bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on Consolidation and Drainage Characteristics of Fine-Grained Tailings in Geotextile Bags Under Dynamic Load
Authors: Ma Lei , Zhang Chao , Guo Xiaogang , Ma Changkun 
Published: September 2023

ABSTRACT
Tailings dams built using tailings have faced several technical challenges in recent years. However, the use of the geotextile bag method can provide a good solution to issues such as difficult dam construction, poor drainage, and stability of the dam. In order to address these concerns, the author conducted an experimental study using the geotextile bag built-in air bag pressurization test method. Nine sets of horizontal test conditions were designed, which included the air bag application position, air bag pressure variation range, and air bag pressure application mode. The research aimed to investigate the dynamic load on the geotextile bag of fine-grained tailings consolidation drainage characteristics. The results showed that the peak pressure of the loaded air bag has the greatest impact on the degree of tailings consolidation drainage rate. The loading method of variable peak pressure was found to be more conducive to increasing tailings retention and practical operation of the project.

TEST BACKGROUND
China is a nation that is rich in mineral resources, and as the mineral processing technology and recovery efficiency continue to improve, the size of tailings has become smaller and smaller. Traditional upstream and midline methods of constructing tailings dams can result in low permeability, high infiltration line, poor drainage, consolidation difficulties, and sand imbalance, which can all affect the stability of the dam. The geotextile bag method has recently gained attention from scientific researchers and engineers due to its good permeability and sand retention function, and has seen some success in the field of tailings dams. However, the role of the geotextile bag method in ensuring the safety and stability of tailings dams needs further exploration. Additionally, there are several new problems that need to be addressed. This paper aims to examine the use of built-in pressurized airbags for accelerating the solidification and drainage of fine-grained tailings in molded bags.
Benchmarking Analytical and Numerical Simulation of Induced Fault Slip
Authors: Novikov A. V. , Shokrollahzadeh Behbahani S. , Voskov D. , Hajibeygi H. , Jansen J. D. 
Published: September 2023

ABSTRACT
Quantification of the poromechanical response of subsurface formations due to human-induced pore pressure fluctuations is critical for the performance and stability assessment of many geo-energy systems. In particular, natural faults in the subsurface introduce the hazard of induced seismicity. Numerical modeling of fault reactivation is challenging, while the specific details of induced stresses and fault slip in reservoirs with displaced (i.e. non-zero offset) faults may cause additional challenges depending on the type of numerical formulation employed. To facilitate the systematic development and testing of numerical tools for the simulation of induced seismicity in faulted reservoirs we developed a set of semi-analytical test problems of increasing complexity, based on inclusion theory and Cauchy singular integral equations. With these we investigate the accuracy of two recently developed Finite Volume (FV) schemes with collocated and staggered arrangements of unknowns. One of them employs a conformal discrete fault model (DFM) which can guarantee sufficient accuracy at the cost of adaptive mesh refinement but may suffer from modelling and computational challenges when addressing large-scale realistic geological configurations. The second one employs an embedded (or non-conformal) discrete fault model (EDFM) which avoids the need for excessive mesh refinement, but of which the accuracy and the range of applicability are still to be investigated. We found that both numerical schemes accurately represent the pre-slip Coulomb stresses, but show different degrees of accuracy in representing the resulting depletion-induced fault slip. The semi-analytical benchmark data are available via DOI 10.4121/22240309.

INTRODUCTION
The kernel of this paper is formed by a series of semi-analytical poro-mechanical test problems of increasing complexity with the aim to systematically compare the capacities of two poro-mechanical finite-volume-based simulation codes: one developed by Novikov et al. (2022b) which employs a discrete fault model (DFM). It forms part of a comprehensive porous media simulation package, the Delft Advanced Reservoir Terra Simulator (DARTS) and will be referred to with that acronym. The second code, developed by Shokrollahzadeh Behbahani et al. (2022), is based on a smoothed version of the embedded discrete fault model (sEFVM) and will be referred to with that last acronym. Both codes are being developed as part of the DeepNL Science4Steer project (NWO, 2017), and Appendices A and B give a brief overview of their characteristic features. The grids used in this study are presented in Appendix C.
Experimental Study of Flow Field in Solution Mining Period of Salt Cavern Gas Storage
Authors: Guan Yueyang , Ban Fansheng , He Qi , Che Yang , Xu Nan 
Published: September 2023

