scholarly journals New approaches in experimental research on rock and fault behaviour in the Groningen gas field

2017 ◽  
Vol 96 (5) ◽  
pp. s55-s69 ◽  
Author(s):  
Christopher J. Spiers ◽  
Suzanne J.T. Hangx ◽  
André R. Niemeijer
Keyword(s):  
Research Programme ◽  
Gas Production ◽  
Reservoir Rock ◽  
Fault Mechanics ◽  
Gas Field ◽  
Reservoir Compaction ◽  
First Results ◽  
Experimental Rock ◽  
Earthquake Generation ◽  
Groningen Gas Field

AbstractThis 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.

scholarly journals Incorporating dwelling mounds into induced seismic risk analysis for the Groningen gas field in the Netherlands

2021 ◽  
Author(s):  
Pauline P. Kruiver ◽  
Manos Pefkos ◽  
Erik Meijles ◽  
Gerard Aalbersberg ◽  
Xander Campman ◽  
...  
Keyword(s):  
The Netherlands ◽  
Seismic Risk ◽  
Site Response ◽  
Gas Production ◽  
Fragility Functions ◽  
Gas Field ◽  
Amplification Factors ◽  
Reservoir Compaction ◽  
Groningen Gas Field ◽  
The Impact

AbstractIn order to inform decision-making regarding measures to mitigate the impact of induced seismicity in the Groningen gas field in the Netherlands, a comprehensive seismic risk model has been developed. Starting with gas production scenarios and the consequent reservoir compaction, the model generates synthetic earthquake catalogues which are deployed in Monte Carlo analyses, predicting ground motions at a buried reference rock horizon that are combined with nonlinear amplification factors to estimate response spectral accelerations at the surface. These motions are combined with fragility functions defined for the exposed buildings throughout the region to estimate damage levels, which in turn are transformed to risk in terms of injury through consequence functions. Several older and potentially vulnerable buildings are located on dwelling mounds that were constructed from soils and organic material as a flood defence. These anthropogenic structures are not included in the soil profile models used to develop the amplification factors and hence their influence has not been included in the risk analyses to date. To address this gap in the model, concerted studies have been identified to characterize the dwelling mounds. These include new shear-wave velocity measurements that have enabled dynamic site response analyses to determine the modification of ground shaking due to the presence of the mound. A scheme has then been developed to incorporate the dwelling mounds into the risk calculations, which included an assessment of whether the soil-structure interaction effects for buildings founded on the mounds required modification of the seismic fragility functions.

scholarly journals Field-wide reservoir compressibility estimation through inversion of subsidence data above the Groningen gas field

2017 ◽  
Vol 96 (5) ◽  
pp. s117-s129 ◽  
Author(s):  
Rob M.H.E. van Eijs ◽  
Onno van der Wal
Keyword(s):  
Induced Seismicity ◽  
Surface Deformation ◽  
Gas Production ◽  
Potential Threat ◽  
Gas Field ◽  
Reservoir Compaction ◽  
The Difference ◽  
Seismological Model ◽  
Groningen Gas Field ◽  
Deformation Measurements

AbstractNot 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.

scholarly journals Development of statistical geomechanical models for forecasting seismicity induced by gas production from the Groningen field

2017 ◽  
Vol 96 (5) ◽  
pp. s175-s182 ◽  
Author(s):  
Stephen J. Bourne ◽  
Stephen J. Oates
Keyword(s):  
Seismic Event ◽  
Gas Production ◽  
Gas Field ◽  
Reservoir Compaction ◽  
Hazard And Risk ◽  
Hazard And Risk Assessment ◽  
Event Rates ◽  
Semi Empirical ◽  
Seismological Model ◽  
Groningen Gas Field

AbstractThis 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.

scholarly journals Drill core from seismically active sandstone gas reservoir yields clues to internal deformation mechanisms

Geology ◽  
2020 ◽  
Author(s):  
Berend A. Verberne ◽  
Suzanne J.T. Hangx ◽  
Ronald P.J. Pijnenburg ◽  
Maartje F. Hamers ◽  
Martyn R. Drury ◽  
...  
Keyword(s):  
Microstructural Analysis ◽  
Gas Production ◽  
Drill Core ◽  
Gas Reservoir ◽  
Gas Field ◽  
Reservoir Compaction ◽  
Key Factor ◽  
Forecasting System ◽  
Internal Deformation ◽  
Dauphiné Twinning

