bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reduced-Order THMC Coupled Simulation of Nuclear Waste Disposal in Shale
Authors: Chang K. W. , LaForce T. , Nole M. , Stein E. R. 
Published: September 2022

ABSTRACT:
Thermal and hydrological behaviors of multiphase pore fluids in the presence of heat cause the near-field thermo-hydro-mechanical-chemical (THMC) coupled processes that can influence performance of geologic radioactive waste repositories. This hydro-thermal impacts may perturb the geomechanical stability of the disturbed rock zone (DRZ) surrounding the drifts in a shale-hosted deep geologic repository, which links heat/fluid flow and chemical/reactive transport between the engineered barrier system (EBS) and the host rock. This work focuses on integrating the effects of a near-field geomechanical process driven by buffer swelling into TH simulations to reduce dimensionality and improve computational efficiency. This geomechanical process can reduce the DRZ permeability, potentially influencing the rate of radionuclide transport and exchange with corrosive species in host rock groundwater that could accelerate waste package degradation. The sensitivity test with variation in host rock permeability indicates that less permeable shale retards re-saturation of the buffer, such that slower increase of swelling pressure delays reduction of DRZ permeability.

1. INTRODUCTION
Clay-rich sedimentary strata (shales and argillaceous formations) are one of the potential geologic media for disposal of radioactive waste in the United States [Shurr (1977), Gonzales & Johnson (1985)] due to their low permeability, high sorption capacity, typically reducing porewaters (which limit radionuclide solubility), and ability to deform elastically/plastically, which promotes self-healing of fractures [Neuzil (2013)]. However, clay-rich rocks tend to be less conductive thermally due to mineral composition [Schon (2011)], which implies that the evolution of shale-based repository systems may be more sensitive to thermal loading/unloading.
In the near-field, the buffer and the host rock mainly influence each other thermally by heat flow, hydraulically by single- or multi-phase fluid flow, mechanically when the buffer absorbs water from the rock and swells, and also chemically by exchange of solutes between groundwater and pore water in the buffer. The changes in hydrological, mechanical and geochemical characteristics of the disturbed rock zone (DRZ) will affect the overall behavior of radioactive waste geological repositories by redistributing stress states, creating additional pathways of solute/radioactive transport or fluid flow [Tsang et al. (2005)]. These simultaneous actions will induce a number of Thermo-Hydro-Mechanical and Chemical (THMC) processes that will significantly affect the evolution and long-term performance of the nuclear waste repository system [Bernier et al. (2017)].
Influence of Curing Time on Oil Well Cement Properties Using Nanoclay
Authors: Ahmed Abdulmalek , Mahmoud Ahmed Abdulhamid , Gowida Ahmed , Elkatatny Salaheldin 
Published: September 2022

ABSTRACT:
Cement matrix is exposed to several loadings, which can harm its key properties and impede its functions, especially at the early age of forming the cement matrix where its properties are not entirely developed. Nanoclay is a powder material with very fine-grained particles which was used as a secondary additive to enhance the properties of cement. This work evaluates the early-time properties of oil well cement prepared with nanoclay powder and compares it with the properties of the base cement (without nanoclay). Several cement samples were prepared and cured for different times (12, 24, 48 and 72 hours) where the compressive strength, permeability, Poisson’s ratio and Young’s modulus of each sample were examined. The results indicated that the compressive strength of both cement systems increased with the increase of the curing time and the nanoclay-based sample had higher strength than base cement. The permeability of the cement decreased as the time of curing increased for the two cement systems and nanoclay cement had lower permeability. Moreover, the Poisson’s ratio decreased and Young’s modulus increased with curing time for both systems and the addition of nanoclay increased its Poisson’s ratio and reduced its Young’s modulus.

