bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the Method of Obtaining Formation Rock Mechanical Parameters by Group Cuttings Method
Authors: Xindong Wang , Lian Chen , Ershuai Li , Xin Zhang , Xinhao Sun , Yuanlin Cao , Zihua Su , Maojiang Ye
Published: November 2022

In drilling engineering, the mechanical properties of formation rocks are essential basic geological parameters. One of the most important tasks at the drilling site is to grasp the mechanical properties of the formation rocks timely and accurately. We take the readily available cuttings on site as the research object to test the compression characteristics. The experiment shows that the compressive stress of group cuttings with the uniaxial compressive strength of rock has an obvious correlation. The relationship model between compressive stress of cuttings compressed to 105% of original rock density and uniaxial compressive strength of original rock is established, and the results conform to an exponential function. When cuttings with different particle sizes (2-10 mm) are used, the coefficient values before the exponential term of the model are stable and the same, only the coefficient of the model is slightly different. The Group cuttings method can reduce or eliminate the disadvantages of discrete experimental results caused by a single cutting defect and individual differences. The new method takes cuttings returned from the drilling site as the test object, which is convenient and quick and can provide a way for the site to obtain the rock mechanics parameters of the drilled formation timely and accurately.

Introduction

Rock mechanics plays a significant role in the petroleum industry, especially in oil & gas drilling and development projects. The study of rock mechanics aims to know the geological engineering parameters such as rock mechanics properties of the reservoir, understand and master the change law of rock mechanics properties, and apply this law to drilling engineering (Qin, 2014). The work includes formation rock drillability analysis, reasonable bit selection, drilling parameter optimization, and wellbore stability analysis. It is one of the most critical tasks to grasp the mechanical properties of formation rocks in time and accurately (Lin, 2014).
Theoretical and Experimental Comparison Study of Weak Point Shape Effect on Openhole Fracturing Pressure
Authors: AlTammar Murtadha J. , Alruwaili Khalid M. , Aidagulov Gallyam , Al-Dakheel Hussain K. , Gwaba Devon , Abbad Mustapha
Published: November 2022

Placing weak point(s) within the well’s stimulated section can reduce fracture initiation pressure (FIP) and thus stimulate the intervals, which otherwise could not be broken down within the pressure limits of completion and pumping equipment. In this work, two essential weak point shapes applicable to the openhole environment were considered: 360° (or circular) notches and perforation holes. The former included blunt (U) and sharp (V) notches, while the latter were represented by single and triple in-plane perforation holes. Triple holes were 120°-phased and, similarly to notches, penetrated the rock within a single plane perpendicular to the wellbore. With a focus on an openhole wellbore parallel to the minimal far-field stress, these weak points were compared by their ability to initiate transverse fracture and reduce fracturing pressure. First, FIP and initiated fracture orientations were simulated using the theoretical model, based on 3D elastic stress analysis and non-local rock fracture criterion. Second, performance of each weak point was tested in a series of large-scale true-triaxial hydraulic fracturing experiments on cement blocks, where boreholes and weak points were casted precisely to the given shape and dimensions. Conducted lab experiments confirmed the theoretically predicted superiority of notches over holes in reducing fracturing pressure.

Introduction

In certain geomechanical settings of today’s increasingly complex tight reservoirs, initiating hydraulic fractures within the pressure limits of the completion and pumping equipment becomes a challenge (Oparin et al., 2016). Placing weak point(s) within the well’s stimulated section can address this high breakdown pressure issue and reduce the number of failed fracturing stages. In the context of multistage openhole fracturing (Bin Asif et al., 2021), circular notches were proposed as such weak points to control the number and location of initiated fractures (Bartko et al., 2016; Chang et al., 2014); and to reduce fracture initiation pressure (FIP) (Aidagulov et al., 2021).
Geomechanical Modelling of Salt Caverns under Operational Loading from Hydrogen Storage
Authors: Speirs D. C. D. , Bere A. , Roberts D.
Published: November 2022

The anticipated prevalence of salt caverns for hydrogen storage makes it increasingly important to establish good numerical modelling techniques to simulate cavern behaviour. This involves many modelling aspects to be addressed including a proper representation of the particular material characteristics of salt and a recognition of the importance of cavern geometry. In this paper we demonstrate a 3-D finite element modelling methodology for simulating salt caverns under the type of cyclic loading expected from seasonal hydrogen production and retrieval. 3-D modelling offers the possibility to represent more complex cavern geometry than is usually represented in such work. The simulations represent generic scenarios but are used to investigate the effect of cavern geometry and variations in model size and boundary conditions. We make use of the recent constitutive model advanced by Reedlunn et al., 2022 which includes an allowance for pressure solution effects contributing to creep, and show that this can have a significant effect on cavern closure.

Introduction

Hydrogen is widely expected to play a major part in the migration away from a carbon-based energy economy and demand for high volume storage solutions is likely to grow considerably in the near future. The use of salt caverns is among the storage methods attracting the most attention.

