bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas Huff-N-Puff with Pressure Containment Strategy Design for the Bakken Wells
Authors: Song Xueling , Wan Xincheng , Rasouli Vamegh , Yu Wei
Published: September 2022

Horizontal well drilling and multistage hydraulic fracturing have been widely applied in the Bakken tight oil reservoir to enhance its recovery. However, the primary oil recovery was low due to the majority of oil being remained in the rock matrix. Gas huff-n-puff (HnP), as an enhanced oil recovery (EOR) method, has been applied to the Bakken wells. However, fracture interference among wells leads to fast pressure decline during the gas injection period and slow recovery during the production period. By designing strategies that combine water injection in the offset wells with gas HnP, the pressure of the gas HnP well can be maintained during the production period. Therefore, the effectiveness of gas HnP can potentially be improved. A five-well reservoir model was built using a third-party reservoir simulator with an embedded discrete fracture modeling method. The simulated production data obtained from the reservoir model was successfully matched with the field data. Multiple natural gas HnP strategies were designed and simulated to compare the EOR performances. The results showed that a larger volume of the injected natural gas contributes to more incremental oil production. Higher water injection pressure provided better pressure containment for the gas HnP well, but high water cut presented a detrimental effect on oil production.

1. INTRODUCTION

The Bakken Formation has witnessed a boost in oil production since 2008. By the end of March 2022, the oil production of the Bakken region was approximately 1.2 million barrels per day (U.S. Energy Information Administration, 2022). Although the Bakken formation is tight with ultra-low reservoir permeability, the applications of horizontal well drilling and multi-stage hydraulic fracturing have contributed to the success of Bakken. A typical Bakken well has 50 stages of hydraulic fractures in the 10,000 ft lateral section. These hydraulic fractures serve as the "channels" that connect the well with the tight Bakken reservoir, thus the oil that was originally locked in the formation could easily flow to the wellbore. The interaction between hydraulic fractures and pre-existing natural fractures also contributes to larger stimulated reservoir volume and promotes incremental oil production (Aoun et al., 2022; Kolawole and Ispas, 2020; Wan et al., 2020a). Currently, the new Bakken wells have an average initial oil production of 1963 barrels per day (U.S. Energy Information Administration, 2022). With the current oil price of $115 per barrel, a new well could generate an average revenue of $225,745 per day. Despite a large amount of oil that has been produced, the oil recovery of the Bakken Formation remains close to 10% (Hoffman and Evans, 2016). Alternative enhanced oil recovery (EOR) strategies are needed to fully recover the shale oil locked in the tight reservoir matrix.
A Case Study on Trim Blast Fragmentation Optimization Using MBF and MSW Models at an Open Pit Mine in Canada
Authors: Yang R. , Pratt L. , Zhao Q. C.
Published: September 2022

A project for monitoring, analysis, and modelling trim blasting at an open pit copper/molybdenum mine in Canada in 2021 was conducted using Orica’s in house developed proprietary tools, which includes the accelerometer near-field vibration monitoring system, the Multiple Seed Waveform (MSW) near- and far-field blast vibration model, and the Multiple Blasthole Fragmentation (MBF) model. Both MSW and MBF models are built on the fundamentals and empirical aspects of blasting mechanics. The blast vibration at the highwalls from trim blasts was predicted with MSW model. The effects of parameters from the blast design scenarios at the mine site were simulated and optimized designs were proposed based on the MBF and MSW modelling. The MBF model explicitly simulates all blast design parameters. The MSW blast vibration model uses multiple seed waveforms at different distances from a blasthole to a point of interest and is suitable for near-field blast vibration at the highwalls. Through the application of the MBF in conjunction with the MSW, various design scenarios can be explored, and rock fragmentation can be optimized while controlling blast vibration levels. These models have been successfully applied to many open pit mines and quarries around the world.

1. INTRODUCTION

For a large open pit mine, it is of vital importance to optimize trim blasts. A trim blast is next to the presplit. To minimize the negative impact on the highwall, trim blasts are often loaded with a low powder factor that results in much coarser fragmentation than the production blasts. The coarser fragmentation increases the cost of the downstream operations. On the other hand, trim blasts with a high powder factor could impact the highwall causing the highwall instability.

Over the recent years, Orica developed a unique system for blast optimization projects. The system includes near-field blast vibration monitoring using accelerometers, the multiple blasthole fragmentation (MBF) model, and the multiple seed waveform (MSW) blast vibration model. The three components of the system are used together to improve blast performance at a site.
Modeling the Effects of Hydraulic Fracturing on Borehole Acoustic Measurements
Authors: Gallardo-Giozza G. , Espinoza D. N. , Torres-Verdín C.
Published: September 2022

Borehole acoustic measurements are commonly used to detect and quantify variations in rock elastic properties by comparing measurements acquired before and after fracturing. While shear-waveform slowness variations are routinely recorded in boreholes, analysis of the corresponding attenuation is mostly limited to laboratory experiments. Interpreting the effects of fractures on borehole acoustic measurements often requires numerical modeling. This paper quantifies the effects of hydraulic fractures perpendicular to the well axis on shear and Stoneley borehole acoustic measurements via numerical modeling. Dipole and low frequency monopole acoustic propagation is simulated in 2D models assuming a borehole elastic and viscoelastic model. We vary casing-cement-formation bonding considering models with open hole, perfect-bond cased hole, well-bond cement bonding and unbonded cased hole. Simulation results show that hydraulic fractures perpendicular to the well axis give rise to attenuation and reflected events for both shear and Stoneley propagation modes. For shear waveforms, casing presence obscures the detection of reflected events, but attenuation is still observed. For Stoneley waveforms, the presence of casing enhances the contrast between casing-formation and fluid-filled fractures. Well-bond casing models are the optimal cased-hole models required for fracture interpretation because fracture features can be observed for both shear-wave and Stoneley modes.

