My first year as Editor-in-Chief of the Netherlands Journal of Geosciences / Geologie en Mijnbouw turned out to be a steep learning curve which showed me all the facets this task brings. It has been a productive year, though. A total of 49 papers were published in three regular and two special issues. The special issues, on the Meuse Valley and on Seismicity of the Groningen Gas Field, were well received and contain papers authored by members of academic and applied institutions, including universities, consultants, advisory institutions, provinces, energy operators and regulatory authorities. This once again proves that thematic issues are a great strength of the Journal and it is good to notice that the Journal has become a medium for a broad geoscientific research community.
我担任《荷兰地球科学杂志》(Netherlands Journal of Geosciences / Geologie en Mijnbouw)主编的第一年经历了艰难的学习，让我了解了这项任务带来的所有方面。尽管如此，今年还是收获颇丰。共发表论文49篇，分3期常刊和2期特刊。关于默兹河谷和格罗宁根气田地震活动性的特刊受到好评，其中包含由学术和应用机构成员撰写的论文，包括大学、顾问、咨询机构、各省、能源运营商和监管机构。这再次证明，专题问题是《华尔街日报》的一大优势，值得注意的是，《华尔街日报》已成为一个广泛的地球科学研究界的媒介。
{"title":"What the future holds for the Netherlands Journal of Geosciences","authors":"J. T. ten Veen","doi":"10.1017/njg.2018.4","DOIUrl":"https://doi.org/10.1017/njg.2018.4","url":null,"abstract":"My first year as Editor-in-Chief of the Netherlands Journal of Geosciences / Geologie en Mijnbouw turned out to be a steep learning curve which showed me all the facets this task brings. It has been a productive year, though. A total of 49 papers were published in three regular and two special issues. The special issues, on the Meuse Valley and on Seismicity of the Groningen Gas Field, were well received and contain papers authored by members of academic and applied institutions, including universities, consultants, advisory institutions, provinces, energy operators and regulatory authorities. This once again proves that thematic issues are a great strength of the Journal and it is good to notice that the Journal has become a medium for a broad geoscientific research community.","PeriodicalId":49768,"journal":{"name":"Netherlands Journal of Geosciences-Geologie En Mijnbouw","volume":"79 1","pages":"1 - 2"},"PeriodicalIF":2.7,"publicationDate":"2018-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88585701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Kruiver, A. Wiersma, F. Kloosterman, G. D. De Lange, M. Korff, J. Stafleu, F. Busschers, R. Harting, J. Gunnink, R. Green, J. van Elk, D. Doornhof
Abstract The shallow subsurface of Groningen, the Netherlands, is heterogeneous due to its formation in a Holocene tidal coastal setting on a periglacially and glacially inherited landscape with strong lateral variation in subsurface architecture. Soft sediments with low, small-strain shear wave velocities (V S30 around 200 m s−1) are known to amplify earthquake motions. Knowledge of the architecture and properties of the subsurface and the combined effect on the propagation of earthquake waves is imperative for the prediction of geohazards of ground shaking and liquefaction at the surface. In order to provide information for the seismic hazard and risk analysis, two geological models were constructed. The first is the ‘Geological model for Site response in Groningen’ (GSG model) and is based on the detailed 3D GeoTOP voxel model containing lithostratigraphy and lithoclass attributes. The GeoTOP model was combined with information from boreholes, cone penetration tests, regional digital geological and geohydrological models to cover the full range from the surface down to the base of the North Sea Supergroup (base Paleogene) at ~800 m depth. The GSG model consists of a microzonation based on geology and a stack of soil stratigraphy for each of the 140,000 grid cells (100 m × 100 m) to which properties (V S and parameters relevant for nonlinear soil behaviour) were assigned. The GSG model serves as input to the site response calculations that feed into the Ground Motion Model. The second model is the ‘Geological model for Liquefaction sensitivity in Groningen’ (GLG). Generally, loosely packed sands might be susceptible to liquefaction upon earthquake shaking. In order to delineate zones of loosely packed sand in the first 40 m below the surface, GeoTOP was combined with relative densities inferred from a large cone penetration test database. The marine Naaldwijk and Eem Formations have the highest proportion of loosely packed sand (31% and 38%, respectively) and thus are considered to be the most vulnerable to liquefaction; other units contain 5–17% loosely packed sand. The GLG model serves as one of the inputs for further research on the liquefaction potential in Groningen, such as the development of region-specific magnitude scaling factors (MSF) and depth–stress reduction relationships (r d).