1. INTRODUCTION
During the practice of drilling operations, cement slurry is pumped into oil and gas wells for the purpose of sealing the rock formation from the well by cementing the steel casing to the wellbore (Backe et al., 1998). Moreover, cement slurry is also used for controlling a zone where considerable losses of drilling mud are happening and setting a kickoff plug for the wellbore (Nelson and Guillot 2006). The main requirements for long term zonal isolation are the proper placement of the cement, providing low permeability, good mechanical durability and the ability to be adapted during the changing conditions of the wellbore (Zhang et al., 2020).
Control Measures to Manage Seismic Risk at the LaRonde Mine, a Deep and Seismically Active Operation
Authors: Sasseville G. , Turcotte P. , Falmagne V. 
Published: September 2022

ABSTRACT:
The LaRonde mine is a world-class deposit of gold-copper and zinc-silver along the Cadillac Fault in the Abitibi-Témiscamingue region of Quebec, Canada. Since its inauguration in 1988, the LaRonde mine has produced over 7 M ounces of gold. Mining operations currently extend 3.2 km below the surface with plans to reach 3.4 km. The LaRonde mine has been dealing with induced seismicity daily since 2003. The seismic activity can exceed MRichter 2, and the pro-active management of seismic risk is a key element to operate this mine at that depth and under these seismically active conditions.
Seismic risk at the LaRonde mine is currently managed through a combination of control measures, including a ground-control-driven mining sequence and level design, dynamic ground support systems, and procedures to limit workforce exposure. These control measures have evolved over time and been adapted to the seismic risk as the operation becomes deeper and larger. The main objective is to maintain a safe work environment while meeting production requirements.
Seismic risk management is an ongoing concern at the LaRonde mine. This paper presents the current state of the strategic and tactical control measures implemented on site to manage seismic risk at the LaRonde mine, and it documents some of the impacts on operational flexibility and performance. The effectiveness of control measures must be quantified to measure improvements year after year and to identify and correct observed deficiencies.

1. INTRODUCTION
Mining at great depth generally involves challenging geotechnical conditions and management of seismicity. Innovation and continuous improvement of mining practices are required to face evolving challenges and maintain a safe work environment. An example of this process at the LaRonde mine is the development of innovative ground support solutions to manage the challenging ground conditions in a strongly foliated and highly deformable rock mass. Seismicity was recorded in the early stages of mining from the Penna shaft, with the first damaging seismic events observed in 2002 as described in Mercier-Langevin and Hudyma (2007). Seismic risk management has been an integral part of mine planning since that time.
A Case Study on Terrestrial SfM Photogrammetry Slope Change Detection Without Stable Ground Control Points
Authors: Butcher B. , Walton G. , Kromer R. , Gonzales E. 
Published: September 2022

ABSTRACT:
Daily remote monitoring of slope processes using terrestrial structure from motion (SfM) photogrammetry is a relatively new technique in engineering geology. In this study, a five-camera photogrammetry monitoring station was installed in the Siguas River Valley near Majes, Peru in December 2020 for long-term monitoring and study of slope processes. The study area includes a retrogressive rockslide-debris slide with areas of rockfall sourced from the head scarp, areas of water-driven erosion, and other related geomorphological processes ranging from 100 to 900 m away from the camera stations. Challenges with photo and point cloud alignment accuracy and, ultimately, change detection accuracy arise due to the constant ground movement and lack of suitable locations for ground control point (GCP) installation. In this paper, we investigate point cloud alignment methods for the purpose of change detection at sites where the distance from the photogrammetry station to the area of interest is variable and where there are no stable GCPs. Additionally, we present preliminary change detection results in relation to landslide movement rates at the site. For the tested methods that produced reasonable results, the average rate of movement for the rockslide-debris slide was estimated to be between 3 and 35 cm per month, on average.

