bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluating Mental Health and Wellbeing of Postgraduate Researchers: Prevalence and Contributing Factors
Authors: Milicev Jelena , McCann Mark , Simpson Sharon A. , Biello Stephany M. , Gardani Maria 
Published: December 2021

AbstractHigh rates of mental ill-health in postgraduate researchers (PGRs) represent a significant barrier to life satisfaction and academic success. Nevertheless, there is little knowledge about the extent and origins of mental health problems of PGRs in the UK. The current study addresses this gap by investigating the prevalence and provenance of anxiety, depression, sleep problems, subjective mental wellbeing, and suicide behaviours of PGRs in the UK. An online survey (N = 479) was used to measure the mental health outcomes and assess their relationships with demographic, trait and academic variables, policy, and social support. We found a high prevalence of mental ill-health and low levels of wellbeing in the current sample. Factors associated with poorer outcomes were female and non-binary gender, non-heterosexual identity, maladaptive perfectionism, workaholism and being in the 5th year of study or above. Resilience, adaptive perfectionism, higher levels of social support and positive evaluations of progress and preparation, departmental climate, and supervisory relationship were associated with more positive outcomes. The current findings contribute new knowledge about the prevalence of mental health symptoms in PGRs in the UK, implying that institutional efforts to improve PGR wellbeing should include strategies to promote equality, diversity, resilience, integration, social support, and work-life balance of PGRs.
‘Save the queen’: female national wheelchair basketball players in gender-segregated and gender-mixed competitive sport
Authors: Greve Steffen , Süßenbach Jessica 
Published: December 2021

AbstractIn the German National Wheelchair Basketball League, men and women play together. On the national teams, on the other hand, they play separately according to gender. In addition, people without disabilities can also participate in wheelchair basketball. The differences in terms of disability and gender are to be classified and, if possible, eliminated in the competition with a classification system. The intersectional analysis of 12 biographical interviews with current national team players shows a clear reproduction of a traditional gender order. The women report various hierarchical relationships on the playing field that are obviously based on gender. Men play in more important positions and are considered more efficient. Yet these phenomena are mostly taken for granted and hardly questioned. Likewise, certain characteristics are attributed and certain roles are assigned to female players based on their gender. The men interviewed do not see these phenomena or do not reflect on them critically. The difference category of disability also has an influence on the competition setting and the gender discrimination.
Naive Introspection in the Philosophy of Perception
Authors: Spener Maja 
Published: December 2021

AbstractIn this paper I critically examine uses of introspection in present-day philosophy of perception. First, I introduce a distinction between two different meanings of the term ‘introspection’: introspective access and introspective method. I show that they are both at work in the philosophy of perception but not adequately distinguished. I then lay out some concerns about the use of introspection to collect data about consciousness that were raised in over a hundred years ago, by some early experimentalist psychologists, part of so-called ‘Introspectionist Psychology’. As I argue, these concerns apply to current philosophical uses of introspection but they are not acknowledged, much less addressed. I explain this by applying the distinction between introspective access and introspective method. As a result, extant arguments relying on introspection-based phenomenal descriptions are methodologically problematic. These problems do not call into question the use of introspection in theorising altogether. But we need to take more care in how we use it.
Optimization of insulation on subsea oil and gas equipment
Authors: Somassoundirame Ramechecandane , Nithiyananthan Eswari 
Published: December 2021

