bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimation of sharp geometric inequality in \(D_{\alpha}\)-homothetically deformed Kenmotsu manifolds
Authors: Siddiqi Mohd Danish , Naaz Siddiqui Aliya , Hakami Ali H. , Hasan M. 
Published: November 2023

In this article, we investigate the Kenmotsu manifold when applied to a \(D_{\alpha}\)-homothetic deformation. Then, given a submanifold in a \(D_{\alpha}\)-homothetically deformed Kenmotsu manifold, we derive the generalized Wintgen inequality. Additionally, we find this inequality for submanifolds such as slant, invariant, and anti-invariant in the same ambient space.
Coupling Fluid Flow and Geomechanical Deformation Using AI & FEM Approaches
Authors: Hamid Osman , Almani Tameem , Qannas Sulaiman , Alshanbari Ghalia 
Published: November 2023

Abstract
Coupling fluid flow and geomechanical deformation is a complex and challenging problem in geomechanics and reservoir engineering. The objective of this study is to develop a robust and accurate numerical model for coupling fluid flow and geomechanical deformation using machine learning (ML) and artificial intelligence (AI) techniques in combination with elastoplastic and finite element method (FEM) approaches.
The study involves developing an elastoplastic model to simulate the deformation of geologic materials under stress and incorporating fluid flow equations into the model using FEM techniques. The two simulators are coupled sequentially. During every sequential coupling step, the flow simulator sends pore pressures to the geomechanics simulator and receives back updated porosity and permeability values. The frequency of the coupling steps is problem-dependent and subject to further optimization and research. In addition, ML and AI techniques are used to reduce the frequency of the coupling steps, which can lead to substantial computational time savings given the fact that solving the geomechanical model numerically is a computationally intensive task. Furthermore, ML and IA techniques can also be used to optimize the input parameters, improve the accuracy of the model, and reduce overall runtime. The AI-based coupled model is tested against the traditional coupled model to validate the results.
The study demonstrates that coupling fluid flow and geomechanical deformation using ML and AI elastoplastic and FEM approaches is a promising area of research that can revolutionize our understanding of complex geological processes. The AI-based numerical model developed in this study provides an efficient and accurate tool for predicting the behavior of geologic materials under stress and can aid in developing more effective strategies for managing natural resources.
The use of ML and AI techniques in combination with elastoplastic and FEM approaches provides an innovative and efficient method for coupling fluid flow and geomechanical deformation. The AI-based numerical model developed in this study is a significant contribution to the field of geomechanics. It has potential applications in various industries, including oil and gas exploration, mining, and geothermal energy.
Sensitivity of Impurities to CO2 Flow in Injection Wells
Authors: Leontidis V. , Voronetska K. 
Published: November 2023

Abstract
The design and the long-term success of carbon injection and storage operations strongly depends on predicting the behavior of CO2 fluids, pure or mixtures. This work presents the impact of different impurities (CH4, CO, N2, O2, Ar, H2, H2S, H2O) in the hydrodynamic and the thermophysical behavior of CO2-rich mixtures in an injection well. A unified in-house well flow simulator (GWellFM), which is based on solving the momentum and the enthalpy balances and integrates the GERG-2008 Equation-of-State for pressure-enthalpy tracking, is applied to model the injection process under different conditions. The objective is to capture the impact of the impurities in the injection scenario in a typical offshore high-pressure reservoir with respect to the compression demands and the behavior of the fluid. Injecting fluids with the standard composition and the typical flow rate results in a slight increase of the wellhead pressure when compared to CO2-only injection. The higher the flow rate, the higher is the injection pressure and the lower bottom-well fluid temperature. On the other hand, increasing the injection temperature demands more pressure and the fluid remains hotter close to the bottom. Transient calculations showed that the initial large difference between the wellbore temperature and the hosting formation at the bottom of the well decreases rapidly with the injection pressure following the same reduction increasing the risk of phase change. Among the binary mixtures tested the presence of H2 and CH4 had the more severe influence causing a significant increase in the compression demands, and H2S the less. H2O or H2 is more likely to cause the appearance of a second phase in the range of conditions tested. Replacing part of other impurities with H2S in multicomponent CO2-rich mixtures could reduce the wellhead pressure in comparison to the initial mixture with the same concentration of CO2.
A New Quick Look Interpretation for Fluid Detection: Theory and Application
Authors: Farfour Mohammed , Foster Douglas J. , Gaci Said 
Published: November 2023

