Begell House Inc.
Journal of Porous Media
JPM
1091-028X
21
11
2018
REFLECTION OF INHOMOGENEOUS WAVES AT THE SURFACE OF A DISSIPATIVE POROELASTIC MEDIA
1025-1040
10.1615/JPorMedia.2018021438
Manjeet
Kumari
Department of Mathematics, Indira Gandhi University, Meerpur, India-122503
M. S.
Barak
Department of Mathematics, Indira Gandhi University, Meerpur, India-122503
M.
Kumar
Department of Mathematics, Dr. B. R. Ambedkar Govt. College, Dabwali, India-125104
propagation
attenuation
pore characteristics
reflection coefficients
In the present problem the reflection of plane harmonic waves at the permeable (or impermeable) boundary of dissipative porous solid is investigated. Porous medium is dissipative in nature due to the viscosity of pores fluid. As a result of incident wave at the stress-free surface, it is found that three reflected waves exist in a dissipative porous solid. All the reflected waves are inhomogeneous in nature (i.e., dissimilar direction of propagation and attenuation). The segmentation of incident energy among versatile reflected waves at the stress-free surface is computed at both permeable and impermeable boundaries. Due to the dissipative nature of medium, conservation of net energy flux at the stress-free surface is prevailed in the mien of an interaction energy between two dissimilar waves. The essences of porosity, Poisson's ratio, viscoelasticity, pore characteristics, and wave frequency on various energy shares are depicted graphically and discussed.
EXPERIMENTAL INVESTIGATION ON THE IMPACT OF INITIAL PORE PRESSURE ON BREAKDOWN PRESSURE OF BOREHOLE RADIAL FRACTURE FOR UNSATURATED MORTAR HYDRAULIC FRACTURING UNDER TRUE TRIAXIAL STRESS
1041-1057
10.1615/JPorMedia.2018021402
Bingxiang
Huang
State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and
Technology, Xuzhou, 221116, China
Xinglong
Zhao
State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and
Technology, Xuzhou, 221116, China
Weichao
Xue
State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and
Technology, Xuzhou, 221116, China
Tianyuan
Sun
State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and
Technology, Xuzhou, 221116, China
porous medium
initial pore pressure
hydraulic fracturing
breakdown pressure
According to the conventional theory of hydraulic fracturing, breakdown pressure decreases with an increase in initial pore pressure. However, in the practice of hydraulic fracturing for gassy coal seams, the higher the gas pressure, the higher the pumping water pressure required to inject into the coal seam. The initial pore gas pressure leads to an increase in water injection pressure. How does the initial pore pressure affect the hydraulic fracturing of unsaturated rock and its breakdown pressure? Experiments on hydraulic fracturing for unsaturated cement mortar samples (300 mm × 300 mm × 300 mm) with five degrees of initial pore pressures were conducted. The influencing law of initial pore pressure on breakdown pressure of borehole radial fracture in hydraulic fracturing was studied with a large-sized true triaxial hydraulic fracturing experimental system. The experimental results show that the hydraulic fracturing of rock is primarily controlled by the stress field, initial pore pressure, and water injection pressure. A critical pore pressure gradient exists for the initiation and propagation of hydraulic fracture. When the pore pressure gradient reaches a critical point, the fracture in rock will occur. With an increase in initial pore pressure, the breakdown pressure of rock increases. The subsequent propagation pressure of hydraulic fracture also increases with an increase in initial pore pressure.
STUDY OF PARTICLE DYNAMICS IN A SWIRLING FLUIDIZED BED BY USING A MESH-TYPE AIR DISTRIBUTOR
1059-1068
10.1615/JPorMedia.2018021481
Muhammad Yasin
Naz
University of Agriculture Faisalabad
Shaharin Anwar
Sulaiman
Department of Mechanical Engineering, Universiti Teknologi Petronas, 32610 Bandar Seri
Iskandar, Perak, Malaysia
Yasin
Khan
College of Engineering, King Saud University, 11451 Riyadh, Saudi Arabia
Abdul
Ghaffar
Department of Physics, University of Agriculture, 38040 Faisalabad, Pakistan
Yasir
Jamil
Department of Physics, University of Agriculture, 38040 Faisalabad, Pakistan
Irfan
Ahmad
College of Engineering, King Saud University, 11451 Riyadh, Saudi Arabia
swirling fluidized bed
mesh-type distributor
particle image velocimetry
velocity vector field
Swirling fluidized beds are being operated with several variants of an air distributor. In this study, a new mesh-type variant of the air distributor was used to investigate the swirling fluidized bed dynamics. MATLAB-based particle
image velocimetry of the swirling fluidized bed was carried out by considering different sizes and densities of the
particles. The velocity fields of the swirling bed were generated at different superficial air velocities. These velocity fields were further processed to obtain an average particle velocity at different locations in the bed. It was revealed that the longer beds form two partially differentiable layers in their swirling regime of operation. A thin layer of particles swirled at the bottom of the bed while a thick layer at the top of the bed followed a bubbling regime. Overall, the average velocity of the particles' inventory increased with superficial air velocity. The particles of 3 mm size swirled uniformly
at a superficial air velocity of 1.4 m/s while 4 mm and 6 mm particles underwent stable swirling at superficial air
velocities of 1.5 m/s and 2.2 m/s, respectively.