荷兰格罗宁根(Groningen)的浅层地下结构是不均匀的，因为它形成于全新世潮汐海岸背景下的冰缘和冰川继承景观，地下结构具有强烈的横向变化。已知具有低、小应变剪切波速(vs30约200 m s - 1)的软沉积物会放大地震运动。了解地下构造和性质及其对地震波传播的综合影响，对于预测地表震动和液化等地质灾害是必不可少的。为了给地震灾害和风险分析提供信息，建立了两个地质模型。第一个是“Groningen现场响应地质模型”(GSG模型)，该模型基于包含岩石地层和岩石分类属性的详细3D GeoTOP体素模型。GeoTOP模型与钻孔、锥贯入试验、区域数字地质和地质水文模型的信息相结合，覆盖了北海超群(基底古近系)从地表到底部的整个范围，深度约为800 m。GSG模型由一个基于地质的微带和14万个网格单元(100米× 100米)的土壤地层学叠加组成，这些网格单元的属性(与非线性土壤行为相关的V S和参数)被分配到每个网格单元。GSG模型作为场地响应计算的输入，然后输入到地面运动模型中。第二个模型是“格罗宁根液化敏感性地质模型”(GLG)。一般来说，松散的沙子在地震中容易液化。为了圈定地表以下40米的松散砂层，GeoTOP结合了从大型锥体穿透测试数据库推断的相对密度。海洋Naaldwijk组和Eem组松散堆积砂的比例最高(分别为31%和38%)，因此被认为是最容易液化的;其他单元含有5-17%松散堆积的砂。GLG模型可作为进一步研究格罗宁根液化潜力的输入之一，如区域特定震级标度因子(MSF)和深度应力减小关系(r d)的发展。
{"title":"Characterisation of the Groningen subsurface for seismic hazard and risk modelling","authors":"P. Kruiver, A. Wiersma, F. Kloosterman, G. D. De Lange, M. Korff, J. Stafleu, F. Busschers, R. Harting, J. Gunnink, R. Green, J. van Elk, D. Doornhof","doi":"10.1017/njg.2017.11","DOIUrl":"https://doi.org/10.1017/njg.2017.11","url":null,"abstract":"Abstract The shallow subsurface of Groningen, the Netherlands, is heterogeneous due to its formation in a Holocene tidal coastal setting on a periglacially and glacially inherited landscape with strong lateral variation in subsurface architecture. Soft sediments with low, small-strain shear wave velocities (V S30 around 200 m s−1) are known to amplify earthquake motions. Knowledge of the architecture and properties of the subsurface and the combined effect on the propagation of earthquake waves is imperative for the prediction of geohazards of ground shaking and liquefaction at the surface. In order to provide information for the seismic hazard and risk analysis, two geological models were constructed. The first is the ‘Geological model for Site response in Groningen’ (GSG model) and is based on the detailed 3D GeoTOP voxel model containing lithostratigraphy and lithoclass attributes. The GeoTOP model was combined with information from boreholes, cone penetration tests, regional digital geological and geohydrological models to cover the full range from the surface down to the base of the North Sea Supergroup (base Paleogene) at ~800 m depth. The GSG model consists of a microzonation based on geology and a stack of soil stratigraphy for each of the 140,000 grid cells (100 m × 100 m) to which properties (V S and parameters relevant for nonlinear soil behaviour) were assigned. The GSG model serves as input to the site response calculations that feed into the Ground Motion Model. The second model is the ‘Geological model for Liquefaction sensitivity in Groningen’ (GLG). Generally, loosely packed sands might be susceptible to liquefaction upon earthquake shaking. In order to delineate zones of loosely packed sand in the first 40 m below the surface, GeoTOP was combined with relative densities inferred from a large cone penetration test database. The marine Naaldwijk and Eem Formations have the highest proportion of loosely packed sand (31% and 38%, respectively) and thus are considered to be the most vulnerable to liquefaction; other units contain 5–17% loosely packed sand. The GLG model serves as one of the inputs for further research on the liquefaction potential in Groningen, such as the development of region-specific magnitude scaling factors (MSF) and depth–stress reduction relationships (r d).","PeriodicalId":49768,"journal":{"name":"Netherlands Journal of Geosciences-Geologie En Mijnbouw","volume":"42 1","pages":"s215 - s233"},"PeriodicalIF":2.7,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87554748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Kettermann, S. Abe, A. Raith, J. de Jager, J. Urai
