncertainties. Finally, we show that geothermal energy is most often related to electricity generation and granite resources, while the only successful deep geothermal site in the UK is a direct-use heating scheme exploiting a sedimentary aquifer

Permeability and mineralogy of the Újfalu Formation, Hungary, from production tests and experimental rock characterization: implications for geothermal heat projects

Hundreds of geothermal wells have been drilled in Hungary to exploit Pannonian Basin sandstones for district heating, agriculture, and industrial heating projects. Most of these sites suffer from reinjection issues, limiting efficient use of this vast geothermal resource and imposing significant extra costs for the required frequent workovers and maintenance. To better understand the cause of this issue requires details of reservoir rock porosity, permeability, and mineralogy. However, publicly available data for the properties of reservoir rocks at geothermal project sites in Hungary is typically very limited, because these projects often omit or limit data acquisition. Many hydrocarbon wells in the same rocks are more extensively documented, but their core, log, or production data are typically decades old and unavailable in the public domain. Furthermore, because many Pannonian sandstone formations are poorly consolidated, coring was always limited and the collected core often unsuitable for conventional analysis, only small remnant fragments typically being available from legacy hydrocarbon wells. This study aims to reduce this data gap and to showcase methods to derive reservoir properties without using core for flow experiments. The methods are thin-section analysis, XRD analysis and mercury intrusion porosimetry, and X-CT scanning followed by numerical flow simulation. We validate our results using permeability data from conventional production testing, demonstrating the effectiveness of our method for detailed reservoir characterization and to better constrain the lateral variation in reservoir properties across the Pannonian Basin. By eliminating the need for expensive bespoke coring to obtain reservoir properties, such analysis will contribute to reducing the capital cost of developing geothermal energy projects, thus facilitating decarbonization of global energy supply

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

An evaluation of interferences in heat production from low enthalpy geothermal doublets systems

Required distance between doublet systems in low enthalpy geothermal heat exploitation is often not fully elucidated. The required distance aims to prevent negative interference influencing the utilisation efficiency of doublet systems. Currently production licence areas are often issued based on the expected extent of the reinjected cold water plume on the moment of thermal breakthrough. The production temperature, however, may not immediately drop to non-economic values after this moment. Consequently, heat production could continue increasing the extent of the cold water plume. Furthermore, the area influenced by pressure because of injection and production spreads beyond the cold water plume extent, influencing not only the productivity of adjacent doublet systems but also the shape of cold water plumes. This affects doublet life time, especially if adjacent doublets have different production rates. In this modelling based study a multi parameter analysis is carried out to derive dimensionless relations between basic doublet design parameters and required doublet distance. These parameters include the spacing between injector and producer of the same doublet, different production rates, aquifer thickness and minimal required production temperature. The results of this study can be used to minimize negative interference or optimise positive interference aiming at improving geothermal doublet deployment efficiency

Cities in decline? A comparative history of Malmo and Newcastle after 1945

No abstract available

Recovery Factor of Geothermal Resources

No abstract available

Public Perception of Geothermal Energy at the Local Level in the UK

Successful development of a new renewable energy technology does not only rely on the success of pilot projects but also to a significant extent on the development of an adequate public engagement strategy. To be able to develop such a strategy a good understanding is required of the public perception of the new technology. Geothermal energy is still an emerging technology in the UK; in the absence of public debate on this topic, media reporting provides a suitable proxy for its public perception. Therefore, this study has gauged the public perception of geothermal energy in the UK by evaluating local news articles from 1980 to 2018. A coding scheme was developed to derive the main themes and to identify both the perceived advantages and hurdles for geothermal development. We focussed on local newspapers to be able to compare public perception in different regions in the UK. Results show a mainly positive perception of geothermal energy in all geographical regions across the UK. Only few articles mention risks, induced seismicity and environmental pollution. In contrast, advantages and positive aspects of geothermal energy, such as its carbon neutral footprint, the enormous amount of available geothermal heat and the potential contribution of geothermal development to the revival of local economies, are much more frequently mentioned. Perceived hurdles that are mostly described in the articles are: (1) the absence of geothermal legislation and subsidies in the UK; (2) the lack of available funding; and finally (3) technological and geological challenges or uncertainties. Finally, we show that geothermal energy is most often related to electricity generation and granite resources, while the only successful deep geothermal site in the UK is a direct-use heating scheme exploiting a sedimentary aquifer

De-risking database for hot sedimentary aquifers

Many of the world’s largest greenhouse gas emitting nations have recently committed to Net Zero or carbon neutrality targets by the year 2045 to 2060. This has led to an increasing investment in geothermal energy technology to diversify power mix and decarbonise energy generation. Amongst existing settings, hot sedimentary aquifers (HSAs) are large and conductive systems, typically occurring in large basin settings that are found across much of the world. They are hot enough, and have sufficient productivity, to provide significant low-carbon resources for heating or electricity purposes. However, there is still a substantial amount of risk associated with HSA projects, which restrains further development of the technology. The risk of failure faced by geothermal operators includes environmental, technical, financial and geological hazards, any of which can lead to unsuccessful geothermal projects. De-risking geothermal development is crucial for meeting prospective development objectives and enabling robust assessment of the potential relationships between the success or failure of a project and its main associated parameters. Key information gaps must also be addressed to tackle and diminish any risk involved with geothermal development. A unique database is under development that aims to capture all publicly available data for failed, and active HSA projects, in order to determine the most important predictive parameters for successful utilisation of HSAs. The database provides comparison data within specific sedimentary basins (e.g. specific to the geological setting of a basin) or nations (e.g. regulatory regime) as well as basin-independent factors across all potential locations (e.g. drilling technology). This paper will summarise findings from data collection, encompassing a suite of project information including reservoir properties and hazards encountered during exploration and operation. Case studies will be discussed from the UK and the Netherlands, and recommendations for best practice in both project development and data curation will be put forward

Injection Triggered Occlusion of Flow Pathways in a Sedimentary Aquifer in Hungary

No abstract available