bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating Pressure and Fronts in Underground Storage Through Tilt Data Inverse Modelling
Authors: Abdollahi R. , Movassagh A. , Kasperczyk D. , Haghighi M. 
Published: August 2024

ABSTRACT:
Seismicity and surface deformation are prevalent outcomes of underground reservoir operations. These deformation data serve as a crucial indirect method into the nature and intensity of subsurface activities. Currently, tiltmeter technology is the most accurate monitoring tools with the accuracy of nano radian. This study aims to utilize surface tilt data acquired from underground storage or production sites to estimate reservoir pressure values and their spatial fronts. To accomplish this, a predictive model was designed to compute surface deformation through numerical methodologies. The model segments the reservoir into smaller elements resembling those used in reservoir simulations. It calculates the resulting deformation caused by pressure alterations by aggregating the results from each individual block under constant pressure conditions. The solution for each block, relies on employing the displacement solution for a thermoelastic strain nucleus within a half-space having a traction-free surface. Integrating a reliable inversion technique with this forward model enables the tracking of pressure fronts in subsurface reservoirs using surface tiltmeter data. The model's proficiency was validated through the utilization of synthetic deformations, highlighting the reliable efficiency of the inversion approach with results demonstrating an error rate below 5%.

1. INTRODUCTION
Surface deformation and reservoir compaction have been recorded in a variety of oil and gas fields and storage facilities, stemming from subsurface activities such as fluid extraction or injection, hydraulic fracturing, and fault slippage. (Chen et al., 2023; Du & Olson, 2001; Okada, 1992; Olson et al., 1997). The deformation resulting from subsurface activities or operations can lead to various geo-mechanical challenges, including casing/cement failure, fault reactivation, fracture extension, and surface/subsurface facility failures, as well as caprock failure. This poses a potential risk to the overall well and reservoir integrity. Therefore, monitoring and analyzing deformation data becomes crucial for detecting potential issues. Additionally, these data serve as indirect optimization tools, providing valuable insights into the size and intensity of underground operations or activities, thereby functioning as an indirect monitoring technique for optimizing overall operations.
Coupled Thermo-Hydro-Mechanical Modeling in Enhanced Geothermal Systems
Authors: Huang Y. , Stansberry A. R. , Lipnikov K. , Moulton J. D. , Hyman J. D. , Sweeney M. R. , Huang X. , Lei Z. , Stauffer P. H. 
Published: August 2024

ABSTRACT:
The coupling and interactions among rock deformation, fluid flow, heat transfer and geochemical reactions has become an essential topic in complex subsurface systems for geothermal energy production. To improve the understanding and minimize the uncertainty in subsurface geothermal energy production operations, a new coupled Thermo-Hydro-Mechanical-Chemical (THMC) framework has been developed at Los Alamos National Laboratory (LANL) since 2020. Three LANL-developed codes: HOSS, Amanzi, and dfnWorks are integrated in the LANL-developed InyanCC THMC coupling framework. The InyanCC THMC framework has been well verified against selected benchmarking problems and the simulation results show good agreement with analytical solutions. Furthermore, the InyanCC framework is used to simulate a fully-coupled Thermal-Hydro-Mechanical problem in a stylized subsurface enhanced geothermal system to investigate the effects of fracture aperture change on the energy production rate. The simulation results represent the cooling down progress of the rock matrix and fractures, demonstrating the capability of InyanCC in simulating THM coupling problems in the field for Enhanced Geothermal Systems. The comparison of heat propagation velocity between changing aperture and fixed aperture simulation further emphasizes the significance of fracture aperture change on the heat transfer in the EGS.