ABSTRACT
Solution mining is the most critical process for salt cavern gas storage. So far Salt cavern gas storages in China are mainly single-well-cavity, and the time of dissolution between two and four years. Solution mining utilize intermediate hanging string and long hanging string for direct circulation and reverse circulation. In the process of solution mining, fluid velocity and different mode of circulation have a great influence on the longitudinal and transverse expansion of the cavity. Therefore, in order to research the changes of the flow field in different working conditions, this study uses Particle Image Velocimetry for flow field analysis. In the laboratory, using large-scale transparent models for laboratory simulation experiments. According to the experimental results, under direct circulation mode, water flows through the right space to upper part. Angle of reflux was in the range of 28° − 56°. The maximum influence radius of direct circulation flow field is 48.1m. In reverse circulation mode, if the distance from the intermediate hanging string to the insoluble matter is less than 2.44m, insoluble matter may affect circulation.

INTRODUCTION
Underground gas storage is important composition part of transporting pipeline system of natural gas (LI Tie et al., 2000). In 2021, China's natural gas consumption will reach 372.6 billion m3, and the reserves required for peak adjustment of natural gas will be 55 billion m3, but the actual reserves only reach about ⅓ of the demand (YANG Chunhe and WANG Tongtao, 2022). Overcoming the unstable supply of clean energy requires accelerating the construction of underground space for large-scale storage (WANYAN Qiqi et al., 2020). Salt cavern gas storage is the main technology for natural gas storage due to its stronger integrity, higher gas injection efficiency and less gas consumption of cushion (ZHU Xingshan et al., 2022). It can not only satisfy the peak regulation demand of the city, but also optimize the production system and gas pipeline network (ZHENG Yali and ZHAO Yanjie, 2010).
A mass of cavity completion data shows that the final cavity volume of salt cavern gas storage deviates from the initial design volume to some extent (WANG Yuangang et al., 2020), so it is particularly important to research the influence of different factors on solution mining.
Coupled Mechanical and Permeability Model for Grain Crushing and Pore Collapse
Authors: Papamichos E. , Berntsen A. N. , Flatebø R. E. , Kristiansen T. G. , Vejbæk O. , Omdal E. 
Published: September 2023

ABSTRACT
The coupled hydromechanical behavior of porous rocks at high compressive stresses is studied. At such stresses, grain crushing, or pore collapse are the primary failure modes. The need to study and model such behaviors is necessary as exploitation of reservoirs reaches depths where stress regimes for such failures are becoming relevant. Experimental data from triaxial compression and Ko tests at different stress ratios are analyzed to model the effects of grain crushing or pore collapse on the stress-strain behavior but also on the changes in the permeability. A stress-dependent permeability model is developed to account for the large drops in permeability associated with these compaction failures. The permeability model modifies the Kozeny-Carman model for permeability as a function porosity to include a stress dependent term linked to grain crushing or pore collapse. Comparison with the experimental results show the validity of the model in capturing permeability changes during compaction failure.

INTRODUCTION
Reservoir rocks are sometimes loaded at high compressive mean stress at deep reservoirs and high depletions. Moreover, proppant or other completions that support the face of boreholes or perforations may result in both high deviatoric and high mean stresses. Such loadings can lead to grain crushing and/or pore collapse of reservoir rocks. Sandstones often experience grain crushing at high mean stresses. A combination of deviatoric and hydrostatic loading facilitates this phenomenon (Papamichos et al. 1993). High porosity chalks on the other hand experience pore collapse where the open skeleton structure of the material breaks, and destructures giving a sharp decline in porosity (e.g., Papamichos et al. 1997). Both phenomena cause fundamental changes in the structure of the rock, the pore space and thus significantly affect the rock permeability. This work proposes a permeability model that is linked to the mechanical failure of the rock due to pore collapse and grain crushing and attempts to simulate the sharp permeability decline observed during grain crushing and pore collapse and which cannot be captured with only porosity dependent permeability models løike the Kozeny-Carman. Experiments are presented for two sandstones and a chalk where these phenomena had been investigated to a certain extent. Based on the experimental results a model was advanced that appears to provide reasonable simulations of the experimental results.
Enhanced Imbibition Through Wettability Alteration During Shut-In Treatment After Hydraulic Fracturing
Authors: Fan Xibin , Wang Wenzhong , Zhu Shijie , Wang Yingwei , Bai Hao , Liang Tianbo 
Published: September 2023

