The factors controlling the migration and enrichment of iron in Archean banded iron formations are important for understanding the formation of iron ore resources. Here we present, for the first time, a micro-three-dimensional modeling method that can be applied to hand specimens of iron ores. This method and petrographic observations, electron probe microanalysis, and the structural deformation characteristics

The macroscopic deformation process of rock is the external performance of microscopic damage in essence, and research from the macro and micro perspectives can effectively reveal the failure mechanism of rock. To further investigate the fracture behaviors of yellow sandstone disc specimens under different loading rates, seven groups of Brazilian disc splitting tests with different loading rates from

Nanoindentation has become an increasingly popular method to determine the mechanical properties of both homogeneous and heterogeneous materials. Rocks are inherently heterogeneous and understanding their mechanical properties is of vital importance for relevant engineering applications. Due to its high precision and resolution in both force and displacement, nanoindentation can be utilized to extract

Due to the spatial variability of material characterisations in deep and large scale excavations, stability assessment is often a challenging task. Numerous slope stability analysis methods based on a range of assumptions and principles are implemented in commercial software packages to ease the process of stability assessment of non-homogeneous and multi-layered slopes. However, the selection of a

Numerical simulation of fracture propagation during hydraulic fracturing is performed based on the extended finite element method. The influences of existing natural fractures and beddings on the formation of fracture network are focused. It is shown that the hydraulic fracture network in the case of random distribution for natural fracture is more conducive to form than that in the case of the regular

In underground engineering practice, the surrounding rocks are subjected to a nonuniform stress field with various radial gradients. In this study, a series of conventional triaxial repetitive impact tests using hollow cylindrical sandstone (HOS) specimens were conducted to reveal the impact waveform features and failure properties of rocks under nonuniform stress conditions. The tests were conducted

A rheological constitutive model for damaged zone evolution of a tunnel is proposed in this paper to describe the strain hardening and softening properties of the excavation-disturbed rock mass. Firstly, the one-dimension rheological model is introduced by connecting the improved St. Venant body with the Nishihara model, and this model can be used to describe the whole process including transient viscoplastic

With the development of carbon dioxide sequestration, the influence of carbon dioxide on coal properties has been paid more and more attention by experts and scholars. Scanning electron microscopy was employed to observe the three-point bending characteristics of bituminous coals treated with or without carbon dioxide gas. The experimental results showed that the carbon dioxide gas treatment had obvious

To evaluate the safety conditions and deformation characteristics of the cemented tailings backfill (CTB) mining disturbed area near shafts of Taohuazui Gold Mine in China, an analytic hierarchy process—fuzzy comprehensive evaluation (AHP-FCE) model for disturbance degree and safety evaluation of backfill mining was established, the historical and current backfill mining processes were simulated based

Pressure-relief mining is the primary method to remove gas and coal outbursts and realize coal and gas simultaneous extraction in deep, high-gas, and low-permeability coal seams. Numerical modeling has been widely used to evaluate the effectiveness of protective coal seam (PCS) longwall mining, which usually employs experiment-derived permeability models to describe permeability changes and coalbed

A wide range of alternatives is available to design a support system to stabilize an underground opening under squeezing conditions. An underground mine development was selected for the research where the underground openings reach to a depth of 1000 m and weak geological formations are present. The operational concerns in the mine development led to a shaft support design having a thick reinforced

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Thermal conductivity is a key parameter for many soil applications, especially for dimensioning shallow and very shallow geothermal systems based on the possible heat extraction rate and for modelling heat transfer processes around high voltage underground cables. Due to the limited purview of direct thermal conductivity measurements, for an investigation of extensive areas, usually other geophysical

The brittleness of rocks plays an important role in the fracture network fracturing process of unconventional oil and gas reservoirs, the drilling efficiency of rock breaking and wall stability, and mining engineering. Rock brittleness has become one of the key parameters in the study of many rock mechanics and related engineering problems. However, there is still no widely accepted definition of brittleness

In the framework of a \({{\hbox {CO}}}_{2}\) storage feasibility study, we evaluate porosity and permeability of shale formations constituting the overburden of a hydrocarbon reservoir, where the gas is stored. These properties are required to perform fluid-flow simulations and analyze possible leakages from the reservoir to the surface. In this process, calibration with well logs is essential. Standard

Radial drilling hydraulic fracturing has become a new stimulation method. The hydraulic fracturing effect of radial drilling on site is not ideal, and the stimulation effect of some wells is not obvious. The hydraulic fracturing effect of radial drilling is closely related to the crack initiation position after radial drilling fracturing. In the past researches on fracture initiation in radial drilling