1. INTRODUCTION
Intensive cropland irrigation in dry climate regions has been linked to increased landslide occurrence, and this relationship has recently become of increased interest to the geohazard scientific community (Garcia-Chevesich et al., 2021). An example of one such area is the Majes district in southern Peru, roughly 150 km to the west of Arequipa. The Siguas River runs through the Majes district, providing drinking water for local populations, water for industrial uses, and water for cropland irrigation. Since the mid 1970’s the amount of land dedicated to irrigation-dependent agriculture has continued to increase along the Siguas River (Lacroix et al., 2020). The north bank of the Siguas River, where it is adjacent to irrigated land, has had numerous landslides in the last four decades, while the southern bank of the river, which remains mostly unirrigated, has had minimal landslide activity within the same timeframe (Graber et al., 2021).
A New Constitutive Model for Rock Salt Viscoplasticity: Formulation, Implementation, and Demonstrations
Authors: Reedlunn Benjamin 
Published: September 2022

ABSTRACT:
This paper presents the formulation, implementation, and demonstration of a new, largely phenomenological, model for the damage-free (micro-crack-free) thermomechanical behavior of rock salt. Unlike most salt constitutive models, the new model includes both drag stress (isotropic) and back stress (kinematic) hardening. The implementation utilizes a semi-implicit scheme and a fall-back fully-implicit scheme to numerically integrate the model’s differential equations. Particular attention was paid to the initial guesses for the fully-implicit scheme. Of the four guesses investigated, an initial guess that interpolated between the previous converged state and the fully saturated hardening state had the best performance. The numerical implementation was then used in simulations that highlighted the difference between drag stress hardening versus combined drag and back stress hardening. Simulations of multi-stage constant stress tests showed that only combined hardening could qualitatively represent reverse (inverse transient) creep, as well as the large transient strains experimentally observed upon switching from axisymmetric compression to axisymmetric extension. Simulations of a gas storage cavern subjected to high and low gas pressure cycles showed that combined hardening led to substantially greater volume loss over time than drag stress hardening alone.

1 INTRODUCTION
Rock salt constitutive models are used to simulate the evolution of mines, boreholes, storage caverns for gases and liquids, and nuclear waste repositories in rock salt formations. A wide variety of models have been proposed for rock salt, yet even the damage-free (micro-crack-free) thermo-viscoplastic behavior remains difficult to capture. The Munson-Dawson model, for example, was recently extended in Reedlunn et al. (2022), but it still cannot capture monotonic hardening behavior over the full range of strain rates typically utilized in laboratory tests (10−12 to 10−4 1/s), or transient non-monotonic hardening behaviors, such as the Bauschinger effect and reverse (inverse transient) creep (Reedlunn, 2020, Section 1).
Coupled THMC Simulation Based on Explicit Fracture Representation Using Extrinsic Cohesive Zone Model
Authors: Ogata S. , Maeda Y. , Fukuda D. , Yasuhara H. , Inui T. , Kishida K. 
Published: September 2022

ABSTRACT:
We presented a new coupled thermal-hydraulic-mechanical-chemical (THMC) simulator by combining the numerical models that can explicitly introduce the rock fracture surfaces to reproduce the processes of changing permeability as realistically as possible. Then, the presented simulator was applied to estimate the long-term evolution in the permeability of a rock mass within a geological disposal system of high-level radioactive waste (HLW). The numerical predictions showed that the time-dependent decrease in permeability was observed only within specific fractures where the geochemical creep (i.e., pressure dissolution) had been induced after disposal of HLW into disposal cavity. This permeability drop was caused by the fracture sealing due to pressure dissolution at asperity contacts in the fracture that depended on the characteristics of each fracture (fracture formation, aperture, closing stress and contact area). Overall, it was implied that the presented simulator had a possibility to reveal the detailed spatial distribution of permeability within a natural barrier during a long-term disposal period of HLW.