Salt caverns are subterranean voids in domal or bedded salt formations, usually created artificially by a process of leaching. They are well suited for hydrogen storage because they can offer large capacity, rapid injection/withdrawal rates, safety advantages and long term cost effectiveness. In addition the technology is proven – such caverns being widely used over many years for the storage of other substances and more recently in limited numbers for hydrogen.
Analysis of Re-Fracturing Effect of Horizontal Wells in Jimsar Shale Oil Field
Authors: Zhao Kun , Lu Linmao , He Yongqing , Li Zeyang , Ren Guangcong , Ma Xinfang , Duan Guifu
Published: November 2022

As the low permeability and porosity, some severe problems including rapid production decline and low recovery ratio usually occur in Jimsar Shale Oil Field. Re-fracturing of horizontal wells is a good treatment to improve oil production and recovery ratio by enlarging the contact area between the wellbore and reservoir. Therefore, the field tests of horizontal well re-fracturing were carried out in Jimsar shale oil reservoir. However, it varied in effect. In this paper, based on the engineering parameters of primary fracturing, a fuzzy evaluation model was established firstly to quantify the potentiality of candidate horizontal wells for re-fracturing. For the test wells, a production history match was completed using reservoir numerical simulation method and the oil saturation before re-fracturing was obtained. By comparing the location of high-saturation area and new perforation, rationality of re-fracturing stages selection is determined. Finally, comprehensively using fracturing pressure and microseismic data, the initiation and propagation areas re-fractured was obtained, which showed the location of new fractures. Above all, the reason for poor re-fracturing effect is analyzed. The results show that quantitative index of each test well ranks low among the candidate wells, which means the test wells have the low potentiality to be re-fractured. For the test wells, numerical simulation results show that new perforations of re-fracturing are not located in high-oil-saturation area. The fracturing pressure of re-fracturing stages is generally smaller than primary fracturing, and the microseismic event locates in highly depleted area, which means large quantities of fluid flow into primary fractures and few new fractures are created during re-fracturing.
Toward Understanding Capillary Residual Entrapment of Hydrogen and Carbon-dioxide in Reservoir Rocks for Underground Gas Storage
Authors: Bawazeer Saleh A.
Published: November 2022

Underground hydrogen storage and carbon dioxide capture and sequestration in geological formations present a prominent solution for a low carbon economy. One of the main trapping mechanisms of the injected gas is the capillary residual entrapment controlled by the wettability characteristics of the reservoir rock. In the literature, there is a scarce of information about the influence of key parameters such as pressure, temperature, and organic content on the storage security. The present work discusses a fundamental capillary-based analysis using Laplace and Young equations to understand the interfacial characteristics of the gas–brine- rock system using experimental contact angle measurements of quartz and calcite samples conducted over a wide range of pressures (5, 10, 15, and 20 MPa) and temperatures (308°K, 323°K, and 343°K) using relevant reservoir brine. The analysis was carried out using typical pore throat radii (1μm) at the up-mentioned reservoir conditions. Furthermore, a correlation for the gas column height as a function of the reservoir pressure and temperature are developed. These results help for better understanding the reservoir efficiency for secure storage of H2 and CO2.

Introduction

Geo-storage technologies have been suggested as a method to store and withdraw large quantities of H2 and CO2. The geologic formation is one of the options that provide a large storage capacity. Structural trapping is the primary mechanism that holds H2 and CO2 in the subsurface geologic formations. The structural trapping is affected greatly by the capillary forces and the pore radius of the formation rocks. The capillary forces, in their turn, depend on the pressure and temperature of the subsurface geologic formations. Therefore, it is vital to assess the effect of these parameters on the storage capacity of H2 and CO2 via structural trapping under given geothermal conditions. Quartz and calcite rocks are among the most common rocks in underground formations. Hence, they are considered in the present study. This work would help in economical industrial-scale prediction of underground storage in the considered rock formations.
Prediction of Borehole Caliper Log Using Machine Learning for Multi-Stage Frac Completions
Authors: AlTammar Murtadha J. , Khan Khaqan , Alfaraj Rima T. , Altwaijri Mohammad H. , Alruwaili Khalid M. , Almarri Misfer J.
Published: November 2022

The objective of this paper is to highlight a new machine learning application to predict a synthetic caliper log using other available Logging While Drilling (LWD) well logs. LWD logs and wireline (WL) mechanical caliper logs for 17 tight gas wells, with more than 120,000 depth data points, were used to train a machine learning model. LWD logs included gamma ray, sonic, density, azimuthal density, porosity, photoelectric log, and mineralogy. The LWD logs were used as main input parameters in the model together with the maximum hole dimeter (Cmax) from wireline data. The model output being the synthetic maximum borehole diameter (Cmax_P) was compared with the measured caliper log. The model was trained with various machine learning algorithms including ensemble algorithms such as XGBoost and recurrent neural network (RNN). In the training process, Leave-One-Out method was implemented where 16 wells were used for training to predict the maximum borehole diameter in the remaining blind well. The results of current dataset showed good prediction accuracy with an average absolute percentage error of less than 6%. In addition, we demonstrated incorporating a physical feature related to geological layering by training the RNN with a window of multiple depth points, which clearly resulted in a predicted caliper curve that was significantly less noisy and had closer characteristics to the measured caliper curve.