Abstract
Numerous methods for fluid analysis and detection are routinely used in formation evaluation and reservoir characterization at well location. These methods are commonly called Quick Look Interpretation (QLI) methods. Examples of these methods include: Rx0/Rt, Apparent water resistivity (Rwa), Conductivity-derived porosity, and wet resistivity method. The QLI requires a number of logs such as resistivity, sonic, and density. All these logs are commonly used in Geo-mechanics to detect normal trends and deviations from them to predict pore pressure and detect over-pressured zones.
This study aims to introduce a new QL method that uses the density’s trend and variation that can be attributed to fluid or to overpressure zones. An apparent fluid density is proposed and computed from the porosity logs assuming the only fluid in the logged intervals is water. The resulting apparent fluid density log is then compared with the recorded density. Large deviations between the apparent and recorded density are interpreted to be due to fluid or to overpressure zones.
As an application, the new QLI method is tested on real data from North Western Australia. Three wells penetrating gas-sand reservoir are selected for the test. Results obtained from the wells inferred that reservoir intervals are clearly identified by clear deviations. Pressure data collected at the wells showed that the deviation from the normal density trend are from fluid and not overpressure.
Study on Time-Varying Characteristics and Rockburst Prediction of Acoustic Emission of a Granite With Initial Temperature Damage
Authors: Li Dejian , Li Chunxiao , Zhao Pengcheng , Li Zeyang 
Published: November 2023

Abstract
To reveal the impact mechanism of initial temperature damage on the rockburst precursor characteristics, firstly, the true triaxial strainburst experiments were conducted on granite with different initial temperature damage. Secondly, based on the time series of acoustic emission signals, the time-varying response characteristics of entropy value, b-value and multifractal spectra width Δα of acoustic emission were analyzed to establish a prediction index of rockburst. Finally, the rockburst prediction effects of three methods for granite with initial temperature damage were evaluated. The results indicated that during the axial stress loading to rockburst, the time-varying response turning point of b-value from stability to gradual decreasing, the entropy value and Δα for a mode of “fluctuation→gradual increasing” can be regarded as the prediction point of rockburst. By establishing a proportional coefficient between the precursor stress and peak stress of rockburst, the rockburst prediction effects of three characterization methods for the acoustic emission time-varying signals were obtained as follows: Δα &gt; b-value &gt; entropy value. Moreover, it was concluded that when the initial damaging temperature reaches 400 ℃, the rockburst suddenness of granite sample is stronger, which is more difficult for the three characterization methods to predict rockburst.
The Role of Geomechanics on Hydrogen Extraction
Authors: Hamid Osman , Alsudairi Nora 
Published: November 2023

Abstract
The role of geomechanics in hydrogen extraction processes is crucial for understanding the behavior of subsurface formations and optimizing extraction techniques. This paper focuses on the modeling and rock testing aspects of geomechanics to investigate the influence of rock properties on hydrogen extraction efficiency and safety. The objective of this study is to explore the role of geomechanical modeling and rock testing in assessing reservoir behavior, wellbore stability, and storage integrity for hydrogen extraction projects. The methodology involves a comprehensive analysis of geomechanical modeling techniques and laboratory rock testing methods. Geomechanical modeling techniques, such as finite element analysis and discrete element modeling, provide valuable insights into the behavior of subsurface formations under different stress and fluid flow conditions. These models can simulate the mechanical response of the reservoir during hydrogen extraction, enabling the prediction of deformations, stress distributions, and potential failure mechanisms. The results highlight the significance of geomechanical modeling and rock testing in assessing the behavior of subsurface formations during hydrogen extraction. Geomechanical models help identify potential geomechanical risks, such as fault reactivation, induced seismicity, and wellbore instability, allowing operators to design optimal extraction strategies and implement appropriate mitigation measures. Rock testing provides crucial input parameters for accurate modeling and enhances the understanding of rock behavior, contributing to the assessment of reservoir performance and storage integrity. The conclusion drawn from this study is that geomechanical modeling and rock testing are essential tools for assessing the role of geomechanics in hydrogen extraction. By integrating these approaches, operators can gain valuable insights into the mechanical behavior of subsurface formations, optimize extraction techniques, and ensure the safe and efficient operation of hydrogen extraction projects. The innovation of this study lies in highlighting the importance of geomechanical modeling and rock testing in the context of hydrogen extraction. By incorporating these approaches, operators can make informed decisions regarding reservoir behavior, wellbore stability, and storage integrity, leading to enhanced operational efficiency and safety.
Reinforcing Cemented Paste Backfill With Basalt Fiber: A Path Towards Sustainable Practice in Mine Backfilling
Authors: Hefni Mohammed 
Published: November 2023