Abstract The presence of salt in dilatant normal faults may have a strong influence on fault mechanics in the Groningen field and on the related induced seismicity. At present, little is known of the structure of these fault zones. This study starts with the geological evolution of the Groningen area, where, during tectonic faulting, rock salt may have migrated downwards into dilatant faults. These fault zones therefore may contain inclusions of rock salt. Because of its rate-dependent mechanical properties, the presence of salt in a fault may introduce a loading-rate dependency into fault movement and affect the distribution of magnitudes of seismic events. We present a first-look study showing how these processes can be investigated using a combination of analogue and numerical modelling. Full scaling of the models and quantification of implications for induced seismicity in Groningen require further, more detailed studies: an understanding of fault zone structure in the Groningen field is required for improved predictions of induced seismicity. The analogue experiments are based on a simplified stratigraphy of the Groningen area, where it is generally thought that most of the Rotliegend faulting has taken place in the Jurassic, after deposition of the Zechstein. This suggests that, at the time of faulting, the sulphates were already transformed into brittle anhydrite. If these layers were sufficiently brittle to fault in a dilatant fashion, rock salt was able to flow downwards into the dilatant fractures. To test this hypothesis, we use sandbox experiments where we combine cohesive powder as analogue for brittle anhydrites and carbonates with viscous salt analogues to explore the developing fault geometry and the resulting distribution of salt in the faults. Using the observations from analogue models as input, numerical models investigate the stick-slip behaviour of fault zones containing ductile material qualitatively with the discrete element method (DEM). Results show that the DEM approach is suitable for modelling the seismicity of faults containing salt. The stick-slip motion of the fault becomes dependent on shear loading rate with a modification of the frequency–magnitude distribution of the generated seismic events.
{"title":"The effect of salt in dilatant faults on rates and magnitudes of induced seismicity – first results building on the geological setting of the Groningen Rotliegend reservoirs","authors":"M. Kettermann, S. Abe, A. Raith, J. de Jager, J. Urai","doi":"10.1017/njg.2017.19","DOIUrl":"https://doi.org/10.1017/njg.2017.19","url":null,"abstract":"Abstract The presence of salt in dilatant normal faults may have a strong influence on fault mechanics in the Groningen field and on the related induced seismicity. At present, little is known of the structure of these fault zones. This study starts with the geological evolution of the Groningen area, where, during tectonic faulting, rock salt may have migrated downwards into dilatant faults. These fault zones therefore may contain inclusions of rock salt. Because of its rate-dependent mechanical properties, the presence of salt in a fault may introduce a loading-rate dependency into fault movement and affect the distribution of magnitudes of seismic events. We present a first-look study showing how these processes can be investigated using a combination of analogue and numerical modelling. Full scaling of the models and quantification of implications for induced seismicity in Groningen require further, more detailed studies: an understanding of fault zone structure in the Groningen field is required for improved predictions of induced seismicity. The analogue experiments are based on a simplified stratigraphy of the Groningen area, where it is generally thought that most of the Rotliegend faulting has taken place in the Jurassic, after deposition of the Zechstein. This suggests that, at the time of faulting, the sulphates were already transformed into brittle anhydrite. If these layers were sufficiently brittle to fault in a dilatant fashion, rock salt was able to flow downwards into the dilatant fractures. To test this hypothesis, we use