Multiphase flow in oil and gas well drilling

223 Pages·2016·6.327 MB·English

by  Sun, Baojiang

Multiphase Flow
in oil and Gas
well drillinG
Multiphase Flow
in oil and Gas
well drillinG
Baojiang sun
China University of Petroleum (East China), China
This edition first published 2016
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Set in 10.5/13.5pt Times by SPi Global, Pondicherry, India
1 2016
Contents
Preface ix
Chapter 1 Introduction 1
1.1 Multiphase flow in the well 2
1.2 Methods 3
1.2.1 Theoretical analysis 3
1.2.2 Experimental study 3
1.2.3 Numerical simulation 4
1.3 Parameters 5
1.4 Multiphase flow Patterns 9
1.4.1 Flow Patterns of Gas‐Liquid Flow 9
1.4.2 Gas‐Liquid Flow Pattern of acid Gas Under
supercritical Condition 14
1.5 Multiphase flow Models 19
1.5.1 Homogeneous Flow Model 19
1.5.2 separated Flow Model 20
1.5.3 Drift‐Flux Model 22
1.5.4 statistical average Model 24
Chapter 2 The Void Fraction Wave and Flow Regime Transition 25
2.1 Introduction 25
2.1.1 Bubble Coalescence and Flow Regime Transition 25
2.1.2 Void Fraction Wave and Flow Regime Transition 28
2.2 Experimental Setup and Methods 32
2.2.1 Experimental setup 32
2.2.2 Observation and Determination of Flow Regimes 33
2.2.3 Flow Resistance Measurement 35
2.2.4 Flow Rate and Void Fraction Wave Measurement 35
2.2.5 Data Processing 37
vi Contents
2.3 formation Mechanism of Slug flow with Low
Continuous Phase Velocity 38
2.3.1 Flow Regime Transition 38
2.3.2 analytical Method 40
2.3.3 Experimental Results 46
2.3.4 Discussion on the Instability of Void
Fraction Wave and Formation Mechanism
of Taylor Bubble 49
2.3.5 Propagation Velocity of Void Fraction Wave 52
2.4 Gas‐Liquid flow Regime transition with High
Continuous Phase Velocity 54
2.4.1 Flow Regime Transition 54
2.4.2 Experimental Results and Discussions 55
2.4.3 Mechanism of Losing stability for Bubbly Flow 62
2.4.4 Velocity of Void Fraction Wave 68
2.4.5 Non‐Linear Properties of the Void Fraction Wave 71
Chapter 3 Multiphase Flow Model for Well Drilling 75
3.1 Continuity Equation 76
3.1.1 Continuity Equation in the annulus 76
3.1.2 Continuity Equation in the Drilling stem 81
3.2 Momentum Equation 82
3.2.1 Momentum Equation in the annulus 82
3.2.2 Momentum Equation in the Drilling stem 83
3.3 Energy Equation 85
3.3.1 Energy Equation in the annulus 85
3.3.2 Energy Equation in the Drilling stem 89
3.4 Applications of the Model 89
3.4.1 Underbalanced Drilling 89
3.4.2 Kicking and Killing 90
3.4.3 Kicking and Killing after acid Gas Influx 92
3.4.4 Kicking and Killing for Deepwater Drilling 93
Chapter 4 Multiphase Flow During Underbalanced Drilling 97
4.1 flow Model 98
4.1.1 Flow‐Governing Equations in the annulus 98
4.1.2 Flow‐Governing Equations in the Drilling stem 99
4.1.3 Energy Equations 100
4.1.4 auxiliary Equations 101
Contents vii
4.2 Solving Processing 111
4.2.1 Definite Conditions 111
4.2.2 Discretization of the Model 112
4.2.3 algorithms 115
4.3 Case Study 118
4.3.1 Gas Drilling 118
4.3.2 Drill Pipe Injection‐aerated Drilling 125
4.3.3 annulus Injection‐aerated Drilling 128
Chapter 5 Multiphase Flow During Kicking and Killing 133
5.1 Common Killing Method 134
5.1.1 Killing Parameters of Driller’s Method and
Wait and Weight Method 134
5.1.2 The Circulate‐and‐Weight Method 138
5.2 Multiphase flow Model 139
5.2.1 Governing Equations for Killing 140
5.2.2 Governing Equation for Kicking 143
5.2.3 auxiliary Equations 143
5.3 Solving Process 143
