bluuebunny/crossref_metadata_2025_split huggingface dataset:
Designing a Reliable Weak Bonded Interface for Fracture Caging Laboratory Validation
Authors: Meng M. , Frash L. P. , K C B. , Madenova Y. , Carey J. W. , Li W. 
Published: September 2023

ABSTRACT
Fracture caging is a proposed approach to geothermal energy extraction that involves using one injection well and multiple boundary wells for continuous fluid injection at high rates and pressures while controlling induced seismicity. To validate this concept, a solid block with a weak layer and injection/production wells will be used to simulate injection induced shear events. Creating a reliable and repeatable weak layer with the necessary bonding strength for shearing is a key challenge. Plaster was selected as the best option due to its light weight, ease of drilling holes, and flexibility in shape. Through experimentation, the optimal interface was found to be between an aluminum surface roughened by 120 grit sandpaper and cured plaster, which provided consistent strength with a friction angle of 42.2 degrees and cohesion of 0.18 MPa. This work helps validate the concept of fracture caging and also has broader implications for civil engineering by providing a reliable method for achieving a weak bonding layer with consistent strength.

INTRODUCTION
The global shift towards renewable energy sources has brought about a renewed focus on the exploration and development of geothermal energy as a sustainable alternative to traditional fossil fuels. Geothermal energy involves harnessing the natural heat stored beneath the Earth's surface to generate electricity or heat, making it a clean and reliable source of energy with a much lower carbon footprint than traditional energy sources.
Despite its great benefits, geothermal energy extraction poses several challenges. One of the primary concerns is the potential for induced seismicity, which can occur when fluids are injected into the subsurface fractured systems and cause shear slip of natural faults. Another challenge facing geothermal energy is its economic viability. The power it generates currently cannot cover the initial capital investment or the return-on-investment period is too long.
To explore geothermal systems in a safe and economically viable manner, a new design approach is needed. One proposed method is fracture caging, which involves using multiple wells for continuous fluid injection and production at high rates and pressure, without causing injection induced seismicity [1-5]. The high flow rate and high pressure hydraulically propping the fracture apertures and promotes the economical profits. This approach is currently being developed and validated from a scientific perspective. One critical step is to experimentally validate the benefits of using multiple boundary wells for a single injection well.
A Critical Review of the Engineering Properties of Extraterrestrial Regolith
Authors: Zou Yuan , Wu Huanyu , Zhang Chi , Yang Wei , Zhao Qi 
Published: September 2023

ABSTRACT
Deep space exploration is the frontier of the development of humanity. Investigators worldwide have conducted extensive research on the engineering characteristics and mineralogical composition of surface materials on the Moon, Mars, and asteroids, which have significant implications for future large-scale spacecraft soft landings and the construction of permanent bases. This work analyzes and summarizes a volume of previous findings on the engineering properties of the regolith of the Moon, Mars, and asteroid Ryugu, including the particle size distribution, bulk density, internal friction angle, cohesion, and presence of water ice. The methods used to obtain these properties are critically reviewed. We discuss their advantages and disadvantages and identify the potential new techniques that can be used to better constrain these engineering properties. This study can help researchers to understand the research progress on extraterrestrial regolith in the engineering properties, as well as prospective research directions in deep space exploration.

INTRODUCTION
Major government space agencies and private companies around the world, such as NASA, CNSA, and SpaceX, have launched ambitious deep space exploration programs to explore the evolution of the solar system and find a potential new habitat for mankind (Wu et al., 2012). Among the extraterrestrial celestial bodies in the solar system, Mars is the focus of the scientific community's attention due to its similarities to Earth (Li et al., 2021). Some key findings concerning Mars have been revealed by a series of probes, especially the landed ones such as InSight and Tianwen-1 (Zou et al., 2021). Due to the remote distance between Mars and Earth, the Moon is considered to be a springboard for Mars exploration (Crawford & Joy, 2014). Lunar exploration is the focus of current deep space exploration programs, including the Artemis program of the United States (Smith et al., 2020), the Chang’e (CE) Project of China (Li et al., 2019), and the Luna program of Russia (Djachkova et al., 2017). In addition, many asteroids have also attracted great interest from researchers, such as Ryugu, Bennu, 2016HO3, etc. (Zhang et al., 2022), and they also have a great chance to contribute to the solution to the evolution of the solar system.
Micro-CT Characterization of Lunar Regolith Using Machine Learning-Based Segmentation
Authors: Wu Huanyu , Zou Yuan , Zhao Qi , Zhang Chi , Yang Wei 
Published: September 2023