1. INTRODUCTION

Borehole acoustic measurements are commonly used to assess the elastic properties of rocks around a well. Rocks can have either natural or hydraulically induced fractures. The presence of fractures often has measurable effects on the acquired borehole acoustic waveforms. Therefore, it is important to understand the role played by fractures on borehole acoustic measurements. Analytical and numerical models enable the estimation of the effect of single and multiple fractures on Stoneley and shear waves (Hornby et al., 1989; Tang and Cheng, 1989; Bakku et al., 2013; Minato and Ghose, 2017, Xu et al., 2021). Numerical modeling represents a technical challenge because analysis of complex geometries is usually required. Two-dimensional (2D) numerical models are powerful tools to understand waveform propagation along the borehole. However, they are limited to only axisymmetric geometries. Three-dimensional (3D) modeling presents technical challenges because it requires a great amount of computational resources. The finite-difference time-domain (FDTD) algorithm is the most extended method for numerical modeling of wave propagation in boreholes (Cheng et al., 1995; Liu et al., 1996; Wang and Tang, 2003; Guan et al., 2009; He et al., 2010). Other methods include finite-element method (FEM) (Michler et al., 2009, Wang et al., 2013, Pardo et al., 2021), frequency-domain hp-adaptative algorithms (Matuszyk et al., 2013), and spectral-element methods (SEM) (Komatitsch and Tromp, 1999; Xu et al., 2021).
Experimental Conditions Affecting Fracturing Research
Authors: Almubarak M. , Germaine J. T. , Einstein H. H.
Published: September 2022

The fracturing behavior and mechanical characterization of rocks are important for many applications in the fields of civil, mining, geothermal, and petroleum engineering. Laboratory testing of rocks plays a major role in understanding the underlying processes that occur on the larger scale and for predicting rock behavior. Fracturing research, such as producing multiple fractures that follow a particular pattern, requires well-defined and consistent boundary conditions. Consequently, the testing design and setup can greatly influence the results. In this study, a comprehensive experimental program using an artificial material was carried out to systematically evaluate the effects of different parameters in rock testing under uniaxial compression. The parameters include the compression platen type, centering of the specimen, loading control method and rate, specimen size, cross-sectional geometry, and boundary constraints. The results show that these parameters have a significant effect on the mechanical behavior of rocks. Using a fixed compression platen helped reduce bulging of the material. Centering of the specimen played a critical role to avoid buckling and unequal distribution of stress. Slower displacement rates can control the energy being released once failure occurs to prevent the specimen from exploding. Larger specimens generally fail at lower stresses compared to smaller specimens. Also, the frictional end effects were investigated by comparing lubricated and non-lubricated end conditions.

1. INTRODUCTION

The knowledge of mechanical behavior of rocks is relevant and important in rock mechanics, particularly when applied to the fields of civil, mining, geothermal, and petroleum engineering (Isah et al., 2020; Almubarak et al., 2020). Laboratory testing has played an important role in characterizing the strength of rocks and understanding fracture behavior (Xu et al., 2016). As will be explained later, the investigation reported in this paper is conducted with an artificial material.

There has been an interest in using artificial model materials for as long as the mechanical testing of rocks has been performed. Rapid prototyping (RP), additive manufacturing (AM), and three-dimensional printing (3DP) are three interchangeable terms that define a set of methods for the fast, precise, and repeatable production of elements (Zhou and Zhu, 2018). The technology was first introduced in the 1980s and is based on the process of joining materials layer-by-layer to form an object using computer-aided design (CAD). Polymeric, metallic, ceramic, and even complex composite components are among the materials used (Ngo et al., 2018). Various 3DP techniques have been developed, including fused deposition manufacturing (FDM), stereolithography (SLA), and selective laser sintering (SLS).
Stochastic Inversion of Wellbore Stability Models Calibrated with Hard and Soft Data
Authors: Nicolaidou E. , Birchwood R. A. , Prioul R. , Rodriguez-Herrera A.
Published: September 2022

Wellbore stability models are used in well-planning to determine the safe mud-weight window for drilling. More generally, calibration of wellbore stability models against observations (such as image logs, caliper measurements, and general drilling observations) is an essential step in constructing reliable 1D and 3D Mechanical Earth Models (MEMs) which are used to design safe drilling, completion, and production strategies. However, such calibration usually produces non-unique results, partly because most common types of calibration data impose only soft (inequality) constraints on wellbore stability models. Such non-uniqueness can be represented using probability density functions (PDFs). In this paper we show the results of stochastic inversion for stress parameters performed by drawing samples from these PDFs using a Markov Chain Monte Carlo procedure. Most types of calibration data (e.g., breakouts, drilling-induced fractures) produce a wide range of possible solutions for the stress parameters. However, the uncertainty reduces dramatically as data from an increasing number of depth locations is simultaneously inverted. The results also illustrate how including depths where breakouts and drilling-induced fractures are absent produces a powerful constraint on inferred stress parameters.

