scholarly journals Modeling of fiber bridging in fluid flow for well stimulation applications

2019 ◽  
Vol 17 (3) ◽  
pp. 671-686 ◽  
Author(s):  
Mehdi Ghommem ◽  
Mustapha Abbad ◽  
Gallyam Aidagulov ◽  
Steve Dyer ◽  
Dominic Brady
Keyword(s):  
Fluid Flow ◽  
Numerical Model ◽  
New Product Development ◽  
Flow Rate ◽  
Empirical Studies ◽  
Operating Conditions ◽  
Solid Particles ◽  
Fluid Viscosity ◽  
Design Guideline ◽  
Fiber Loading

AbstractAccurate acid placement constitutes a major concern in matrix stimulation because the acid tends to penetrate the zones of least resistance while leaving the low-permeability regions of the formation untreated. Degradable materials (fibers and solid particles) have recently shown a good capability as fluid diversion to overcome the issues related to matrix stimulation. Despite the success achieved in the recent acid stimulation jobs stemming from the use of some products that rely on fiber flocculation as the main diverting mechanism, it was observed that the volume of the base fluid and the loading of the particles are not optimized. The current industry lacks a scientific design guideline because the used methodology is based on experience or empirical studies in a particular area with a particular product. It is important then to understand the fundamentals of how acid diversion works in carbonates with different diverting mechanisms and diverters. Mathematical modeling and computer simulations are effective tools to develop this understanding and are efficiently applied to new product development, new applications of existing products or usage optimization. In this work, we develop a numerical model to study fiber dynamics in fluid flow. We employ a discrete element method in which the fibers are represented by multi-rigid-body systems of interconnected spheres. The discrete fiber model is coupled with a fluid flow solver to account for the inherent simultaneous interactions. The focus of the study is on the tendency for fibers to flocculate and bridge when interacting with suspending fluids and encountering restrictions that can be representative of fractures or wormholes in carbonates. The trends of the dynamic fiber behavior under various operating conditions including fiber loading, flow rate and fluid viscosity obtained from the numerical model show consistency with experimental observations. The present numerical investigation reveals that the bridging capability of the fiber–fluid system can be enhanced by increasing the fiber loading, selecting fibers with higher stiffness, reducing the injection flow rate, reducing the suspending fluid viscosity or increasing the attractive cohesive forces among fibers by using sticky fibers.

Flow Features Analysis of Throttle Notches of Proportional Direct Valve

2011 ◽  
Vol 189-193 ◽  
pp. 2285-2288
Author(s):  
Wen Hua Jia ◽  
Chen Bo Yin ◽  
Guo Jin Jiang
Keyword(s):  
Fluid Flow ◽  
Dynamic Behavior ◽  
Flow Rate ◽  
Discharge Coefficient ◽  
3D Models ◽  
Operating Conditions ◽  
Flow Models ◽  
Flow Features ◽  
Rate Discharge ◽  
Spool Valve

Flow features, specially, flow rate, discharge coefficient and efflux angle under different operating conditions are numerically simulated, and the effects of shapes and the number of notches on them are analyzed. To simulate flow features, 3D models are developed as commercially available fluid flow models. Most construction machineries in different conditions require different actions. Thus, in order to be capable of different actions and exhibit good dynamic behavior, flow features should be achieved in designing an optimized proportional directional spool valve.

Experimental Study on the Effect of Pinch Parameters and Fluid Viscosity to Flow in Closed Loop Impedance Pump

2014 ◽  
Vol 660 ◽  
pp. 932-936
Author(s):  
M. Mazwan Mahat ◽  
R.N. Izzati ◽  
Ilya Izyan Shahrul Azhar ◽  
Izdihar Tharazi
Keyword(s):  
Fluid Flow ◽  
Flow Rate ◽  
Supply Voltage ◽  
Maximum Flow ◽  
Elastic Tube ◽  
Fluid Viscosity ◽  
Ventricular Assist ◽  
Tube Section ◽  
Impedance Pump ◽  
Device Use

This paper aims to analyse the performance of impedance pump that uses energy mismatch to drive fluid flow. The experimental setup mainly focus to establish the relationship between the fluids flow rates in elastic tube section connected between two ends of solid tube and pinch mechanism location as well as fluid viscosity. Measurement of fluid flow rate or representation of its velocities resulting from the pumping mechanism is measured using two different supply voltage and constant pincher width. These measured parameters resulting from the pinch mechanism of the elastic tube section were varied at different pinch location along itsx-axis direction; divided into two main cases namely (1) 2 V and (2) 3 V at 40 mm to 140 mm pinch location. From the voltage variation, it is found that the maximum flow rate given by voltage 3.0 V at pinch location 40 mm while for the effect of viscosity, the highest flow rate is 93 ml/min. The profiles obtained revealed the characteristic of valve less pump to be the new model of new Ventricular Assist Device use in cardiac patient as well as further explanation about the factor that influence the characteristic of elastic tube.