ABSTRACT
On 17 December 2020, China's Chang’e-5 mission returned about 1.73 kg of lunar regolith from one of the youngest basalt units in northern Oceanus Procellarum. The mineralogy of the lunar surface regolith provides a wealth of information on its geological history, and the characterization of lunar regolith at high spatial resolution has been a significant goal of lunar exploration. In this study, we combine high-resolution micro-CT imaging and a state-of-the-art machine learning-based image processing approach to assess morphological and physical properties of the lunar regolith sample returned by Chang’e-5 mission. The lunar regolith sample was scanned by an X-ray micro-computed tomography (micro-CT) with a spatial resolution of 2.48 μm. A pixel-wise random forest classifier was employed to segment the volume data into regolith particles considering multiple features including intensity, edge and texture. On the basis of segmented images, the particle size distribution of the lunar regolith sample was extracted. The average density of the sample is estimated to be around 1582 kg/m3 based on a calibration of the relationship between the image intensity and material density. Particles with extremely high-density mineral phases (around 4500 kg/m3) in the sample are considered rich in metal elements such as iron and titanium. In addition, we were able to extract particles with distinguished features such as isolated pores, which implies the possible melting and solidification process related to past meteorite impacts. This study provides a workflow for micro-CT imaging-based analysis of lunar regolith.

INTRODUCTION
Characterization of lunar regolith is a key element in lunar base construction and in-situ resource utilization. Lunar exploration is currently the focus of deep space exploration programs around the world, including NASA's Artemis program (Creech et al., 2022) and China National Space Administration's Chang’e (CE) Project (Li et al., 2019). These exploration programs are ultimately expected to achieve a long-term human presence on the Moon. On 17 December 2020, roughly 1.73 kg of lunar regolith samples were brought back to Earth by China's CE-5 mission, which was the first-time sample return since the Apollo era around 50 years ago (Li et al., 2022). These lunar regolith samples came from a basaltic area in the northern Oceanus Procellarum (Qian et al., 2021), which is rather away from the previous nine sampling sites accomplished by NASA's Apollo missions and USSR's Lunar missions (Li et al., 2022). These samples provide us with rare opportunities to conduct experimental analysis using more precise methods in the laboratory, which has invaluable implications for deep space exploration research, compared to methods of remote detection of orbiters and in-situ investigation of lunar rovers.
Numerical Simulation of the Underground Storage Cavern Using FDEM
Authors: Wu Huanyu , Zhao Qi , Shen Jiayi , Li Hanze 
Published: September 2023

ABSTRACT
Underground storage cavern has been increasingly exploited as it has many advantages such as reducing investment, economizing land use and improving safety compared with storage above the ground surface. We employ the hydromechanical coupled FDEM to simulate the excavation and operation phases of the underground storage cavern with a water curtain system (WCS), taking into consideration the natural discrete fracture network (DFN). The simulation results captured the propagation and slipping of the pre-existing DFN during the excavation and operation process. We quantitatively evaluate the containment performance based on the water inflow and pore pressure distribution. This study provides new insights into evaluating the stability of cavern-surrounding rock masses and containment performance of underground storage caverns.