1. INTRODUCTION

Mechanical Earth models (MEMs) encompass the parameters needed to predict deformation and failure of rocks such as rock mechanical properties and in situ stresses. They constitute an essential tool for predicting safe mud weight windows while drilling and are used to inform the well planning process. Traditional methods for calibrating MEMs are tedious, due to their subjective nature, as they rely entirely on the judgement and experience of the analyst. Calibration of MEMs also requires cumbersome and time-consuming fine-tuning of a large number of parameters and computational options.

These problems can potentially be addressed through the implementation of automatic search schemes. To this end, we have developed a Bayesian inversion scheme to search for tectonic strain parameters, εxx, εyy, that control the magnitudes of the minimum (σh), and maximum (σH) horizontal stresses derived from a poroelastic stress model (Thiercelin and Plumb, 1991):

(Equation)
Multiwell DAS Microseismic and Strain Measurements Diagnostics
Authors: Chavarria J. Andres , Oukaci Y. , Laflame L.
Published: September 2022

Fiber Optic diagnostics are increasingly being used in reservoir development. Traditionally the use of the fiber has focused on either the completion or seismic diagnostics. Here we present how Distributed Acoustic Measurements (DAS) can be processed for joint microseismic (MS) and low frequency strain (LF-DAS). Using a three-dimensional network of fibers during unconventional reservoir development we analyze the dual measurements taken from various vantage points. By using DAS receivers within vertical and horizontal well trajectories we do a full 3D MS mapping. The DAS MS catalog was compared in space and time with respect to the strain data recorded by the same fibers. The significance of this work is that broad band DAS measurements that include MS and LF strain are an effective tool to illuminate the mechanisms for fracture generation. 3D distributions of DAS MS and LF strain events provide the framework for a more accurate description of the injection processes and its reservoir response during stimulation. By combining the two measurements we reveal how these two complimentary, but simultaneously run, measurements illuminate the subsurface and fracturing process. Here we demonstrate how MS and DAS strain respond to different aspects of the fracture generation process within the reservoir.

1. INTRODUCTION

Increasingly fiber optic networks with Distributed Acoustic Sensing (DAS) Interrogator Units (IU) are being used to monitor various processes in the subsurface. Amongst these are aspects of induced seismicity or fracture network generation tied to injection processes for storage purposes or more often, for unconventional reservoir development. DAS measurements provide broad bandwidth measurements. Initially DAS sensing was developed for seismic studies and it was quickly realized that it could be used for monitoring other aspects within the wellbore. In recent years DAS diagnostics within unconventional resources have been used to monitor injection processes with permanent installed fibers. More recently this monitoring has extended to fibers positioned in neighboring wells which allow for a fracture propagation analysis within the reservoir connecting the treatment and sensing well (Jin and Roy, 2017; Ugueto et al 2020). This crosswell monitoring has focused on low frequency strain signals due to high sensitivity of the tools to the opening and closing of developing fracture networks. This has opened the door to various analysis including accurate fracture models that predict the fracture growth in 3D as seen by monitoring fibers (Borne et al., 2021).
Numerical Modeling of Coupled Thermal-Hydro-Mechanical Processes in Salt Formations for Geologic Disposal of Large Nuclear Waste Canisters
Authors: Tounsi H. , Rutqvist J. , Hu M. , Wolters R. , Blanco-Martín L.
Published: September 2022

Salt has long been considered as a potential host rock for the geological disposal of radioactive waste because of its favorable properties, including self-sealing, low permeability and high thermal conductivity. The feasibility of nuclear waste disposal within salt formations has been investigated mainly for small-sized canisters, widely considered in many national nuclear waste disposal programs. Direct disposal of larger-sized canisters originally designed for spent nuclear fuel storage and transportation has lately been examined as a promising and cost-effective alternative. However, the amount of decay heat released by large canisters may cause high temperature in the backfill surrounding the canisters and in the host rock. This results in pressure and stress changes that may affect the long-term repository performance. To analyze it, the TOUGH-FLAC simulator is used to conduct fully coupled Thermal-Hydro-Mechanical (THM) simulations of a generic salt repository for large-sized canisters. In this code, large deformation has been considered allowing to accommodate viscous compaction of the crushed salt backfill as well as the long-term stress changes in salt host rock. The simulations show that the peak temperature in the backfill and in the host rock can be reduced by adjusting the distance between the canisters along emplacement tunnels or the spacing between the tunnels themselves. Nevertheless, the thermal pressurization in the salt host rock and in the crushed salt backfill, following the reconsolidation of the backfill, seems to be less sensitive to these spacing adjustments. Consequently, the pore-pressure could potentially exceed the lithostatic stress causing an increase of permeability and a fluid infiltration into the rock mass that may last more than 1000 years after the waste canister emplacement. Thus, it is critically important to analyze and manage these coupled THM processes for a safe and effective disposal of nuclear waste in salt formations.

1 INTRODUCTION

Geologic disposal of large-sized canisters, originally designed for spent nuclear fuel storage and transportation, has lately been examined as a promising and cost-effective alternative to conventional smaller-scale canisters commonly considered in many national nuclear waste disposal programs (Hardin et al., 2015).
Evolutions of Dynamic Elastic Properties of Opalinus Clay Under Varying Stress Paths
Authors: Liu L. , Chalaturnyk R. , Deisman N. , Zambrano G.
Published: September 2022

Understanding the elastic stiffness evolution of the host rock under stress is important in the prediction of ground deformation during the construction and operation of a radioactive waste repository. The relationship established between dynamic elastic properties and stress also allows for an accurate interpretation of seismic survey and borehole sonic logging data in the field.