sandbox experiments where we combine cohesive powder as analogue for brittle anhydrites and carbonates with viscous salt analogues to explore the developing fault geometry and the resulting distribution of salt in the faults. Using the observations from analogue models as input, numerical models investigate the stick-slip behaviour of fault zones containing ductile material qualitatively with the discrete element method (DEM). Results show that the DEM approach is suitable for modelling the seismicity of faults containing salt. The stick-slip motion of the fault becomes dependent on shear loading rate with a modification of the frequency–magnitude distribution of the generated seismic events.","PeriodicalId":49768,"journal":{"name":"Netherlands Journal of Geosciences-Geologie En Mijnbouw","volume":"10 1","pages":"s87 - s104"},"PeriodicalIF":2.7,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89629288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This paper describes a research programme recently initiated at Utrecht University that aims to contribute new, fundamental physical understanding and quantitative descriptions of rock and fault behaviour needed to advance understanding of reservoir compaction and fault behaviour in the context of induced seismicity and subsidence in the Groningen gas field. The NAM-funded programme involves experimental rock and fault mechanics work, microscale observational studies to determine the processes that control reservoir rock deformation and fault slip, modelling and experimental work aimed at establishing upscaling rules between laboratory and field scales, and geomechanical modelling of fault rupture and earthquake generation at the reservoir scale. Here, we focus on describing the programme and its intended contribution to understanding the response of the Groningen field to gas production. The key knowledge gaps that drive the programme are discussed and the approaches employed to address them are highlighted. Some of the first results emerging from the work in progress are also reported briefly and are providing important new insights.
{"title":"New approaches in experimental research on rock and fault behaviour in the Groningen gas field","authors":"C. Spiers, S. Hangx, A. Niemeijer","doi":"10.1017/njg.2017.32","DOIUrl":"https://doi.org/10.1017/njg.2017.32","url":null,"abstract":"Abstract This paper describes a research programme recently initiated at Utrecht University that aims to contribute new, fundamental physical understanding and quantitative descriptions of rock and fault behaviour needed to advance understanding of reservoir compaction and fault behaviour in the context of induced seismicity and subsidence in the Groningen gas field. The NAM-funded programme involves experimental rock and fault mechanics work, microscale observational studies to determine the processes that control reservoir rock deformation and fault slip, modelling and experimental work aimed at establishing upscaling rules between laboratory and field scales, and geomechanical modelling of fault rupture and earthquake generation at the reservoir scale. Here, we focus on describing the programme and its intended contribution to understanding the response of the Groningen field to gas production. The key knowledge gaps that drive the programme are discussed and the approaches employed to address them are highlighted. Some of the first results emerging from the work in progress are also reported briefly and are providing important new insights.","PeriodicalId":49768,"journal":{"name":"Netherlands Journal of Geosciences-Geologie En Mijnbouw","volume":"13 1","pages":"s55 - s69"},"PeriodicalIF":2.7,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87083801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Willems, A. Vondrak, D. Munsterman, M. Donselaar, H. Mijnlieff
Abstract 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.