1. INTRODUCTION
As one of the clean renewable and sustainable energy resources, geothermal energy has been widely applied for electricity generation, heating, and cooling in many countries. Department of Energy's GeoVision Study and EarthShot Initiative has outlined that the breakthroughs in enhanced geothermal system (EGS) technologies could unlock over 100 GW of clean power in the US (DOE 2019; Augustine et al. 2022).
Geothermal energy is often produced by circulating water through a high temperature reservoir where the fractures and joints inside the reservoir play a key role by introducing the dominant flow paths. Pandey et al. (2015) found that the dynamic change of fracture aperture will greatly affect the production temperature. A variety of studies in the past have pointed out that heat extraction rates are very sensitive to fracture spacing (Fox et al. 2013; Ekneligoda and Min Ki-Bok 2014) and fracture geometries (Andrade et al., 2004).
Probabilistic Rockfall Analysis in 3D in the Peña Colorada Open Pit (Colima, Mexico)
Authors: Yalan L. A. , Samaniego J. A. , Pozo R. R. , Jiménez E. , Villa J. A. 
Published: August 2024

ABSTRACT:
Rockfall events are one of the most difficult geotechnical conditions to predict and control in a mining operation. This study is focused on the Peña Colorada open pit (Colima, Mexico), where a series of rockfalls occurred on the main slope during the period of Hurricane Lidia (October 2023). The proposed methodology is based on a probabilistic analysis and field inspections to identify potential rockfall sectors. The topographic survey was obtained with photogrammetry using a drone for identifying potential sectors. Then, the properties such as restitution coefficients and the friction angle has been calibrated based on field tests of the different terrains observed on the main slope (rock and spill). The results obtained in the Rfall 3D simulations are interpreted, compared, and calibrated with real-scale field tests performed on the main slope. Finally, solutions to mitigate rockfall risk are proposed, such as temporary or permanent closure of haul roads or implementation of barriers.

1. INTRODUCTION
Open pit mining is a mining method for metallic and non-metallic minerals. While this approach has advantages in terms of accessibility and efficiency, it also presents significant challenges related to rockfall risks.
Rockfall risk in open-pit mining represents a constant hazard for workers in mining operations. Rock falls can cause serious injury or even loss of life and its origin is related to earthquakes, blasting or even weather conditions, such as rain or hurricanes.
The methodology proposed considered a field inspection, photogrammetry survey by drone, use of rockfall 3D software, calibration by field tests and geotechnical control implementation as barriers.

2. PEÑA COLORADA OPEN PIT

2.1. Open pit description
The Peña Colorada Mine is a open pit mine located in Colima, México. It is owned by ArcelorMittal and produced an estimated 3.8 million tons per annum (Mtpa) of iron. As part of the business chain, Peña Colorada Mine is one of the key assets of Ternium and ArcelorMittal in México.
Recommended interramp slope angles for Phase 4A are based on bench geometries that resulted from the backbreak analysis using an 80% reliability of achieving the required 12.7 m catch bench width for a double bench configuration. Resulting interramp slope angles for 28 m double benching range from 45 to 49°. The recommended slope design angles require average bench face angles of at least 72° (see Fig. 1).
Modeling Transient Wellbore Behavior and Near-Wellbore Damage During Carbon-Dioxide Injection in Depleted Gas Reservoirs
Authors: De Gennaro V. , Vasper A. C. 
Published: August 2024

ABSTRACT:
In this paper we describe a study focused on modeling the dynamic wellbore behavior and assessing completion and near-wellbore damage in the context of carbon dioxide (CO2) injection to depleted gas reservoirs. The results of the multiphase flow simulator in terms of pressure and temperature distributions along the well for various timesteps have been used as boundary conditions of the dynamic reservoir simulator. The reservoir model considers a near-wellbore region fully saturated in CO2. Thermal-hydraulic-mechanical (THM) coupling for completion and surrounding rock has been enabled, linking the reservoir simulator to the geomechanical simulator. A simple staggered coupling scheme [also called one-way coupling (OWC)] has been used to describe the behavior of the host rock and completion and evaluate potential damage during simulated injection scenarios. The results enable us to investigate the influence of various parameters, with the objective of supporting the design of carbon capture and storage (CCS) injection wells and materials, plus the definition of procedures that can reduce the risks associated with thermal shock.