AbstractOptimization of insulation on subsea oil and gas equipment can lead to significant cost and weight reduction. A judicious combination of commercially available Finite Element Analysis (FEA) software with evolutionary optimization algorithms can efficiently serve this purpose. In the present study, the optimization of insulation on a gate valve has been presented with due emphasis on the methodology adapted. A parameterized model of the gate valve with several dimensions of interest has been chosen for the numerical experiment. Of the various Design of Experiment (DOE) techniques, the Optimal Space Filling (OSF) method has been considered for generating the samples owing to its robustness and the associated computational cost. The insulation in subsea systems is usually supposed to satisfy two contradicting constraints, it must be ensured that the temperature of the production fluid remains above the Hydrate Formation Temperature (HFT) and at the same time the production fluid temperature cannot be too high, as to create structural damage of the seals in High Pressure High Temperature (HPHT) applications. The sample cases are run simultaneously in a cluster and a response surface is created using genetic aggregation using the various samples those are generated by OSF. The resulting response surface is finally subjected to optimization using the calculus based/gradient based methods. In the present investigation, the optimization is performed using the NonLinear Programming with Quadratic Lagrangian (NLPQL) and Adaptive Single Objective (ASO) Methods. The results obtained show that almost two thirds of the insulation can be effectively removed without compromising on the thermal efficiency of the system. Similar savings have been witnessed in several other cases/subsea geometries that the authors are aware of. The presented case is truly representative of a wide class of subsea applications and the proposed methodology can be suitably adjusted to customer specific requirements to provide suitable results.
A new three-dimensional effective water-flooding unit model for potential tapping of remained oil in the reservoirs with rhythmic conditions
Authors: Zhu Weiyao , Zou Cunjia , Wang Jiulong , Liu Wenchao , Wang Jiqiang 
Published: December 2021

AbstractAfter long-term water injection development, most of the oilfields in China have entered the stage of high-water cut, which has reached up to 90%. Due to the strong heterogeneity of the reservoir, more than 50% of the oil remains underground in most oilfields. Therefore, how to predict the distribution and content of remaining oil quickly and accurately in heterogeneous reservoir has become the key of EOR. In this paper, a new effective water-flooding unit model is established based on a three-dimensional flow function, which can characterize the influence of vertical heterogeneity on flow and the streamline distribution. In addition, two shape functions are defined in the model to characterize the oil–water two-phase flow characteristics in an injection-production unit. The results show that the streamline in the lower part of the positive rhythm reservoir is denser, which leads to the formation of dominant seepage channel with ease. However, for the reverse rhythm reservoir, dominant seepage channel forms in the upper part of the reservoir. Besides, for the two types of reservoirs, the greater the permeability difference is, the faster the water cut increases. Furthermore, under the same rhythm condition, the positive rhythm reservoir reaches 90% water cut half a year earlier than the anti-rhythm reservoir. This study provides new insight and guidance for the development of remaining oil in rhythmic reservoirs.
Hydrocarbon reservoir characterization of “Otan-Ile” field, Niger Delta
Authors: Fagbemigun Tokunbo Sanmi , Ayuk Michael Ayu , Oyanameh Olufemi Enitan , Akinrinade Opeyemi Joshua , Amosun Joel Olayide , Sanuade Oluseun Adetola , Hammed Olaide Sakiru , Oyebamiji Ajibola Rashidat 
Published: December 2021

AbstractOtan-Ile field, located in the transition zone Niger Delta, is characterized by complex structural deformation and faulting which lead to high uncertainties of reservoir properties. These high uncertainties greatly affect the exploration and development of the Otan-Ile field, and thus require proper characterization. Reservoir characterization requires integration of different data such as seismic and well log data, which are used to develop proper reservoir model. Therefore, the objective of this study is to characterize the reservoir sand bodies across the Otan-Ile field and to evaluate the petrophysical parameters using 3-dimension seismic and well log data from four wells. Reservoir sands were delineated using combination of resistivity and gamma ray logs. The estimation of reservoir properties, such as gross thickness, net thickness, volume of shale, porosity, water saturation and hydrocarbon saturation, were done using standard equations. Two horizons (T and U) as well as major and minor faults were mapped across the ‘Otan-Ile’ field. The results show that the average net thickness, volume of shale, porosity, hydrocarbon saturation and permeability across the field are 28.19 m, 15%, 37%, 71% and 26,740.24 md respectively. Two major faults (F1 and F5) dipping in northeastern and northwestern direction were identified. The horizons were characterized by structural closures which can accommodate hydrocarbon were identified. Amplitude maps superimposed on depth-structure map also validate the hydrocarbon potential of the closures on it. This study shows that the integration of 3D seismic and well log data with seismic attribute is a good tool for proper hydrocarbon reservoir characterization.
Characterization and analysis of naturally fractured gas reservoirs based on stimulated reservoir volume and petro-physical parameters
Authors: Al-Rubaye Ali , Al-Yaseri Ahmed , Ali Muhammad , Ben Mahmud Hisham 
Published: December 2021

