bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prediction of Liquid Loading in Changning Shale Gas Well
Authors: Li Jia , Jiang Zeyin , Liu Shuang , Wen Ming , Li Na 
Published: August 2024

ABSTRACT:
Addressing the technical challenge of fluid accumulation in Changning shale gas wellbores, we employed the Beggs Brill model to establish a tubing pressure drop calculation model. By integrating this model with the calculation model for annular static gas column pressure and fitting the casing pressure and bottom hole flow pressure production data, we derived a comprehensive calculation model for determining the depth of fluid accumulation in both the tubing and annulus. The accuracy of the model was validated through on-site assessments involving flow pressure, static pressure, and liquid accumulation depth testing. Utilizing Java language and a web development framework, we developed a wellbore fluid accumulation prediction software. This software enables production performance analysis and prediction of wellbore fluid accumulation, providing essential technical support for accurately forecasting fluid accumulation in Changning shale gas wells.

1. INTRODUCTION
During the middle and later stages of exploitation, the decline in gas production from Changning shale gas wells can be attributed to insufficient formation energy. Inadequate liquid carrying capacity in the production of gas wells during these stages is a consequence of the backflow of fracturing fluid retained from the early stages, leading to a susceptibility to wellbore fluid accumulation. [1-3] Consequently, predicting wellbore fluid accumulation becomes paramount for ensuring the stability of the shale gas well production process.
To address this, scholars have extensively researched methods for predicting wellbore fluid accumulation. Classic empirical calculation models, such as those proposed by Duns-Ros, Hagedorn-Brown, Orkiszewski, and Beggs-Brill et al., [4-7] are based on a wealth of experimental data and empirical formulas. In a later stage, Hasan et al.[8] introduced a new expression for liquid holdup grounded in the drift flow model. However, the empirical coefficients of traditional models have poor calculation accuracy in the Changning block, these models have limitations when applied to the conditions of calculating wellbore fluid accumulation in Changning shale gas wells, making it challenging to accurately predict the characteristics of wellbore fluid accumulation.[9]
To tackle the challenge of accurately predicting fluid accumulation, a novel pressure drop calculation model for gas-liquid two-phase flow in the Changning shale gas wellbore was developed. The accuracy of the model was validated through on-site assessments involving flow pressure, static pressure, and liquid accumulation depth testing. Additionally, corresponding software for predicting wellbore fluid accumulation was created, ensuring an accurate forecast of fluid accumulation in the wellbore.
Dynamic Rock Testing and Implications for Blast-Induced Ground Vibration Mitigation
Authors: Tetteh H. N. , Rinehart A. J. , McLemore V. T. , Li W. F. 
Published: August 2024

ABSTRACT:
mining requires continuous production through rock fragmentation by drilling and blasting. Drilling and blasting are essential to productivity but can result in blast-induced ground vibration issues in sensitive communities. Civil and geotechnical strategies considering rock structure and behavior under cyclic loading conditions can be used to predict ground vibration behavior and mitigate its effect. This study investigates key physics in cyclic dynamic wave propagation in rocks and provides fundamental results on dynamic wave propagation and attenuation in phyllite and granite under field-representative cyclic loading conditions. Supporting tests – x-ray diffraction (XRD) and porosity measurement are designed to characterize the physical and mineralogical behavior of the rocks. Uniaxial Compressive Strength (UCS) tests established the strong mechanical heterogeneity for both rocks and form the basis of the proposed mathematical model to predict each's monotonic rock strength. The mathematical model was developed based on the UCS to verify indicator points for subsequent cyclic experiments. Future work includes: (1) application of the mathematical model; (2) determination of wave propagation and attenuation in rocks under cyclic loading; and (3) investigation of coupling between rock damage accumulation and wave propagation. The experimental results are crucial to understand the fatigue process and predict rock behavior over time.

1. INTRODUCTION
In order to liberate minerals in the mining process, blasting is conducted in a measured and controlled manner to expose orebodies for mechanical excavation (Darling, 2011). In mineral projects, the mining methods usually dictate the tools and explosives used to accomplish blasting. The mechanism of blasting breaks the continuum of the rocks for various mining purposes. In the instance of hard rock mining operations, production holes of a specific diameter and depth are drilled according to the mine plan and orientation of the orebody. Explosives used in blasting operations are selected based on several factors including the type and size of the ore zone, rock hardness, and the type of fragmentation required by the processing plant.
Generally, drill and blast activities require the design of a drill plan comprising a boring of specified bedding and spacing for production holes in panels; loading of explosives (priming, stemming, emulsifying); attachment of detonators and delays, and subsequent detonation (manual or electric).
The energy from blast detonation is primarily expended in rock breakage but some of the energy is wasted due to factors such as overcharging. This wasted energy travels from the blast site in the form of ground vibration and airwaves and dissipates in various forms including ground vibration, noise, dust, heat, and noxious gasses – giving rise to some undesirable environmental effects if not mitigated (Gad et al., 2005).
Wellbore Stability Analysis of Wells in Paradox Play in Southeastern Utah: Investigating the Impact of Salt Mobility
Authors: Xing Pengju , McCormack Kevin , Edelman Eric , List Dave , Maxwell Gregor , McLennan John 
Published: August 2024