In this work, the dynamic elastic properties of Opalinus Clay are determined using axial ultrasonic surveys at varying stress steps in triaxial tests. The evolutions of the P- and S-wave velocities are investigated along different stress paths, respectively with constant mean stress (CMS) and constant radial stress (CRS). For CMS testing, a cycle of triaxial compression and extension is performed. It is shown that P-wave velocity gradually reduced at the stage of triaxial compression and reversing the stress path in triaxial extension does not fully recover the velocity changes. The onset of specimen damage is identified at a deviator stress threshold where the velocity change diverts from its current trend in either triaxial compression or extension. The stress threshold differs between triaxial compression and extension, and it is inversely related to the water saturation of the Opalinus Clay.

Before damage initiation, dynamic Young’s modulus shows a minor degradation under the CMS path, whereas it increases under the CRS path in triaxial compression. Both trends agree with the measured evolutions of static Young’s modulus of argillaceous claystones at similar stress levels. This study provides additional experimental guidance for constitutive modeling of stress-dependent elastic stiffness for this rock type.

1. INTRODUCTION

Opalinus Clay is a shale with low permeability and has self-sealing potential upon the intake of moisture. It is considered as a possible host rock for future radioactive waste disposal in Switzerland (Bossart et al., 2017). Understanding the geomechanical response of the Opalinus Clay allows for the safe construction and operation of a disposal repository (Amann et al., 2017). One of the key geomechanical properties that have been under investigation is elastic stiffness.
Dynamic and Static Characterization of Bio-Cemented Soils
Authors: Khan Z. , Mehrabi R. , Atefi-Monfared K. , Cascante G.
Published: September 2022

Microbially induced calcite precipitation (MICP) is a ground improvement technique where the metabolic activities of bacteria are utilized to produce calcium carbonate precipitants at the grain contacts or within the pore spaces, enhancing bonding between the soil particles thus generating artificially cemented rocks with improved stiffness/strength properties. A key challenge in practical implementation of this technology is determining the percentage of the produced bio-cement and characterization of the resulting weakly consolidated rocks. Non-destructive techniques (NDT) are ideal for monitoring the percentage of the produced bio-cement, which is of a non-uniform and heterogenic nature, as well as the characteristics of the bio-induced cemented rock. In this study, we have conducted a series of controlled laboratory column tests where various bio-cemented samples were produced. NDT experiments including S-wave velocity measurements were taken along samples to determine bio-cementation and characterize the enhanced strength properties. Advanced signal processing techniques were conducted to interpret the findings. Results were compared against unconfined compressive tests (UCS). Findings provide a novel insight into utilization of NDT and interpretation of the results for charactering weakly consolidated rocks.

1. INTRODUCTION

Microbiological-induced calcite precipitation (MICP) is a ground improvement technique that utilizes ureolytic microorganisms capable of hydrolyzing urea to generate calcium carbonate minerals, referred to as bio-cement (Stocks-Fisher et al. 1999). The resulting enhanced engineering properties in soils treated through MICP are governed by the distribution of bio-cement at the pore-scale, which is heterogeneous and complex in nature. When the produced bio-cement is precipitated at the soil particle contacts, it can enhance bonding between soil particles thus improve shear stiffness and shear strength, compressibility and dilatancy tendencies, and liquefaction resistance (e.g., DeJong et al., 2006; Martinez and DeJong, 2009; Montoya and DeJong 2015). The hydraulic characteristics of bio-treated soils however are found to be mainly impacted by the percentage of the bio-cement produced in the pores (pore filling).
Analysis of Transparent Gelatin as a Reservoir Analogue for Hydraulic Fracturing Laboratory Experiments
Authors: Michael A.
Published: September 2022

Gelatin was often used as a reservoir analogue material to model hydraulic fracturing in brittle, hydrocarbon-filled rock formations, with its transparency allowing direct, visual observation of the fracture growth. Nevertheless, not many studies elaborate on the scalability of laboratory experiments where gelatin was used in comparison to actual field-scale hydraulic fracture treatments. Model laws from the literature derived to relate lab-scale physical models displaying hydraulic fracture growth to the prototype parameters are used to assess the representation of elastic deformation, crack formation energy, treatment time, and confining stress environment, honoring the governing laws of fluid-driven fracture propagation in linearly elastic media. In this work, the lab-scale parameters of an experimental study on gelatin blocks of 7-to-8%-by-weight concentration are assessed against typical slickwater and crosslinked gel fracture treatment parameters from the Barnett Shale as part of a dimensional scaling evaluation. The analysis shows the gelatin reservoir analogue scaling better against crosslinked gel compared to slickwater field operations, with the laboratory conditions accentuating Mode I fracture toughness over viscous fluid effects, compared to the field. Subsequently, a set of laboratory parameters is proposed at a higher gelatin concentration (18-to-19%-by-weight), yielding improved scalability against field operations, minimizing the difference between the lab-scale and the corresponding field-scale values of each dimensionless group, within the constraints of the available laboratory equipment. Finally, the implications of the absence of leakoff in experiments on gelatin specimens is discussed and comparisons are made between gelatin and other transparent lab-scale reservoir analogues.