Prediction of Cuttings Transport Behavior under Drill String Rotation Conditions in High-Inclination Section

2020 ◽  
Vol 34 (10) ◽  
pp. 2059035
Author(s):  
Shihui Sun ◽  
Jinyu Feng ◽  
Zhaokai Hou ◽  
Guoqing Yu
Keyword(s):  
Fluid Flow ◽  
Flow Rate ◽  
Drilling Fluid ◽  
Drill String ◽  
Additional Contribution ◽  
Fluid Viscosity ◽  
Fluid Flow Rate ◽  
Cuttings Transport ◽  
Hole Cleaning ◽  
Cuttings Bed

Cuttings are likely to accumulate and eventually form a cuttings bed in the highly-deviated section, which usually lead to high friction and torque, slower rate of penetration, pipe stuck and other problems. It is therefore necessary to study cuttings transport mechanism and improve hole cleaning efficiency. In this study, the cuttings-transport behaviors with pipe rotation under turbulent flow conditions in the highly deviated eccentric section were numerically simulated based on Euler solid–fluid model and Realizable [Formula: see text]–[Formula: see text] model. The resulted numerical results were compared with available experimental data in reported literature to validate the algorithm, and good agreement was found. Under the conditions of drill string rotation, cuttings bed surface tilts in the direction of rotation and distributes asymmetrically in annulus. Drill string rotation, drilling fluid flow rate, cuttings diameter, cuttings injection concentration and drilling fluid viscosity affect the axial velocity of drilling fluid; whereas drilling fluid tangential velocity is mainly controlled by the rotational speed of drill string. Increase in value of drill string rotation, drilling fluid flow rate or hole inclination will increase cuttings migration velocity. Notably, drill string rotation reduces cuttings concentration and solid–fluid pressure loss, and their variations are dependent on inclination, cuttings injection concentration, cuttings diameter, drilling fluid velocity and viscosity. However, when a critical rotation speed is reached, no additional contribution is observed. The results can provide theoretical support for optimizing hole cleaning and realizing safety drilling of horizontal wells and extended reach wells.

Influence of operating conditions of milled peat jet transport on relative sliding of air and solid phases

2020 ◽  
pp. 57-60
Author(s):  
S. M. Petrenko ◽  
◽  
N. I. Berezovsky ◽  
Keyword(s):  
Energy Consumption ◽  
Flow Rate ◽  
Solid Phase ◽  
Operating Conditions ◽  
Solid Particles ◽  
Component Mixture ◽  
Mixture Flow ◽  
Milled Peat ◽  
Pipeline Route ◽  
Solid Phases

Air-and-peat mixture in horizontal jet transport pipeline is considered as a compressible two-component mixture with uniform distribution of solid peat particles in continuous air phase. Such heterogeneous medium flow is substituted for a flow of interpenetrating air phase and a quasi-solid phase approximating the flow of discrete particles. Such approach makes it possible to write individual equations of continuity and motion for each phase, but it is required to introduce the forces of aerodynamic interference at the phase boundaries in the motion equations. From the analysis of the known theoretical and experimental research data on jet transport of granular materials, it is possible to identify some parameters such that variation of any of these parameters changes the jet transport energy consumption. Such parameters are: jet capacity per mass of air and solid, Qair and Qs (kg/s) or input-output characteristic of mass concentration, μ = Qs/Qair; reduced velocities of air, Vair, solid particles, Vs, and soaring, Vsn, hereinafter called the flow-rate mode parameters, as well as the size and density of solid particles and the profile of the jet pipeline route. The flow-rate mode parameters are simply registered in the jet transport tests. The numerical determination procedure of the actual operating conditions of milled peat jet transport is justified. The known experimental data on jet transport of milled and treated peat are processed. It is found that the relative sliding ratio is functionally connected with all operating conditions in horizontal jet transport. The change of any parameter or their combination induces transition to air-and-peat mixture flow with various relative sliding of air and solid phases at different energy consumption of horizontal jet transport.