Europe’s largest gas field, the Groningen field (the Netherlands), is widely known for induced subsidence and seismicity caused by gas pressure depletion and associated compaction of the sandstone reservoir. Whether compaction is elastic or partly inelastic, as implied by recent experiments, is a key factor in forecasting system behavior and seismic hazard. We sought evidence for inelastic deformation through comparative microstructural analysis of unique drill core recovered from the seismogenic center of the field in 2015, 50 yr after gas production started, versus core recovered before production (1965). Quartz grain fracturing, crack healing, and stress-induced Dauphiné twinning are equally developed in the 2015 and 1965 cores, with the only measurable effect of gas production being enhanced microcracking of sparse K-feldspar grains in the 2015 core. Interpreting these grains as strain markers, we suggest that reservoir compaction involves elastic strain plus inelastic compression of weak clay films within grain contacts.

Discrete Element Method modelling of Groningen reservoir compaction using a new contact model describing elastic and inelastic grain-scale interactions

2020 ◽  
Author(s):  
Mohammad Hadi Mehranpour ◽  
Suzanne J. T. Hangx ◽  
Chris J. Spiers
Keyword(s):  
Induced Seismicity ◽  
Inelastic Deformation ◽  
Field Measurements ◽  
Contact Model ◽  
Geophysical Research ◽  
Gas Field ◽  
Reservoir Compaction ◽  
Compaction Behavior ◽  
Groningen Gas Field

<p>Predicting reservoir compaction resulting from fluid depletion is important to assess potential hazards and risks associated with fluid production, such as surface subsidence and induced seismicity. Globally, many producing oil and gas fields are experiencing these phenomena. The giant Dutch Groningen gas field, the Netherlands, is currently measuring up to 35 cm of surface subsidence and experiencing widespread induced seismicity. To accurately predict reservoir compaction, reservoir-scale models incorporating realistic grain-scale microphysical processes are needed. As a first step towards that aim, Discrete Element Method (DEM) modeling can be used to predict the compaction behavior of granular materials at the cm/dm-scale, under a wide range of conditions representing realistic in-situ stress and pressure conditions.</p><p>Laboratory experiments on the reservoir of the Groningen gas field, the Slochteren sandstone, have shown elastic deformation, inelastic deformation due to clay film consolidation, and inelastic deformation due to grain sliding and grain failure. Since the available contact models for DEM modeling do not yet incorporate all of these grain-scale processes, a new contact model, the Slochteren sandstone contact model (SSCM), was developed to explicitly take these mechanisms into account and integrate them into Particle Flow Code (PFC), which is a powerful DEM approach.</p><p>In SSCM the blunt conical contact with an apex angle close to 180˚ is assumed to properly model the elastic behavior, as well as the grain failure mechanism. Compacting an assembly of particles with this type of contact model, results in a range of contact shapes, from point to long contacts, which is compatible with microstructural observations of Slochteren sandstone.  The deformation of thin intergranular clay coatings is implemented following the microphysical model proposed by Pijnenburg et al. (2019a).</p><p>The model allows for the systematic investigation of porosity, grain size distribution and intergranular clay film content on compaction behavior. The model was calibrated against a limited number of hydrostatic and deviatoric stress experiments (Pijnenburg et al. 2019b) and verified against an independent set of uniaxial compressive experiments (Hol et al. 2018) with a range of porosities, grain size distributions and clay content. The calibrated model was also used to make predictions of the compaction behavior of Slochteren sandstone. These predictions were compared to field measurements of in-situ compaction and showed an acceptable match if the uncertainties of field measurements are considered in calculations.</p><p>References:</p><p>Pijnenburg, R.P.J., Verberne, B.A., Hangx, S.J.T. and Spiers, C.J., 2019. Intergranular clay films control inelastic deformation in the Groningen gas reservoir: Evidence from split‐cylinder deformation tests. Journal of Geophysical Research: Solid Earth.</p><p>Pijnenburg, R.P.J., Verberne, B.A., Hangx, S.J.T. and Spiers, C.J., 2019. Inelastic deformation of the Slochteren sandstone: Stress‐strain relations and implications for induced seismicity in the Groningen gas field. Journal of Geophysical Research: Solid Earth.</p><p>Hol, S., van der Linden, A., Bierman, S., Marcelis, F. and Makurat, A., 2018. Rock physical controls on production-induced compaction in the Groningen Field. Scientific reports, 8(1), p.7156.</p>