1. INTRODUCTION

Analogue experimental work is –bar none– a fundamental branch of scientific method. Selecting the appropriate analogue material, which satisfies a set of criteria determining whether a candidate analogue material can be considered a laboratory version of the natural counterpart is one of the biggest challenges when developing an experimental study. This paper elaborates on the scalability of transparent gelatin as a reservoir analogue in hydraulic fracturing block experiments.
Osmotic Ion Concentration Control of Steady-State Subcritical Fracture Growth in Shale
Authors: Nguyen Hoang T. , Bažant P. Zdenek
Published: September 2022

The mechanism of formation of natural cracks in sedimentary rocks in the geologic past is an important problem in hydraulic fracturing. Why are the natural cracks roughly parallel and equidistant, and why is the spacing in the order of 10 cm rather than 1 cm or 100 cm? Fracture mechanics alone cannot answer these questions. Here it is proposed that fracture mechanics must be coupled with the diffusion of solute ions (Na+ and Cl− are considered here), driven by an osmotic pressure gradient. Parallel equidistant cracks are considered to be subcritical and governed by the Charles-Evans law. The evolution in solute concentration also affects the solvent pressure in the pores and cracks, altering the resistance to frictional sliding. Only steady-state propagation and periodic cracks are studied. An analytical solution of the crack spacing as a function of the properties of the rock as well as the solvent and solute, and the imposed far-field deformation is obtained. Finally, the stability of the growth of parallel cracks is proven by examining the second variation of free energy. Stability of the periodic growth state is also considered.

1 INTRODUCTION

The deep layers of sedimentary rocks such as shale and sandstone are usually intersected by systems of nearly parallel natural cracks either filled by mineral deposits or closed by creep over a million year life span. Their spacing is roughly uniform and is on the order of 0.1 m (rather than 1 m or 0.01m). These cracks likely play an important role in hydraulic fracturing for gas or oil recovery (aka fracking, fraccing or frac) (Rahimi-Aghdam et al., 2019, e.g.). Therefore, understanding the mechanism of their formation in the distant geologic past is of interest.

What controls the spacing of the nearly parallel cracks in shale? According to the fracture mechanics alone, the crack spacing is arbitrary. If propagating parallel equidistant cracks are in a critical state, stability analysis shows that many cracks would have to stop growing, causing a great increase of their average spacing, which was obviously not the case (Bažant et al., 2014).
The Impact of Strain Amplitude on Young's Modulus in Water-Saturated Sandstone
Authors: Mews K. S. , Holt R. M. , Lozovyi S.
Published: September 2022

Strain amplitude, frequency, stress conditions, and fluid saturation influence the stiffness response of rocks. In order to quantify the effect of frequency and strain amplitude, we performed low-frequency measurements on fully saturated Bentheimer sandstone samples to measure the dynamic stiffness at seismic frequencies (0.5 – 143 Hz) with strain amplitudes ranging from 10−7 to 10−5 . In order to quantify the effect of pressure, we increased the effective stress subsequently. The results show that Young’s modulus decreases with increasing strain amplitude even in the seismic-frequency range. The applied wave-stress signal contains the first harmonic at the central frequency, but the measured wave strain rate spectrum contains higher-order harmonics indicating hysteresis in the stress-strain response. The increased signal at higher-order harmonics is only captured for higher strain amplitudes. The general trend shows a decreasing signal with increasing order of harmonics. Remarkable is that the 3rd harmonic indicates a stronger signal than the 2nd harmonic and the 5th harmonic a stronger signal than the 4th. Understanding non-linearities and non-elastic mechanisms and their dependency on the strain amplitude for saturated samples are fundamental for the link between dynamic and static properties of reservoir rocks.

1 INTRODUCTION

It is well known that some materials show an extreme non-linear response. Studies on those non-linear effects, even for small strains, started several decades ago (Winkler et al., 1979), revealed as non-linear stress-strain, harmonic generation, non-linear attenuation, and resonant peak shift. It was found that frequency, stress, strain amplitude, and fluid saturation affect non-linearity the most (Tutuncu et al., 1998).

Van Den Abeele and Johnson (1996) found from experimental studies on Berea sandstone that non-linearity exists even on strains as small as 10−7 . The higher-order harmonic generation shows that odd harmonics dominate the even harmonics (Van Den Abeele and Johnson, 1996; Johnson and Rasolofosaon, 1996; Johnson and Rasolofosaon, 1996; Saltiel et al., 2017). Though these acoustic measurements were performed on frequencies in the kHz region (Van Den Abeele and Johnson, 1996; Johnson and Rasolofosaon, 1996). It is, however, rare to find a non-linearity description of higher-order harmonics for seismic frequency measurements (Rivière et al., 2016).
Flexible and Accessible 4D Subsurface Visualization Using a Web-Based Platform
Authors: Pratt M. J. , Knox H. A. , Johnson T. C. , Kneafsey T. J.
Published: September 2022

4D subsurface visualization using a web platform can provide improved communication, education and outreach to non-experts and stakeholders. It allows for the improved understanding of complex relationships and interactions that occur in inaccessible locations where many experimental testbeds exist. The use of a web-based visualization tool lessens the cognitive impact further by reducing the need of specialized software. Users can define their own exploration of a 3D or 4D scene, adding and removing data as needed, and they are able to make informed decisions based on accurate model visualizations, while providing a collaborative tool that can be accessed on any platform using a browser window. Here we show the tool with example geophysical data collected from the EGS Collab project that includes borehole logs and preliminary conductivity model results. The tool is also able to point to real time streams to display up-to-the-second data as an experiment is ongoing. This level of latency can also provide operators with essential information that can direct an experiment’s progress. Additionally, this tool can leverage augmented and virtual reality (AR, VR) capabilities of certain mobile devices and head-mounted displays, providing further engaging visualization possibilities.