Geothermal resource quantification requires underground temperature and volume information, which can be challenging to accurately assess at the regional scale. The analytical solution for steady-state heat conduction with internal heat generation is often used to calculate temperature at depth, while geological models can provide volume information. Both approaches were originally combined in a single

To describe the mechanical behavior of interfaces existing in rocks, a three-dimensional contact element model with a certain thickness was proposed that could simultaneously consider the heterogeneity, damage evolution and state variation of interfaces. The Weibull distribution function was employed to describe the rock heterogeneity. The damage evolution of the contact element was analyzed by using

This study prepared transversely isotropic rock-like specimens in three groups of layer thickness ratios, alternating with two kinds of rock-like materials. The conventional triaxial compression tests confirm mechanical difference of the two rock-like materials. The velocities of ultrasonic wave (longitudinal wave VP) are measured for each transversely isotropic rock-like specimen before uniaxial compressive

With the development of deep energy resources, understanding variations in the physical and mechanical properties of rocks at different depths is significant. In this paper, core samples from ten different burial depths (1000 m, 1300 m, 1600 m, 1850 m, 2600 m, 3500 m, 4800 m, 5100 m, 5600 m, and 6400 m) were collected from the Songke No. 2 (SK-2) well and the Daqing Oilfield. To the best of our knowledge

Permeability and meso-structure evolution of coal are crucially important to the profound understanding of coal–gas interactions in the enhanced coalbed methane recovery and in controlling gas outburst. Very few studies focus on the effect time has on these interactions We performed a series of experiments on the permeability evolution of coking coal subjected to the long-term exposure of triaxial

Fluid flow through rock media is highly significant in underground water management, the geothermal recovery process, and various underground engineering applications. Fractures have a critical effect on the fluid flow through low-permeability rocks since they serve as the major flow channels in the rock formation. Consequently, the evaluation of fracture permeability is crucial to many engineering

Blasting operations create significant problems to residential and other structures located in the close proximity of the mines. Blast vibration is one of the most crucial nuisances of blasting, which should be accurately estimated to minimize its effect. In this paper, an attempt has been made to apply various models to predict ground vibrations due to mine blasting. To fulfill this aim, 112 blast

The rational choice of perforation arrangement and injection angle is of great significance to improve the efficiency of synchronous fracturing and to achieve the stimulation of the shale reservoir. In this paper, the influence of perforation angle and perforation arrangement on the crack propagation mechanism and rock failure mode of synchronous fracturing is studied based on the particle discrete

The characteristics of the particle size distribution (PSD) are an important reflection of energy consumption during rock drilling and drilling efficiency. A new approach incorporating both fine and coarse fractions of the PSD to supplement the typical approach of merely utilizing D50 (50% passing diameter) to index drilling resistance and efficiency is reported in this paper. A series of drilling

Main factors influencing the wide range of apertures (from 50 to 400 mm) of mining-induced horizontal fractures (Torezko-Snezhnyanskaya coal area, Ukraine) at traditional (without grout injection into bed separation) longwall coal mining were analysed. Apertures of these fractures were directly measured (using an original experimental device) in vertical boreholes drilled from ground surface to active

Safe mining depth constitutes the key to the open-pit mine development, it is significant to research the safe mining depth. First, According to the field geological investigation and geophysical exploration, the existing landslides were summarized and analyzed to obtain the potential destabilization and failure modes in mine, which laid the effective reference for the slope stability analysis in the

Acoustic transmission along the drill string for measurement while drilling (MWD) is an effective solution to the problem of the low transmission rate that results from mud pulse transmission. However, the actual downhole acoustic waves are affected by many factors, such as drilling fluid properties and, formation boundaries, and their effects on acoustic wave transmission in drill string are not thoroughly

Many large engineering projects, e.g., the Sichuan–Tibet Railway, inevitably cross the earthquake active areas and the geology complicated zones, facing the challenges of dynamic disturbances and disasters. In view of this, the conceptualization of engineering disturbed rock dynamics is proposed in this paper, aiming to systematically study the rock dynamic behavior and response subjected to engineering

The classification of rock slopes and the determination of rock extent are essential for slope stability analysis. At present, the efficiency of artificial methods is low and affected by subjective factors. A convolution neural network model for rock slope image analysis is established based on the Tensorflow. 80,000 rock slope images are extracted and compressed using convolution and pooling. Then

In an enhanced geothermal system (EGS), fractures and fracture networks are the predominant elements for fluid flow and heat transfer through the artificial reservoir. In this work, different conceptual discrete fracture networks were generated by characterizing the fracture number, fracture bifurcation and fracture connectivity of the fracturing area. A thermal–hydraulic (TH) coupled mathematical

