scholarly journals Comparing poroelastostatics and poroelastodynamics: Numerics, solvers and algorithms

2021 ◽  
Author(s):  
Saumik Dana
Keyword(s):  
Seismic Design ◽  
Fault Slip ◽  
Climate Mitigation ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems ◽  
Underground Structures ◽  
Wastewater Disposal ◽  
Energy Technologies ◽  
Time Marching ◽  
Mitigation Projects

Understanding the causality between the events leading upto and post fault slip and the earthquake recording is important for seismic design and monitoring of underground structures, bridges and reinforced concrete buildings as well as climate mitigation projects like carbon sequestration and energy technologies like enhanced geothermal systems or oilfield wastewater disposal. While the events leading upto fault slip are typically governed by poroelastostatics, the events post fault slip can easily transition into poroelastodynamics territory due to runaway fault slip velocities. There are marked differences in the numerics of poroelastostatics and poroelastodynamics, and a simple switch from one algorithm to another based on fault slip velocities is not trivial. In fact, an understanding of expected fault slip velocities is critical apriori, as an algorithm which can seamlessly transition from time marching in poroelastostatics realm to poroelastodynamics realm and vice-versa is extremely difficult to achieve. We present the numerics of both physics and point out the differences between the two in this work.

scholarly journals Porting OpenMP to GPGPU to accelerate Krylov space computations in coupled geodynamics simulator

2021 ◽  
Author(s):  
Saumik Dana
Keyword(s):  
Reinforced Concrete ◽  
Carbon Sequestration ◽  
Seismic Design ◽  
Fault Slip ◽  
Reinforced Concrete Buildings ◽  
Wastewater Disposal ◽  
Energy Technologies ◽  
Krylov Space ◽  
Time Marching ◽  
Flow Simulator

Understanding the causality between the events leading upto and post fault slipand the earthquake recording is important for seismic design and monitoring ofunderground structures, bridges and reinforced concrete buildings as well as climatemitigation projects like carbon sequestration and energy technologies like enhancedgeothermal systems or oilfield wastewater disposal. While the events leading uptofault slip are typically governed by poroelastostatics, the events post fault slip caneasily transition into poroelastodynamics territory due to runaway fault slip velocities.An understanding of expected fault slip velocities is critical apriori, as an algorithmwhich can seamlessly transition from time marching in poroelastostatics realm toporoelastodynamics realm and vice-versa is extremely difficult to achieve. That beingsaid, every effort in the direction of accelerating the computations on the flow sideare a necessary step forward in rendering a fast coupled geodynamics simulator.In this document, we present a framework in which we study the porting of theOpenMP parallelism of the flow simulator to a GPGPU

scholarly journals Deep learning for earthquake detection and location

2021 ◽  
Author(s):  
Saumik Dana
Keyword(s):  
Deep Learning ◽  
Seismic Wave Propagation ◽  
The United States ◽  
Economic Losses ◽  
Climate Mitigation ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems ◽  
Underground Structures ◽  
Earthquake Detection ◽  
Earthquake Losses

Understanding the causality between the events leading to fault slip and the earthquake recording is important for seismic design and monitoring of underground structures, bridges and reinforced concrete buildings as well as climate mitigation projects like carbon sequestration and energy technologies like enhanced geothermal systems or oilfield wastewater disposal. The Federal Emergency Management Agency (FEMA) reported in 2017, that earthquake losses in the United States add up to about \$6.1 billion dollars annually. This number only addresses direct economic losses to buildings, and does not cover damage and losses to critical facilities, transportation and utility lifelines or indirect economic losses. A holistic framework to study earthquakes would incorporate seismic wave propagation and pressure perturbations, and have a dialogue with the deep learning framework for earthquake detection and location. In this document, we delve into the deep learning module.

scholarly journals Introducing GEOFIT: Cost-Effective Enhanced Geothermal Systems for Energy Efficient Building Retrofitting

Proceedings ◽  
2018 ◽  
Vol 2 (15) ◽  
pp. 557 ◽  
Author(s):  
Thomas Messervey ◽  
Marco Calderoni ◽  
Angel Font ◽  
Mikel Borras ◽  
Ray Sterling ◽  
...  
Keyword(s):  
Energy Efficient ◽  
Cost Effective ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems ◽  
Low Carbon ◽  
Low Carbon Economy ◽  
Energy Technologies ◽  
Executive Agency ◽  
Energy Efficient Building ◽  
Carbon Economy