1. INTRODUCTION & BACKGROUND

Three and 4D visualization is an appropriate and intuitive way to represent subsurface geophysical data. The regions of study are always inaccessible so visualization will always be required to represent collected subsurface information.

However, data visualization within the geosciences is often limited to 2D slices, static views of 3D representations flattened onto a 2D plane for publication, or a predefined camera path around a 3D structure of interest. These visuals are limiting and are often misunderstood, requiring the observer to reconstruct the 3D structures often with a lack of depth cues such as occlusion or perspective distortion.

Geophysical interpretation often requires the overlap of disparate datasets to glean the full understanding of the processes that are playing out. Visualization tools must be able to synthesize a variety of data types and formats and display them in an intuitive way to be effective. A 4D representation is the most true-to-life and therefore requires the least spatial reasoning when presented well. Furthermore, the spatial relationships between complex 3D shapes are much more intuitively understood when visualized in 3D. There is less onus on the viewer to reconstruct the 3D scene from dimension reduced cross-sections that are often used due to the current prevalence of 2D platforms such as screens and documents.
Effects of Acupuncture on Neuropathic Pain: Mechanisms in Animal Models
Authors: Jang Jae-Hwan , Park Hi-Joon
Published: September 2022

Neuropathic pain is a chronic condition/disease characterized by mechanical and thermal pain. Neuropathic pain can have various comorbidities such as depression, anxiety disorders and cognitive impairment, and as a result, can have a detrimental effect on quality of life. Pain and comorbid symptoms are often complicated, intertwined, affect each other, and present difficulties in treatment. Therefore, it is necessary to improve both pain and comorbid symptoms to treat neuropathic pain. Acupuncture is effective in treating not only pain but other conditions/diseases such as depression, anxiety, and cognitive impairment. Recently, acupuncture was reported to be effective in improving comorbid symptoms in patients with chronic pain. This review aimed to describe the mechanisms of action of acupuncture on the brain with respect to the improvement of comorbid symptoms that appeared in animal models of chronic neuropathic pain. Comorbidity-pain studies were comprehensively reviewed. Both manual acupuncture and electroacupuncture improved not only mechanical and thermal pain but also comorbid symptoms such as depression, anxiety, and cognitive impairment in patients with chronic neuropathic pain. The results of this review suggest that comorbid symptoms can be improved through various mechanisms, including the dopamine system in the brain, glutamate system, inflammation, epigenetic modulation, and mitochondrial function.
Pemanfaatan Vidam (Video Animasi) Etika Politik dalam Islam Untuk Menambah Wawasan Kepemimpinan Siswa Kelas IV SD
Authors: Amaria Wa Ode Lely , Amelia Rina Riana , Maharani Puteri Intan Risma , Aeni Ani Nur
Published: September 2022

Saat ini teknologi informasi dan komunikasi sudah berkembang sangat pesat. Contohnya pada proses pembelajaran, yang mana sekarang ini dilaksanakan secara daring (Dalam Jaringan) semenjak adanya pandemi covid-19. Pengembangan Video Animasi menjadi salah satu strategi yang dapat digunakan oleh guru dalam proses pembelajaran, karena media ini sangat mudah untuk dibuat serta diakses oleh peserta didik. Dengan Video Animasi ini, diharapkan siswa dapat secara mudah memahami materi yang disampaikan oleh guru. Dalam penelitian ini, digunakan metode desain and development atau desain dan pengembangan yang mana pada penelitian ini menggunakan Vidam (Video Animasi) yang berisi materi mengenai etika politik dalam islam dan bertujuan untuk menambah wawasan kepemimpinan anak sekolah dasar. Oleh karena itu, dibuat materi kepemimpinan ini dengan cara yang berbeda agar mereka memahami bahwa menjadi seorang pemimpin yang baik itu harus mengetahui etika dalam berpolitik dan juga menjadikan mereka sebagai pemimpin yang menjadi teladan bagi seluruh masyarakat.
Yuk Belajar PKn Menjadi Sebuah "Alat" Bagi Guru PKn Dalam Mengembangkan Cara Mengajar dan Belajar Peserta Didik Di Era Pandemi
Authors: Rahmi Desi Afianti
Published: September 2022

Tujuan program kegiatan Yuk Belajar PKn ini yaitu untuk mengembangkan cara mengajar dan belajar peserta didik di era pandemi dan sebagai "alat" bantu bagi guru PKn dalam mencapai pembelajaran terbaik dan efektif bagi pembelajaran dalam jaringan (online) dan  luar jaringan (offline) bagi pesera didik  kelas XII SMAN 1 Tamansari Bogor. Program kegiatan ini dilakukan dengan terintegrasi antara Youtube dan Google Classroom sebagai wadah untuk mudah mengaksesnya. Fitur yang diberikan Yuk Belajar PKn (yang sudah terintegrasi dengan Google Classroom) bagi siswa: Video Pembelajaran, Materi PKn dalam Powerpoint, Rangkuman dan  berbagai quiz evaluasi yang bisa diakses kapanpun di manapun. Cara belajar menggunakan Yuk Belajar PKn yang sudah terintegrasi: Minggu pertama (Siswa diberikan materi berupa Video, Ppt dan rangkuman. Minggu kedua adalah melanjutkan sub pematerian sampai sub pematerian anggap selesai. Minggu ketiga  adalah Ulangan harian, karena sudah mendapatkan materi yang mudah diakses. Minggu keempat adalah pengulangan, sehingga siswa lebih nyaman dalam mengakses materi pembelajaran.
نظرية التطوّر قراءة من منظور قرآني
Authors: Dr. Tahsin Abdul Rahman
Published: September 2022