1. INTRODUCTION
CO2 sequestration has emerged as a promising strategy to mitigate greenhouse gas emissions and play a part in climate change control by safely injecting significant quantities of CO2 deep underground, while ensuring permanent containment integrity.
During injection, temperature and pressure changes within the wellbore and its vicinity impact completion equipment, tubulars including casing and liners, annular fluids, cement, and subsurface formations. Extreme temperature variations may also alter rock properties and fluid behavior. These thermal and pressure variations can affect injectivity and will induce mechanical stresses within the well system, cement, and surrounding rocks; Oldenburg (2006), Pekot et al. (2011). Understanding these effects is crucial for assessing and ensuring the integrity of the well, host rock, and seals, while minimizing or eliminating formation damage and optimizing CO2 injection strategies.
For seabed temperatures ranging between 5 to 15°C the CO2 is in liquid phase and denser. Transportation of liquid CO2 is a favored option for many offshore projects. Similar considerations may apply to the well completion, where the injection of a denser fluid reduces tubing head pressure and tubing size requirements.
Machine Learning Application for CCUS Carbon Storage: Fracture Analysis and Mapping in the Illinois Basin
Authors: Liu G. , Kumar A. , Harbert W. , Siriwardane H. , Crandall D. , Cunha L. 
Published: August 2024

ABSTRACT:
In this paper, an innovative method comprising of multi-tiered analysis has been developed to leverage advanced Machine Learning (ML) techniques to process passive seismic monitoring data acquired over a three-year injection period into a CO2 storage site in the Illinois Basin for potential fracture/fault analysis. The study is aimed at contributing to monitoring design and de-risking operation for carbon capture, utilization, and storage (CCUS) and improving monitoring, verification, and accounting (MVA) of injected subsurface CO2. Information on fractures from well logs and core data is integrated together to develop a comprehensive understanding of how these fractures correlate with the rock petrophysical properties. The fracture networks obtained from this approach can directly benefit field operations and reservoir management decision-making for CCUS, which include the dynamic injection scheduling/workover, risk assessment, and further monitoring design. Furthermore, the proposed methodology is potentially applicable to oil and gas assets as well as geothermal development, operations, and monitoring.

1. INTRODUCTION
Injecting significant volume of anthropogenic carbon dioxide (CO2) into geological reservoirs is one of the piloted practices for greenhouse gas reduction. These operations have gained considerable traction in the last decade as a viable option to reduce the long-term environmental footprint. However, monitoring the storage reservoir to ensure safe and long-term storage of CO2 for de-risk operations and storage management is undergoing dynamic shifts, expanding opportunities for implementing innovative techniques and applications, especially for the commercial-scale deployment. This study is part of the Science-informed Machine Learning (ML) for Accelerating Real-Time Decisions in Subsurface Applications (SMART) Initiative which have funded by the US Department of Energy Carbon Storage program to transform our ability to make better, informed decisions related to the subsurface through real-time visualization, forecasting, and virtual learning. The outcomes of the SMART Initiative are science-informed machine learning-based tools that can be applied at carbon storage sites throughout the nation and the world to 1) improve the ability to consolidate technical knowledge, site-specific characterization information, and real-time data in a digestible way; 2) enable the optimization of carbon storage reservoirs by creating a capability for "real-time" forecasting of carbon storage reservoir behavior; and 3) improve the ability to understand and communicate subsurface behavior during carbon storage operations to non-experts. The ultimate objectives aim in helping accelerate the deployment of field scale carbon storage in the US and the world.
Shifting Highwall Blast Vibration Frequencies Higher Maintaining PPV Lower from Near-Field Blasts
Authors: Yang R. , Proulx J. P. R. , Rodriguez A. 
Published: August 2024

ABSTRACT:
Shifting blast dominant frequency at highwalls has been a desired target for an improved blast design. However, documented cases of successful frequency shifting have been little in literature. This paper presents a successful case of shifting frequency of blasts. The blast monitoring collected useful data for the site rock characterization – vibration (stress) attenuation versus scaled distance; site resonant frequency, and ground p-wave velocity from signature hole blasts. Using the multiple seed waveforms that are encoded within the site frequency response, the Multiple Seed Waveform (MSW) model accurately predicted the dominant frequency at highwalls from near-field blasts. Blast design scenarios were then modeled for blast vibration PPV's and dominant frequency. With parameters from the signature hole blast vibration and fragmentation measurement, the Multiple Blasthole Fragmentation (MBF) and MSW models are established for the site. The models can be used to explore benefits from various blast design scenarios. The delay timing in terms of lower PPV and higher dominant frequencies for the pits were recommended – an increase in frequency of 10 Hz at a hard rock pit using the recommended timing and an increase in frequency of 5 Hz at another relatively soft rock pit with the recommended timing.