Abstract
Cemented paste backfill (CPB) is a mixture of mine tailings, hydraulic binder, water, and other additives. CPB is used to backfill underground cavities created during ore extraction, reducing tailings exposure to the environment. However, the consumption of cement in CPB not only increases the operational cost of CPB but also runs counter sustainable mining practices. This prompted scholars to seek environmentally friendly alternatives without compromising CPB properties. Therefore, this experimental study was conducted to investigate the effect of utilizing basalt fiber (BF) as a sustainable material in CPB applications. CPB samples were prepared with different dosages of BF (0.5%, 0.75%, and 1%) using two different fiber lengths (12-mm and 18-mm). CPB samples were tested for unconfined compressive strength (UCS) after 7, 14, and 28 days of curing. The findings show that BF can improve UCS by up to 35% compared to the reference mixture. This potential alternative offers a sustainable solution to mitigate the negative impacts associated with cement use in CPB applications.
High Temperature Influence in Pore Pressure Prediction – Case Study in Offshore Malaysia
Authors: Kamaruddin Nik M Fadhlan Nik , Ern Kevin Teng Ging 
Published: November 2023

Abstract
Pore pressure studies are key components for well design engineering and economics consideration to safely reach deep petroleum resources. However, in deeper reservoirs, additional geological processes are favorable for secondary overpressure mechanisms which may lead to uncertainty in pore pressure prediction. Analyses conducted are interpreted together with petrophysical, stress and pressure plots such as depth-based velocity-density, porosity-effective vertical stress, field data (formation and temperature) and observations (stress and pressure measurements). The results show the highest uncertainties in predictions versus actual measurements are often observed at 80 to 140 degree Celsius. This temperature range is often related to less predictable fluid properties and pressure due to probable complex geological processes such as hydrocarbon generation, diagenesis, metagenesis, chemical compaction and alteration. For each temperature range, the estimation errors are plotted and assessed based on field observations. The paper highlights the differences between estimation of pore pressure and actual measurements at a range of temperatures and the evaluation of uncertainties associated with temperature in pore pressure prediction. The origins of overpressure and associated geological processes are important in providing thorough and improved understanding on the effects of temperature and the pore pressure prediction reliability. The paper presents an improved methodology and workflow in pore pressure prediction coupled with petrophysical analysis for range of temperatures which provides additional insights for timely decision making. It also aims to encourage the community and industry to consider the replication and potentially improving the workflow for determining uncertainty and increasing understanding in pore pressure prediction at elevated temperatures.
Fracture Propagation-Rate and Fracture Half-Length Estimated for an Individual Fracturing Stage Using Dynamic Balancing of Fluid Pressures: Eagle Ford Case Study
Authors: Oshaish Ali , Weijermars Ruud 
Published: November 2023