Introduction

In multi-stage fracturing well completions, running a wireline mechanical caliper log is critical to obtain reliable measurements of borehole geometry along the lateral to identity packers’ placement depth for achieving adequate zonal isolation between successive fracturing stages. However, in many instances, wireline caliper logs cannot be run due to borehole conditions and drilling challenges. In such cases, various logging-while-drilling (LWD) well logs could be utilized to derive a synthetic caliper log.
Application of Machine Learning for Real-Time Prediction of Sonic Well Logs Using Surface Drilling Parameters and Gamma Ray
Authors: Alfaraj Rima T. , AlTammar Murtadha J. , Hamid Osman
Published: November 2022

The objective of this study is to utilize drilling parameters and gamma-ray (GR) well logs to predict compressional and shear sonic logs while drilling using machine learning techniques. Surface drilling parameters and various wellbore logs of 10 horizontal gas wells were used in this study to train the machine learning model. The drilling parameters include the rate of penetration (ROP), weight on bit (WOB), drillpipe rotation (RPM), torque (T), standpipe pressure (SPP), and mud flowrate (GPM). Petrophysical logs included GR, compressional wave slowness (DTCO), and shear wave slowness (DTSM). GR and drilling parameters were used as inputs in the model, with the model output being DTCO and DTSM. The model was trained with the XGBoost algorithm, and the prediction results on two blind wells showed an average absolute percentage error of less than 10%. Utilizing drilling parameters to predict well logs could have a significant business impact. This study demonstrates the application of machine learning for log prediction using drilling parameters in deep, long horizontal gas wells.

Introduction

Accurate determining rock mechanical and petrophysical properties is crucial in mitigating drilling risks and optimizing well productivity. Compressional and shear sonic travel time logs are critical rock petrophysical parameters, especially when it comes to formation evaluation and rock characterization for geophysical applications to predict rock elastic properties (Hossain et al., 2010; Wollner et al., 2017). Poor prediction of sonic log parameters may lead to improper estimation of rock elastic parameters resulting in severe consequences in investment decisions (Potter & Foltinek, 1997).
Hydrogen Wettability Measurement of Saudi Basaltic Rocks at Underground Storage Conditions
Authors: Alanazi Amer , Al Malallah Murtadha , Mowafi Mahmoud , Badeghaish Wael , Hoteit Hussein , Al-Yaseri Ahmed , Al-Hamad Jafar
Published: November 2022

Underground hydrogen (H2) storage is a prominent technique for enabling H2-based economy via offering a large-scale storage medium. Recently, volcanic basaltic formations have been investigated as a potential medium for gas storage due to their thickness, vast extension, and potential volumetric capacity. Wettability is one of the essential parameters studied to understand the capillary-entrapment of the stored gas in porous media. Therefore, in this study, we evaluate the wettability of rock/H2/brine system of two different saudi basaltic rock samples by measuring the contact angles using relevant reservoir brine (10% NaCl) under storage conditions at temperature of 323K and varying pressures (3 to 28 MPa). The measurements were conducted using the modified sessile drop method and surface roughness was determined to ensure accurate results. The results showed relatively low variation with pressure. Saud basalt-1 with higher Si-O-Si and hydroxyl group bondings from FTIR demonstrated better sealing conditions for H2 storage than Saudi basalt-2. Additionally, the pore throat radius has a proportional relationship with 𝑝𝑐𝑒 and ℎ𝑔𝑚𝑎𝑥. Smaller pore-size basaltic rocks are better for safe and secure storage, and a potential effective capillary entrapment of H2.

Introduction

Governments and countries worldwide are adapting strict environmental regulations to reduce harmful anthropogenic emissions of greenhouse gases such as carbon dioxide (CO2), attributed mainly to the burning of fossil fuels (Hashemi et al., 2021; IEA, 2018). Alternatively, hydrogen (H2) emerges as a promising clean fuel to support decarbonization by converting energy production from fossil fuels into a more environmental-friendly form and supporting clean energy from renewable resources such as wind turbines and solar power (Pan et al., 2021). However, wide-scale implementation of an H2-based economy requires a medium of Giga to Tera scale storage capacity, which can be theoretically offered by geological formations such as saline aquifers, depleted oil and gas reservoirs, and salt caverns (Heinemann et al., 2021).
Feasibility Evaluation of Hydraulic Fracture Penetrating Propagation in Sand-Mud Interlayer Reservoirs under Different Combinations of Fracturing Parameters
Authors: Wu Guangai , Tao Lei , Jiang Hu , Guo Xu , Zhang Anshun , Tang Xuanhe , Zhu Haiyan
Published: November 2022