A STUDY OF FLUID-MEMBRANE INTERACTIONS THAT LIMIT THE OUTPUT OF PERISTALTIC MICROPUMPS

2011 ◽  
Vol 11 (02) ◽  
pp. 325-336 ◽  
Author(s):  
CHAN YOUNG PARK ◽  
MAIYA SHUR ◽  
C. FORBES DEWEY
Keyword(s):  
Fluid Flow ◽  
Numerical Model ◽  
Flow Rate ◽  
Middle Layer ◽  
Bottom Layer ◽  
Experimental Models ◽  
Hydrodynamic Performance ◽  
Fluid Membrane ◽  
Peristaltic Micropump ◽  
Relationship Of

In many microfluidic devices, fluid flow is generated using micropumps like peristaltic micropumps. However the hydrodynamic performance of peristaltic micropumps has not been fully understood and furthermore the effect of dynamic interaction of pumping membrane and fluid flow has not been studied yet. To fill this gap, we studied the hydrodynamic performance of a peristaltic micropump using a numerical model incorporating the fluid-solid interactions. The model consisted of 3 layers; the top layer was the flow channel of 10 μm high, the middle layer was the 5~30 μm thick pumping membrane and the bottom layer was the 3 or 5 pumping chambers. By applying a pumping sequence at a frequency between 16~166 Hz, we calculated flow rate for at least 4 cycles and used the fourth or fifth cycle to evaluate the flow rate per a cycle. We found that the numerical model closely replicated the frequency vs. flow rate relationship of a peristaltic micropump as shown earlier in experimental models. We further found that the flow rate of a peristaltic micropump could be improved by increasing the number of pumping chambers or the thickness of pumping membrane.

Analytical Dynamic Modeling of Line-Focus Solar Collectors

1981 ◽  
Vol 103 (3) ◽  
pp. 244-250 ◽  
Author(s):  
J. D. Wright
Keyword(s):  
Fluid Flow ◽  
Flow Rate ◽  
Industrial Process ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Fluid Flow Rate ◽  
Digital Controllers ◽  
Dynamics Models ◽  
Line Focus

Solar thermal electric power and industrial process heat systems may require a constant outlet temperature from the collector field. This constant temperature is most efficiently maintained by adjusting the circulating fluid flow rate. Successful tuning of analog or digital controllers requires a knowledge of system dynamics. Models relating deviations in outlet temperature to changes in inlet temperature, insolation, and fluid flow rate illustrate the basic responses and the distributed-parameter nature of line-focus collectors. When plotted in dimensionless form, the frequency response of a given collector is essentially independent of the operating conditions, suggesting that feedback controller settings are directly related to such easily determined quantities as collector gain and fluid residence time.

Thermal Performance Analysis of the Stationary Reflector/Tracking Absorber (SRTA) Solar Concentrator

1975 ◽  
Vol 97 (3) ◽  
pp. 451-456 ◽  
Author(s):  
J. F. Kreider
Keyword(s):  
Fluid Flow ◽  
High Temperature ◽  
Flow Rate ◽  
Thermal Performance ◽  
Concentration Ratio ◽  
Heat Energy ◽  
Operating Conditions ◽  
Fluid Flow Rate ◽  
Wide Range ◽  
Temperature Heat

The performance of a novel solar energy concentrating system consisting of a fixed, concave spherical mirror and a sun-tracking, cylindrical absorber is analyzed in detail. This concentrating system takes advantage of the spherical symmetry of the mirror and its linear image which, when taken together, form a tracking, solar-concentrating system in which only the small cylindrical absorber need move. The effects of mirror reflectance, concentration ratio, heat transfer fluid flow rate, radiative surface properties, incidence angle, an evacuated absorber envelope, and insolation level upon thermal performance of the concentrator are studied by means of a mathematical model. The simulation includes first order radiation and convection processes between the absorber and its concentric glass envelope and between the envelope and the environment; radiation processes are described by a dual-band, gray approximation. The energy equations are solved in finite difference form in order that heat flux and temperature distributions along the absorber may be computed accurately. The results of the study show that high-temperature heat energy can be collected efficiently over a wide range of useful operating conditions. The analysis indicates that mirror surface reflectance is the single most important of the principal governing parameters in determining system performance. Efficiency always increases with concentration ratio although the rate of increase is quite small for concentration ratios above 50. High fluid flow rate (i.e., lower operating temperature), an evacuated envelope, or a highly selective surface can enhance performance under some conditions. The conclusion of the study is that high-temperature heat energy can be generated at high efficiency by the present concentrator with present technology in sunny regions of the world.

Mathematical modeling of the fluid flow in a mixing device for melting/dissolving solid particles in a liquid alloy

2014 ◽  
Vol 1611 ◽  
pp. 19-24
Author(s):  
J. A. Delgado-Álvarez ◽  
J. G. Perea-Zurita ◽  
A. Antonio-Morales ◽  
C. González-Rivera ◽  
M. A. Ramírez-Argáez
Keyword(s):  
Mathematical Model ◽  
Fluid Flow ◽  
Residence Time ◽  
Stokes Equations ◽  
Volume Of Fluid ◽  
Momentum Conservation ◽  
Operating Conditions ◽  
Solid Particles ◽  
Alloying Elements ◽  
Ansys Fluent