ABSTRACT:
This study investigated two incidents of pipe sticking that occurred during the drilling of well State 36-2LNW-CC in the Paradox Play in Utah. The study indicates that the pipe sticking could be associated with a combination of several mechanisms, all potentially active to some degree - wellbore breakout/limited caving and kinematic pipe constraint, fault slip, and salt creep. These three failure mechanisms might work together or one of them could dominate the pipe sticking. A more comprehensive analysis of the three mechanisms was conducted for the second stuck-pipe incident. The results show that increasing the mud weight from 13.0 ppg (used during the second stuck-pipe incident) to even 14.0 ppg could mitigate the risk of wellbore failure and stuck pipe. In addition, while back-reaming should be avoided (damage to gauge on PDC cutters), drilling ahead incrementally and pulling back periodically may be advisable in salt/clastic sequences.

1. INTRODUCTION
The Paradox Hydrocarbon Play in southeastern Utah could be among the most significant unconventional plays in the western USA. However, due to the unique geomechanical setting of salt/clastic cycles, it has witnessed several drilling challenges that may impact its future development. These include pipe sticking and well control events due to the high formation pressure in the reservoir. We conducted a comprehensive investigation into certain pipe sticking incidents, such as two stuck-pipe incidents in well State 36-2LNW-CC, using drilling data, wireline logs, and laboratory core test data. Several issues were identified as possible causes including wellbore stability associated with extensive salt interbedding between clastic layers. Multiple primary modes of salt mobility were identified, including creep, fault slippage in either the evaporites or the clastics, and more conventional wellbore instability (breakout or caving), any or all of which could have contributed to pipe sticking.
Understanding these mechanisms, as presented in this study, is crucial in mitigating future drilling challenges and ensuring the efficiency of operations within the Paradox Hydrocarbon Play.
The paper first describes the two stuck-pipe incidents during the drilling of well State 36-2LNW-CC and discusses the possible reasons. Then, a more comprehensive analysis of the three mechanisms (wellbore breakout, fault slip, and creep) was conducted for the second stuck-pipe incident. Finally, recommendations are proposed to mitigate the drilling challenges.
Numerical Evaluation of Mass Transfer Process on Acid Reactive Flow in Carbonate Rocks
Authors: Cunqi Jia , Saif Alkaabi , Kamy Sepehrnoori 
Published: August 2024

ABSTRACT:
Acid stimulation in carbonate rocks represents a quintessential application of reactive flow in subsurface porous media. Unlike chemical reactions that occur in solution, the chemical reactions involved in acid stimulation are essentially heterogeneous reactions. During the reaction process, the acid fluid and the solid matrix are accompanied by the mass transfer of reactants and products. This work is motivated to investigate the effect of the mass transfer process on the acid stimulation process. The two-scale continuum model is employed for capturing mass and momentum transfer, updating rock property parameters and acid fluid transport and reaction process parameters in response to pore structure changes. A comprehensive parametric study is conducted to examine the effect of the mass transfer rate on the acid breakthrough volume. The results show that compared with the influence of velocity and viscosity of the fluid phase, the ratio of surface reaction rate and mass transfer rate of the acid fluid is more sensitive to changes in pore radius and molecular diffusion rate. A smaller breakthrough volume is calculated with consideration of acid mass transfer compared to that calculated without consideration of acid mass transfer and less solid matrix being dissolved.

1. INTRODUCTION
Carbonate reservoirs contain a significant portion of the world oil and gas resources (Fredd and Fogler 1999, Panga, Ziauddin 2005). The complex nature of carbonates, including strong heterogeneity and the presence of fractures and vugs, represent technical challenges (Jia, Huang 2021, Jia, Sepehrnoori 2021). During oil and gas production, eroded particles accumulate near the wellbore and impede flow, thus diminishing the connection between the well and the reservoir and impacting productivity (Jia, Alkaabi 2023, Cunqi, Saif 2023). To combat this, acid is injected into the formation to dissolve carbonate minerals and form wormholes in a process known as matrix acidizing. This process provides higher conductivity pathways between the well and reservoir, bypassing formation damage and stimulating productivity (Dong 2018, Dong, Zhu 2018).
Study on Microscopic Pore-Fracture Structure of Metamorphic Buried Hill Reservoirs
Authors: Wang Xifeng , Huang Shijun , Zhao Fenglan , Liu Xinrong 
Published: August 2024