INTRODUCTION
Underground storage caverns have better performance on safety, security, economy, and greater environmental acceptance compared with traditional storage infrastructures such as storage tanks and pipelines. Several large underground storage caverns have been constructed, for example, Jurong rock caverns in Singapore (Zhou & Zhao, 2016) and Huangdao underground oil storage caverns in China (Wang et al., 2015).
Underground storage caverns are constructed in fractured rock masses, confining the storage medium (such as oil and gas) by maintaining groundwater pressure around caverns which is also called hydraulic confinement (Aberg, 1978; Froise, 1987; Lindblom, 1997). The basic principle of underground containment the cavern is that no gas could leak as long as the water pressure increases along all possible gas leakage paths away from the cavern (Goodall et al., 1988). To enhance the sealing performance, water curtain systems (WCS) are constructed to manually control the pore pressure distribution by regulating the water curtain pressure. (Shi et al., 2018). Previous studies has evaluated the stability of excavated rock masses (Mohanty & Vandergrift, 2012; Ma et al., 2016; Zhuang et al., 2017) and containment performance (Xu et al., 2018; Liu et al., 2021) by using in-situ monitoring methods and numerical simulation.
However, the fracture propagation and slip induced by the excavation and operation of the storage cavern, as well as the resultant fluid pressure variation, have not been illustrated.
The Geotechnical Aspects of a Pillar Recovery Project in the DOZ Cave Mine
Authors: Putra F. , Meiharriko Hasan R. , Hamman J. P. E. 
Published: September 2023

ABSTRACT
The Deep Ore Zone (DOZ) mine is a part of the PT Freeport Indonesia (PTFI) underground cave mining complex. It is the third lift in the Ertsberg East Skarn System (EESS). These mines are located on elevations between 3,000 to 4,500 amsl in an area with very high rainfall of approximately 5,500 mm per year.
A significant challenge in the operations of the DOZ mine is the handling and management of wetmuck. As mining progressed since the start of production in 2000, the percentage of wetmuck drawpoints increased dramatically against the dry muck drawpoints. This condition impacted the ore blending strategy in the ore pass systems to mitigate the ore spill hazard in the ore flow systems.
To overcome this dry: wet muck ratio problem, an option for pillar recovery to increase the dry muck tonnages was evaluated. Pillar recovery strategies along the major pillar apexes in inactive extraction levels was initiated. This challenging project took place in six panels between 2019 - 2021 and had to deal with a long history of abandoned areas, active wetmuck issues, closed drawpoints and panel instability concerns.
This paper aims to provide an overview on the management of the pillar recovery project, geotechnical assessment of pillars and wetmuck to ensure safety and production targets are met.

INTRODUCTION
The Deep Ore Zone (DOZ) cave mine is a part of the PTFI underground mining complex that implement the block cave mining method between 3,000 to 4,500 amsl. DOZ mine is the third lift in the Ertsberg East Skarn System (EESS) orebody after the Gunung Bijih Timur (GBT) Mine and Intermediate Ore Zone (IOZ) Mine (Figure 1). The topography around these mines is extremely rugged and typical of the Jaya Wijaya Mountain range in West Papua, Indonesia. Wet weather with very high rainfall that averages 5500 mm per year (Widijanto et al., 2012). The very high rainfall combined with the block cave mining methods, that has broken through into the open pits or to surface, is one of the main contributors to the wetmuck at PTFI. Other contributing factors include lithology, fragmentation and draw rates (See Section 4.1 for detail Wetmuck Classification).
Comparison of Geological Profiles from Borehole Data Based 3D Geological Model and Geophysical Testing
Authors: Wu Shifan , Zhang Yu , Chu Jian , Chiam Kiefer , Goh Kok Hun 
Published: September 2023

ABSTRACT
Three-dimensional (3D) geological modeling has been used for design and construction works to overcome the complex nature of underground geological conditions. The accuracy and reliability of geological information reflected by the 3D model are critical for engineers to make sound judgement. The 3D model is usually established using borehole data. The data gaps between boreholes affect the accuracy of the 3D geological model. Instead of getting additional borehole data, geophysical survey is a promisingly cost-effective method to fill the data gaps and improve the assessment of the underground uncertainties. In this study, a case of using the seismic surface wave methods to determine the engineering rockhead and thus fill the data gap in the 3D geological model is presented. In relation to a subway project in Singapore, the combination of geophysical methods and 3D geological model for rockhead detection at this site was explored. Seismic geophysical survey was carried out to map the rockhead which was calibrated and verified using borehole data. This improves the accuracy of the rockhead obtained from 3D geological model. Through this study, a procedure of using geophysical methods to obtain additional data to verify and update the existing 3D geological model has been established.