Low-porosity, extra-low-permeability tight sandstone oil and gas reservoirs have become an important research area for hydraulic fracturing. Sand-mud interlayer is often developed in this type of reservoir in the longitudinal direction. The heterogeneous distribution of oil layers and mud shale barrier layers in the longitudinal direction will lead to restrict propagation of hydraulic fractures in the fracture height direction, which affects the effective stimulated reservoir volume significantly. In this paper, a finite element model of hydraulic fracture propagation in sand-mud interlayer was established based on the real characteristics of the target block formation to study the hydraulic fracture penetrating propagation feasibility under different combinations of fracturing parameters in the tight sandstone reservoir in the target block, and the model verification was completed with the field data. A total of three types of variable orthogonal combinations of 7 kinds of viscosities of fracturing fluid, 5 kinds of injection rate and 8 kinds of thicknesses of barrier layer were carried out to explore the penetration feasibility of hydraulic fracture under the commonly used combination of low injection flow rate and high viscosity in offshore and high injection flow rate and low viscosity in onshore shale gas reservoirs. And the feasibility evaluation plate of the hydraulic fracture penetration propagation in sand-mud interlayer is established. The method for evaluating the feasibility of hydraulic fracture penetrating propagation in sand-mud Interlayer under different combinations of fracturing parameters can be well applied to the tight sandstone reservoir in this paper. And it will provide theoretical guidance for hydraulic fracture design and fracturing parameter optimization. In addition, the method can also be applied to the fracturing development of shale reservoirs with sand-mud interlayers.
Compaction and Subsidence Geomechanics: A Case Study from the North Sea
Authors: Green S. , Hickman R. J. , Cox P.
Published: November 2022

We present a case study for the assessment of depletion of the Blythe Field in the Southern North Sea and the potential impact on the overlying Dudgeon windfarm, including an analytical solution, and make comparisons with the well-studied analogue Groningen Field before presenting the results. The key focus of this analysis was to aid in the assessment of how oil and gas activities could co-exist with other operations in the same location, namely the impact between infrastructures at the surface and in the sub-surface. The results of the study, and the validation via the comparison to the analogue Groningen Field, provide confidence that production and depletion of the Blythe Field will have minimal-to-no impact on the Dudgeon windfarm that sits directly above the field on the seabed. Studies of this type allow for conventional oil and gas activities and other types of energy production to be safely risked and assessed in terms of being active in the same location, maximizing the potential for energy generation whilst minimizing the risk to the infrastructure, the environment, and to health and safety.

Introduction

Blythe and Elgood were initially discovered between 1966 and 1990 and now sit under the Dudgeon windfarm. The current operator plans to drill two wells to produce 70 bcf of gas during 6 years of production, with an associated pore pressure decrease and reservoir compaction which may affect the overburden sequence and requires assessment.

Reservoir compaction and land subsidence occur when large amounts of pore fluids have been withdrawn from underground reservoirs. Magnitudes of compaction and subsidence in oil and gas fields vary greatly depending on characteristics of the rock properties and field geometry. The effects of compaction and subsidence range from beneficial to detrimental; examples include seabed subsidence at the Ekofisk Field leading to remedial action required on the jack-up rig and casing damage such as that at the Valhall and Shearwater fields. Therefore, assessment of the potential for large magnitude compaction and subsidence must be carried out during field planning.
Laboratory Experiments on the Cyclic Gas Injection Process Using CO2, C2H6, and C3H8 To Evaluate Oil Recovery Performance and Mechanisms in Unconventional Reservoirs
Authors: Sennaoui B. , Pu Hui , Malki M. L. , Afari A. S. , Larbi A. , Tomowewo O. S. , Araghi R. H. R.
Published: November 2022