البحث تناول موضوعاً شغل فكر علماء الإسلام بخصوص في القرن العشرين من الميلاد، وهو كون نظرية التطوّر الداروينية تتنافى مع النصوص الدينية وبخاصة القرآن الكريم أم لا تتنافى؟ وفي هذا المجال أوردنا في البداية شرحاً مقتضباً عن نظرية التطوّر والنظرية المضادة لها، وهي نظرية الثبات والقضايا التي تدور حولهما، ثمّ أوردنا كلمات بعض القائلين بكلّ من النظريتين. والمهم من وجهة نظر دينية هو معرفة ما إذا كانت النظرية الداروينية مخالفة للنصوص القرآنية أم غير متنافية معها. فسردنا أدلّة أولئك الذين يرون وجود تناف بين نصوص القرآن والنظرية، كما أوردنا أدلة اولئك الذين يرون نصوص القرآن متوافقة مع النظرية. وأوردنا أيضاً الآيات التي لا يبدو منها تأييد لأي من النظريتين ذات الصلة (التطوّر والثبات). وناقشنا أدلّة الطرفين، وما انتهينا إليه هو رؤية تختلف عن المألوف، وهي كون الدين والكتب السماوية تحمل في طياتها أهدافاً غير الأهداف التي يسعى إليها البشرية والعلماء، وكلّ من علماء الطبيعة والدين يسعون لأهداف مختلفة، فالعلماء يسعون لكشف مجهولات الطبيعة، بينما يسعى الدين للتهذيب وإقرار قوانين تعالج النفوس وتصحّح سيرة البشرية في شؤون منها استخدام العلم بالنحو الصحيح ولا تداخل بين الطرفين، ولا ينبغي لنا أن نستكشف المجهولات الطبيعية من خلال الكتب السماوية التي تستهدف أموراً غيرها التي يستهدفها العلم، وإلاّ كان عملنا تحميلاً للنصوص الدينية بما لا تحتمله. وما ينبغي القول به في هذا المجال هو أنّ النصوص الدينية ذات الصلة بالموضوع لم تتطرّق للنظريتين أصلاً، وقراءة البعض لها بما ينسجم مع كلّ من النظريتين قراءة مخالفة للهدف الأساس من الدين وبعثة الأنبياء، ولا ينبغي البحث عن مواضيع علمية مثل الفيزياء والكيمياء أو الأحياء وأصولها في القرآن، فذلك ممّا ينبغي أن تبحث عنه عقول البشرية من خلال مناهجهم المختلفة ولا ينبغي البحث عنه في القرآن.
Dataset de Estimativas populacionais desagregada por município e idade 2014-2020
Authors: Albuquerque Aldéryck Félix de , Barros Abílio Nogueira , Alencar Andreza , Nascimento André , Bittencourt Ibsen Mateus , Mello Rafael Ferreira
Published: September 2022

Neste estudo busca-se solucionar a falta de dados de estimativas populacionais segmentadas por município e idade, no período de 2014 a 2020 para todos os municípios do Brasil, através da criação de um Dataset que fornece estes dados de forma estruturada e enriquecida com características para facilitar seu reuso, partindo de dados oficiais como do IBGE e do Ministério da Saúde e processados por uma metodologia já aprovada por um órgão de Estado. Além da implantação da metodologia para geração do Dataset, também são discutidas oportunidades de melhoria no método de processamento, direcionando assim futuros estudos de desagregação populacional considerando as particularidades dos conjuntos de dados dos órgãos de Estado no Brasil.
Indicadores e Dados Municipais: Um banco de dados para avaliar a eficiência das despesas públicas
Authors: Davis Paula Guelman
Published: September 2022

Este artigo descreve a construção de um banco de dados com dados financeiros e operacionais dos municípios do Brasil. Foram coletados dados públicos referentes a despesas por função (educação, saúde, segurança, entre outros), indicadores e outros dados que refletem a realidade municipal nas áreas de educação, saúde, segurança pública, desenvolvimento, saneamento e situação fiscal. Foram integrados e transformados dados de várias fontes que permitiram estudos sobre a correlação entre a performance dos municípios nos indicadores socioeconômicos e as despesas públicas correspondentes, de forma a acompanhar e avaliar os efeitos das políticas públicas.
Exchange Rate Volatility and Macroeconomic Performance in Nigeria
Authors: Mary Bello Kehinde , Oluseun Olayungbo David , Ayodele Folorunso Benjamin
Published: September 2022