AbstractFracture is one of the most important geological phenomena that affect the production of hydrocarbon compounds in broken carbonate reservoirs. However, fracture controlling factors must be combined with well data to achieve accurate fracture modeling. Therefore, structural data, drilling data, well flow diagrams, cores data, wells production data, and dynamic reservoir data have been considered here. Finally, by combining the above-mentioned information and through statistical and mathematical methods, the mechanism of fracture creation, general trends, and dominant fracture patterns are determined. These patterns are directly related to the tectonic regime and the stresses governing the region. For the first time, in this paper, we divided Zubair carbonate gas reservoir into 10 zones based on porosity and water saturation, and shale volume variation. We conclude that just four-zone of these are economic producible. Besides, the dominant lithology of this formation is more than limestone and a small number of thin shale layers. We defined types of cross-sectional petro-physical graphs and confirmed them by the geological graphic diagram prepared at the head.
A coupling flow model for fractured horizontal well and anisotropic tight gas reservoir
Authors: Lian P. Q. , Ma C. Y. , Duan T. Z. , Zhao H. W. 
Published: December 2021

AbstractThe development of multistage fracturing technology in horizontal wells is a great impulsion to the successful development of unconventional resources. The hydraulic fractures distribute regularly along the horizontal wellbore, forming a seepage channel for fluids in tight gas reservoir and greatly improving the productivity of horizontal wells. Based on Green function and Neumann product principle, we establish a flow model of fractured horizontal well coupled with anisotropic tight gas reservoir under both unsteady state and pseudo-steady state and propose a method to solve this model. The calculation results show that flow rate of horizontal well under the early unsteady state is larger than that under the pseudo-steady state. There is no interference among fractures in the early unsteady state, and flow rate is in direct proportion to fracture numbers. Affected by frictional and acceleration pressure drop, flow rate of the end fractures is obviously larger than other fractures in pseudo-steady state. The permeabilities in different directions have great influence on well flow rate distribution. With the increasing Kx, the interference between the fractures is reduced, and the flow distribution is more balanced. When Ky becomes larger, the interference between fractures are stronger, and the “U” shape distribution of the wellbore flow is more significant.
Numerical simulation on the effect of fractures geometries for shale gas development with discrete fracture network model
Authors: Liu Songze , Wei Jianguang , Ma Yuanyuan , Liu Xuemei , Yan Bingxu 
Published: December 2021

AbstractThe shale gas reservoir is regarded as a dual medium consisting of fracture (hydraulic fracture and discrete natural fracture network) and rock matrix, the seepage process in the fracture and rock matrix is fully considered and a mathematical model of seepage flow in accordance with Darcy's law was established. The results show the influence order of hydraulic fracture geometry on the cumulative production. Compared with the hydraulic fracture aperture of 10–4 m, when the aperture is 10–5 m and 10–6 m, the cumulative production is reduced by 88.0% and 99.7%, respectively. Compared with the hydraulic fracture length is 100 m, when the length is 200 m and 300 m, the cumulative production is increased by 38.2% and 62.4%, respectively. The increase in the natural fracture aperture increases the fracture permeability, which make it more conducive to gas flow into the fracture, thereby increasing the cumulative production. The increase in the number of natural fractures makes the connectivity of the shale reservoir becomes better and the cumulative production increases more.
Research on numerical method for evaluation of vertical well volume fracturing effect based on production data and well test data
Authors: Xia Debin , Yang Zhengming , Li Daolun , Zhang Yapu , Zhao Xinli , Yao Lanlan 
Published: December 2021

