Modeling and Analysis on the Effect of Two-Phase Flow on Wormhole Propagation in Carbonate Acidizing

SPE Journal ◽  
2017 ◽  
Vol 22 (06) ◽  
pp. 2067-2083 ◽  
Author(s):  
W.. Wei ◽  
A.. Varavei ◽  
K.. Sepehrnoori
Keyword(s):  
Two Phase Flow ◽  
Mobility Ratio ◽  
Phase Model ◽  
Phase Flow ◽  
Oil Viscosity ◽  
Injection Wells ◽  
Two Phase ◽  
Matrix Acidizing ◽  
Modeling And Analysis ◽  
Carbonate Acidizing

Summary Matrix acidizing is a stimulation technique aiming at improving formation permeability or bypassing damaged zones. In this process, acid is injected through the well into the wellbore vicinity to dissolve the rock. For either production or injection wells, the formation may contain multiple phases (oil and water) near the wellbore region when acid treatment begins. In this paper, a two-phase two-scale continuum model is developed to simulate wormhole propagation under radial coordinates. The model describes the mechanisms of convection, dispersion, and reaction in two-phase flow during matrix acidizing. We have validated the simulation model with two methods: one is to compare with the previous simulation results; the other is to compare with the analytical solution. We have investigated conditions that will affect the wormhole-propagation process, including rock wettability, oil viscosity, and initial oil saturation. It is found that the water/oil mobility ratio is a key factor that affects acidizing efficiency. In addition, we have proposed a new criterion for acid breakthrough because the pressure response is affected not only by reaction, but also by overall mobility change in the formation. The traditional criterion for the single-phase model is no longer applicable to the current two-phase model. The results show that adverse water/oil mobility ratio leads to a higher efficiency for wormhole breakthrough. In carbonate reservoirs with heterogeneity, water/oil displacement and wormhole propagation contribute to narrower, less-branched channels. For the first time, it is possible to simulate formations with multiple phases during carbonate acidizing. The presented model improves our understanding in the optimization of carbonate acidizing.

Experimental Characterization of Oil-Refrigerant Two-Phase Flow

2000 ◽  
Author(s):  
V. T. Lacerda ◽  
A. T. Prata ◽  
F. Fagotti
Keyword(s):  
Flow Visualization ◽  
Two Phase Flow ◽  
Working Fluid ◽  
Phase Flow ◽  
Oil Viscosity ◽  
Two Phase ◽  
Mixture Flow ◽  
Horizontal Tubes ◽  
Constant Diameter ◽  
Oil Flow

Abstract Several phenomena occurring inside refrigerating systems depend on the interaction between the refrigeration oil and the refrigerant working fluid. Regarding the refrigeration cycle, good miscibility of oil and refrigerant assure easy return of circulating oil to the compressor through the reduction of the oil viscosity. Inside the compressor the lubricant is mainly used for leakage sealing, cooling of hot elements and lubrication of sliding parts. In the compressor bearing systems the presence of refrigerant dissolved in the oil greatly influences the performance and reliability of the compressor due to the outgassing experienced by sudden changes in temperature and pressure resulting in a two-phase mixture with density and viscosity strongly affecting the lubricant characteristics. A general understanding of the oil-refrigerant mixture flow is crucial in developing lubrication models to be used in analysis and simulation of fluid mechanics problems inside the compressor. In the present investigation the refrigeration oil flow with refrigerant outgassing is explored experimentally. A mixture of oil saturated with refrigerant is forced to flow in two straight horizontal tubes of constant diameter. One tube is used for flow visualization and the other is instrumented for pressure and temperature measurements. At the tubes inlet liquid state prevails and as flow proceeds the pressure drop reduces the gas solubility in the oil and outgassing occurs. Initially small bubbles are observed and eventually the bubble population reaches a stage where foaming flow is observed. The flow visualization allowed identification of the two-phase flow regimes experienced by the mixture. Pressure and temperature distributions are measured along the flow and from that mixture quality and void fraction were estimated.

Single and two-phase flow modeling and analysis of a coaxial vacuum tube solar collector

Solar Energy ◽  
2012 ◽  
Vol 86 (1) ◽  
pp. 175-189 ◽  
Author(s):  
Abdul Waheed Badar ◽  
Reiner Buchholz ◽  
Felix Ziegler
Keyword(s):  
Solar Collector ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Modeling ◽  
Two Phase ◽  
Vacuum Tube ◽  
Modeling And Analysis

A Two-Phase Flow Model with VOF for Free Surface Flow Problems

2012 ◽  
Vol 232 ◽  
pp. 279-283 ◽  
Author(s):  
Wei Zhang ◽  
You Hong Tang ◽  
Cheng Bi Zhao ◽  
Cheng Zhang
Keyword(s):  
Free Surface ◽  
Flow Model ◽  
Two Phase Flow ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Phase Model ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Problems ◽  
Fluid Sloshing

A numerical model based on the two-phase flow model for incompressible viscous fluid with a complex free surface has been developed in this study. The two-step projection method is employed to solve the Navier–Stokes equations in the numerical solutions, and finite difference method on a staggered grid is used throughout the computation. The two-order accurate volume of fluid (VOF) method is used to track the distorted and broken free surfaces. The two-phase model is first validated by simulating the dam break over a dry bed, in which the numerical results and experimental data agree well. Then 2-D fluid sloshing in a horizontally excited rectangular tank at different excitation frequencies is simulated using this two-phase model. The results of this study show that the two-phase flow model with VOF method is a potential tool for the simulation of nonlinear fluid sloshing. These studies demonstrate the capability of the two-phase model to simulate free surface flow problems with considering air movement effects.