The Groningen Gas Field: Fifty Years of Exploration and Gas Production from a Permian Dryland Reservoir

2011 ◽  
pp. 11-33 ◽  
Author(s):  
JÜRGEN GRÖTSCH ◽  
ARNOUD SLUIJK ◽  
KEES Van OJIK ◽  
MARTIN De KEIJZER ◽  
JORIS GRAAF ◽  
...  
Keyword(s):  
Gas Production ◽  
Gas Field ◽  
Groningen Gas Field

Statistical mechanics-based forecasting of induced seismicity within the Groningen gas field

2020 ◽  
Author(s):  
Stephen Bourne ◽  
Steve Oates
Keyword(s):  
Size Distribution ◽  
Induced Seismicity ◽  
Gas Production ◽  
Linear Functions ◽  
Fault System ◽  
Induced Earthquakes ◽  
Gas Field ◽  
Hazard And Risk ◽  
Stress Dependent ◽  
Groningen Gas Field

<p>Geological faults may fail and produce earthquakes due to external stresses induced by hydrocarbon recovery, geothermal extraction, CO<sub>2</sub> storage or subsurface energy storage. The associated hazard and risk critically depend on the spatiotemporal and size distribution of any induced seismicity. The observed statistics of induced seismicity within the Groningen gas field evolve as non-linear functions of the poroelastic stresses generated by pore pressure depletion since 1965. The rate of earthquake initiation per unit stress has systematically increased as an exponential-like function of cumulative incremental stress over at least the last 25 years of gas production. The expected size of these earthquakes also increased in a manner consistent with a stress-dependent tapering of the seismic moment power-law distribution. Aftershocks of these induced earthquakes are also observed, although evidence for any stress-dependent aftershock productivity or spatiotemporal clustering is inconclusive.</p><p>These observations are consistent with the reactivation of a mechanically disordered fault system characterized by a large, stochastic prestress distribution. If this prestress variability significantly exceeds the induced stress loads, as well as the earthquake stress drops, then the space-time-size distribution of induced earthquakes may be described by mean field theories within statistical fracture mechanics. A probabilistic seismological model based on these theories matches the history of induced seismicity within the Groningen region and correctly forecasts the seismicity response to reduced gas production rates designed to lower the associated seismic hazard and risk.</p>

scholarly journals Probabilistic earthquake locations of induced seismicity in the Groningen region, the Netherlands

2020 ◽  
Vol 222 (1) ◽  
pp. 507-516 ◽  
Author(s):  
Jonathan D Smith ◽  
Robert S White ◽  
Jean-Philippe Avouac ◽  
Stephen Bourne
Keyword(s):  
The Netherlands ◽  
Depth Distribution ◽  
Velocity Model ◽  
Gas Production ◽  
Gas Field ◽  
Arrival Times ◽  
S Waves ◽  
Reservoir Compaction ◽  
Earthquake Locations ◽  
Projection Techniques

SUMMARY The Groningen gas reservoir, situated in the northeast of the Netherlands, is western Europe’s largest producing gas field and has been in production since 1963. The gas production has induced both subsidence and seismicity. Seismicity is detected and located using the Koninklijk Nederlands Meteorologisch Instituut shallow-borehole array for the period 2015–2017, incorporating the back projection techniques of QuakeMigrate and the nonlinear location procedure to constrain earthquake locations and depths. The uncertainties on the estimated depths are estimated taking into account velocity model, changes in station array geometry and uncertainties in the measurement of arrival times of the P and S waves. We show that the depth distribution of seismicity is consistent with nucleation within the reservoir (28 per cent) or in the overburden (60 per cent) within ∼500 m from the top of the reservoir. Earthquakes with hypocentres in the overburden likely originate from overlying Zechstein anhydrite caprock. Based on their depth distribution, it seems like the earthquakes are primarily driven by the elastic strain in the reservoir and overburden, induced by the reservoir compaction. We estimate the probability of earthquakes nucleating beneath the reservoir in the underlying Carboniferous limestone and basement, to be no more than 12 per cent.

