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Emerging Advances in Petrophysics: Porous Media Characterization and Modeling of Multiphase Flow

A special issue of Energies (ISSN 1996-1073).

Deadline for manuscript submissions: closed (30 September 2018) | Viewed by 58601

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Special Issue Editors

reservoir simulations; finite element methods; flash calculation; deep learning algorithms
Interests: numerical oil reservoir simulations and computational transport phenomena; computational thermodynamics of reservoir fluid; finite element methods
Special Issues, Collections and Topics in MDPI journals
Department of Civil & Environmental Engineering, University of Alberta, Edmonton, AB, Canada
Interests: wettability evaluation of unconventional resources; rock-fluids interactions; EOR techniques in tight oil formations; surfactant EOR; formation damage reduction; scaling
Special Issues, Collections and Topics in MDPI journals
William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
Interests: gas separation; CO2 capture; polymeric membrane; membrane separation; membrane contactor; membrane absorption; modeling; membrane preparation; membrane characterization
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Petrophysics, especially studies on porous media characterization and multiphase flow, are relevant to multi-disciplinary porous media research, such as hydrocarbon extraction, geosciences, environmental issues, hydrology, biology, and so on. The relevant stakeholders in this issue are the petroleum industry, subsurface water, air and water pollution authorities and service companies, environmental authorities, and bio-material society. Reliable characterization of porous media and multiphase flow functions is crucial to many simulation applications, including studies of residual water or oil in hydrocarbon reservoirs and long-term storage of supercritical CO2 in geological formations.

We invite investigators to submit original research articles, case studies, as well as review articles, to address the challenges that are related to porous media characterization and multiphase flow, which will stimulate continuous efforts on new and modern methods and techniques for petrophysics.

Prof. Dr. Jianchao Cai
Assoc. Prof. Shuyu Sun
Assoc. Prof. Hassan Dehghanpour
Dr. Zhien Zhang
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • rock characterization and reconstruction
  • hydrofracturing methods
  • tight porous media analysis
  • pore network modeling
  • upscaling of single-phase and multiphase flows
  • fractal modeling
  • multiscale modeling of porous media flow
  • oil and gas flow in unconventional formations
  • coupled transport phenomena
  • gas capture and storage
  • capillary pressure-saturation curve
  • wettability of geological media and its variation

Published Papers (16 papers)

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Editorial

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5 pages, 160 KiB  
Editorial
Emerging Advances in Petrophysics: Porous Media Characterization and Modeling of Multiphase Flow
by Jianchao Cai, Shuyu Sun, Ali Habibi and Zhien Zhang
Energies 2019, 12(2), 282; https://0-doi-org.brum.beds.ac.uk/10.3390/en12020282 - 17 Jan 2019
Cited by 7 | Viewed by 2554
Abstract
With the ongoing exploration and development of oil and gas resources all around the world, applications of petrophysical methods in natural porous media have attracted great attention. This special issue collects a series of recent studies focused on the application of different petrophysical [...] Read more.
With the ongoing exploration and development of oil and gas resources all around the world, applications of petrophysical methods in natural porous media have attracted great attention. This special issue collects a series of recent studies focused on the application of different petrophysical methods in reservoir characterization, especially for unconventional resources. Wide-ranging topics covered in the introduction include experimental studies, numerical modeling (fractal approach), and multiphase flow modeling/simulations. Full article