The study examined the asymmetric relationship between exchange rate volatility and macroeconomic performance in Nigeria covering the period between 1986Q1 and 2019Q4. The Non-linear Generalised Autoregressive Distributive Conditional Heteroscedasticity (GARCH) model was employed. The study was motivated as a result of periodic increase in exchange rate of naira to a dollar and instability of macroeconomic variables in the economy. The presence of Autoregressive Distributive Conditional Heteroscedasticity (ARCH) effect established the use of non-linear GARCH models which showed that volatility was persistent over the period of study. Consequently, the result revealed that exchange rate volatility exhibited a positive relationship with trade balance, industrial output and inflation in the study period. Thus, good news prevailed more over bad news in the foreign exchange market. The study therefore recommended that monetary authorities in Nigeria should regulate exchange rate and macroeconomic variables in order to control the general price level in the economy.
Interaction of Grassland Ecosystem with Livelihood and Wildlife Sustainability: Tanzanian Perspectives
Authors: Yoram Kavana Pius , Kija Bukombe John , Kija Hamza , Nindi Stephen , Nkwabi Ally , Lipende Iddi , Maijo Simula , Naftali Baraka , M. Kakengi Victor , Ntalwila Janemary , Ndimuligo Sood , Fyumagwa Robert
Published: September 2022

In Tanzania, pure grasslands cover is estimated to be 60,381 km2, about 6.8% of the total land area, and is distributed in different parts. These grasslands are diverse in dominant grass species depending on rainfall, soil type, altitude, and management or grazing system. They support livestock and wildlife distributed in different eco-tomes and habitats of the country. The potential of grasslands for the livelihood of rural people is explicit from the fact that local people depend solely on natural production to satisfy their needs for animal products. Analysis of grazing lands indicated that livestock population, production of meat, and milk from grasslands increased. But the wildlife population, when considered in terms of livestock equivalent units (Large Herbivore Units) showed a declining trend. The contribution of grasslands to the total volume of meat produced in the country showed a declining state, while milk production showed a slight increase. This situation entails a need to evaluate the grasslands of Tanzania to ascertain their potential for supporting people’s livestock, wildlife, and livelihood. This study concluded that more research is needed to establish the possibility of grasslands to keep large numbers of grazing herbivores for sustainable livestock and wildlife production.
Vortex Dynamics in Complex Fluids
Authors: Ohmura Naoto , Masuda Hayato , Wang Steven
Published: September 2022

The present chapter provides an overview of vortex dynamics in complex fluids by taking examples of Taylor vortex flow. As complex fluids, non-Newtonian fluid is taken up. The effects of these complex fluids on the dynamic behavior of vortex flow fields are discussed. When a non-Newtonian shear flow is used in Taylor vortex flow, an anomalous flow instability is observed, which also affects heat and mass transfer characteristics. Hence, the effect of shear-thinning on vortex dynamics including heat transfer is mainly referred. This chapter also refers to the concept of new vortex dynamics for chemical process intensification technologies that apply these unique vortex dynamics in complex fluids in Conclusions.
Perspective Chapter: Microemulsion as a Game Changer to Conquer Cancer with an Emphasis on Herbal Compounds
Authors: Janani S.K. , Sureshkumar Raman , Dhanabal S.P.
Published: September 2022

Microemulsions are lipid based drug delivery system consisting of oil, water, surfactant and often a co-surfactant. They are prepared in order to deliver the drug in an effective manner so as to obtain the desired therapeutic activity. Compared to other conventional therapy, they can deliver the drug in an efficient manner because of their characteristics like reduced particles size, lipid based drug delivery system, thermodynamic stability and economical scale up. Anti-cancer drugs can be easily incorporated into microemulsion so as to target the cancer cells. This helps in increasing the solubility, permeability and absorption of the poorly soluble and poorly permeable drugs, thereby helping in enhancing the bioavailability of the drug. In this chapter, we are also focusing on the herbal based formulations that will be helpful in effectively fighting against cancer cells with less or no side effects. A light has also been shed on the advantages and disadvantages of the microemulsions that will be helpful in considering them as an effective model to conquer cancer and promote the same in the upcoming years.
Green Energy Applications of Hematite (α-Fe2O3), Magnetite (Fe3O4), and Maghemite (γ-Fe2O3) Nanoparticles Based Hydroelectric Cell
Authors: Chand Verma Kuldeep , Goyal Navdeep
Published: September 2022

Recently invented hydroelectric cell (HEC) is emerging as a better alternative for green electrical energy devices. HEC is fabricated as to generate electricity via splitting of water into H3O+ and OH− ions without releasing any toxic product. In iron oxides, Hematite (α-Fe2O3), magnetite (Fe3O4) and maghemite (γ-Fe2O3) nanoparticles HEC are recently reported for their remarkable electrical response by splitting water molecules. Fe3O4 HEC 4.8 cm2 surface size has delivered 50 mA short circuits current. Li ions into Fe3O4 stabilize electrical cell response to 44.91 mA with open-circuit voltage 0.68 V. Maghemite based HEC delivered a maximum short circuit current 19 mA with emf 0.85 V using water 200 μL. Maximum off-load output power 27.6 mW has been delivered by 4.84 cm2 area hematite-HEC which is 3.52 times higher with 7.84 mW power as generated by Li-Mg ferrite HEC. Maximum electrical power 16.15 mW delivered by maghemite HEC is 0.58, 0.42 times lower than respective magnetite, hematite HECs. In more applicability of iron oxides, the multiferroic nanocomposites of BaTiO3 with 85% CoFe2O4 has been shown maximum short circuit current 7.93 mA and 0.7 V emf by sprinkling few drops of water on HEC surface. Li0.3Ni0.4Fe2.3O4 and Mg0.8Li0.2Fe2O4 HECs also have some remarkable results for green energy generation.