Reservoir Formation Damage Episode 1 Part 1 pdf

RESERVOIR
FORMATION
DAMAGE
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Fundamentals,
Modeling,
Assessment,
and
Mitigation
University
of
OMafcattia
Gulf Publishing Company
Houston,
Texas
RESERVOIR
FORMATION
DAMAGE
Faruk Civan
Reservoir
Formation
Damage
Copyright
©2000
by
Gulf
Publishing Company, Houston, Texas.
All
rights
reserved. This book,

or
parts thereof,
may not be
reproduced
in any
form
without express written permission
of
the
publisher.
Gulf
Publishing Company
Book Division
P.O.
Box
2608
D
Houston, Texas 77252-2608
10
987654321
Library
of
Congress
Cataloging-in-Publication
Data
Civan,
Faruk.
Reservoir
formation damage
:

fundamentals, modeling,
assessment,
and
mitigation
/
Faruk Civan.
p. cm.
Includes bibliographical references
and
index.
ISBN
0-88415-301-0
(alk.
paper)
1.
Hydrocarbon
reservoirs.
2.
Petrolum—Geology.
I.
Title.
TN870.57.C58 2000
622'.338—dc21
00-027480
Printed
in the
United States
of
America.
Printed

on
acid-free paper
(°o).
IV
Dedicated
to
my
family
and
Dr.
C. M.
Sliepcevich
with
love
and
appreciation
This page intentionally left blank
Contents
Preface,
xv
CHAPTER
1
Overview
of
Formation Damage
Summary,
1.
Introduction,
1.
Common Formation

Damage Problems, Factors,
and
Mechanisms,
4.
Team
for
Understanding
and
Mitigation
of
Formation Damage,
6.
Objectives
of the
Book,
6.
References,
7.
PARTI
Characterization
of the
Reservoir Rock
for
Formation Damage
CHAPTER
2
Mineralogy
and
Mineral
Sensitivity

of
Petroleum-Bearing Formations
10
Summary,
10.
Introduction,
10.
Origin
of
Petroleum-Bearing
Formations,
11.
Constituents
of
Sedimentary Rocks,
11.
Composition
of
Petroleum-Bearing Formations,
12.
Mineral
Sensitivity
of
Sedimentary Formations,
14.
Mechanisms
of
Clay
Swelling,
22.

Models
for
Clay Swelling,
25.
Graphical
Representation
of
Clay Content,
42.
Hayatdavoudi Hydration
Index
(HHI),
43.
References,
44.
CHAPTER
3
Petrography
and
Texture
of
Petroleum-Bearing
Formations
49
Summary,
49.
Introduction,
49.
Petrographical Characteristics,
49.

References,
63.
vn
CHAPTER
4
Petrophysics-Flow
Functions
and
Parameters
66
Summary,
66.
Introduction,
66.
Wettability
Alteration,
66.
End-Point Saturations,
72.
Alteration
of the Row
Functions:
Capillary
Pressure
and
Relative Permeability,
72.
References,
77.
CHAPTER

5
Permeability
Relationships
80
Summary,
80.
Introduction,
80. The
Carman-Kozeny
Hydraulic
Tubes
Model,
80. The
Modified Carman-Kozeny Equation
Incorporating
the Row
Units Concept,
83. The
Modified
Carman-
Kozeny
Equation
for
Porous Media Altered
by
Deposition,
84. The
Row
Efficiency
Concept,

84. The
Plugging-Nonplugging Parallel
Pathways
Model,
87.
Multi-Parameter Regression Models,
92.
Network
Models,
92.
Modified Fair-Hatch Equation,
93.
Power-
Law
Row-Units Equation,
94.
Effect
of
Dissolution/Precipitation
on
Porosity
and
Permeability,
94.
Effect
of
Deposition/Dissolution
and
Stress
on