Low primary recovery percentages (usually 10% or less) in unconventional reservoirs, such as the Three Forks Formation in the Williston Basin, mean that potentially billions of barrels of oil are left behind in the reservoirs. Gas enhanced oil recovery (EOR) pilot studies that were performed in the Three Forks Formation suggest that cyclic gas injection is a viable approach for enhancing oil recovery in unconventional reservoirs. Due to limited knowledge of the cyclic gas injection mechanisms and the interaction between the injected gases and Three Forks reservoir fluids, additional investigations are mandatory despite of the pilot studies and the published findings in the Three Forks Formation. This paper conducts a series of experiments on core samples from the Upper Three Forks (UTF) and Middle Three Forks (MTF) under different constraints. The parameters that affect the performance of the cyclic gas injection during the Huff and Puff (HnP) technique are analyzed, including soaking time in miscible and immiscible conditions, injection pressure, vapor-supercritical states, density change, gas type (CO2), Ethane (C2H6), Propane (C3H8), within these formations (Upper Three Forks, and Middle Three Forks), and the microscopic pore distribution effect on hydrocarbon transport for the production using the Nuclear Magnetic Resonance (NMR) approach. The findings indicated that the soaking time improved recovery factors significantly below and close to the CO2's minimum miscibility pressure (MMP), but its effectiveness decreased for the injection pressures over the MMP. At low injection pressures, propane (C3H8) was shown to be the most effective gas, followed by ethane (C2H6) and then carbon dioxide (CO2). Due to a significant shift in density, ethane (C2H6) and carbon dioxide (CO2) both performed better during increasing pressure. In contrast, increasing the injection pressure of propane (C3H8) above 6.89 MPa did not affect the performance since the density of propane at 6.89 MPa caused a negligible density change. Additionally, the NMR measurements conducted at the UTF indicated that in the first cycle of HnP, oil extraction was dominated by micropores, mesopores, and less by small pores. Increasing the HnP cycles, micropores will be the dominant source of oil production. However, in MTF, the mesopores were the dominant pore distributions, followed by small pores, which affect the micro oil mobilization during the HnP process. This work provides a new insight into understanding the mechanisms of gas HnP enhanced recovery in the Three Forks formation, which is of great significance for the efficient hydrocarbon exploitation and greenhouse gas utilization in the Three Forks.
Geomechanical Feature Classification with a New Logging-While-Drilling Dual Ultrasonic Tool
Authors: Yamamoto H. , Blyth M. , Sakiyama N. , Shrivastava C. , Sagara M. , Barry A.
Published: November 2022

Effective geomechanical analysis requires a thorough understanding of the complexities of the formations drilled, such as stress-induced anisotropy, intrinsic anisotropy, azimuthal heterogeneity, drilling induced and natural fractures, and/or borehole damage. The identification and classification of these features can be complex, particularly when multiple different types are present together. The conventional sonic tools can struggle to differentiate these effects when more than one is present and often are lacking in the capability needed to clearly resolve them mainly because of the limited spatial resolution associated with the probing sonic frequencies. A new logging-while-drilling (LWD) dual ultrasonic tool has been developed, that provides high-resolution, full-azimuth, ultrasonic compressional and shear (P&S) slowness images together with ultrasonic borehole images and caliper that can be used to help address this formation complexity on multiple scales and so to improve geomechanical models and analysis. In this paper, we study feasibility of classifying formation geomechanical features, such as intrinsic anisotropy, stress-induced anisotropy, and azimuthal heterogeneity, using the ultrasonic P&S slowness from the LWD dual ultrasonic tool, and discuss conditions when such classification is expected to be successful and when more integrated approach is needed to address complexity of formations.

Introduction

Understanding the complexity of formation mechanical properties is very important for effective geomechanical analysis, such as the optimal design of hydraulic fracturing or wellbore stability analysis for safe and cost-effective drilling. Conventionally, standard sonic logging has been used to provide key acoustics measurements to characterize the formation mechanical properties axially, azimuthally, and radially (Pistre et al., 2005). These measurements are made at sonic frequencies, which results in an intrinsic limitation for resolving layers smaller than 1-ft thickness, because of the probing wavelength at these operating frequencies. A recently developed LWD dual ultrasonic tool demonstrated the ability to deliver P&S slowness measurements and images that resolve inch-scale bedding (Blyth et al., 2021). The P&S slownesses measured at ultrasonic frequencies deliver measurements with 2-in vertical resolution and in 16 azimuthal sectors around the wellbore. The tool also provides borehole images and calipers with ultrasonic pulse-echo measurements. P&S images from the field test data showed evidence that both intrinsic and stress-induced anisotropy can be revealed using LWD dual ultrasonic data at a similar fine resolution scale.
New Approach for Stress Computation during Loading and Unloading in Modified Cam Clay Model
Authors: Mirkalaei Seyed Mousa Mousavi , Tran David , Shrivastava Vijay , Nghiem Long , Chidambaram Prasanna , Ali Siti Syareena M , Mazeli Abdul Hakim , Phuat Tan Chee
Published: November 2022

Modified Cam-Clay model is often used for simulation of soft geomaterials such as soil or sand. In this model, Young’s modulus continuously changes via the bulk modulus. Poisson’s ratio can change or be kept constant. If the Poisson’s ratio is kept constant, shear modulus will change with time. If the shear modulus is kept constant, Poisson’s ratio is allowed to change with time. In general, the effective stress tensor at time t+1 can be computed when all state variables at time t are known. The material can be either in elastic or plastic mode depending on the stress state. In the case of plasticity, there are many steps involved to obtain a correct stress so that the equilibrium force balance could be satisfied within a tolerance. In the case of plastic deformation when the stress is out of a yield surface at time t+1, the stress must be brought back to the yield surface. The stress computation procedure during loading and unloading has an important effect on the results of deformation and rebounding after a plastic deformation. In this study a new approach for stress computation during loading and plastic unloading path is introduced. In the new proposed method, the relationship between mean effective stress change and volumetric strain change is used as a parameter to determine the amount of plastic deformation during unloading. The new approach will be appropriate for any case with large residual strain and a proposed exponential parameter (n) will determine based on the value of residual strain. A sensitivity analysis was carried out for different values of the exponential parameter which showed the displacement to be gradually less sensitive when the value of the parameter “n” is 1.003 or higher during the unloading stage. This method was then implemented and successfully tested for a study on matured offshore Malaysian field.
Well Log Prediction Using Deep Sequence Learning
Authors: Li Weichang , Fu Lei , AlTammar Murtadha J.
Published: November 2022