Understanding the consequences of mining is most important in order to prevent negative outcomes for the environment as natural systems are used by humans for agriculture/silviculture. The present manuscript deals with the impact of subsidence due to underground coal mining on native soil. Depth-wise changes in soil texture and nutrient components in four layers; 0–15 cm, 16–30 cm, 31–45 cm and 46–60 cm

In recent studies, the links between hydrocarbon accumulations and gold mineralizations have been examined. According to the results obtained from these studies, it has been reported that gold and hydrocarbons are carried and deposited by the same hydrothermal fluids. In the Seferihisar Uplift, the Efemçukuru Gold Operation possesses the largest proven gold reserves of Turkey. For this reason, in this

The determination of deformation parameters of rock material is an essential part of any design in rock mechanics. The goal of this paper is to show, that there is a relationship between static and dynamic modulus of elasticity (E), modulus of rigidity (G) and bulk modulus (K). For this purpose, different data on igneous, sedimentary and metamorphic rocks, all of which are widely used as construction

“Slick-water” fluids routinely used in hydraulic fracturing contain friction-reducing agents and clay-stabilizers that may influence on the strength and stability of reservoir rocks and preexisting faults. We performed laboratory measurements on four powered shale reservoir rocks with different carbonate contents recovered from Longmaxi Formation in Sichuan Basin of China, to examine the potential

To verify the feasibility of rock breakage with abrasive air jet, the effect of abrasive water jet and abrasive air jet on rock breaking is compared and analyzed. In this paper, the mechanism of abrasive acceleration in abrasive water jet and the abrasive air jet is theoretically investigated. The numerical relationship between abrasive kinetic energy and inlet pressure of abrasive water jet and the

Engineered Geothermal Systems (EGS) are promising, but high-risk targets for baseline energy generation. Technology breakthrough is needed to lower the high risks from largely unknown geologic variables and the limited control of the coolant flow field underground. A new, robust EGS (REGS) arrangement and creation technology is reviewed featuring innovative fracture opening, stabilization and permeability

High-power laser has been considered as a potential method of rock breakage through melting. However, high energy consumption and low efficiency are the main restrictions for applying laser technology in rock excavation and fragmentation. A new rock breakage method which combines pulsed laser and induced cavitation is described in this paper, with potentially low energy consumption and high efficiency

Based on conventional triaxial cyclic loading–unloading compression tests, the axial and lateral elastic–plastic strains of sandstone under confining pressures of 5, 10, 20 and 30 MPa were analyzed. The results showed that the lateral stress–strain plastic hysteresis loop is more obvious than the axial direction under cyclic loading. The axial and lateral elastic strains of the specimens are nonlinearly

CO2 fracturing can perform better in enhancing the unconventional gas production than water-based fracturing by avoiding serious reservoir permeability damage. The evolution of the fracture permeability of created and natural fractures during exposure to different fracturing fluids is critical to the effectiveness of CO2 fracturing. Therefore, a comprehensive steady-state permeability tests by using

Understanding microwave-assisted breakage and fracturing of hard rocks necessitates the characterisation of the dielectric properties of basic rock-forming minerals. In the literature, there is a significant discrepancy in the loss factors (i.e., the ability of minerals in absorbing microwave energy) of the gangue minerals due to the fact that different unsuitable and inconsistent measurement techniques

In the Midway Sunset Oil Field in Central California, operators inject steam into the shallow diatomite formation to enhance heavy oil recovery through imbibition, wettability alteration, and viscosity reduction, among other mechanisms. The injected steam, however, does not always remain in the reservoir or return through the wells. In two zones in the study area, the steam comes out at the surface

Geothermal energy is one of the renewable energy sources that have gained extensive recognition as an alternative energy source to fossil fuel energy because of its sustainability and low impact on the environment. However, in spite of the benefits of geothermal energy, drilling costs often hinders the development of geothermal fields for production. The drilling costs can be reduced to a great extent

Geothermal energy is one of the most promising renewable energies due to its high load factor. This work is devoted to presenting the conceptualizations and research advances made at Shenzhen University on the exploration and utilization of low/medium-temperature geothermal energy based on the geothermal resource potential and characteristics of the Guangdong-Hong Kong-Macao Greater Bay Area. The results

In Qinghai Province of China, the Gonghe Basin is characterized as a potential hot dry rock (HDR) area due to the high heat flow rate and high-temperature records from several springs and drillings. However, the regional geothermal mechanism is still disputable and then essential to be discussed for the HDR exploration strategy, even for analysis in other areas. Geophysical methods are useful tools

Carbon capture and sequestration (CCS) is necessary to mitigate global warming caused by anthropogenic \(\hbox {CO}_{2}\) emissions in the atmosphere. However, due to very high storage cost, it is difficult to sustain the CCS industry. The hot sedimentary and dry rock reservoirs with very high temperature can support both geothermal energy production, and carbon geosequestration economically, provided