Research

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15 pages, 3157 KiB  
Article
Pore Structure Characterization and the Controlling Factors of the Bakken Formation
by Yuming Liu, Bo Shen, Zhiqiang Yang and Peiqiang Zhao
Energies 2018, 11(11), 2879; https://0-doi-org.brum.beds.ac.uk/10.3390/en11112879 - 24 Oct 2018
Cited by 19 | Viewed by 3203
Abstract
The Bakken Formation is a typical tight oil reservoir and oil production formation in the world. Pore structure is one of the key factors that determine the accumulation and production of the hydrocarbon. In order to study the pore structures and main controlling [...] Read more.
The Bakken Formation is a typical tight oil reservoir and oil production formation in the world. Pore structure is one of the key factors that determine the accumulation and production of the hydrocarbon. In order to study the pore structures and main controlling factors of the Bakken Formation, 12 samples were selected from the Bakken Formation and conducted on a set of experiments including X-ray diffraction mineral analysis (XRD), total organic carbon (TOC), vitrinite reflectance (Ro), and low-temperature nitrogen adsorption experiments. Results showed that the average TOC and Ro of Upper and Lower Bakken shale is 10.72 wt% and 0.86%, respectively. The Bakken Formation develops micropores, mesopores, and macropores. However, the Upper and Lower Bakken shale are dominated by micropores, while the Middle Bakken tight reservoir is dominated by mesopores. The total pore volume and specific surface area of the Middle Bakken are significantly higher than those of the Upper and Lower Bakken, indicating that Middle Bakken is more conducive to the storage of oil and gas. Through analysis, the main controlling factors for the pore structure of the Upper and Lower Bakken shale are TOC and maturity, while those for Middle Bakken are clay and quartz contents. Full article
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16 pages, 12366 KiB  
Article
Impacts of the Base-Level Cycle on Pore Structure of Mouth Bar Sand Bars: A Case Study of the Paleogene Kongdian Formation, Bohai Bay Basin, China
by Xixin Wang, Jiagen Hou, Yuming Liu, Ling Ji, Jian Sun and Xun Gong
Energies 2018, 11(10), 2617; https://0-doi-org.brum.beds.ac.uk/10.3390/en11102617 - 01 Oct 2018
Cited by 3 | Viewed by 2453
Abstract
The pore structure of rocks can affect fluid migration and the remaining hydrocarbon distribution. To understand the impacts of the base-level cycle on the pore structure of mouth bar sand bodies in a continental rift lacustrine basin, the pore structure of the mouth [...] Read more.
The pore structure of rocks can affect fluid migration and the remaining hydrocarbon distribution. To understand the impacts of the base-level cycle on the pore structure of mouth bar sand bodies in a continental rift lacustrine basin, the pore structure of the mouth bar sand bodies in the ZVC (ZV4 + ZV5) of the Guan195 area was studied using pressure-controlled mercury injection (PMI), casting sheet image and scanning electron microscopy (SEM). The results show that three types of pores exist in ZVC, including intergranular pores, dissolution pores, and micro fractures. The porosity is generally between 1.57% and 44.6%, with a mean value of 19.05%. The permeability is between 0.06 μm2 and 3611 μm2, with a mean value of 137.56 μm2. The pore structure heterogeneity of a single mouth bar sand body in the early stage of the falling period of short-term base-level is stronger than that in the late stage. During the falling process of the middle-term base level, the pore structure heterogeneity of a late single mouth bar sand body is weaker than that of an early single mouth bar sand body. In the long-term base-level cycle, the pore structure heterogeneity of mouth bar sand bodies becomes weaker with the falling of the base-level. Full article
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14 pages, 2331 KiB  
Article
Engineering Simulation Tests on Multiphase Flow in Middle- and High-Yield Slanted Well Bores
by Dan Qi, Honglan Zou, Yunhong Ding, Wei Luo and Junzheng Yang
Energies 2018, 11(10), 2591; https://0-doi-org.brum.beds.ac.uk/10.3390/en11102591 - 28 Sep 2018
Cited by 5 | Viewed by 2602
Abstract
Previous multiphase pipe flow tests have mainly been conducted in horizontal and vertical pipes, with few tests conducted on multiphase pipe flow under different inclined angles. In this study, in light of mid–high yield and highly deviated wells in the Middle East and [...] Read more.
Previous multiphase pipe flow tests have mainly been conducted in horizontal and vertical pipes, with few tests conducted on multiphase pipe flow under different inclined angles. In this study, in light of mid–high yield and highly deviated wells in the Middle East and on the basis of existent multiphase flow pressure research on well bores, multiphase pipe flow tests were conducted under different inclined angles, liquid rates, and gas rates. A pressure prediction model based on Mukherjee model, but with new coefficients and higher accuracy for well bores in the study block, was obtained. It was verified that the newly built pressure drawdown prediction model tallies better with experimental data, with an error of only 11.3%. The effect of inclination, output, and gas rate on the flow pattern, liquid holdup, and friction in the course of multiphase flow were analyzed comprehensively, and six kinds of classical flow regime maps were verified with this model. The results showed that for annular and slug flow, the Mukherjee flow pattern map had a higher accuracy of 100% and 80–100%, respectively. For transition flow, Duns and Ros flow pattern map had a higher accuracy of 46–66%. Full article
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15 pages, 3657 KiB  
Article
Evaluation of the Vertical Producing Degree of Commingled Production via Waterflooding for Multilayer Offshore Heavy Oil Reservoirs
by Fei Shen, Linsong Cheng, Qiang Sun and Shijun Huang
Energies 2018, 11(9), 2428; https://0-doi-org.brum.beds.ac.uk/10.3390/en11092428 - 13 Sep 2018
Cited by 12 | Viewed by 3165
Abstract
Recently, commingling production has been widely used for the development of offshore heavy oil reservoirs with multilayers. However, the differences between layers in terms of reservoir physical properties, oil properties and pressure have always resulted in interlayer interference, which makes it more difficult [...] Read more.