ABSTRACTA study of the fluid flow in a mixing device proposed to dissolve alloying elements in iron baths is performed through a mathematical model in order to predict the best operating conditions for a proper melting/dissolution of solid alloying particles. The mathematical model consists in the mass and momentum conservation equations (continuity and Turbulent Navier-Stokes equations), and the standard two k-epsilon turbulence model. The model is numerically solved in transient regime with the Volume of Fluid algorithm (VOF) to calculate the vortex shape. VOF is built-in the CFD (Computational Fluid Dynamics) software ANSYS FLUENT 14. A flow of metal enters tangentially in the mixing chamber of the proposed mixing device (taken from an open patent) to generate a vortex. The shape and height of the vortex reached in this chamber depends on several design variables, but in this work only the presence or absence of a barrier in the device is analyzed. Results are obtained on the vortex sizes and shapes, liquid flow patterns, turbulent structure, residence times of the particles of alloying elements added to the melt and mixing times (Residence time distribution curves) of two devices: one with a barrier and the other without this barrier. It is found that the presence of the barrier in the device increases turbulence, destroys the vortex, decreases the residence time of the particles, and decreases the volume of fluid in the device. Most of the features of the barrier are detrimental for mixing and inhibits melting/dissolution of the alloying elements. Then, it is suggested a device without the presence of barrier for better performance.

Nonempirical Apparent Permeability of Shale

2014 ◽  
Vol 17 (03) ◽  
pp. 414-424 ◽  
Author(s):  
H.. Singh ◽  
F.. Javadpour ◽  
A.. Ettehadtavakkol ◽  
H.. Darabi
Keyword(s):  
Fluid Flow ◽  
Pore Size ◽  
Flow Rate ◽  
Gas Flow ◽  
Operating Conditions ◽  
Pore Geometry ◽  
Apparent Permeability ◽  
Knudsen Flow ◽  
Proposed Model ◽  
Shale Reservoirs

Summary Physics of fluid flow in shale reservoirs cannot be predicted from standard flow or mass-transfer models because of the presence of nanopores, ranging in size from one to hundreds of nanometers, in shales. Conventional continuum-flow equations, such as Darcy's law, greatly underestimate the fluid-flow rate when applied to nanopore-bearing shale reservoirs. As a result of the existence of nanopores in shales, the molecular mean free path becomes comparable with the characteristic geometric scale, and we hypothesize that under this condition, Knudsen diffusion, in addition to correction for the slip boundary condition, becomes the dominant mechanism. Recently, a few models have been developed that use various empirical parameters to account for these modifications (Javadpour 2009; Civan 2010; Darabi et al. 2012). This paper aims to provide a different approach to modeling apparent permeability in shale reservoirs. The proposed model is analytical, free of any empirical coefficients, and has been derived without invoking the assumption of slip flow at the pore wall. Our model of apparent permeability represented by a single analytical equation, depends only on pore size, pore geometry, temperature, gas properties, and average reservoir pressure. The proposed model is valid for Knudsen numbers less than unity and it stands up under the complete operating conditions of a shale reservoir. Our model reasonably predicts results as reported by other models. Finally, the model shows that pore-surface roughness and mineralogy have a negligible influence on gas-flow rate, whereas pore geometry and pore size play a significant role in the proportion of diffusion in total flow rate. Our study shows that a combination of Darcy flow and Knudsen flow—ignoring the Klinkenberg effect—can describe gas flow for a range of Knudsen flow applicable to a shale-gas system.

Computational Modelling of Fluid Flow in Radial Diffusers With Irregular Boundaries

2006 ◽  
Author(s):  
Viviana Cocco Mariani ◽  
Alvaro Toubes Prata
Keyword(s):  
Fluid Flow ◽  
Numerical Model ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Numerical Solutions ◽  
Computational Modelling ◽  
Reynolds Numbers ◽  
Valve Seat ◽  
Irregular Geometries

Radial diffusers are the basic geometry for the automatic valves in reciprocating hermetic compressors. In the present work numerical solutions for the laminar isocoric flow in radial diffusers are performed to investigate the influence of some geometry modifications on the mass flow, rate and on the resultant force on the valve. The numerical model was able to handle irregular geometries making use of a regular mesh, and was validated through comparisons with experiments. Results are presented in terms of the effective flow and force area of valves which are important efficiency parameters for the modelling and design of reciprocating hermetic compressors. The efficiency parameters are presented and explored in terms of small modification of the valve geometry, for Reynolds numbers varying from 1000 to 2500 and two values of the gap between valve reed and valve seat. The flow was significantly affected by the geometry modifications, indicating that with little effort the performance of automatic valves can be substantialy improved. For instance, with a small chamfer of 5° at the outlet of the valve feeding orifice, the effective force area was increased by 30 percent.

Sign in / Sign up

Export Citation Format

Share Document