The smooth joint contact model has been used extensively to simulate the shear behaviour of joints in the numerical simulations with particle flow code. Results from existing studies have revealed that this model suffers from the particle interlocking problem taking place at the shear displacement greater than the minimum particle diameter. To solve this problem, the shear box genesis approach was

Venezuela’s largest heavy-oil deposits are found primarily in the Faja del Orinoco Belt. These deposits exhibit a low production rate under the cold flow method. The objective of this study is to model the impact of steam injection on the fluid dynamics, geomechanics, and seismic attributes for the Faja del Orinoco steam-assisted gravity drainage pilot project. In order to make core testing more representative

Geothermal and solar pv are future energy sources, as both these renewables draw energy from natural heat sources i.e. the Earth and the Sun. While geothermal energy utilizes Earth’s heat for power generation and for direct applications, like space cooling and dehydration, solar energy captures the Sun’s energy and converts the energy to electricity through solar pv cells. The quartz required to manufacture

In recent years, due to the shortage of fossil fuel energy and the deterioration of the environment, increasing attention has been paid to the utilization of geothermal power, especially medium–low-temperature geothermal energy, which occupies a large proportion of hot water resources. This paper summarizes the research status of Bi2Te3-, MgAgSb-, Mg3Sb2-, Mg2(Si,Sn,Ge)- Ag2Se-and AbSbTe2-based near-room-temperature

When simulating production a vapor–water mixture, it is usually assumed that boiling occurs already in the well. But this is not always the case; a phase transition can also arise in the reservoir. In this regard, a mathematical model is proposed that describes the associated heat and mass transfer processes in the reservoir around the production well and in the wellbore itself. The vaporization is

This paper presents a case study of the geotechnical characterization for subsidence analyses of an Italian clastic rock gas reservoir at about 1200–1400 m sub sea level. A coherent and exhaustive dataset including lab data and well log measurements allowed to address the main aspects of the rock material characterization. The a priori qualitative inspection of the cores showed significant variability

Eastern part of peninsular India has exposed Precambrian metasediments, granitic gneissic rocks, basic and ultrabasic intrusives. More than 30 thermal springs issuing through these rocks have been located in the states of Bihar, Jharkhand, and West Bengal. Based on chemical geothermometry of these thermal waters, the reservoir temperatures are estimated to be in the range of 100–195 °C. The area has

A technology has been proposed for the integrated development of low-temperature geothermal resources for using their thermal and water potentials for various purposes. The possibility is substantiated for efficient development of geothermal resources by construction of binary geothermal power plants (GeoPP) using idle oil and gas wells that will significantly reduce capital investments for their building

A laser flash method (micro-flash apparatus LFA 457) and differential scanning calorimeter (DSC 204 F1) were employed to study of the temperature effect on the thermophysical properties (thermal diffusivity \(a\), heat capacity \(C_{\text{P}}\) and thermal conductivity \(\lambda\)) of the natural reservoir rock sample. A relationship between the thermophysical properties behavior and the physical–chemical

The current technology for enhanced geothermal system (EGS) typically involves drilling of deep injection and production wells to inject cold water into the injection well to the EGS reservoir depth, to extract heat by permeating through the fractured hot rock masses, collected by the production well and return to the surface as heated water. In this article, a new approach is proposed to develop EGS

Technological solutions have been proposed for extraction of heat accumulated in hot dry rock with various energy potentials. To extract the heat of low-temperature dry rock mass is shown to be advisable to ensure low heat carrier flow rates in the DHE; so for the depths H = 100, 200 m, the water flow rate G = 0.5–0.6 kg/s is optimal. The technology is presented for a hybrid solar–geothermal system

Deep geothermal energy exploitation has gained a lot of attentions in energy field due to its large reserve. Enhanced geothermal system (EGS) is the only one mode to explore hot dry rock (HDR) with real engineering practice throughout the world. To date, it is also a topic facing several key issues among sustainable and renewable energies because no commercialized mode has been made. Rock plays an

Surfactant and polymer are used to improve oil recovery. The micro-emulsion phase composition, viscosity and interfacial tension vary with salinity and injection concentration of chemicals. The viscosity contrast which is very large for heavy oil reservoirs, results in various types of viscous instabilities. There is no comprehensive field-scale modelling on the viscous fingering affecting the oil

Human beings have been benefiting from geothermal energy for different uses since the dawn of civilization in many parts of the world. One of the earliest uses of geothermal energy was for heating and it was used extensively by Romans in Turkey. The Aegean region is favored with a large number of thermal springs known since ancient times. However, it was in the twentieth century that geothermal energy