Sonic logs including compressional and shear travel time logs (DTC and DTS, respectively) are important measurements for subsurface elastic and geomechanic property characterization. However, these log types are not always measured in practice or incomplete in many oil and gas wells for economic and other practical reasons. We propose to accurately predict these types of log data from the traditional common types of well log measurement data using deep sequence learning methods. After anomalous data removal and augmenting the ratio DTC/DTS as a new lithology differentiating feature, the preprocessed inputs were fed into a bidirectional Long Short-Term Memory (LSTM) model for training to minimizing the error in predicting the sonic logs. Once trained, the model is then applied at the target wells to predict the sonic logs. The predicted sonic logs match the actual values with good accuracy. This entirely data-driven approach significantly reduces dependency on prior domain knowledge, providing a generalization advantage that enables automated large-scale well log prediction across fields.

Introduction

Well-log data analysis and interpretation are commonly conducted and play a central role in quantitative reservoir characterization, formation and completion evaluation (Ellis 2007, Glover 2014). Various borehole measurements provide information to determine reservoir rock composition such as solid and fluid volume fractions, as well as rock types, etc. When integrated with seismic data, multiple types of well log data can help reduce geologic interpretation ambiguity and improve hydrocarbon reservoir models. Certain well logs, like GR, resistivity, density, and neutron, are considered as “easy-to-acquire” conventional well logs and are deployed in most wells. However due to cost consideration or access limitation, other types of well logs, like nuclear magnetic resonance (NMR), dielectric dispersion, elemental spectroscopy, and dipole/shear sonic, are deployed in a limited number of wells and not as commonly available, or missing at certain depth intervals in an area of interest. On the other hand, sonic or acoustic logs, which measures the travel time of an elastic wave through the formation, are important in many applications. For instance, seismic-well tie requires sonic and density logs as inputs. Geomechanical parameters, very challenging to directly measure, may be derived from sonic logs aided with additional information such as rock types (Chen and Zhang 2020). Additionally, sonic logs also provide information to derive formation porosity, for stratigraphic correlation, and identification of lithologies, facies, fractures and compaction (Glover 2014).
Definition of Mud Weight Window Using 3D Numerical Models for Drilling Through Shaley Formations in Rumaila Field – Southern Iraq
Authors: Al-Asadi Yousif M. B. , Nasreldin Gaisoni , Al-Shahwan Muwafaq F. J.
Published: November 2022

The giant Rumaila oilfield in south Iraq has been plagued by a number of wellbore instabilities. The shaley formations in this field pose the greatest challenges to drilling operations, accounting for approximately 90% of the problems. Stuck pipe, tight hole, and borehole collapse are examples of the incidents commonly encountered even while drilling vertical wells. The main objectives of this study were to generate a mud weight window cube for different trajectory scenarios by examining the impact of depletion on field performance and drilling integrity for making life-of-reservoir decisions. The derived mechanical properties were taken from their respective 1D mechanical earth models (MEM) by utilizing the available mechanical core test data and populating in 3D space. The final 3D MEM has been calibrated against field observations. This paper presents a well planning tool for translating the geomechanical modeling results to operational parameters, and in so doing, informing well trajectory planning and optimization.

Introduction

Reservoir geomechanics play a vitally important role in minimizing drilling activity costs and informing field development planning. Comprehensive geomechanical models (1D, 3D and 4D) have been built in the Rumaila Field based on a wide array of inputs taken from 14 wells distributed across the field. The analysis examined the stress changes in the main reservoirs—namely: Mishrif and Zubair Main Pay—and addressed the instability issues in all Rumaila formations encountered while drilling, by using the available openhole logs, core mechanical test data, production data, and pressure data. The main objectives of this study were to build a fieldscale geomechanical model with a view to assessing the impact of production-induced stress changes on field performance and generating mud weight cubes at different timesteps (Al-Asadi 2021).
Le jardin arboré : un écrin pour l’immeuble, à travers des exemples en Alsace
Authors: Modanese Cécile
Published: November 2022