INTRODUCTION
Three-dimensional (3D) geological modeling has been widely used for underground design and construction works to overcome the complex nature of underground geological conditions (Dong et al., 2015; Pan et al., 2018; Pan et al., 2020; He et al., 2020; Zhu et al., 2021). The accuracy and reliability of the geological information indicated by the 3D model are critical for engineering practitioners to comprehend and visualize the subsurface conditions and make a sound judgement (Wu et al., 2022; Qi et al., 2021). It is considerably significant and valuable in practice to locate the top surface of moderately weathered rock (Weathering Grade III or better) in the 3D geological map since the geo-materials and mechanical behaviors start to vary apparently from this interface. The engineering rockhead is conventionally identified via the traditional geotechnical investigation which involves drilling boreholes and the subsequent interpretation of the borehole logs and coring samples. The accuracy of the interpreted rockhead or geological profile largely depends on the borehole quantity, location and spacing, as well as the interpretation of geologist. When the boreholes are sparse, the uncertainties become large and thus additional boreholes are required to reduce them. Unfortunately, getting more borehole data is expensive. It is also challenging to carry out drilling works within restricted areas such as urbanized cities or inaccessible terrains such as natural reserve or lakes.
Effect of Water Saturation on Failure Behaviour of Mudstones Under High Pressures
Authors: Iyare U. C. , Frash L. P. , Carey J. W. , Blake O. O. , Ramsook R. 
Published: September 2023

ABSTRACT
Water as pore fluid is an important factor that influence rock deformation and failure behaviour. This paper presents an experimental study on the effects of water saturation on the failure behaviour of mudstones at high confining pressures. Triaxial compression experiments were performed at confining pressures up to 130 MPa, on dry and water-saturated mudstone samples. Results including stress-strain curves, failure strength, and failure modes, showed that the mudstones experienced brittle, brittle-ductile transition, and ductile failure behaviour as the confining pressure increases. The results also revealed that water significantly weakened the rock, thereby reducing the failure strength and causing the rock to become ductile at lower confining pressure compare to dry conditions. Furthermore, in water-saturated conditions, the brittle-ductile transition behaviour is accompanied by shear band fractures and ductile flow, as opposed to shear fractures to shear band fractures in dry conditions. The findings of this study could provide valuable information for optimizing hydraulic fracturing techniques and improving production efficiency in unconventional oil and gas reservoirs by identifying the conditions and depths of the transition from brittle to ductile failure behavior.

INTRODUCTION
Crustal rocks typically contain some form of pore fluid, and most of these fluids are water (Price, 1975). Understanding how pore fluids affect the mechanical properties of rocks is crucial in solving a range of problems in geotechnical and geological applications. For example, water's significant impact on the strength and deformability of rocks has been linked to many rock engineering hazards like landslides (Iverson, 2000). Water has been shown in numerous studies to weaken the mechanical strength of various types of rock, including mudstone, sandstone, granitic rocks, and quartzite. (Cai et al., 2019; Lu et al., 2017; Wasantha and Ranjith, 2014). When rocks are saturated with water, they become weaker and more prone to failure. This is because water can act as a lubricant between the individual particles, reducing the frictional forces that hold the particles together. As a result, the rock may experience reduced strength, stiffness, and cohesion, as well as an increased risk of creep, plastic deformation, and failure rates (Brantut et al., 2013; Chen et al., 2019; Wong et al., 2016).
A Rock Physics Feasibility Study of the Geothermal Lodgepole Reservoir, North Dakota
Authors: Alamooti M. , Namie S. 
Published: September 2023