1. BACKGROUND
In a typical mine operation, productivity and efficiency begin with drilling and blasting efforts, however, additional challenges related to blasting can be impactful to a mining operation. Blast designs must be adapted to the site geological features and rock properties to achieve improved operations. To support the mining operator's effort, a suite of blasting technologies is required at the mine to drive blast optimization and wall control.
A large gold mine has two production pits – one with relatively competent rock and the other one with fractured rock. Current timing templates used by the short-term planning were created over 5 years ago – and given changes in geology and rock structures, the timing templates may not be providing suitable vibration or wall control outcomes.
Tunneling in Alpine Fault Zones – Case Study Semmering Base Tunnel
Authors: Wannenmacher Helmut , Entfellner Manuel , Fiest Thomas , Schubert Wulf 
Published: August 2024

ABSTRACT:
In Alpine fault zones with high in-situ stress, tunneling can result in substantial and enduring ground deformations. The magnitude of deformations is closely tied to the applied excavation- and support concept, though typically, they can reach tens of centimeters. The principle of yielding is based on the idea that as deformation increases, the need for support capacity decreases.
Yielding elements, as a part of the shotcrete lining, represent the state-of-the-art method for tunneling in Alpine fault zones. These elements help to prevent the shotcrete lining from being overstressed during the early curing process. This is particularly important close to the tunnel face, where the deformation rate is highest, and the shotcrete strength is at its lowest. Furthermore, long-term creep deformations of the rock mass can be absorbed with such a lining system. This lining system provides a higher support resistance level than steel sets, thus allowing for controlled deformations at a reasonable cost. This approach has proved effective and cost-efficient in numerous projects with challenging geotechnical conditions. Radial deformations caused by the rock pressure are transformed into a tangential closure of the ductile lining. Hence, the load-dependent stiffness of the yielding elements must be less than the time-dependent stiffness of the shotcrete at all times to avoid overstressing. Since displacement development depends on the distance to the face and time, the tunneling process requires high flexibility in the excavation and support concept. The Semmering Base Tunnel is a single-track, double-tube railway tunnel currently under construction in Austria. With the alignment of the 27.3 km long tunnel, major fault zones under high overburden have to be crossed. An extraordinary excavation- and support concept is applied to control the vast deformations of up to 200 cm. A temporary pilot tunnel is excavated to increase pre-relaxation of the highly stressed ground and ease excavation conditions for later tunnel widening. For both tunnels, a shotcrete lining with yielding elements is applied. A novel yielding element was invented to overcome the drawbacks of existing systems. This novel HS-EPS yielding element consists of a high-strength expanded polystyrene, which makes it lightweight and enables safe and rapid installation. Furthermore, the modular setup of the element permits on-site adaption to react to actual deformation patterns and changing ground conditions. Recent experiences from the application at the Semmering Base Tunnel are presented.
Probabilistic Distribution Model to Predict Fracture Height
Authors: Oyarhossein M. , Dusseault M. B. 
Published: August 2024

ABSTRACT:
The Hydraulic Fracturing Simulation (HFS) fluid pressure gradient during propagation is almost always less than the rock mass horizontal minimum stress gradient. In models with independent lateral stresses, a fracture will grow more in a direction that requires less "work" needed to extend the fracture and increase its aperture. We study geometry of a fracture where a one-layer single fracture model is present to assess how fractures propagate. We use UDEC™, to model a 2D domain, and our results offer better understandings of fracture geometry. We then provide a probabilistic model to examine which outcomes distribution is more suitable to predict fracture height. We have found that a Log Normal distribution seems more suitable for fracture height outcome values. We then examined our model results with those from other solutions equations—Sneddon, GdK, and PKN—using Monte-Carlo simulation. Our model results show an acceptable agreement with the semianalytic and analytic expressions presented in those classic contributions to the subject of hydraulic fracture propagation.