Recently, commingling production has been widely used for the development of offshore heavy oil reservoirs with multilayers. However, the differences between layers in terms of reservoir physical properties, oil properties and pressure have always resulted in interlayer interference, which makes it more difficult to evaluate the producing degree of commingled production. Based on the Buckley–Leverett theory, this paper presents two theoretical models, a one-dimensional linear flow model and a planar radial flow model, for water-flooded multilayer reservoirs. Through the models, this paper establishes a dynamic method to evaluate seepage resistance, sweep efficiency and recovery percent and then conducts an analysis with field data. The result indicates the following: (1) the dynamic difference in seepage resistance is an important form of interlayer interference during the commingled production of an offshore multilayer reservoir; (2) the difference between commingled production and separated production is small within a certain range of permeability ratio or viscosity ratio, but separated production should be adopted when the ratio exceeds a certain value. Full article
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9 pages, 2324 KiB  
Article
The Creep-Damage Model of Salt Rock Based on Fractional Derivative
by Hongwei Zhou, Di Liu, Gang Lei, Dongjie Xue and Yang Zhao
Energies 2018, 11(9), 2349; https://0-doi-org.brum.beds.ac.uk/10.3390/en11092349 - 06 Sep 2018
Cited by 47 | Viewed by 3809
Abstract
The use of salt rock for underground radioactive waste disposal facilities requires a comprehensive analysis of the creep-damage process in salt rock. A computer-controlled creep setup was employed to carry out a creep test of salt rock that lasted as long as 359 [...] Read more.
The use of salt rock for underground radioactive waste disposal facilities requires a comprehensive analysis of the creep-damage process in salt rock. A computer-controlled creep setup was employed to carry out a creep test of salt rock that lasted as long as 359 days under a constant uniaxial stress. The acoustic emission (AE) space-time evolution and energy-releasing characteristics during the creep test were studied in the meantime. A new creep-damage model is proposed on the basis of a fractional derivative by combining the AE statistical regularity. It indicates that the AE data in the non-decay creep process of salt rock can be divided into three stages. Furthermore, the authors propose a new creep-damage model of salt rock based on a fractional derivative. The parameters in the model were determined by the Quasi-Newton method. The fitting analysis suggests that the new creep-damage model provides a precise description of full creep regions in salt rock. Full article
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17 pages, 6063 KiB  
Article
Characterization and Prediction of Complex Natural Fractures in the Tight Conglomerate Reservoirs: A Fractal Method
by Lei Gong, Xiaofei Fu, Shuai Gao, Peiqiang Zhao, Qingyong Luo, Lianbo Zeng, Wenting Yue, Benjian Zhang and Bo Liu
Energies 2018, 11(9), 2311; https://0-doi-org.brum.beds.ac.uk/10.3390/en11092311 - 02 Sep 2018
Cited by 30 | Viewed by 3682
Abstract
Using the conventional fracture parameters is difficult to characterize and predict the complex natural fractures in the tight conglomerate reservoirs. In order to quantify the fracture behaviors, a fractal method was presented in this work. Firstly, the characteristics of fractures were depicted, then [...] Read more.
Using the conventional fracture parameters is difficult to characterize and predict the complex natural fractures in the tight conglomerate reservoirs. In order to quantify the fracture behaviors, a fractal method was presented in this work. Firstly, the characteristics of fractures were depicted, then the fracture fractal dimensions were calculated using the box-counting method, and finally the geological significance of the fractal method was discussed. Three types of fractures were identified, including intra-gravel fractures, gravel edge fractures and trans-gravel fractures. The calculations show that the fracture fractal dimensions distribute between 1.20 and 1.50 with correlation coefficients being above 0.98. The fracture fractal dimension has exponential correlation with the fracture areal density, porosity and permeability and can therefore be used to quantify the fracture intensity. The apertures of micro-fractures are distributed between 10 μm and 100 μm, while the apertures of macro-fractures are distributed between 50 μm and 200 μm. The areal densities of fractures are distributed between 20.0 m·m−2 and 50.0 m·m−2, with an average of 31.42 m·m−2. The cumulative frequency distribution of both fracture apertures and areal densities follow power law distribution. The fracture parameters at different scales can be predicted by extrapolating these power law distributions. Full article
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19 pages, 11568 KiB  
Article
Experimental Study on Sensitivity of Porosity to Pressure and Particle Size in Loose Coal Media
by Chenghao Zhang, Nong Zhang, Dongjiang Pan, Deyu Qian, Yanpei An, Yuxin Yuan, Zhe Xiang and Yang Wang
Energies 2018, 11(9), 2274; https://0-doi-org.brum.beds.ac.uk/10.3390/en11092274 - 29 Aug 2018
Cited by 6 | Viewed by 3468
Abstract
A new experimental method for characterizing the porosity of loose media subjected to overburden pressure is proposed based on the functional relationships between porosity, true density, and bulk density. This method is used to test the total porosity of loose coal particles from [...] Read more.
A new experimental method for characterizing the porosity of loose media subjected to overburden pressure is proposed based on the functional relationships between porosity, true density, and bulk density. This method is used to test the total porosity of loose coal particles from the Guobei coal mine in Huaibei mining area, China, in terms of the influence of pressure and particle size on total porosity. The results indicate that the total porosity of loose coal under 20 MPa in situ stress is about 10.22%. The total porosity and pressure obey an attenuated exponential function, while the total porosity and particle size obey a power function. The total porosity of the loose coal is greatly reduced and the sensitivity is high with increased pressure when stress levels are low (shallow burial conditions). However, total porosity is less sensitive to pressure at higher stress when burial conditions are deep. The effect of particle size on the total porosity reduction rate in loose coal is not significant, regardless of low- or high-pressure conditions; i.e., the sensitivity is low. The total porosity remains virtually unchanged as particle size changes when pressure exceeds 20 MPa. Overall, the sensitivity of total porosity to pressure is found to be significantly higher than sensitivity to particle size. Full article