GEOFIT, “Deployment of novel GEOthermal systems, technologies and tools for energy efficient building retrofitting,” is a recently launched 4-year H2020 project funded by the Innovation and Networks Executive Agency (INEA) under the call topic LCE-17-2017: Easier to install and more efficient geothermal systems for retrofitting buildings. GEOFIT is a part of INEA’s Energy Portfolio Low Carbon Economy (LCE), Renewable Energy Technologies (RET) and brings together 24 partners from 10 European countries to work on the development of novel and smart shallow geothermal systems. This paper introduces the project.

scholarly journals Towards understanding earthquake triggering due to enhanced geothermal systems

2021 ◽  
Author(s):  
Saumik Dana
Keyword(s):  
Wave Propagation ◽  
Fracture Propagation ◽  
Friction Model ◽  
Fault Slip ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems ◽  
Earthquake Triggering ◽  
Fault Interaction ◽  
Poroelastic Media ◽  
Fracture Interaction

The effect of fluid pulse driven fractures (FPDF) propagating in poroelastic media on fault slip in the presence of natural fractures is a complicated interplay between fracture propagation, fracture-fracture interaction, fracture-fault interaction, friction model governing fault slip and wave propagation associated with pulsing injection. Furthermore, the problem is stochastic due to the uncertainty associated with the existing fracture-fault topology.

scholarly journals Fault slip potential induced by fluid injection in the Matouying EGS field, Tangshan seismic region, North China

2022 ◽  
Author(s):  
Chengjun Feng ◽  
Guangliang Gao ◽  
Shihuai Zhang ◽  
Dongsheng Sun ◽  
Siyu Zhu ◽  
...  
Keyword(s):  
Stress Field ◽  
North China ◽  
Active Faults ◽  
Fault Slip ◽  
Quantitative Risk Assessment ◽  
Fluid Injection ◽  
Enhanced Geothermal Systems ◽  
Geothermal Systems ◽  
Seismic Region ◽  
Hydraulic Stimulation

Abstract. The Tangshan region is one of the most seismically active areas in the North China, and the 1976 M 7.8 earthquake occurred on July 28th near the Tangshan fault zone. The Matouying Enhanced Geothermal Systems (EGS) field is located ~90 km away from Tangshan City. Since the late 2020, preliminary hydraulic stimulation tests have been conducted at depths of ~3965–4000 m. Fluid injection into geothermal reservoir facilitates heat exchanger system. However, fluid injection may also induce earthquakes. In anticipation of the EGS operation at the Matouying uplift, it is essential to assess how the fault slip potential of the nearby active and quiescent faults will change in the presence of fluid injection. In this study, we first characterize the ambient stress field in the Tangshan region by performing stress tensor inversions using 98 focal mechanism data (ML ≥ 2.5). Then, we estimate the principal stress magnitudes near the Matouying EGS field by analyzing in situ stress measurements at shallow depths (~600–1000 m). According to these data, we perform a quantitative risk assessment using the Mohr-Coulomb framework in order to evaluate how the main active faults might respond to hypothetical injected-related pore pressure increases due to the upcoming EGS production. Our results mainly show that most earthquakes in the Tangshan seismic region have occurred on the faults that have relatively high fault slip potential in the present ambient stress field. At well distances of less than 15 km, the probabilistic fault slip potential on most of the boundary faults increase with continuing fluid injection over time, especially on these faults with well distances of ~6–10 km. The probabilistic fault slip potential increases linearly with the fluid injection rate. However, the FSP values decrease exponentially with increased unit permeability. The case study of the Matouying EGS field has important implications for the deep geothermal exploitation in China, especially for Gonghe EGS (in Qinghai province) and Xiong’an New Area (in Hebei province) geothermal reservoirs that are close to the Quaternary active faults. Ongoing injection operations in the regions should be conducted with these understandings in mind.

Simple approach to obtain ground amplification motion of surface soil deposits with a radical change of depth

2005 ◽  
Vol 42 (2) ◽  
pp. 491-498
Author(s):  
Dae-Sang Kim ◽  
Kazuo Konagai
Keyword(s):  
Seismic Design ◽  
Surface Soil ◽  
Underground Structure ◽  
Free Field ◽  
Alluvial Soil ◽  
Radical Change ◽  
Simple Approach ◽  
Clear Understanding ◽  
Underground Structures ◽  
Soil Deposits

Earthquake observations at different sites within alluvial soil deposits have demonstrated that the motion of buried underground structures closely follows that of the surrounding soil. Therefore, it is usual in a seismic design process to apply free-field ground displacements through Winkler-type soil springs to an underground structure to evaluate stress patterns induced within its structural members. Using a simplified approach, this paper provides a clear understanding of resonant horizontal ground displacement of and strain in a surface soil deposit with a radical change of depth and of where they occur.Key words: simple approach, seismic design, earthquake, resonance, underground structures.

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