André Chastel précisait que le champ d’intervention de l’inventaire des richesses artistiques de la France s’étendait de « la cathédrale à la petite cuillère ». Aujourd’hui, la villa est associée à son parc. Son analyse inclut progressivement le relevé des essences végétales. La présence d’une des plus conséquentes pépinières européennes en Alsace, les pépinières Baumann de Bollwiller fondées vers 1735 a permis la création de nombreux parcs et jardins tout au long du XIXe siècle. Ceux-ci sont le reflet d’un art de vivre allant de pair avec l’architecture et la décoration des intérieurs. Les arbres deviennent ainsi de nouveaux matériaux décoratifs pour l’art des jardins permettant au parc arboré de sublimer l’architecture en lui offrant un écrin prestigieux. Le jardin est en outre pensé pour être vu depuis l’édifice faisant parfois preuve d’une cohérence étonnante entre la création architecturale et paysagère.
Information Value in Social Media: An Integrated Approach to Preventive Behaviors under COVID-19
Authors: Cu Le Xuan
Published: November 2022

Information content via social media has received attention from the community during the pandemic. This work aims to examine a preventive behavior model due to information value through social media under COVID-19 in Vietnam. This model is formulated based on the integration of Health Belief Theory (HBT) and the Elaboration Likelihood Model (ELM). A web-based survey is performed to collect data from 321 respondents who have utilized social media to seek and accumulate COVID-19-related information. The results indicate that perceived threat and self-efficacy are two vital predictors of readiness to uptake preventative behaviors. Additionally, information dimensions (i.e., information quality and information credibility) are crucial motivations underlying perceived threat and self-efficacy. Information quality well surmises information credibility. Finally, theoretical and practical implications are discussed.
The Mediating Role of Job Satisfaction in the Relationship between Personality Traits and Organizational Commitment of Public Sector Employees in Hanoi City
Authors: Nam Nguyen Danh , Lan Uong Thi Ngoc
Published: November 2022

Managers normally have an advantage over the market in predicting firm-specific events. This creates information asymmetry between managers of the firm and the market. The purpose of this paper is to investigate the relationship between firm value and information asymmetry in Vietnam. Our data include 202 non-financial companies with 606 firm-year observations collected from the two main stock exchange markets in Vietnam including Hanoi Stock Exchange and Ho Chi Minh Stock Exchange, covering 3 years from 2017-2019. The finding of this study indicates that two variables measuring information asymmetry (ASYDISP, ASYDUM) negatively impact firm value. Besides, control variables such as return on assets, leverage, firm size, and intangible assets are found to have significant effects on firm value.
The Effects of Labor Characteristics on Firm Productivity: Empirical Evidence from Vietnam
Authors: Vo Dut Van , Duong Long Hoang , Tran Man Minh Lam , Nguyen Phu Thanh
Published: November 2022

The paper investigates how labor characteristics affect firm productivity. Recent arguments on the relationship vary. On one hand, the labor force enhances firms’ financial strengths thanks to their manufacturing poductivity; on the other hand, such effects impede operations if overlooked. We proposed three hypotheses with views on such characteristics. First, leadership experience and second, a highly-trained firm labor force are both positively associated with firm productivity, whereas obstruction by labor laws has a negative effect on productivity. In a 123-firm dataset surveyed by the World Bank, the paper reveals that leadership experience and highly trained labor positively affect firm productivity while no statistical evidence was found of obstruction by labor laws. The major findings suggest that, firstly, labor-related theories are properly verified with different analysis settings; secondly, labor characteristics are the primary firm-level competitive power so they should be treated appropriately; thirdly, Vietnamese firms are not likely to be hindered by the country-level labor laws. However, the study constrains itself by not being conducted on a panel dataset to show the pattern over time, and by not treating the leadership experience in a proper, multifaceted way to capture their contribution comprehensively to the business-doing culture in Vietnam.
Towards Automating the Integration of Legacy IEDs into Edge-Supported Internet of Smart Grid Things
Authors: Modesto Wanderson , Bastos Lucas , Venâncio Neto Augusto , Rosário Denis , Cerqueira Eduardo
Published: November 2022

The prominence of the SG-to­Cloud continuum will pave the way towards advanced Smart Grid (SG) ecosystems and will enable cutting Edge applications and servers into the power energy vertical at unprecedented innovation levels. During the design of future Smart Grid ecosystems, legacy Intelligent Eletronic Device (IED) cannot be left behind, whereby their full integration into the Internet of Smart Grid Things(IoSGT) reveals itself as a continuous issue. In an attempt to tackle this challenge, we are introducing the Legacy Smart Grid to IoT Integration Approach(SG2IoT), which automates the integration of multiple legacy IEDs in a scalable and flexible environment made possible by the IoSGT. Aside from that, the SG2IoT establishes an SG­to­Cloud continuum for provisioning architectural modular components for running in a distributed approach at Cloud facilities spread in Edge and central datacenters. Finally, the SG2IoT impact estimation was made up of harnessing a prototype running atop a lab­premised testbed that features real­world technologies. Outcome analysis proves the viability of the SG2IoT lightweight approach by establishing an SG­to­Cloud continuum to afford low times responses and affordable IoSGT scalability.
The Effectiveness of Mindfulness-based Cognitive Therapy on Academic Emotions and Academic Optimism of Procrastinating Students
Authors: Asani Samad , Panahali Amir , Abdi Reza , Badri Gargari Rahim
Published: November 2022