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17 pages, 3995 KiB  
Article
Multifractal Characteristics and Classification of Tight Sandstone Reservoirs: A Case Study from the Triassic Yanchang Formation, Ordos Basin, China
by Zhihao Jiang, Zhiqiang Mao, Yujiang Shi and Daxing Wang
Energies 2018, 11(9), 2242; https://0-doi-org.brum.beds.ac.uk/10.3390/en11092242 - 27 Aug 2018
Cited by 27 | Viewed by 2697
Abstract
Pore structure determines the ability of fluid storage and migration in rocks, expressed as porosity and permeability in the macroscopic aspects, and the pore throat radius in the microcosmic aspects. However, complex pore structure and strong heterogeneity make the accurate description of the [...] Read more.
Pore structure determines the ability of fluid storage and migration in rocks, expressed as porosity and permeability in the macroscopic aspects, and the pore throat radius in the microcosmic aspects. However, complex pore structure and strong heterogeneity make the accurate description of the tight sandstone reservoir of the Triassic Yanchang Formation, Ordos Basin, China still a problem. In this paper, mercury injection capillary pressure (MICP) parameters were applied to characterize the heterogeneity of pore structure, and three types of pore structure were divided, from high to low quality and defined as Type I, Type II and Type III, separately. Then, the multifractal analysis based on the MICP data was conducted to investigate the heterogeneity of the tight sandstone reservoir. The relationships among physical properties, MICP parameters and a series of multifractal parameters have been detailed analyzed. The results showed that four multifractal parameters, singularity exponent parameter (αmin), generalized dimension parameter (Dmax), information dimension (D1), and correlation dimension (D2) were in good correlations with the porosity and permeability, which can well characterize the pore structure and reservoir heterogeneity of the study area, while the others didn’t respond well. Meanwhile, there also were good relationships between these multifractal and MICP parameters. Full article
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17 pages, 5562 KiB  
Article
Flow Simulation of Artificially Induced Microfractures Using Digital Rock and Lattice Boltzmann Methods
by Yongfei Yang, Zhihui Liu, Jun Yao, Lei Zhang, Jingsheng Ma, S. Hossein Hejazi, Linda Luquot and Toussaint Dono Ngarta
Energies 2018, 11(8), 2145; https://0-doi-org.brum.beds.ac.uk/10.3390/en11082145 - 17 Aug 2018
Cited by 34 | Viewed by 3657
Abstract
Microfractures have great significance in the study of reservoir development because they are an effective reserving space and main contributor to permeability in a large amount of reservoirs. Usually, microfractures are divided into natural microfractures and induced microfractures. Artificially induced rough microfractures are [...] Read more.
Microfractures have great significance in the study of reservoir development because they are an effective reserving space and main contributor to permeability in a large amount of reservoirs. Usually, microfractures are divided into natural microfractures and induced microfractures. Artificially induced rough microfractures are our research objects, the existence of which will affect the fluid-flow system (expand the production radius of production wells), and act as a flow path for the leakage of fluids injected to the wells, and even facilitate depletion in tight reservoirs. Therefore, the characteristic of the flow in artificially induced fractures is of great significance. The Lattice Boltzmann Method (LBM) was used to calculate the equivalent permeability of artificially induced three-dimensional (3D) fractures. The 3D box fractal dimensions and porosity of artificially induced fractures in Berea sandstone were calculated based on the fractal theory and image-segmentation method, respectively. The geometrical parameters (surface roughness, minimum fracture aperture, and mean fracture aperture), were also calculated on the base of digital cores of fractures. According to the results, the permeability lies between 0.071–3.759 (dimensionless LB units) in artificially induced fractures. The wide range of permeability indicates that artificially induced fractures have complex structures and connectivity. It was also found that 3D fractal dimensions of artificially induced fractures in Berea sandstone are between 2.247 and 2.367, which shows that the artificially induced fractures have the characteristics of self-similarity. Finally, the following relations were studied: (a) exponentially increasing permeability with increasing 3D box fractal dimension, (b) linearly increasing permeability with increasing square of mean fracture aperture, (c) indistinct relationship between permeability and surface roughness, and (d) linearly increasing 3D box fractal dimension with increasing porosity. Full article
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20 pages, 3340 KiB  
Article
The Effect of Oil Properties on the Supercritical CO2 Diffusion Coefficient under Tight Reservoir Conditions
by Chao Zhang, Chenyu Qiao, Songyan Li and Zhaomin Li
Energies 2018, 11(6), 1495; https://0-doi-org.brum.beds.ac.uk/10.3390/en11061495 - 08 Jun 2018
Cited by 28 | Viewed by 4444
Abstract
In this paper, a generalized methodology has been developed to determine the diffusion coefficient of supercritical CO2 in cores that are saturated with different oil samples, under reservoir conditions. In theory, a mathematical model that combines Fick’s diffusion equation and the Peng-Robinson [...] Read more.
In this paper, a generalized methodology has been developed to determine the diffusion coefficient of supercritical CO2 in cores that are saturated with different oil samples, under reservoir conditions. In theory, a mathematical model that combines Fick’s diffusion equation and the Peng-Robinson equation of state has been established to describe the mass transfer process. In experiments, the pressure decay method has been employed, and the CO2 diffusion coefficient can be determined once the experimental data match the computational result of the theoretical model. Six oil samples with different compositions (oil samples A to F) are introduced in this study, and the results show that the supercritical CO2 diffusion coefficient decreases gradually from oil samples A to F. The changing properties of oil can account for the decrease in the CO2 diffusion coefficient in two aspects. First, the increasing viscosity of oil slows down the speed of the mass transfer process. Second, the increase in the proportion of heavy components in oil enlarges the mass transfer resistance. According to the results of this work, a lower viscosity and lighter components of oil can facilitate the mass transfer process. Full article