ABSTRACT
Tight oil reservoirs are characteristic of low porosity and permeability, complex pore-throat network, and typically oil-wet, which results in a low oil recovery rate of less than 10%. Surfactant can alter the rock wettability while maintaining an ultralow adsorption rate on rock surface, and thus can be a promising method to enhance the oil recovery. This paper uses the numerical simulation method to understand how shut-in pressure affects the imbibition of fracturing fluid when rock wettability changes. Results show that wettability has a great influence on water imbibition depth of fracturing fluid and the change of water saturation at the invasion front. There is a positive correlation between the imbibition rate and the water-oil interfacial tension in a water-wet reservoir, but a negative correlation in an oil-wet reservoir. In water-wet reservoirs, when the shut-in pressure keeps the same, the water imbibition rate is linear to sqrt (K/ϕ), and increases with the interfacial tension. When the oil-wet reservoir is altered to water-wet, although the water imbibition rate is reduced by 37%, water saturation in the invasion front significantly increases from 0%-1.75% to 8%-15%, resulting in an enhanced water imbibition efficiency of 6.25% to 15%.

INTRODUCTION
Abundant oil and gas resources are present in tight reservoir formations, which are widely distributed all over the world. Tight reservoirs have small pore radius, few effective pores, and complicated pore throats with abundant microfractures[1]. In this kind of reservoir, the traditional water flooding method is difficult to achieve the effective use of crude oil. Hydraulic fracture is needed to improve the conductivity of the matrix[2]. Research and practice indicate imbibition flooding can significantly improve recovery in fractured tight reservoirs[3]. In general, imbibition refers to the spontaneous entry of the wetting-phase fluid into the pore throat of the rock under the action of capillary forces, displacing the non-wetting phase fluid in the pores[4]. To study the imbibition characteristics and imbibition displacement mechanism of tight reservoir can provide an effective method for improving the recovery efficiency of tight reservoir.
Probabilistic Stress Prediction: Poroelastic Profiles and Paths in the Permian Basin, USA
Authors: Amalokwu K. , Crawford B. , Chhatre S. , Manchanda R. , Becker G. 
Published: September 2023

ABSTRACT
Knowledge of the in-situ state of stress is fundamental to all subsurface geomechanics/rock engineering endeavors and predicting layer-to-layer variation of horizontal principal stress magnitudes is imperative for a wide range of energy-related applications. In addition, the ability to forecast subsequent changes to these horizontal stress magnitudes associated with pore fluid pressure depletion or injection (stress paths) is vital for unconventional resources development planning, including predicting maximum injection pressures for gas containment associated with cyclic "huff and puff" enhanced oil recovery (EOR). Poroelastic theory describes the fundamental mechanical behavior of fluid-bearing porous rocks including unconventional resource rocks, and as such provides a useful framework for understanding subsurface stresses and how they impact operations. However, due to the highly heterogeneous nature of unconventional resource rocks, oftentimes deterministic predictions are not sufficient for business purposes but rather a probabilistic approach is necessary to adequately explore the full range of possible outcomes. We present practical Permian Basin applications of predictive tools based on poroelastic theory and Monte Carlo simulation for rapid geomechanical assessment of susbsurface stress profiles (e.g., as input for probabilistic hydraulic fracture modeling), and to bound likely stress paths associated with EOR injection for predicting gas containment pressures and surface compressor requirements. Practical applications related to the Permian Basin, onshore USA are presented.