5.3.1 Definite Conditions 143
5.3.2 Discretization of the Model 146
5.3.3 algorithms 148
5.4 Case Study 149
5.4.1 Basic Parameters of the Well 149
5.4.2 simulations of Overflow 150
5.4.3 Hydraulic Parameters for Killing 151
Chapter 6 Multiphase Flow During Kicking
and Killing with Acid Gas 155
6.1 flow Model 156
6.1.1 Flow Governing Equations for Killing acid Gas Kicking 156
6.1.2 Flow Governing Equations for acid Gas Kicking 158
6.1.3 auxiliary Equations 158
6.2 the Solving Process 160
6.2.1 Definite Conditions 160
6.2.2 algorithms 163
6.3 Simulations and Case Study 164
6.3.1 Basic Parameters of the Well 164
6.3.2 acid Gas Compressibility and Density in the Wellbore 164
viii Contents
6.3.3 acid Gas solubility in the Wellbore 166
6.3.4 acid Gas Expansion in the Wellbore 168
6.3.5 Impact on the Pit Gain 169
Chapter 7 Multiphase Flow During Kicking and Killing
in Deepwater Drilling 173
7.1 Common Deepwater Killing Method 174
7.1.1 Dynamic Killing Method 174
7.1.2 advanced Driller’s Method 176
7.1.3 additional Flow Rate Method 178
7.2 flow Model 181
7.2.1 Governing Equations for Deepwater Well Killing 182
7.2.2 Governing Equations for Kicking 188
7.2.3 auxiliary Equations 189
7.3 the Solving Process 191
7.3.1 Definite Conditions 191
7.3.2 algorithms 194
7.4 Case Study 195
7.4.1 Basic Parameters of the Well 195
7.4.2 simulations of Kicks and Blowout 195
7.4.3 simulation of the Killing Process 198
References 203
Author Index 211
Subject Index 213
Preface
Multiphase flow plays an important role in the oil and gas industry. For novel and
precisely controlled drillings, especially, it is the basic method to predict hydraulic
parameters and design operation processes. Many previous studies have been done
by our group in this field for basic theories, experimental evaluations and numerical
simulations. Thus, we considered that a systematic collection of these works would
be helpful for engineers and other researchers.
This book focuses on the multiphase flow problems in the annulus or pipe, such
as flow patterns, flow resistance, flow stability, multiphase fluids mixing, separat-
ing, uniformity mechanism, and so on. It starts from experimental observations of
void fractions waves and flow pattern transition. A global multiphase flow model
that includes all the necessary fluid components for drilling and well control is
introduced. With this background, this model is applied for drilling techniques such
as underbalanced drilling, kicking/killing during normal drilling, during drilling in
acid gas formations, and deepwater drilling. The flow model is modified for each of
these different applications, and different processes for solving the models are
developed. Case studies are presented to show the results, and to validate the
flow models.
There are seven chapters in this book. Chapter 1 introduces the objectives,
purpose and study methods of multiphase flow for drillings. Basic parameters, flow
patterns and four popular multiphase flow models are generally described. Chapter 2
focuses on studies of void fraction waves and flow pattern transition mechanisms of
gas‐liquid flow in the pipe or annulus. The experimental method of observing void
fraction waves is introduced, and data analyzing methods are discussed. The laws
of gas‐liquid flow regime transition in low and high continuous phase velocity are
analyzed, and conditions and factors of flow regime transition are presented.