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20 pages, 5483 KiB  
Article
A Simple Fractal-Based Model for Soil-Water Characteristic Curves Incorporating Effects of Initial Void Ratios
by Gaoliang Tao, Yin Chen, Lingwei Kong, Henglin Xiao, Qingsheng Chen and Yuxuan Xia
Energies 2018, 11(6), 1419; https://0-doi-org.brum.beds.ac.uk/10.3390/en11061419 - 01 Jun 2018
Cited by 28 | Viewed by 3991
Abstract
In this paper, a simple and efficient fractal-based approach is presented for capturing the effects of initial void ratio on the soil-water characteristic curve (SWCC) in a deformable unsaturated soil. In terms of testing results, the SWCCs (expressed by gravimetric water content) of [...] Read more.
In this paper, a simple and efficient fractal-based approach is presented for capturing the effects of initial void ratio on the soil-water characteristic curve (SWCC) in a deformable unsaturated soil. In terms of testing results, the SWCCs (expressed by gravimetric water content) of the unsaturated soils at different initial void ratios were found to be mainly controlled by the air-entry value (Ψa), while the fractal dimension (D) could be assumed to be constant. As a result, in contrast to the complexity of existing models, a simple and efficient model with only two parameters (i.e., D and Ψa) was established for predicting the SWCC considering the effects of initial void ratio. The procedure for determining the model parameters with clear physical meaning were then elaborated. The applicability and accuracy of the proposed model were well demonstrated by comparing its predictions with four sets of independent experimental data from the tests conducted in current work, as well as the literature on a wide range of soils, including Wuhan Clay, Hefei and Guangxi expansive soil, Saskatchewan silt, and loess. Good agreements were obtained between the experimental data and the model predictions in all of the cases considered. Full article
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15 pages, 19631 KiB  
Article
Numerical Study on the Characteristic of Temperature Drop of Crude Oil in a Model Oil Tanker Subjected to Oscillating Motion
by Guojun Yu, Qiuli Yang, Bing Dai, Zaiguo Fu and Duanlin Lin
Energies 2018, 11(5), 1229; https://0-doi-org.brum.beds.ac.uk/10.3390/en11051229 - 11 May 2018
Cited by 7 | Viewed by 4573
Abstract
During tanker transportation, crude oil is heated occasionally to ensure its good flowability. Whether the heating scheme is scientific or not directly influences the safety and economy of the tanker transportation. The determination of a scientific heating scheme requires fully understanding of the [...] Read more.
During tanker transportation, crude oil is heated occasionally to ensure its good flowability. Whether the heating scheme is scientific or not directly influences the safety and economy of the tanker transportation. The determination of a scientific heating scheme requires fully understanding of the characteristic of oil temperature drop during tanker transportation. However, the oscillation caused by the marine environment leads to totally different thermal and hydraulic characteristic from that of the static cases. Therefore, a systematic investigation of thermal and hydraulic process of the motion system is more than necessary. Since the marine is subjected to rotational and/or translational motion, the essence of the temperature drop process is an unsteady mixed convection process accompanied with free liquid surface movement. In this study, the movement of the free liquid surface and the characteristic of the temperature drop of the crude oil in the cargo when the tanker is subjected to rotational motion were investigated using ANSYS FLUENT (15.0, Ansys, Inc., Canonsburg, PA, USA) with user defined functions. The research result shows that the oscillating motion leads to the motion of the free surface, converting the natural convection for the static case to forced convection, and thus significantly enhancing the temperature drop rate. It is found that the temperature drop rate is positively related to the rotational angular velocity. Full article
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19 pages, 4258 KiB  
Article
An Investigation of Parallel Post-Laminar Flow through Coarse Granular Porous Media with the Wilkins Equation
by Ashes Banerjee, Srinivas Pasupuleti, Mritunjay Kumar Singh and G.N. Pradeep Kumar
Energies 2018, 11(2), 320; https://0-doi-org.brum.beds.ac.uk/10.3390/en11020320 - 02 Feb 2018
Cited by 9 | Viewed by 3869
Abstract
Behaviour of flow resistance with velocity is still undefined for post-laminar flow through coarse granular media. This can cause considerable errors during flow measurements in situations like rock fill dams, water filters, pumping wells, oil and gas exploration, and so on. Keeping the [...] Read more.
Behaviour of flow resistance with velocity is still undefined for post-laminar flow through coarse granular media. This can cause considerable errors during flow measurements in situations like rock fill dams, water filters, pumping wells, oil and gas exploration, and so on. Keeping the non-deviating nature of Wilkins coefficients with the hydraulic radius of media in mind, the present study further explores their behaviour to independently varying media size and porosity, subjected to parallel post-laminar flow through granular media. Furthermore, an attempt is made to simulate the post-laminar flow conditions with the help of a Computational Fluid Dynamic (CFD) Model in ANSYS FLUENT, since conducting large-scale experiments are often costly and time-consuming. The model output and the experimental results are found to be in good agreement. Percentage deviations between the experimental and numerical results are found to be in the considerable range. Furthermore, the simulation results are statistically validated with the experimental results using the standard ‘Z-test’. The output from the model advocates the importance and applicability of CFD modelling in understanding post-laminar flow through granular media. Full article
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Review