1. INTRODUCTION
When examining the performance of the geological disposal facility of high-level radioactive waste (HLW) for preventing the migration of radionuclides, it is significantly important to numerically simulate the evolution processes of permeability within a rock mass that works as a natural barrier. During the disposal period of HLW, the convolved phenomena such as rock fracturing during excavation of disposal cavity, heat radiation from waste package, fluid-driven transport, and kinetic dissolution/precipitation of the minerals may occur within a natural barrier. The complex interactions between these phenomena, namely, coupled thermal-hydraulic-mechanical-chemical (THMC) interactions, may bring about the change in permeability of a rock mass.
Particularly, permeability distribution within a natural barrier is influenced by the transition of a rock mass from continuum to discontinuum due to the short-term rock fracturing during the excavation of the disposal cavity. In addition, subsequent occurrence of mineral reactions (e.g., pressure dissolution, free-face dissolution/precipitation) within rock fractures after disposing HLW may have non-negligible impacts on permeability evolution over the long-term. Pressure dissolution is a mineral dissolution caused at the asperity contacts within rock fractures, which may depend on compressive stress acting on a fracture plane and temperature (Yasuhara et al. (2011)). Previous work by Yasuhara et al. (2011) have shown that pressure dissolution can cause the permeability reduction of rock fractures by several orders magnitude over a long duration.
The Mechanical Properties of Three Types of Shale Oil Reservoirs and Its Influence on Hydraulic Fracturing
Authors: Wang Xiaoqiong , Qian Yuping , Wang Junhua , Kong Fanxi , Ge Hongkui 
Published: September 2022

ABSTRACT:
The premise of hydraulic fracturing is to have an accurate and detailed understanding of the rock mechanical properties and fracture propagation law of shale reservoir. In this paper, a systematic and comprehensive evaluation of the mechanical properties is carried out based on the shale oil reservoir in the south of Songliao Basin, Jilin Province. Based on the analysis of the mineral composition, the microstructure, rock mechanics of three types of shale oil reservoirs in the laboratory, combined with the field fracturing, logging data and the in-situ stress, the fracture propagation law of the three types of reservoirs is obtained, and the suggestions for fracturing are put forward. The results showed that there are two significant characteristics in the study area. One is the development of bedding, which is easy to form horizontal fractures. Influenced by bedding and stress, it is not suitable for horizontal well fracturing. The other is the high content of clay minerals, and the applicability of conventional slick hydraulic fracturing fluid is poor. It is suggested to use vertical well or directional well to carry out volume fracturing. In this way, the effect of bedding can be effectively used to open and communicate the bedding and form a larger fracture network.

1. INTRODUCTION
Hydraulic fracturing is the key technology of shale oil and gas development. Through large-scale volume fracturing of shale oil and gas reservoir, a dispersion volume fracture network (volume fracturing) is formed (Cipolla et al., 2008), so that shale oil and gas stored in ultra-low permeable shale reservoir can be developed industrially (Cipolla et al., 2008; Guo et al., 2014; Sierra et al., 2010). The premise of hydraulic fracturing is to have an accurate and detailed understanding of the rock mechanical properties and their influences on hydraulic fracture (Vernik et al., 1992; Vernik et al., 1997; Clarkson et al.,2013). The formation and extension mechanism of hydraulic fracture in shale oil reservoir is complex. It is of great significance to master the formation mechanism of artificial fracture network for evaluating the effectiveness of hydraulic fracturing.
Numerical Study of Three-Dimensional Blast-Induced Damage Patterns Resulting from Simultaneous Borehole Blasting of Hard Rocks
Authors: Thomas R. N. , Bird R. E. , Paluszny A. , Zimmerman R. W. 
Published: September 2022

ABSTRACT:
Simultaneous detonation of charges in closely spaced boreholes is a commonly used blasting technique for frag-mentation and construction. Blasting is a challenging phenomenon to model, due to the complexity of the mechanical deformation, fracturing, and fragmentation, and the spatial scales involved. Blast wave models must consider the possibility of constructive interference between separate waves in three-dimensions. A three-dimensional finite element method is used to study the induced damage in a general hard rock tunnel blast setting. The Johnson Holmquist-2 elastoplastic-damage model is used to quantify shear and tensile failure. In simulations with two blastholes separated by up to one meter, damage patterns emanating from boreholes interact to form self-organizing ‘fracture-like’ structures. Mechanical interaction between the two blasts is a function of the input charge wave properties, blasthole separation, and distance along the charge, with high concentrations of damage at the free boundary representing the tunnel wall. Constructive interference between the two blast waves is not shown to directly induce additional damage zones, and instead, interaction results from the overlap and slight extension of each blasthole’s damage zone towards the other.