INTRODUCTION
A wide range of energy-related applications require knowledge of in-situ stress state (and its evolution) to various levels of detail/scale. For some applications, an estimate of in situ stresses in a particular formation or region is sufficient, while for many other applications, layer to layer variation of stress is required. Knowledge of layer-to-layer variation of horizontal principal stress magnitudes is vital for a wide range of energy-related applications including drilling (wellbore stability); completions (hydraulic fracturing); mechanical seal capacity/caprock integrity (underground gas storage, carbon capture, utilization and storage), in-fill drilling and field development (parent-child well interactions, depletion planning) and abandonment (Warpinski & Teufel, 1989; Thiercelin & Plumb, 1994; Peška & Zoback, 1995).
Reconstruct Laminated Shale Cores/specimens for Numerical Modeling by Physics-Informed Image Processing
Authors: Zhao Gaobo , Ruan Mindi , Tulu Ihsan Berk , Li Xin , Xue Yuting 
Published: September 2023

ABSTRACT
This paper proposes end-to-end physics-informed image processing to construct the digital twin of laminated shale cores/specimens and extract the number, spacing, length, and frequency of bedding planes. Specifically, the image stitching technique was applied to eliminate any distortion that may arise from projecting 3D objects onto 2D images. Then, based on shale physics information (gradient difference between different pixels in the image due to various mineral components), an edge detection algorithm was used to extract one-pixel-wide bedding planes from the shale image. Furthermore, a depth-first search algorithm was used to collect the point coordinates of each line. The coordinates gathered from the 2D image were used to generate the model of the laminated shale specimens/cores in UDEC. A variable sensitivity analysis of the reconstructed shale was performed using the proposed method. This work will improve the reliability of laminated shale modeling to further investigate the influence of bedding planes on the macro mechanical properties of shale rockmass.

INTRODUCTION
Laminated shale is a fissile clastic sedimentary rock whose mechanical properties depend largely on the geometrical properties of bedding planes, which are also known as beds, bedding, and laminations. Bedding planes are inevitably considered when scholars investigate different aspects of shale, such as mechanical properties, brittle failure, crack propagation, multiphase coupling, shale rock physics model, and so on, particularly in numerical modeling (Calvo et al., 1998; Amann et al., 2011; Liu and Liu, 2021; Zhao et al., 2022a,b).
In the fields of rock mechanics and mining, it has been agreed that bedding planes are the weaker component of the shale rockmass matrix (Einstein et al., 1969; Josh et al., 2012; Esterhuizen et al., 2013; Lisjak et al., 2014; Moradian et al., 2016; Seyed Ghafouri et al., 2022; Yuan et al., 2022). Generally in numerical and analytical analysis, the geometry of bedding planes is simplified as continuous, straight, and equidistant to simplify the solution approach (Sone, 2012; Morgan and Einstein, 2014; Morgan, 2015; Xue and Mishra, 2017; Zhao, 2022; Seyed Ghafouri et al., 2022). The above assumptions are feasible when simulating the preidentified macro characteristics of a specific shale rockmass, but might become unreasonable/questionable when the failure mechanism of shale rockmass is investigated on a laboratory or field scale. This is because shale specimen modeling with those assumptions is oversimplified and cannot reveal the true nature of the failure process and crack propagation.
The Hith Formation: A Potential Regional Seal for CO2 Sequestration
Authors: Sierra Hernandez Maria C. , Boehm Nicolas , van Buchem Frans , Finkbeiner Thomas , Li Zihao , Espinoza D. Nicolas 
Published: September 2023

ABSTRACT
The Late Jurassic Hith Formation is an anhydrite deposit with an average thickness of &gt; 90 m. It forms an important regional seal for major hydrocarbon accumulations over large parts of the Arabian Peninsula. In Saudi Arabia, the only location where the Hith Formation outcrops is the Dahal Hit cave south of the capital of Riyadh. The Hith is being studied as an important seal for CO2 sequestration. To achieve this, it is vital to know its geomechanical properties and chemical reactivity, especially when exposed to CO2 under reservoir temperature and pressure conditions. From a literature review of anhydrites, we obtained global value ranges for strength, stiffness and acoustic properties. All of which indicate that anhydrites are generally stiff and strong rocks. This enables us to benchmark properties from the Hith anhydrite measured on hand specimens taken from the Hit cave. Resulting compressive strength of our samples averages 145 MPa, which is within the range reported in the literature. Compressional velocities average at 5300 m/s, not as high as literature values. Shear velocities on the other hand match the literature reported values of around 3250 m/s. We further reviewed and investigated the effect of brine composition and CO2 on the chemo-mechanical behavior of the Hith anhydrite through micro-scratch testing. Experiments confirm the capability of the micro-scratch test to quantify chemomechanical alteration.