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19 pages, 6699 KiB  
Review
Prevention of Potential Hazards Associated with Marine Gas Hydrate Exploitation: A Review
by Fangtian Wang, Bin Zhao and Gang Li
Energies 2018, 11(9), 2384; https://0-doi-org.brum.beds.ac.uk/10.3390/en11092384 - 10 Sep 2018
Cited by 33 | Viewed by 4676
Abstract
Marine gas hydrates (MGHs), which have great potential for exploitation and utilization, account for around 99% of all global natural gas hydrate resources under current prospecting technique. However, there are several potential hazards associated with their production and development. These are classified into [...] Read more.
Marine gas hydrates (MGHs), which have great potential for exploitation and utilization, account for around 99% of all global natural gas hydrate resources under current prospecting technique. However, there are several potential hazards associated with their production and development. These are classified into four categories by this paper: marine geohazards, greenhouse gas emissions, marine ecological hazards, and marine engineering hazards. In order to prevent these risks from occurring, the concept of “lifecycle management of hazards prevention” during the development and production from MGHs is proposed and divided into three stages: preparation, production control, and post-production protection. Of these stages, economic evaluation of the resource is the foundation; gas production methods are the key; with monitoring, assessment, and early warning as the guarantee. A production test in the Shenhu area of the South China Sea shows that MGH exploration and development can be planned using the “three-steps” methodology: commercializing and developing research ideas in the short term, maintaining economic levels of production in the medium term, and forming a global forum to discuss effective MGH development in the long term. When increasing MGH development is combined with the lifecycle management of hazards prevention system, and technological innovations are combined with global cooperation to solve the risks associated with MGH development, then safe access to a new source of clean energy may be obtained. Full article
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Other