1 INTRODUCTION
Drilling and blasting continues to be a key method for mining and excavation (Lu et al., 2012). Many blasting applications, such as bench blasting or tunnel excavation, involve drilling and blasting multiple holes in close proximity to one another in order to generate overlapping fractured zones (Cho and Kaneko, 2004). Efficient use of explosives reduces costs, improves sustainability, and ensures that the extent of the excavation disturbed zone is minimized, the latter being an important constraint for the construction of radioactive waste disposal facilities (e.g., Tsang et al., 2005; Kwon et al., 2009) and many civil engineering projects (e.g., Sharafat et al., 2019). Due to the complex physics of blasting and rock fragmentation, a fully mathematical description of the process is not possible, and blast operation designs often make use of empirical formulas (Liqing and Katsabanis, 1997). In particular, the dynamic weakening (damaging) of rock introduces challenges for models, and upscaling of damage is necessary to avoid resolving the complex geometry of fracturing and fragmentation. Numerical approaches are therefore used widely to understand the process of blasting (e.g., Liqing and Katsabanis, 1997; Yilmaz and Unlu, 2013; Yang et al., 2015; Hajibagherpour et al., 2020; Ji et al., 2021; Pu et al., 2021).
Impact of Undrained Pore Pressure Response on Expected Failure Stress in Anisotropic Shales
Authors: Duda M. I. , Holt R. M. , Stenebråten J. F. , Stroisz A. M. 
Published: September 2022

ABSTRACT:
The connection between undrained pore pressure response to stress in shales and fault reactivation, drilling problems and microseismicity observed at significant distances from hydrocarbon reservoirs and injection zones has not been thoroughly studied and is usually disregarded in geomechanical modelling workflows. In our study, we examine to what extent the inclusion of the pore pressure response affects the amplitude of total stress changes expected to cause shear failure in several overburden and outcrop shales. We combine poroelastic pore pressure coefficients and Mohr-Coulomb failure envelope parameters estimated through triaxial laboratory experiments to model the total stress increases at failure for a wide range of loading scenarios and medium orientations. We consider both isotropic and anisotropic pore pressure parameters - we explore the differences in modelling outcomes the two sets of parameters yield, as well as the impact of the individual parameters on the expected stresses at failure. We observed that shear failure in shales is expected at significantly lower stresses changes and is plausible in a much wider range of loading paths once the undrained pressure response in considered, and therefore we postulate that it should be taken into account during injection or production operations safety assessment.

1. INTRODUCTION
Injection into or production from a subsurface reservoir have been documented to lead to fault activation, microseismic activity, and borehole stability issues in the reservoir and its surroundings (e.g., Pine et al., 1983; Raleigh et al., 1976; Zoback & Harjes, 1997). In some cases, these undesired phenomena occurred in the over-and underburden at significant distances from the reservoir subjected to pore pressure change (e.g., Odonne et al., 1999; Rutqvist et al., 2008; Segall, 1989).
This has triggered an ongoing discussion of the causes of these events. Until now, it was primarily associated with pore fluid migration through fractures and fault planes throughout low permeable under- and over-burden, as well as with stress transfer (e.g., Vasco et al., 2018; Verdon et al., 2011; Williams-Stroud et al., 2020; Zhou et al., 2008) caused by injection- or production-induced pore pressure changes in the reservoir (e.g., Geertsma, 1973; Morita et al., 1989; Rudnicki, 1999).