AbstractVolume transformation technology has become a key technology for developing low-permeability/tight oil and gas reservoirs. Evaluating the post-fracturing effect is very important for the development plan formulation and fracturing plan evaluation. In this paper, the vicinity of the main fracture is divided into the main fracture zone and the secondary fracture zone. The main fracture with infinite conductivity and the branch fracture with increased permeability are used to describe the transformation area. Based on this physical model, a numerical model considering the nonlinear seepage characteristics of the reservoir, stress sensitivity, wellbore storage and skin effects was established. Based on this numerical model, a comprehensive evaluation method for the fracturing effect of volume modification of vertical wells based on well test data and production data was established and this method was applied to three typical vertical wells. The results show that conventional vertical fracturing vertical wells can only form a single primary fracture and the range of equivalent permeability increase is very small. Volume fracturing can form a fracture network composed of primary fractures and secondary fractures, and increase the equivalent permeability of the fracture network area. The fracture half-length, equivalent permeability and reconstruction area of the volume fracturing well are dynamically changing and gradually decrease with the increase in production time and the fracturing effect becomes weak until it fails.
New proxy models for predicting oil recovery factor in waterflooded heterogeneous reservoirs
Authors: Al-Jifri Mohamed , Al-Attar Hazim , Boukadi Fathi 
Published: December 2021

AbstractTo predict the recovery factor (RF) in waterflooded layered oil reservoirs, two empirical relationships were derived. Both correlations use four independent variables. These are reservoir heterogeneity (characterized by permeability variation coefficient), permeability anisotropy (ratio of vertical to horizontal permeability), viscosity of the injected water, and water injection rate. One of the correlations estimates RF at water breakthrough time (RFBT) and the other evaluates RF at the end of project (RFEOP). Each correlation comes in an expanded form with more parameters and a reduced form with fewer parameters. Both models are based on the global linear model. Eclipse black-oil simulation was used to determine RF for generic reservoirs with different combinations of permeability variation, permeability anisotropy, injected water viscosities, and water injection rates. A total of 192 data sets have been generated. Out of these, 144 data sets (about 75% of the generated sets) were used for model development and 48 data sets (about 25% of the generated sets) were used for model testing and validation. The expanded forms of the new developed correlations gave reliable estimates of RFBT and RFEOP with absolute average percent difference (AAPCD) of 6.9 and 1.02, respectively. The reduced forms yielded slightly higher AAPCDs of 8.30 and 1.04, respectively. When tested against 48 simulation-generated data sets, the expanded forms yielded excellent fits for RFBT and RFEOP with AAPCDs of 14 and 6.5, respectively. The reduced forms showed comparable fit with AAPCDs of 16.9 and 6.70, respectively. The highest RFEOP of 50.6% was achieved for a generic reservoir with a permeability variation in V = 0.1 and a permeability anisotropy of kz/kx = 1.0. This particular reservoir needs to be waterflooded using a water viscosity of µw = 1.0 cp and a water injection rate of qi = 10,000 bpd. Finally, when tested against the Guthrie–Greenberger and the API statistical study, using a single field data set, the proposed correlations gave higher absolute percent difference of 22.9 and 22.7 compared to 0.758 and 19.2 for Guthrie–Greenberger and the API statistical study, respectively.
The implementation of Water Alternating (WAG) injection to obtain optimum recovery in Cornea Field, Australia
Authors: Abdullah Nurafiqah , Hasan Nurul 
Published: December 2021

AbstractThe Water Alternating Gas (WAG) process is a cyclic process of injecting alternating water followed by gas. The main purpose of WAG injection is to improve both macroscopic and microscopic sweep efficiency, maintaining nearly initial high pressure, slow down the gas breakthrough and reduced oil viscosity. WAG injection also decreases the residual oil saturation resulted from the flow of three phases and effects associated with relative permeability hysteresis. The study area is in the Cornea Field located in Browse Basin, Western Australia. This study is conducted because there is no investigation on WAG injection feasibility in this field. In this study, two-phase bounding imbibition and drainage relative permeability model (Stone 1 and Stone 2) along with two-phase hysteresis model (Land, Carlson or Killough) were used. From the result, Carlson two-phase hysteresis model with Stone 1 correlation shows more oil was recovered. Therefore, it is a feasible model to be used compared with other models. From sensitivity analysis, it shows that highest oil was recovered at WAG ratio 1:1. Since it is a miscible reservoir, 1:1 ratio is more efficient and it is insensitive to trapping. Also, oil production increased with the shortest WAG cycle time at 180 days due to minimum miscibility pressure reached. In addition, it is best to inject water as the first phase to be injected into the reservoir compared to CO$$_{2}$$