7 pages, 2981 KiB  
Brief Report
Data Report: Molecular and Isotopic Compositions of the Extracted Gas from China’s First Offshore Natural Gas Hydrate Production Test in South China Sea
by Jianliang Ye, Xuwen Qin, Haijun Qiu, Wenwei Xie, Hongfeng Lu, Cheng Lu, Jianhou Zhou, Jiyong Liu, Tianbang Yang, Jun Cao and Rina Sa
Energies 2018, 11(10), 2793; https://0-doi-org.brum.beds.ac.uk/10.3390/en11102793 - 17 Oct 2018
Cited by 50 | Viewed by 3723
Abstract
Three hundred gas samples recovered from SHSC-4 during China’s first gas hydrate production test in the South China Sea were examined for gas component and isotopic composition. According to the gas chromatography analysis, all the gas samples from SHSC-4 are predominated by CH [...] Read more.
Three hundred gas samples recovered from SHSC-4 during China’s first gas hydrate production test in the South China Sea were examined for gas component and isotopic composition. According to the gas chromatography analysis, all the gas samples from SHSC-4 are predominated by CH4, with minor N2 + O2, as well as trace amounts of CO2, C2H6, and C3H8. No H2S was detected. The molecular and isotopic data of the gas samples fall into the region of “mixed origin” on the plot of C1/(C2 + C3) − δ13C1, which is close to the microbial origin. The discrimination diagram of δ13C1 − δDCH4 shows that the methane in all of the samples is of microbial origin, and is derived from the CO2 reduction. Full article
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