MODELLING THE FLUID FLOW AND MASS TRANSFER THROUGH POROUS MEDIA WITH EFFECTIVE VISCOSITY ON THE THREE-DIMENSIONAL BOUNDARY LAYER
1069-1084
10.1615/JPorMedia.2018021347
Ramesh B.
Kudenatti
Department of Mathematics, Bangalore University, Central College Campus, Bangalore-560001, India
Shashi Prabha
Gogate S.
Department of Mathematics, Bangalore University, Central College Campus, Bangalore-560
001, India
three-dimensional boundary layer
porous media
effective viscosity
mass transfer
Keller-box
asymptotics
The Brinkman model is used to investigate the steady three-dimensional laminar boundary-layer viscous flow over a
constant and permeable wedge surface in a porous medium by taking an effective viscosity (which is different from fluid
viscosity μ;) μ;eff . The wall surface is assumed to be permeable so that suction/injection is possible. This work is motivated mainly by the lack of consensus in the available literature on the range of effective viscosity, and therefore most of the investigations have considered μ;eff = μ;. Also, the porosity factor of a porous medium has been neglected in several studies. Thus the present work provides a model for quantifying the effective viscosity by incorporating the porosity in the volume averaged Prandtl's boundary layer equations, which are derived from the averaged Navier-Stokes equations for large Reynolds number. Using appropriate similarity transformations to transform the nonlinear boundary-layer equations into two third-order nonlinear coupled ordinary differential equations, a new form of equations is proposed. A well-known numerical Keller-box method is used for the solution of these equations to study fluid flow near the interface between a free fluid and a porous medium. Various results for the velocity profiles and skin frictions are discussed
for all physical parameters involved in the study. The results show that the boundary-layer thickness increases
for enhanced viscosity ratio and porosity, whereas it is found to decrease for other parameters. For certain parameters, the boundary-layer separation appears near the surface but reattachment takes place away from it. However, due to influences of porous and suction, the separation can effectively be controlled. Further, these results are affirmed by the asymptotic solution of the governing equations for far-field behavior. The physical dynamics of these mechanisms are discussed.
NUMERICAL AND OPTIMIZATION STUDY OF MIXED CONVECTION DUE TO A ROTATING CYLINDER IN A POROUS CAVITY
1085-1096
10.1615/JPorMedia.2018021182
Fatih
Selimefendigil
Mechanical Engineering Department, Celal Bayar University, Manisa, 45140, Turkey
Hakan F.
Öztop
Department of Mechanical Engineering, Technology Faculty, Firat University, Elazig, Turkey; Mechanical Engineering Department, Faculty of Engineering, King Abdulaziz University,
P.O. Box 40844, Jeddah 21511, Saudi Arabia
porous medium
rotating cylinder
finite element method
In this study, numerical study and optimization for a mixed convection in a porous cavity due to an inner rotating
cylinder were performed by using the Galerkin weighted residual finite element method. An optimum circular cylinder
size that maximizes average heat transfer along the hot wall was determined, and numerical simulation was performed
for various values of Rayleigh number (between 104 and 106), angular rotational velocity of a circular cylinder (between -0.001 and 0.01), Darcy number (between 10-5 and 10-2), and porosity of the porous medium (between 0.25 and 0.5). The rotating cylinder with optimum size was found to have profound effects on the fluid flow and heat transfer
characteristics, and 107.20% of heat transfer enhancement is obtained at the highest rotational speed when compared to motionless cylinder configuration. Local and average Nusselt number enhances with higher values of Rayleigh number, angular rotational speed of the cylinder (clockwise rotational direction), porosity, and permeability of the porous medium. Average heat transfer rate along the hot wall increases almost linearly with porosity of the porous medium. The average heat transfer rate versus Darcy number shows a saturated-type nonlinear curve near the step,
especially for lower values of Richardson number and Hartmann number.