2

because water has high mobility ratio while CO$$_{2}$$

2

can result in early breakthrough in the reservoir.
On evaluating the potential of nanocomposites for heavy oil recovery
Authors: Inoue Hiroki , Nguele Ronald , Katia Nchimi Nono , Sasaki Kyuro 
Published: December 2021

AbstractThe present work investigates potential of nanocomposite (NCP) for enhancing the production in heavy oil formation. NCP was extracted from bauxite ore and the spectral characterization revealed that NCP was a crystalline material whose matrix consists of 64.5 wt.% alumina oxide (Al2O3), 15.7 wt.% iron oxide (Fe2O3), and 19.8 wt.% silica oxide (SiO2). The nanocomposite fluid, obtained by dispersing NCP into the targeted formation brine, showed a good dispersion over the two first days beyond which a hetero-aggregation, visible to the naked eye, was observed. Coreflooding assays, performed on Berea sandstone saturated with a heavy mineral oil (ρ = 0.854 g/cm3), revealed that 0.25wt.% of NCP dispersed in the formation brine yields a poor recovery. However, increasing the load in NCP from 0.25 to 0.75 wt.% and subsequently 1 wt.% using the same formation brine, showed an increase in the oil recovery up to 14.1% after the waterflooding stage. It was further found that the RF could be as high as 18.3% if 0.25 wt.% NCP was dispersed in a surface-active material (Polyvinyl alcohol, PVA in this study). The result was 4% higher than a scenario in which PVA was used alone. Moreover, it was shown that altering the composition of the preflush could increase the production to up to 11.3%. A comparative analysis with single nanoparticle revealed that the EOR using NCP was six-fold higher compared to that of SiO2 taken alone and 1.5-fold lower than those of Al2O3 or Fe2O3 taken alone.
Geomechanical analysis of formation deformation and permeability enhancement due to low-temperature CO2 injection in subsurface oil reservoirs
Authors: Khurshid Ilyas , Fujii Yoshiaki 
Published: December 2021

AbstractSeveral benefits of CO2 injection are reported in the literature such as its ability to mitigate greenhouse gas emissions and the increase in oil recovery at a low cost. However, the correlated reservoir-engineering problems with low-temperature CO2 injection including formation damage and leakage risk are still uncertain and has not been comprehensively investigated. This research examines the effect of low-temperature CO2 on lowering of formation breakdown pressure, and the associated formation damage from a geomechanical prospective. This study presents the coupling of the equilibrium stress equation, the system energy balance equation, continuity equation, and saturation equation to develop thermoporoelastic model for the reservoir rock. We determined the cooling-induced formation damage due to decrease in temperature and thermal stresses, formation contraction and tensile stresses, and examine its effects on formation properties, stresses, joint and fracture stability. We observed that low-temperature CO2 would create a low thermal stress region and thus the formation could fail in tension. This process might increase formation permeability but it would decrease the stability of reservoir, basement and caprock. We analyzed several factors affecting formation deformation such as injection rate for both miscible and immiscible CO2 flooding, formation porosity, depth, temperature, and formation breakdown pressure. We also compared our results and findings with experimental data, finding excellent match and similar consequences. Furthermore, as a sequence of low-temperature CO2 injection, the initial formation breakdown pressure was initially at 2560 psi and it reduced to 1928 for immiscible case and 1270 psi for miscible case in the selected case study. We also propose that shallow reservoirs should be avoided for CO2 capture and storage because of stability issues.