1. INTRODUCTION
Since the early studies of Hydraulic Fracturing Stimulation (HFS), fracture geometry has proven to be a useful and interesting subject to model and predict (Geertsma & Haafkens, 1979; Perkins & Kern, 1961). Although these models, referred to as GdK and PKN, have some limitations in the predictions of fracture heights in 2D, they are widely popular because of their simplicity and practicality. Subsequently, as more high-quality HFS field data became available (Fisher & Warpinski, 2012a, 2012b; Palmer & Kutas, 1991; Stegent et al., 2020; Warpinski, 1985, 2011b, 2011a), research has become more focused on how to verify the prediction accuracy of mathematical and numerical models, concentrating on the geometry of single induced fractures—height, width, aperture.
An induced fracture system is a complex phenomenon in HFS, given heterogeneities in stress, elastic properties, and rock mass fabric (bedding, joints, lithological contrasts…). Fractures (joints) can be naturally present in the rock mass, they can be created by injection, or existing fractures can be extended during the HFS operation. Opening of fractures (Mode I) is well-understood, and dilatant shear (Mode II) of appropriately oriented natural fractures can lead to larger stimulated volumes. Putting other factors aside, it is widely accepted that larger area fractures (Modes I and II) within the target formation are desirable (Kim & Moridis, 2015; Soroush et al., 2011). The overall success of HFS, if only higher production or injection rates are considered, is related to the larger surface contact area that the stimulated fracture network affords: the higher the direct surface area created and the larger the stimulated volume, the better the flow outcomes.
A Modeling Study of Injection-Induced Rupture and Seismicity in Complex Faults
Authors: Cao M. , Rutqvist J. , Guglielmi Y. , Tounsi H. , Mital U. , Cihan A. , Glubokovskikh S. , Reagan M. , Jordan P. , Birkholzer J. 
Published: August 2024

ABSTRACT:
The potential for activating faults associated with geologic carbon sequestration is an issue of concern both related to induced seismicity and CO2 leakage. Faults are usually simplified (e.g., single, planar and homogeneous) in numerical simulations for the sake of computational efficiency. However, such simplifications might significantly impact the outcome of the analysis related to estimating the potential for fault activation and seismic magnitude. Thus, this paper focuses on the evaluation of injection-induced rupture and seismicity in faults of complex geometry. In this paper, we use a coupled multiphase fluid flow and geomechanical simulator (TOUGH-FLAC) to investigate the impact of complex fault geometries on fault rupture temporal and areal evolution and associated seismicity. Various meshing capabilities have been tested and adapted to allow us to discretize more complex and realistic fault geometries that might exist in subsurface formations. These fault geometries are taken as an input for the TOUGH-FLAC simulator to investigate fault reactivation induced by CO2 injection. The model demonstrates the importance of fault geometry on the spatial distribution and temporal evolution of rupture.

1. INTRODUCTION
Fluid injection has the potential to induce fault reactivation during subsurface engineering activities, such as CO2 sequestration, enhanced geothermal systems, enhanced oil/gas recovery, and shale gas development (Cao et al., 2023; Cao and Sharma, 2023, 2022; Guglielmi et al., 2021; Park et al., 2020). The potential for activating faults associated with geologic carbon sequestration is an issue of concern both related to induced seismicity and CO2 leakage (Rutqvist et al., 2002; Rutqvist and Tsang, 2002). Faults are usually simplified (e.g., single, planar, and homogeneous) in numerical simulations for the sake of computational efficiency (Luu et al., 2022; Rinaldi et al., 2015, 2014; Rutqvist and Tsang, 2002). However, such simplifications might significantly impact the outcome of the analysis related to estimating the potential for fault activation and seismic magnitude. This paper focuses on the evaluation of injection-induced rupture and seismicity in non-planar faults.