Chapter 3 presents a global multiphase flow model for drillings. This model is
based on mass, momentum and energy conservation. All possible components of
the fluids for drillings are taken into account, and specific drilling or control
techniques relevant to this model are introduced. Applications of the model are
also discussed.
x Preface
Chapter 4 presents a multiphase flow model for underbalanced drilling. This
model is simplified from the global multiphase flow model in Chapter 3. A solving
process and a computing algorithm for this model are also presented. Cases of gas
drilling, riser aerated and annulus injection‐aerated drilling are studied in order to
validate the flow model. Chapters 5 to 7 are applications of the global multiphase
flow model for kicking/killing during normal drilling, during drilling with acid gas
and during deepwater drilling. The flow model is simplified for each working con-
dition, with solving processes and computing algorithms presented.
From the case studies in Chapter 5, simulations of multiphase flow during
kicking/killing in normal drilling are made. Hydraulic parameters of killing are
computed, and the proper killing operation for specific cases is discussed. In the
case studies in Chapter 6, the impact of solubility of acid gas and phase transformation
of supercritical acid gas are evaluated for wellbore multiphase flow. The laws of
acid gas expansion in the wellbore are analyzed. In Chapter 7, the impact of seawater
temperature field and hydrates phase transformation are specially studied. The
multiphase flow model is built for different positions, such as the wellbore, the riser
above the mud line and the chock line. Factors that influence the deepwater killing
operation are analyzed from simulation results.
This book includes basic multiphase flow theories of oil and gas well drilling. It
also gives consideration to the basic techniques, operations and computing methods
that concern drilling engineers. We hope it is helpful to researchers, graduate stu-
dents and engineers who study multiphase flow for oil and gas well drilling. Criticism
is welcome and, when constructive, will be very useful for future revisions.
The results of this book are based on grants from the National Basic Research
Program of China (973 Program, 2015CB251200), National Natural Science
Foundation of China (U1262202, 50874116, 51004113), and the Program for
Changjiang Scholars and Innovative Research Team in University (IRT1086). We
thank them all for their support. We thank the researchers who are listed in the
references, whose results are the source of our studies. We thank professor Deli
Gao for his guidance on the writing and publishing of this work. Dr. Zhiyuan Wang,
Dr.  Yonghai Gao, Dr. Hao Li, et al. from China University of Petroleum
participated in the writing of this book. Dr. Xiaogang Yang from Delft University
of Technology, Prof. Xuedong Wu and Dr. Bangtang Yin from China University
of Petroleum proofread and translated the English version. We thank them all for
their contributions.
Chapter 1
Introduction
Abstract
Most of the fluid flows in the petroleum engineering are multiphase flows. For instance,
the drilling fluid, during the common drilling of oil and gas wells, is a gas‐solid phase.
There are various macroscopic models for multiphase, such as the homogeneous flow
model, the separated flow model, the drift‐flux model and the statistical average
model. These models are all based on the conservation laws of mass, momentum and
energy. The basic parameters to describe a single phase flow are velocity, mass flow
rate, and volumetric flow rate. Besides, in wellbore multiphase flow, the mass flow rate,
volumetric fraction and velocity of each phase are also the important parameters.
Although the mass proportion of gas‐liquid phase is the same, the fluid behaviors
change with the different gas‐liquid distribution. Recognition of these characteristics is
of great significance in multiphase flow study.
Keywords: drift‐flux model; flow parameters; flow patterns; gas well drilling;
homogeneous flow model; multiphase flow models; oil well drilling; separated
flow model; statistical average model
A multiphase flow is a fluid flow that comprises more than one phase of matter. The
phase defines the different chemical and physical properties of the matter, and the
interface between different phases should be physically distinguished for multiphase
flow. The same matter in different states, such as gas, liquid and solid, is considered
as different phases. Insoluble chemicals with the same state are also considered as
different phases. For instance, the fluid flow of ice and water, or vapor and water, is
a multiphase flow. The fluid flow of oil and water is also a multiphase flow. However,
the fluid flow of salt and water solution is not, because this solution is a homogene-
ous fluid without any physical interface between the two components.
The study of multiphase flow started at the beginning of the 20th century.
Multiphase flow is widely applied in industry, such as in power generation, nuclear
Multiphase Flow in Oil and Gas Well Drilling, First Edition. Baojiang Sun.
© 2016 Higher Education Press. All rights reserved. Published 2016 by John Wiley & Sons Singapore Pte. Ltd.