Abstract
This study presents a new analytical model for determining the growth-rate of hydraulic fractures during the pumping of a fracturing stage. Unlike existing commercial and numerical tools for final fracture half-length estimation, the present model is able to accommodate time-dependent parameters used in actual field operations and shows how this controls the stepwise evolution of fracture half-length over the duration of the stage treatment. The model analyzes the pressure gains and losses across the well system during the fracturing treatment operation, which solves for the Sneddon pressure used subsequently to estimate the extent and rate of the hydraulic fracture growth from the perforation clusters outward until the ultimate half-length is established. Using a practical spreadsheet template, the pressure balance model accounts for all the pressure gains and losses occurring during a typical hydraulic fracturing job. The model revealed practical results and reasonable values for the fracture half-length, in close agreement with independent estimations of fracture half-length for the same Eagle Ford well. The average propagation rate of a planar fracture, with an elliptical cross-section (in map view) of 1.8 mm width for the minor axis and fixed height of 100 ft, is 1.54 ft/min (0.026 ft/s), with high and low rates ranging between 2.81 and 0.220 ft/min. The final hydraulic fracture half-length at the end of the fracturing job was 212 ft. However, the effectively propped fracture half-length determined in independent studies using production analysis is somewhat smaller (144 ft), which indicates that the tip-end of the final fracture (212-144 ft= 68 ft) was not effectively propped, and effectively closed after the treatment.
Optimization of Perforation Parameters for Shale Gas Horizontal Wells in Weiyuan Block, Sichuan Basin
Authors: Yang Yadong , Wang Yixuan , Deng Cai , Gu Mingzhe , Huang Liuke , Sheng Mao , Ren Lejia 
Published: November 2023

Abstract
Horizontal well multi-cluster fracturing has been recognized as an effective technology to extract shale gas resources. This paper proposed a full 3D model of multi-cluster fractures propagation with perforation tunnels by using 3D lattice method. The oriented perforation and spiral perforation modes were compared to understand their distinct of multiple fractures initiation and propagation. The particular conditions of Weiyuan shale gas block and the strike-slip fault were taken account. The uniformity of fractures propagation and their impacting factors were analyzed. Results demonstrated that the oriented perforation promotes plannar fractures with less twist but the number of perforation tunnels is relatively small with big perforation friction comparing to the spiral perforation. The case study takes the optimized combination of engineering parameters to achieve the uniform propagation with the pumping rate for single cluster of above 2m³/min, perforation density of 6 per foot, and the cluster spacing of over 10m. This work provides a modeling workflow to consider the perforation tunnels and the optimized parameters for uniform hydraulic fracturing.
An Assessment of Wellbore Integrity During the Planned Injection of CO2 Within a Depleted Reservoir Through Numerical Analyses
Authors: Adisornsupawat K. , Press D. J. , Fischer K. , Tan C. P. 
Published: November 2023

Abstract
Geomechanics workflows are being increasingly utilized within the industry to assess the risks associated with oil and gas recovery during depletion, including well integrity issues due to reservoir compaction and possible fault reactivation as reservoir pressures decline over the lifecycle of the field. However, little work has been conducted on the feasibility of utilizing existing production wells for the safe injection of CO2 as part of a carbon capture and storage (CCS) project.
Field-wide 3D analyses conducted to date have taken a macroscopic view in terms of reservoir performance, but little work has been conducted at the wellbore centric scale. For the cases where a depleted field is being considered for long-term CO2 containment, it is vital that the effects of temperature are included in the reservoir flow model. Injected CO2 can be many hundreds of degrees cooler than the in-situ reservoir rock formations and exposure to these cooler temperatures will induce sudden deformations in the vicinity of the injector well. As the temperature front progresses into the reservoir, cap-rock integrity may be breached due to reductions in effective stress, in addition to the possible creation of tensile fractures. The resulting stress changes due to thermal diffusion may also have a significant effect on the wellbore architecture itself, as the cooling formation will exert tensile strains on the wellbore casing and surrounding cement.
This study examines the effects of injecting cool CO2 into a relatively deep, thermally active reservoir, on the wellbore architecture and whether the induced strains in the reservoir formation arising from both increases in pressure and reductions in temperature can be safely withstood.
Study on Tensile Properties of Siliceous Cemented Sandstone Under Different Water-Bearing States
Authors: Luo Zuo-sen , Zhu Zuo-xiang , Deng Hua-feng 
Published: November 2023