{"title":"Regional geothermal aquifer architecture of the fluvial Lower Cretaceous Nieuwerkerk Formation – a palynological analysis","authors":"C. Willems, A. Vondrak, D. Munsterman, M. Donselaar, H. Mijnlieff","doi":"10.1017/njg.2017.23","DOIUrl":"https://doi.org/10.1017/njg.2017.23","url":null,"abstract":"Abstract 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.","PeriodicalId":49768,"journal":{"name":"Netherlands Journal of Geosciences-Geologie En Mijnbouw","volume":"17 1","pages":"319 - 330"},"PeriodicalIF":2.7,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84345429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The assessment of the seismic hazard and risk associated with the extraction of gas from the Groningen field involves a chain of modelling efforts. The first step is a description of the 3D distribution of reservoir properties in the reservoir – the static reservoir model – and is the subject of this paper. Consecutive steps in the chain of models are described elsewhere in this volume. The construction of a static reservoir model is not strictly a scientific endeavour, but many of the applied modelling techniques are underpinned by extensive scientific research. This paper aims to give a general introduction to the approach followed by NAM to build static models for the Groningen field. More detailed accounts of the applied modelling techniques, the assessment of associated uncertainties or the usage of multiple modelling scenarios are beyond the scope of the current paper, but are referenced in the text.
{"title":"Introduction to the Groningen static reservoir model","authors":"C. Visser, Jose L. Solano Viota","doi":"10.1017/njg.2017.25","DOIUrl":"https://doi.org/10.1017/njg.2017.25","url":null,"abstract":"Abstract The assessment of the seismic hazard and risk associated with the extraction of gas from the Groningen field involves a chain of modelling efforts. The first step is a description of the 3D distribution of reservoir properties in the reservoir – the static reservoir model – and is the subject of this paper. Consecutive steps in the chain of models are described elsewhere in this volume. The construction of a static reservoir model is not strictly a scientific endeavour, but many of the applied modelling techniques are underpinned by extensive scientific research. This paper aims to give a general introduction to the approach followed by NAM to build static models for the Groningen field. More detailed accounts of the applied modelling techniques, the assessment of associated uncertainties or the usage of multiple modelling scenarios are beyond the scope of the current paper, but are referenced in the text.","PeriodicalId":49768,"journal":{"name":"Netherlands Journal of Geosciences-Geologie En Mijnbouw","volume":"83 1","pages":"s39 - s46"},"PeriodicalIF":2.7,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80505694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Not long after discovery of the Groningen field, gas-production-induced compaction and consequent land subsidence was recognised to be a potential threat to groundwater management in the province of Groningen, in addition to the fact that parts of the province lie below sea level. More recently, NAM's seismological model also pointed to a correlation between reservoir compaction and the observed induced seismicity above the field. In addition to the already existing requirement for accurate subsidence predictions, this demanded a more accurate description of the expected spatial and temporal development of compaction. Since the start of production in 1963, multiple levelling campaigns have gathered a unique set of deformation measurements used to calibrate geomechanical models. In this paper we present a methodology to model compaction and subsidence, combining results from rock mechanics experiments and surface deformation measurements. Besides the optical spirit-levelling data, InSAR data are also used for inversion to compaction and calibration of compaction models. Residual analysis, i.e. analysis of the difference between measurement and model output, provides confidence in the model results used for subsidence forecasting and as input to seismological models.
{"title":"Field-wide reservoir compressibility estimation through inversion of subsidence data above the Groningen gas field","authors":"Rob M.H.E. van Eijs, Onno van der Wal","doi":"10.1017/njg.2017.30","DOIUrl":"https://doi.org/10.1017/njg.2017.30","url":null,"abstract":"Abstract Not long after discovery of the Groningen field, gas-production-induced compaction and consequent land subsidence was recognised to be a potential threat to groundwater management in the province of Groningen, in addition to the fact that parts of the province lie below sea level. More recently, NAM's seismological model also pointed to a correlation between reservoir compaction and the observed induced seismicity above the field. In addition to the already existing requirement for accurate subsidence predictions, this demanded a more accurate description of the expected spatial and temporal development of compaction. Since the start of production in 1963, multiple levelling campaigns have gathered a unique set of deformation measurements used to calibrate geomechanical models. In this paper we present a methodology to model compaction and subsidence, combining results from rock mechanics experiments and surface deformation measurements. Besides the optical spirit-levelling data, InSAR data are also used for inversion to compaction and calibration of compaction models. Residual analysis, i.e. analysis of the difference between measurement and model output, provides confidence in the model results used for subsidence forecasting and as input to seismological models.","PeriodicalId":49768,"journal":{"name":"Netherlands Journal of Geosciences-Geologie En Mijnbouw","volume":"42 1","pages":"s117 - s129"},"PeriodicalIF":2.7,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78203848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This paper describes the ongoing experimental and analytical activities that are being carried out to develop fatality and consequence models for the estimation of ‘Inside Local Personal Risk’ (ILPR) of buildings within the Groningen field. ILPR is defined as the annual probability of fatality for a hypothetical person who is continuously present without protection inside a building. In order to be able to estimate this risk metric, a robust estimate of the probability of collapse of structural and non-structural elements within a building is needed, as these have been found to be the greatest drivers of fatality risk. To estimate the collapse potential of buildings in Groningen, structural numerical models of a number of representative case studies have been developed and calibrated through in situ and laboratory testing on materials, connections, structural components and even full-scale buildings. These numerical models are then subjected to increased levels of ground shaking to estimate the probability of collapse, and the associated consequences are estimated from the observed collapse mechanisms.