ABSTRACT:
The reservoir space of metamorphic buried hill reservoirs are complex and the heterogeneity is strong. It is difficult to fully characterize the micro pore and fracture structure of single resolution digital core. In this paper, multi-resolution CT and FIB-SEM scanning were performed on the cores of metamorphic buried hill reservoirs. The image registration method is used to match the core images of different resolutions. The union of pore structure at each resolution is taken to characterize the distribution law of pore and fractures quantitatively. The results showed that multi-scale digital core can more fully reflect the multi-type and multi-scale pore and fracture structure of metamorphic buried hill reservoir; The total porosity of the core is 1.25 %. The fracture is the main storage and seepage space. This method realizes the multi-scale characterization of the microscopic pore and fracture structure of metamorphic buried hill reservoirs, and provides a reference for similar complex reservoir research.

1. INTRODUCTION
A large number of buried hill reservoirs have been recognized worldwide, such as Zeit Bay, Bach Ho, Bozhong 19-6 fields, and so on (Mi et al., 2023; Trice et al., 2022). A buried hill is defined as a hydrocarbon accumulation in younger sedimentary formations in buried hill traps. The lithologies of buried hill reservoirs include metamorphic, igneous, and sedimentary rocks (Han et al., 2020). According to statistics, metamorphic rocks account for 40% of the world's total buried hill reservoirs, and oil and gas reserves account for 75% of the total reserves (Zhang et al., 2023). However, the metamorphic buried hill reservoir has developed fractures, complex spatial structure, and strong heterogeneity (Liu et al., 2020). An accurate understanding of the microstructure of metamorphic buried hill reservoirs is the key to the efficient development of such reservoirs.
The digital core has the unique advantages of non-destructive and three-dimensional characterization, which greatly retains the original characteristics of reservoir pores and fractures, and is an effective means of reservoir microstructure research. However, there is a contradiction between the field of view and the resolution of the digital core (Lin et al., 2019). When the resolution is low, a larger core size can be obtained, but at the same time, some microstructure information will be lost. When the resolution is high, the microscopic characteristics of the core are more refined, but there may be a problem that the representative volume unit (Gitman et al., 2007; Kanit et al., 2003) cannot be obtained. Therefore, it is necessary to integrate multi-scale information to describe the core structure.
An Autoencoder-Based Deep Learning Model for Enhancing Noise Characterization and Microseismic Event Detection in Underground Longwall Coal Mines Using Distributed Acoustic Sensing Monitoring
Authors: Tourei A. , Martin E. R. , Ankamah A. T. , Hole J. A. , Chambers D. J. A. 
Published: August 2024

ABSTRACT:
The longwall mining method is designed to optimize coal extraction through controlled roof caving, which inevitably induces seismicity. This research employs a distributed acoustic sensing (DAS) system incorporating a fire-safe fiber-optic cable strategically installed underground within an operational longwall coal mine. Despite lower sensitivity than traditional seismometers, DAS sensing technology benefits from dense sensor spacing and close proximity to the active face, where many microseismic events occur. To automatically detect seismic events within the voluminous DAS data records, we employ convolutional autoencoder deep learning models that can be used for anomaly (potential seismic event) detection in power spectral density (PSD) images of DAS recordings. The kernel density estimation (KDE) technique is used to calculate the probability density function (PDF) for the density scores of the latent space (representation of compressed data). We then use this calculated parameter as a threshold to distinguish between the PSD associated with background noise and with potential seismic events. The DAS monitoring system in conjunction with the developed deep learning model could enhance longwall coal mining safety and efficiency by offering valuable data from its densely deployed multichannel sensors near mining operations.

1. INTRODUCTION
Longwall mining is an efficient underground mining method for extracting a variety of stratified resources including coal, potash, and soda ash and represents a considerable advancement over conventional methods (Peng, 2019). A modern longwall primarily consists of hydraulic shields that support the roof and floor, a cutting device (e.g., a shearer or plow) that travels along the face extracting slices of coal, and an armored conveyor belt, which transports the resource to a larger mine haulage system. Normally longwall mining is safe and efficient, but a variety of ground control-related hazards are possible, especially in deep mines. One of the most significant of these hazards is a class of dynamic failures associated with induced seismicity and damage to mine workings, generally referred to as coal bursts or mine bumps. Much like tectonic earthquakes, mining-induced seismicity is difficult to predict and can have devastating consequences. For example, over the past several decades, coal bursts have killed hundreds of miners (Zhang et al., 2017).
Parameter Study on Crystalline and Sedimentary Rock for High-Level Radioactive Waste Disposal Considering the Geological Characteristics of the Korean Peninsula
Authors: Cheon D. S. , Park J. Y. , Jin K. W. , Lee H. 
Published: August 2024