ABSTRACT
Geothermal energy extraction from the Earth's crust requires a thorough understanding of the mechanisms that enhance fluid flow in rocks. Geoscientists must evaluate the elements that regulate the development of permeability networks and the parameters that control rocks’ responses to stimulation procedures across various spatial and time scales. The Williston Basin is a major geological depression with complex stratigraphic sequences, and its rocks’ complex microstructures and mineral compositions make it challenging to assess effective moduli accurately. In addition, the Lodgepole Formation in the Williston Basin is a primary geothermal aquifer with low-salinity waters co-produced with oil and gas, which are often discarded as waste. This study aimed to develop a rock physics model of the Lodgepole formation, emphasizing its geomechanics and petrophysical features, and explore the connections to locate additional geothermal energy sources in the future. The study used several methods to estimate rock physics characteristics, including elastic modulus of minerals and rock pore shape and found that the intra-particle model matches the available data.

INTRODUCTION
The Lodgepole Formation, is the second deepest (Fig. 1) of the Williston Basin's four principal geothermal aquifers. The Formation has been identified as a potential source of low-salinity geothermal fluids co-produced with oil and gas. These fluids are often considered waste and are discarded by reinjection into the ground. However, North Dakota is now exploring harnessing geothermal waters to produce power. To evaluate the geothermal potential of the Lodgepole Formation, it is essential to understand the geomechanical and petrophysical features of the rocks in the Formation. Non-typical reservoir rocks, such as tight sandstones and shales, are known for their complex microstructures and mineral compositions, making it challenging to assess their effective moduli. Additionally, data from the literature may only sometimes be accurate since XRD data is only continuous at some levels, and the elastic modulus information for minerals can vary based on the study location.
Data-Driven Models for Predicting Rate of Penetration Based on Machine Learning Algorithms
Authors: Liu Yang , Xi Yang , Xiang Xingyun , Ma Tianshou , Chen Sitong 
Published: September 2023

ABSTRACT
Data-driven models are used extensively for predicting rate of penetration (ROP). However, what data-driven algorithm is best suited to ROP prediction is currently undecided. In this paper, the data-driven model based on back propagation neural network (BP-ANN) and random forest (RF) algorithms are proposed respectively to predict ROP. The features that include both the engineering and formation parameters are selected as the model inputs by combining physical drilling laws and correlation analysis. The optimal hyperparameter combinations of the model are found by cross-validation. The MAE, MSE and R2 are adopted as the indicators to evaluate the model performance. The case study illustrates how accurately and rapidly the data-driven model can be used to predict the ROP. The results indicate that the RF model can track the data-based ROPs more accurate even if hyperparameters optimization is ignored. The MAE, MSE and R2 of the optimized model are 0.243m/h, 1.599m2/h2, 0.989, respectively. While for the BP-ANN model, the predicted ROPs can achieve a more desired result after hyperparameters optimization, but it still cannot come close to the result of RF model. The present model provides some methodological bases for the further study on optimizing drilling parameters.

INTRODUCTION
Rate of penetration (ROP) is one of the key factors affecting drilling period and operating cost. Over the past few decades, researchers in drilling engineering field have been devoted to accurately predict and obtain an optimal value of ROP. Several physics-based models, e.g. the Maurer model (Maurer, 1962), the Warren model (Warren, 1987), the B-Y model (Bourgoyne and Young, 1974), the Hareland model (Hareland and Rampersad, 1994), the Detournay model (Detournay et al., 2008), the Motahhari model (Motahhari et al., 2010), are therefore proposed to predict ROP. All of these models take into account the engineering and geological factors to various extent, however, it still exists a great many limits in itself, especially in the extremely complex downhole environments. The primary reason is that the strong nonlinear relations between the ROP and the governing factors are not thoroughly understood (Zhang et al., 2022).