Background: Academic procrastination refers to the deliberate postponement of academic assignments despite being aware of the negative consequences. Objectives: This study aimed to investigate the effectiveness of mindfulness-based cognitive therapy on academic emotions and academic optimism among procrastination students. Methods: The present study was a semi-intervention type. The statistical population of the study consists of all procrastinating students of Payame Noor University, Bostan Abad Branch, who were studying in the academic year 2020. The study sample included 30 undergraduate students who were selected by convenience sampling and randomly divided into two groups (15 persons in the intervention group and 15 persons in the control group). Also, the intervention group was treated for eight sessions of one hour based on Kabat Zinn treatment protocol. To collect data, Tuckman Procrastination Questionnaire, Pekrun Academic Emotions (2002), and Academic Optimism Questionnaire were used. To analyze the data, covariance was used, which was analyzed with SPSS-23. Results: The results showed that mindfulness-based cognitive therapy increased positive emotions such as pleasure (P < 0.01), hope (P < 0.01) pride (P < 0.01), and decreased negative emotions, i.e., anger (P < 0.01), anxiety (P < 0.01), shame (P < 0.01), disappointment (P < 0.01), and fatigue (P < 0.01) in the intervention group. Also, the results of the variable of academic optimism showed that cognitive therapy based on mindfulness was associated with an increase in the components of trust (P < 0.01) and academic emphasis (P < 0.01), while on the component of the sense of identity (P > 0.01) had no significant effect. Conclusions: Based on the findings of the present study, it was found that mindfulness training can be used as an effective intervention to moderate positive academic emotions and increase students' academic optimism.
Prevalence of Risk Factors of Urinary Tract Infections in Infants and Children in Arak, Iran: A Cross-sectional Study
Authors: Shabani Yazdan , Sadeghi Hajar , Yousefichaijan Parsa , Shabani Davoud , Rafiee Fatemeh
Published: November 2022

Background: Urinary tract infection (UTI) is one of the most common childhood infections. Urinary tract infections are divided into simple and complex types. If the bladder infection is not treated, it can cause secondary kidney infections, such as acute pyelonephritis, which can lead to kidney scar or permanent kidney damage. A significant percentage of patients of any age are re-infected after antimicrobial treatments during the first six months after the first period of UTI. Objectives: This research aimed to investigate the risk factors affecting UTI in infants and children hospitalized in Arak Amir Kabir Hospital in 2017-2018 to prevent UTI and its secondary complications. Methods: In this cross-sectional study, the data collection tool was a validated questionnaire to gather the child's demographic characteristics, including age, sex, type of nutrition, circumcision, age of circumcision, as well as information about fetal birth weight, chronic maternal diseases such as diabetes and stress, and residence place. The content validation method was used to determine the validity of the checklist, and the test-retest was used for reliability. Data were analyzed by SPSS version 22 software. Results: Sixty four percent of children had the normal ultrasound, while 22% had hydronephrosis and nephrolithiasis on ultrasound. The average thickness and size of the right kidney were 71.75 and 9.11, and those of the left kidney were 9.11 and 9.50, respectively. The most common microorganism was Escherichia coli. Conclusions: Given the importance of prevention and timely diagnosis and treatment of UTI to prevent kidney injuries, it is necessary to find UTI risk factors as the first step to preventing children from secondary kidney injuries.
Motives for using social networks and social network addiction in a time of pandemic
Authors: Cuadrado Esther , Carmen Tabernero , Castillo-Mayén Rosario , Luque Bárbara , Moreno-Bella Eva
Published: November 2022

The lockdown situation caused by COVID-19 has increased the use of social networks, which could, in turn, increase social networks addiction. This research consists of two integrated studies aimed at (1) developing and validating the Social Networks Motives Scale (SN-MotiveS) and (2) examining the relationships between the frequency of use of social networks and the motives for why individuals use social networks with social networks addiction, as well as the evolution of these variables over time before (through a retrospective assessment), during, and after lockdown. During lockdown, an online questionnaire was distributed to a sample of 482 participants (Study 1). After lockdown, 114 participants from Study 1 completed a second online questionnaire, forming a longitudinal study (Study 2). Study 1 showed a robust fit for the multifactorial structure of the SN-MotiveS with four factors (socialization, escapism, prosocial behavior, and self-presentation), supporting the external validity of the scale, and the expected correlation patterns were found with social networks frequency of use, abuse, and addiction. Study 2 showed that all the motives increased during lockdown except for self-presentation, whereas after lockdown only prosocial behavior and employment (added in Study 2) decreased significantly. Moreover, the self-presentation and escapism motives acted as mediators in the relationship between social networks frequency of use and social networks addiction. This research provides a reliable instrument to measure the motives for using social networks both during a pandemic and in normal times. In addition, it highlights the importance of paying special attention to escapism motives for predicting social networks addiction in periods of lockdown.