{"title":"Developing fragility and consequence models for buildings in the Groningen field","authors":"H. Crowley, R. Pinho, B. Polidoro, J. van Elk","doi":"10.1017/njg.2017.36","DOIUrl":"https://doi.org/10.1017/njg.2017.36","url":null,"abstract":"Abstract This paper describes the ongoing experimental and analytical activities that are being carried out to develop fatality and consequence models for the estimation of ‘Inside Local Personal Risk’ (ILPR) of buildings within the Groningen field. ILPR is defined as the annual probability of fatality for a hypothetical person who is continuously present without protection inside a building. In order to be able to estimate this risk metric, a robust estimate of the probability of collapse of structural and non-structural elements within a building is needed, as these have been found to be the greatest drivers of fatality risk. To estimate the collapse potential of buildings in Groningen, structural numerical models of a number of representative case studies have been developed and calibrated through in situ and laboratory testing on materials, connections, structural components and even full-scale buildings. These numerical models are then subjected to increased levels of ground shaking to estimate the probability of collapse, and the associated consequences are estimated from the observed collapse mechanisms.","PeriodicalId":49768,"journal":{"name":"Netherlands Journal of Geosciences-Geologie En Mijnbouw","volume":"434 1","pages":"s247 - s257"},"PeriodicalIF":2.7,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83616946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. van Wees, P. Fokker, K. van Thienen-Visser, B. Wassing, S. Osinga, B. Orlic, S. A. Ghouri, L. Buijze, M. Pluymaekers
Abstract In the Netherlands, over 190 gas fields of varying size have been exploited, and 15% of these have shown seismicity. The prime cause for seismicity due to gas depletion is stress changes caused by pressure depletion and by differential compaction. The observed onset of induced seismicity due to gas depletion in the Netherlands occurs after a considerable pressure drop in the gas fields. Geomechanical studies show that both the delay in the onset of induced seismicity and the nonlinear increase in seismic moment observed for the induced seismicity in the Groningen field can be explained by a model of pressure depletion, if the faults causing the induced seismicity are not critically stressed at the onset of depletion. Our model shows concave patterns of log moment with time for individual faults. This suggests that the growth of future seismicity could well be more limited than would be inferred from extrapolation of the observed trend between production or compaction and seismicity. The geomechanical models predict that seismic moment increase should slow down significantly immediately after a production decrease, independently of the decay rate of the compaction model. These findings are in agreement with the observed reduced seismicity rates in the central area of the Groningen field immediately after production decrease on 17 January 2014. The geomechanical model findings therefore support scope for mitigating induced seismicity by adjusting rates of production and associated pressure change. These simplified models cannot serve as comprehensive models for predicting induced seismicity in any particular field. To this end, a more detailed field-specific study, taking into account the full complexity of reservoir geometry, depletion history and mechanical properties, is required.