INTRODUCTION
In last two centuries, there has been an almost two-fold increase in carbon dioxide (CO2) atmospheric concentration, from 280 ppm in the late 1700's to 410 ppm in 2020 (Trends in CO2, 2023; Lelandais et al., 2022). Rising CO2 emissions are believed to have caused an un-natural increase in global temperatures (Gil-Alana and Monge, 2020). Many countries – Saudi Arabia included – are committed to decrease their CO2 emissions. Despite growth in renewable energy generation, fossil fuels with their associated CO2 emissions will likely remain the primary source of energy in the near future. Furthermore, using fossil fuels combined with sequestration makes transition and use of unstable zero-carbon energy sources more efficient and economical (Zoback and Smit, 2023). Hence sequestration is necessary for competitive and efficient de-carbonization of energy production and to mitigate the impacts of today's climate crisis.
Rock Physical Modeling of Sheared Fractures: Permeability-Resistivity-Seismic Velocity Relationship Explored via Digital Rock Physics Approach
Authors: Sawayama K. , Ishibashi T. , Jiang F. , Tsuji T. 
Published: September 2023

ABSTRACT
Fluid flow through faults controls subsurface transport processes, considerably impacting seismic hazards and geoengineering such as enhanced geothermal systems (EGS). Recent advances in geophysical techniques have detected changes in electrical resistivity and seismic velocity due to crustal stress changes, and possibly predicted the changes in subsurface fluid flow. However, we could not quantitatively interpret these geophysical monitoring data due to the absence of rock physical models for fractured rocks. This study investigated changes in permeability, resistivity, elastic wave velocity, and their respective relationships at elevated normal stress by performing numerical simulations of various fracture models with changing fracture surface roughness and shear displacement. The results show that permeability-resistivity and permeability-velocity relationships are less dependent on any geometric characteristics, but controlled by the percolation based on microscopic flow analysis. Our finding suggests that Overall, resistivity is more sensitive to less connected flow regime, while seismic velocities are more sensitive to connected flow regime.

INTRODUCTION
The fluid-flow characteristics of fractured geological formations are of critical interest in a number of areas including fluid resources (e.g., geothermal fluids, shale oil, and groundwater), geological storage or disposal, and seismic hazard assessment (fault reactivation, slow slip, and induced seismicity). Numerous studies have revealed that fluid-flow properties are constrained by fracture surface topography, which is also altered by shear displacement and stress (e.g., Chen et al., 2017; Durham and Bonner, 1994; Durham, 1997; Ishibashi et al., 2015; Pyrak-Nolte and Morris, 2000; Watanabe et al., 2008 Witherspoon et al., 1980; Zimmerman et al., 1992). Insitu stress is never constant during geoengineering developments or on the geological time scale, and consequently the aperture distribution and associated hydraulic properties also must change in natural settings.
Although direct measurement of permeability changes is challenging, geophysical observations are potential approaches to evaluate the permeability change. Many studies have reported changes in seismic velocities or electrical resistivity that may reflect subsurface stress changes associated with hydraulic stimulation, earthquakes or geothermal fluid production (e.g., Brenguier et al., 2008; Didana et al., 2017; Mazzella and Morrison, 1974; Nimiya et al., 2017; Park, 1991; Sánchez-Pastor et al., 2019Taira et al., 2018; Tsuji et al., 2021; Johnson et al., 2021). It would be advantageous if changes in permeability caused by subsurface stress changes could be linked to these geophysical properties that could be remotely monitored.