scholarly journals Hazard and risk assessments for induced seismicity in Groningen

2017 ◽  
Vol 96 (5) ◽  
pp. s259-s269 ◽  
Author(s):  
Jan van Elk ◽  
Dirk Doornhof ◽  
Julian J. Bommer ◽  
Stephen J. Bourne ◽  
Steve J. Oates ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Seismic Hazard ◽  
Data Acquisition ◽  
Induced Seismicity ◽  
Research Programme ◽  
Gas Production ◽  
Probabilistic Seismic Hazard ◽  
Gas Field ◽  
Hazard And Risk ◽  
Hazard And Risk Assessment

AbstractEarthquakes associated with gas production have been recorded in the northern part of the Netherlands since 1986. The Huizinge earthquake of 16 August 2012, the strongest so far with a magnitude of ML = 3.6, prompted reassessment of the seismicity induced by production from the Groningen gas field. An international research programme was initiated, with the participation of many Dutch and international universities, knowledge institutes and recognised experts.The prime aim of the programme was to assess the hazard and risk resulting from the induced seismicity. Classic probabilistic seismic hazard and risk assessment (PSHA) was implemented using a Monte Carlo method. The scope of the research programme extended from the cause (production of gas from the underground reservoir) to the effects (risk to people and damage to buildings). Data acquisition through field measurements and laboratory experiments was a substantial element of the research programme. The existing geophone and accelerometer monitoring network was extended, a new network of accelerometers in building foundations was installed, geophones were placed at reservoir level in deep wells, GPS stations were installed and a gravity survey was conducted.Results of the probabilistic seismic hazard and risk assessment have been published in production plans submitted to the Minister of Economic Affairs, Winningsplan Groningen 2013 and 2016 and several intermediate updates. The studies and data acquisition further constrained the uncertainties and resulted in a reduction of the initially assessed hazard and risk.

scholarly journals Microphysics of Inelastic Deformation in Reservoir Sandstones from the Seismogenic Center of the Groningen Gas Field

2020 ◽  
Vol 53 (12) ◽  
pp. 5301-5328
Author(s):  
Ronald P. J. Pijnenburg ◽  
Christopher J. Spiers
Keyword(s):  
Simple Analysis ◽  
Gas Field ◽  
Hydrocarbon Production ◽  
Reservoir Compaction ◽  
Compaction Behavior ◽  
In Situ Conditions ◽  
Reservoir Sandstones ◽  
Groningen Gas Field ◽  
Cam Clay

AbstractPhysics-based assessment of the effects of hydrocarbon production from sandstone reservoirs on induced subsidence and seismicity hinges on understanding the processes governing compaction of the reservoir. Compaction strains are typically small (ε < 1%) and may be elastic (recoverable), or partly inelastic (permanent), as implied by recent experiments. To describe the inelastic contribution in the seismogenic Groningen gas field, a Cam–clay-type plasticity model was recently developed, based on the triaxial test data obtained for sandstones from the Groningen reservoir (strain rate ~ 10−5 s−1). To underpin the applicability of this model at production-driven strain rates (10−12 s−1), we develop a simplified microphysical model, based on the deformation mechanisms observed in triaxial experiments at in situ conditions and compaction strains (ε < 1%). These mechanisms include consolidation of and slip on µm-thick clay films within sandstone grain contacts, plus intragranular cracking. The mechanical behavior implied by this model agrees favourably with the experimental data and Cam–clay description of the sandstone behavior. At reservoir-relevant strains, the observed behavior is largely accounted for by consolidation of and slip on the intergranular clay films. A simple analysis shows that such clay film deformation is virtually time insensitive at current stresses in the Groningen reservoir, so that reservoir compaction by these mechanisms is also expected to be time insensitive. The Cam–clay model is accordingly anticipated to describe the main trends in compaction behavior at the decade time scales relevant to the field, although compaction strains and lateral stresses may be slightly underestimated due to other, smaller creep effects seen in experiments.

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