Abstract
This paper investigates the degradation of tensile strength of rock under water-rock interaction. To achieve the research objectives, siliceous cemented sandstones with accretionary and sedimentary characteristics were collected from the Three Gorges Reservoir area. Uniaxial compression, Brazilian splitting tests, and cross-sectional scanning electron microscopy were conducted. The test results underwent qualitative and quantitative analyses. Additionally, a numerical model was developed using the discrete element method, specifically employing the soft-hard double contact PBM model. The impact of water on tensile strength of rock was examined based on both numerical and experimental findings. Research findings: (1) The tensile strength of sandstone decreases as the water content increases. From dry to saturated conditions, the water content increases by 2.01%, resulting in a 49.93% decrease in tensile strength. (2) Increasing water content leads to changes in sandstone microstructure, dissolution of water-soluble minerals, and gradual expansion of microspores and fractures. Sedimentary cementation is more prone to softening in water than accelerated cementation. (3) The error between PFC2D simulation and laboratory test results is less than 5%, confirming the accuracy of the soft-hard double contact PBM model. (4) Under dry, natural, and water-saturated conditions, the numerical sample exhibits a decrease in the ratio of hard and soft contact fractures, an increase in the ratio of shear and tensile cracks, loosening of bonds, and a decrease in overall bearing capacity. These findings provide a foundation for analyzing the degradation mechanism of tensile properties of rock under water-bearing conditions.
Modeling Squirt Dispersion and Attenuation of Ultrasonic in Fluid-Saturated Rocks at the Core Scale
Authors: Chen Yiwei , Dong Pingchuan 
Published: November 2023

Abstract
Modeling dispersion and attenuation of ultrasonic wave in fluid-saturated rocks at core scale, the effect of the local flow of the pore fluid induced by the passing wave can’t be neglected. The squirt-flow mechanism between pores of different shapes and orientations should be considered in the ultrasonic simulation of the pore structure. A core scale modeling method for velocity dispersion and attenuation of saturated carbonate at laboratory frequencies is developed based on the ultrasonic pulse transmission method, can be used to simulate the effect of the different pore structure on velocity dispersion and attenuation of core samples. The elastic moduli matrix of stress-strain function of rock contain stiff pores and compliant pores are described by the squirt flow model and the velocity dispersion and attenuation are calculated by waveform of two piezoelectric transducers. Then, the methods of obtaining the parameters in the model are introduced. For the validation, we consider several models consisting of different pore space embedded in an elastic solid grain material, it shows our model considering squirt-flow is in good agreement with the results of petrophysical experiments.
GELİBOLULU MUSTAFA ÂLÎ’NİN MUHYİDDİN MEHMED-İ DÂGÎ MENÂKIBI
Authors: AKSOYAK İ. Hakkı 
Published: November 2023

Menakıpnameler Osmanlı edebiyatının özgün türlerinden biridir. Bu yayınla gelibolulu Mustafa Âlî tarafından derlenen Muhyiddin Mehmed-i Dâgî menâkıbı latinize edilip özeti verilmektedir. Nüshası hakkında British Museum’da Or. 96791; British Museum Or.1279 numaralı kayıtlar verilmektedir. Elimizde metnin geç istinsah edilmiş kopyası bulunmaktadır
Mehmed-i Dâgî Menâkıbı iki yönden önemlidir. İlki, Gelibolulu Mustafa Âlî gibi bürokrat ve entelektüel kimliğe sahip birinin derlemesidir. İkincisi de bir yöreye ait bir evliyanın eserinin okura ulaşmasıdır.
Dâî Mehmet Efendi başka tarikatlar içinde de yer alabilmiş halvetî şeyhidir. Evliya Çelebi ve Atayî de bu şeyhe özel önem vermişlerdir. Hatta evliya Çelebi ziyaretince bulunmuştur. Gelibolulu Mustafa Âlî de Geliboluya uzun bir aradan sonra döndüğünde bu menakıbı derler. Menakıpnamede konuşma üslubu hakimdir. Zaman zaman yöresel kelimelere de yer verilir.
Bu çalışma ile Mehmed Dâî Menakıbnamesi latinize edildikten sonra tasavvufî kelimelerin anlamları dipnotlarla verilmiştir.