FRACTAL ANALYSIS OF PORE STRUCTURES IN LOW PERMEABILITY SANDSTONES USING MERCURY INTRUSION POROSIMETRY
1097-1119
10.1615/JPorMedia.2018021393
Fuyong
Wang
Research Institute of Enhanced Oil Recovery, China University of Petroleum (Beijing), No. 18
Fuxue Road, Beijing 102249, P.R. China
Liang
Jiao
Research Institute of Enhanced Oil Recovery, China University of Petroleum (Beijing), No. 18
Fuxue Road, Beijing 102249, P.R. China
Zhichao
Liu
Research Institute of Enhanced Oil Recovery, China University of Petroleum (Beijing), No. 18
Fuxue Road, Beijing 102249, P.R. China
Xiqun
Tan
National Engineering Laboratory for Exploration and Development of Low-Permeability Oil
and Gas Fields, Xi'an 710018, P.R. China
Congle
Wang
Research Institute of Enhanced Oil Recovery, China University of Petroleum (Beijing), No. 18
Fuxue Road, Beijing 102249, P.R. China
Jian
Gao
State Key Laboratory of Enhanced Oil Recovery, Research Institute of Petroleum Exploration
and Development, CNPC, Beijing 100083, P.R. China
low permeability sandstone
pore structure
fractal theory
mercury intrusion capillary pressure (MICP)
permeability
Pore structures of low permeability sandstones collected from the Yanchang Formation in the Ordos Basin of China
were analyzed using mercury intrusion porosimetry (MIP) with fractal theory. Six different fractal models were applied
to calculate the fractal dimension from mercury intrusion capillary pressure (MICP), and the relationships between
the calculated fractal dimensions and the sandstone petrophysical properties were analyzed. The results show that low permeability sandstones have obvious fractal characteristics, and the fractal dimensions calculated from the 3D capillary tube model have the strongest correlations with petrophysical properties and are most suitable for analyzing pore structures. The fractal dimensions of all the pores have strong and positive correlations with the fractal dimensions of small pores but have no obvious correlation with the fractal dimensions of large pores. Compared with the modified Winland model, fractal permeability models can accurately predict the permeability of low permeability sandstones.
THE ROLE OF FRACTURE CAPILLARY PRESSURE ON THE BLOCK-TO-BLOCK INTERACTION PROCESS
1121-1136
10.1615/JPorMedia.2018028668
Morteza
Dejam
Department of Petroleum Engineering, College of Engineering and Applied Science, University
of Wyoming, 1000 E. University Avenue, Laramie, Wyoming 82071-2000, USA
fracture capillary pressure
capillary continuity
block-to-block interaction
oil recover
numerical simulation
Characterization of fractures and the study of multiphase fluid movement through fractures in fractured porous media
present difficult challenges to reservoir engineering. Interaction between porous matrix blocks and fractures plays a significant role in oil recovery from double-porosity reservoirs. The block-to-block interaction (or capillary continuity) between porous matrix blocks is a key contributor to the gas-oil gravity drainage mechanism in the gas-invaded zone of naturally fractured reservoirs, which increases the oil recovery. In a continuum scale, fracture is a part of the stack of blocks where there is a pressure difference between the gas and oil phases inside the fracture (called fracture capillary pressure). However, the physics of this capillary pressure and how it affects the gravity drainage mechanism in a stack of porous matrix blocks through the block-to-block interaction process need to be addressed theoretically. In this work a direct fine-grid numerical simulation along with various fracture capillary pressure models, including zero, constant,
and saturation-dependent Brooks and Corey (1964), van Genuchten (1980), and Dindoruk and Firoozabadi (1995)
functions, are applied to study their influence on oil recovery and therefore the block-to-block interaction process in fractured porous media. Numerical simulation predictions show the positive effect of fracture capillary pressure on oil recovery of a stack porous matrix blocks. The results reveal that the zero fracture capillary pressure model results in a lower ultimate oil recovery factor (23.8%) as compared to the constant (25.8%) and saturation-dependent Brooks and Corey (1964) (28.1%), van Genuchten (1980) (27.5%), and Dindoruk and Firoozabadi (1995) (24.6%) models. These observations are in good agreement with the results in literature. The findings can improve our understanding of the role of fracture capillary pressure on the block-to-block interaction process, which is important in oil recovery from naturally fractured reservoirs using the gravity drainage mechanism.
A NEW SEMIANALYTICAL PRESSURE TRANSIENT MODEL TO INTERPRET WELL TEST DATA IN RESERVOIRS WITH LIMITED EXTENT BARRIERS
1137-1162
10.1615/JPorMedia.2018028846
Meisam
Adibifard
Dave C. Swalm School of Chemical Engineering, Mississippi State University, Starkville,
Mississippi 39759, USA
Mohammad
Sharifi
Department of Petroleum Engineering, Amirkabir University of Technology, Tehran, Iran
well testing
partially faulted reservoirs
limited extent baffle
transient flow
Due to the lack of enough models to interpret transient well test data in reservoirs with limited baffles/faults, a novel
semianalytical model is developed in this study based on the concepts of imaginary wells and superposition in time and
space. The proposed model was validated by comparing its results with outcomes of a numerical well test simulator, and statistical parameters such as root mean square error (RMSE) analysis, residual plots, and the R-squared parameter
were used to verify the accuracy of the model. Furthermore, a sensitivity analysis was performed over the length of the
fault and the distance of the fault from the wellbore. Although RMSE for the derivative data varies between 0.5 and
9 psi for various fault and well scenarios, it varies between 2.88 and 26 psi for the pressure drop data. Residual data scattered around the zero horizontal line and R-squared values larger than 0.99 revealed the robustness of the proposed algorithm. To reduce the computational time, a logarithmic function was applied to distribute the imaginary wells along the limited fault. Ultimately, the developed model can be embedded into commercial well test software where there is a lack of limited fault models to analyze the pressure transient data.