{"title":"Geomechanical models for induced seismicity in the Netherlands: inferences from simplified analytical, finite element and rupture model approaches","authors":"J. van Wees, P. Fokker, K. van Thienen-Visser, B. Wassing, S. Osinga, B. Orlic, S. A. Ghouri, L. Buijze, M. Pluymaekers","doi":"10.1017/njg.2017.38","DOIUrl":"https://doi.org/10.1017/njg.2017.38","url":null,"abstract":"Abstract In the Netherlands, over 190 gas fields of varying size have been exploited, and 15% of these have shown seismicity. The prime cause for seismicity due to gas depletion is stress changes caused by pressure depletion and by differential compaction. The observed onset of induced seismicity due to gas depletion in the Netherlands occurs after a considerable pressure drop in the gas fields. Geomechanical studies show that both the delay in the onset of induced seismicity and the nonlinear increase in seismic moment observed for the induced seismicity in the Groningen field can be explained by a model of pressure depletion, if the faults causing the induced seismicity are not critically stressed at the onset of depletion. Our model shows concave patterns of log moment with time for individual faults. This suggests that the growth of future seismicity could well be more limited than would be inferred from extrapolation of the observed trend between production or compaction and seismicity. The geomechanical models predict that seismic moment increase should slow down significantly immediately after a production decrease, independently of the decay rate of the compaction model. These findings are in agreement with the observed reduced seismicity rates in the central area of the Groningen field immediately after production decrease on 17 January 2014. The geomechanical model findings therefore support scope for mitigating induced seismicity by adjusting rates of production and associated pressure change. These simplified models cannot serve as comprehensive models for predicting induced seismicity in any particular field. To this end, a more detailed field-specific study, taking into account the full complexity of reservoir geometry, depletion history and mechanical properties, is required.","PeriodicalId":49768,"journal":{"name":"Netherlands Journal of Geosciences-Geologie En Mijnbouw","volume":"85 1","pages":"s183 - s202"},"PeriodicalIF":2.7,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84334881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This paper reviews the evolution of a sequence of seismological models developed and implemented as part of a workflow for Probabilistic Seismic Hazard and Risk Assessment of the seismicity induced by gas production from the Groningen gas field. These are semi-empirical statistical geomechanical models derived from observations of production-induced seismicity, reservoir compaction and structure of the field itself. Initial versions of the seismological model were based on a characterisation of the seismicity in terms of its moment budget. Subsequent versions of the model were formulated in terms of seismic event rates, this change being driven in part by the reduction in variability of the model forecasts in this domain. Our approach makes use of the Epidemic Type After Shock model (ETAS) to characterise spatial and temporal clustering of earthquakes and has been extended to also incorporate the concentration of moment release on pre-existing faults and other reservoir topographic structures.
{"title":"Development of statistical geomechanical models for forecasting seismicity induced by gas production from the Groningen field","authors":"S. Bourne, S. Oates","doi":"10.1017/njg.2017.35","DOIUrl":"https://doi.org/10.1017/njg.2017.35","url":null,"abstract":"Abstract This paper reviews the evolution of a sequence of seismological models developed and implemented as part of a workflow for Probabilistic Seismic Hazard and Risk Assessment of the seismicity induced by gas production from the Groningen gas field. These are semi-empirical statistical geomechanical models derived from observations of production-induced seismicity, reservoir compaction and structure of the field itself. Initial versions of the seismological model were based on a characterisation of the seismicity in terms of its moment budget. Subsequent versions of the model were formulated in terms of seismic event rates, this change being driven in part by the reduction in variability of the model forecasts in this domain. Our approach makes use of the Epidemic Type After Shock model (ETAS) to characterise spatial and temporal clustering of earthquakes and has been extended to also incorporate the concentration of moment release on pre-existing faults and other reservoir topographic structures.","PeriodicalId":49768,"journal":{"name":"Netherlands Journal of Geosciences-Geologie En Mijnbouw","volume":"3 1","pages":"s175 - s182"},"PeriodicalIF":2.7,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75030352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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