ABSTRACT:
The selection of bedrock for deep geological disposal of high-level radioactive waste (HLW) typically depends on the geological characteristics of each country. In Korea, plutonic rock, gneiss, and sedimentary rock constitute 30%, 30%, and 25% of the geological composition, respectively, and the bed rock for deep geological repository has not yet been determined. In this study, 750 m deep drilling was conducted on several rock types. The drilling location was selected in consideration of the tectonic structure and the rock types. Several field tests were conducted using boreholes in granite and sedimentary rocks, as well as laboratory tests using cores. Among various evaluation parameters, uniaxial compressive strength, in-situ stress, hydraulic conductivity, fault development etc. were obtained and compared between granite and sedimentary rock. Through a series of analyses, it was found that in the case of crystalline rocks in Korea, granite from the Mesozoic Jurassic and in the case of sedimentary rocks, Jinju and Jindong formation from the Mesozoic Cretaceous period are likely candidate rock types. However, since it is the result of utilizing a small number of boreholes, it is expected that numerous in-depth investigations and mineralogical analyzes will be required.

1. INTRODUCTION
Korea began site selection for nuclear power plants in 1964, and Gori Unit 1 began commercial operation for the first time in 1978. In 1978, the first year of nuclear power generation, it generated 2,324 GWh, accounting for 7.4% of Korea's total power generation, but in 2022, it generated 176,054 GWh, accounting for 29.6% of the total power generation, playing an important role in Korean industry. However, like any other country that uses nuclear power, the issue of disposal of spent nuclear fuel generated from nuclear power generation is an important task to resolve. Currently, Korea temporarily stores high-level radioactive waste within nuclear power plants.
In December 2021, the government announced the second high-level radioactive waste management master plan and presented basic policies for high-level radioactive waste, facility plans such as site selection, technology development, and investment strategies. A step-by-step site selection procedure was presented to establish a deep disposal facility for high-level radioactive waste, and objectives and major activities for site suitability investigation were presented. According to the 2nd management master plan, site selection is scheduled to be carried out over a period of 13 years after the start of the project (Fig. 1)
An Assessment of Geomechanical Considerations in Thermal Energy Storage Systems Using 3D Coupled Thermo-Hydro-Mechanical Models
Authors: Mutlu U. , Ghassemi A. , Boitnott G. 
Published: August 2024

ABSTRACT:
Thermal Energy Storage (GeoTES) systems are designed to store heated or chilled brine to be produced when needed for power generation or district heating and cooling. High permeability and porosity sedimentary reservoirs have the potential to store large quantities of brine. In this study we present a geomechanics workflow that integrates subsurface data, from a US Texas Gulf Coast field site, with a fully coupled 3D Thermo-Hydro-Mechanical (THM) model. Our geomechanical modeling approach incorporates THM coupled solutions to simulate flow through porous media and heat transfer while considering progressive formation failure. 3D geomechanical model results show that THM loading conditions can lead to progressive damage around the wellbore and mechanical/flow alteration. Results also suggest that operational parameters can be optimized to minimize these alterations with direct implications to flow channeling and fines migration. Furthermore, preliminary Thermo-Hydro-Chemical (THC) simulations explore the scaling potential of the same thermal storage system using brine chemistry from offset wells. In the model, brine with measured concentrations of the major chemical constituents from the nearby well is heated and cooled (under pressure) to simulate injection of the brine under temperature and pressure. The relative changes in concentrations of various minerals, quantified from THC models, suggest that chemistry can play a significant role in thermal storage systems.

1. INTRODUCTION
Solar and wind power are key in our transition to a net-zero carbon future. While abundant and cost-competitive, they are variable, intermittent and their energy supply not always optimized to meet demand needs. For example, the shift to a clean, efficient, and modern grid is essential to California's economy and its environment. This transition to a low-carbon grid provides challenges and opportunities, as the state incorporates increasing amounts of renewable energy into the electric system.
When renewable resources generate more electricity than is needed, markets automatically reduce the production of energy from renewable resources, or "curtail" generation. While curtailment is an acceptable operational tool, as increasing amounts of renewable resources, oversupply conditions are expected to occur more often. System Operators are seeking solutions to avoid or reduce the amount of curtailment of renewable power to maximize the use of clean energy sources.