Simulation of Two-Phase Flow in Carbon Dioxide Injection Wells

2011 ◽  
Author(s):  
Lawrence J. Pekot ◽  
Pierre Petit ◽  
Yasmin Adushita ◽  
Stephanie Saunier ◽  
Rohan Lakdasa De Silva
Keyword(s):  
Carbon Dioxide ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Carbon Dioxide Injection ◽  
Injection Wells ◽  
Two Phase

Evaluation of Advanced Two-Phase Flow and Combustion Models for Predicting Low Emission Combustors

2000 ◽  
Vol 123 (4) ◽  
pp. 817-823 ◽  
Author(s):  
G. Klose ◽  
R. Schmehl ◽  
R. Meier ◽  
G. Maier ◽  
R. Koch ◽  
...  
Keyword(s):  
Experimental Data ◽  
Two Phase Flow ◽  
Numerical Models ◽  
Computational Method ◽  
Phase Model ◽  
Combustion Model ◽  
Phase Flow ◽  
Two Phase ◽  
Low Emission ◽  
Good Agreement

The development of low-emission aero-engine combustors strongly depends on the availability of accurate and efficient numerical models. The prediction of the interaction between two-phase flow and chemical combustion is one of the major objectives of the simulation of combustor flows. In this paper, predictions of a swirl stabilized model combustor are compared to experimental data. The computational method is based on an Eulerian two-phase model in conjunction with an eddy dissipation (ED) and a presumed-shape-PDF (JPDF) combustion model. The combination of an Eulerian two-phase model with a JPDF combustion model is a novelty. It was found to give good agreement to the experimental data.

scholarly journals Numerical Simulation of Sloshing in LNG Tanks With a Compressible Two-Phase Model

2007 ◽  
Author(s):  
Rik Wemmenhove ◽  
Roel Luppes ◽  
Arthur E. P. Veldman ◽  
Tim Bunnik
Keyword(s):  
Numerical Simulation ◽  
Free Surface ◽  
Numerical Model ◽  
Pressure Distribution ◽  
Two Phase Flow ◽  
Phase Model ◽  
Phase Flow ◽  
Two Phase ◽  
Model Scale ◽  
Flow Effects

The study of liquid dynamics in LNG tanks is getting more and more important with the actual trend of LNG tankers sailing with partially filled tanks. The effect of sloshing liquid in the tanks on pressure levels at the tank walls and on the overall ship motion indicates the relevance of an accurate simulation of the fluid behaviour. This paper presents the simulation of sloshing LNG by a compressible two-phase model and the validation of the numerical model on model-scale sloshing experiments. The details of the numerical model, an improved Volume Of Fluid (iVOF) method, are presented in the paper. The program has been developed initially to study the sloshing of liquid fuel in spacecraft. The micro-gravity environment requires a very accurate and robust description of the free surface. Later, the numerical model has been used for calculations for different offshore applications, including green water loading. The model has been extended to take two-phase flow effects into account. These effects are particularly important for sloshing in tanks. The complex mixture of the liquid and gas phase around the free surface imposes a challenge to numerical simulation. The two-phase flow effects (air entrapment and entrainment) are strongly affected by both the filling ratio of the tank and the irregular motion of the tank in typical offshore conditions. The velocity field and pressure distribution around the interface of air and LNG, being continuous across the free surface, requires special attention. By using a newly-developed gravity-consistent discretisation, spurious velocities at the free surface are prevented. The equation of state applied in the compressible cells in the flow domain induces the need to keep track on the pressure distribution in both phases, as the gas density is directly coupled to the gas pressure. The numerical model is validated on a 1:10 model-scale sloshing model experiment. The paper shows the results of this validation for different filling ratios and for different types of motion of the sloshing tank.

scholarly journals Modeling Two-Phase Flow With Offshore Applications

2005 ◽  
Author(s):  
Rik Wemmenhove ◽  
Erwin Loots ◽  
Roel Luppes ◽  
Arthur E. P. Veldman
Keyword(s):  
Numerical Model ◽  
Gas Phase ◽  
Flow Model ◽  
Two Phase Flow ◽  
Gas Bubbles ◽  
Phase Model ◽  
Green Water ◽  
Phase Flow ◽  
Complex Flow ◽  
Two Phase

With the trend towards offshore LNG production and offloading, sloshing of LNG in partially filled tanks has become an important research subject for the offshore industry. LNG sloshing may induce impact pressures on the containment system and may affect the motions of the LNG carrier. So far, LNG sloshing has been studied mainly using model experiments with an oscillation tank. However, the development of Navier-Stokes solvers with a detailed handling of the free surface allows the numerical simulation of sloshing. It should be investigated, however, how accurate the results of this type of simulations are for this complex flow problem. The paper first presents the details of the numerical model, an improved Volume Of Fluid (iVOF) method. The program has been developed initially to study the sloshing of liquid fuel in satellites. Later, the numerical model has been used for calculations of green water loading and the analysis of anti-roll tanks, including the coupling with ship motions. Recently, the model has been extended to incorporate two-phase flow. This extension improves its ability to simulate the effect of gas bubbles of different sizes. Gas bubbles are present in virtually all relevant offshore situations; not only at LNG sloshing but also during green water events, bow slamming and water entry. In a two-phase flow model, both the liquid and the gas phase can have their own continuity and momentum equations. The handling of the compressibility of the gas phase is a major issue in the design of a two-phase flow model. However, as a first step in the modeling process, the gas phase is considered as incompressible. For a dambreak experiment, results of the one-phase model, the incompressible two-phase model and model experiment results have been compared. It is shown that the physics are more accurately simulated with the incompressible two-phase model. Furthermore, the paper will show results of the incompressible model for LNG sloshing. The physics of LNG sloshing and several other applications can be approached better by taking the compressibility into account. Therefore, as a second step, a compressible model is currently under construction, involving adiabatic compression of the gas phase.

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