Porosity
and
Permeability,
95.
Effect
of
Temperature
on
Porosity
and
Permeability,
95.
Exercises,
96.
References,
97.
CHAPTER
6
Instrumental
and
Laboratory
Techniques
for
Characterization
of
Reservoir
Rock
102
Summary, 102. Introduction, 102. Formation Evaluation, 103.
X-Ray

Diffraction,
107. X-Ray
CT
Scanning, 107. X-Ray
Fluoroscopy,
108. Scanning
Electron
Microscope
(SEM), 108.
Thin Section Petrography, 109. Petrographic Image Analysis,
109.
Polarized
Light Microscopy, 109. Nuclear Magnetic
Resonance Spectroscopy (NMR),
110.
Acoustic Techniques,
111. Cation Exchange Capacity,
111.
£
(Zeta)-Potential,
116.
Wettability,
117.
Mineral Quantification, 120. References, 123.
PART
11
Characterization
of the
Porous
Media

Processes
for
Formation
Damage
CHAPTER
7
Multi-Phase
and
Multi-Species
Transport
in
Porous
Media
Summary,
128. Multi-Phase
and
Species Systems
in
Porous
128
Vlll
Media, 128. Multi-Species
and
Multi-Phase Macroscopic
Transport Equations, 133. References, 138.
CHAPTER
8
Participate
Processes
in

Porous
Media
140
Summary,
140. Introduction, 140.
Paniculate
Processes,
141.
Forces
Acting Upon Particles, 145. Rate Equations
for
Paniculate
Processes
in
Porous Matrix, 148. References, 160.
CHAPTER
9
Crystal
Growth
and
Scale
Formation
in
Porous
Media
164
Summary,
164. Introduction, 164. Inorganic Precipitation, 164.
Organic Precipitation, 165. Crystallization, 166. Grain Nucleation,
Growth,

and
Dissolution, 167. Crystallization Kinetics, 171.
Particle Growth
and
Dissolution
in
Solution, 174. Scale Formation
and
Dissolution
at the
Pore
Surface, 176. Crystal Surface Displace-
ment
by
Dissolution
and
Precipitation, 178. References, 178.
PART
III
Formation
Damage
by
Participate
Processes
CHAPTER
10
Single-Phase
Formation
Damage
by

Fines
Migration
and
Clay
Swelling
183
Summary, 183. Introduction,
183.
The
Thin
Slice
Algebraic
Model,
184.
The
Compartments-in-Series
Ordinary Differential
Model, 197. Simplified Partial Differential Model, 199.
The
Plugging-Nonplugging
Parallel
Pathways
Partial
Differential
Model,
221.
Model Considering
the
Clayey Formation Swelling
and

Indigeneous
and
External Particles, 208. Model Assisted
Analysis
of
Experimental
Data,
213. References, 235.
CHAPTER
11
Two-Phase
Formation
Damage
by
Fines
Migration
238
Summary,
238. Introduction, 238. Formulation, 239. Fluid
and
Species Transport,
241.
Wettability
Transformation
and
Interface
Transfer
of
Particles, 247. Particle Retention
in

Porous Media, 247.
Filter Cake Formation
on the
Injection Face,
251.
Model Assisted
Analysis
of
Experimental Data,
251.
References, 259.
IX
CHAPTER
12
Cake
Filtration:
Mechanism,
Parameters
and
Modeling
Summary,
262. Introduction, 263. Incompressive Cake Filtration,
265. Compressive Cake Filtration Including Fines Invasion,
291.
References,
318.
262
PART
IV
Formation

Damage
by
Inorganic
and
Organic
Processes
CHAPTER
13
Inorganic
Scaling
and
Geochemical
Formation
Damage
323
Summary, 323.
Introduction,
323.
Geochemical
Phenomena—
Classification,
Formulation, Reactions
in
Porous Media, 326.
Geochemical Modeling, 335. Graphical Description
of the
Rock-
Fluid Chemical Equilibria, 339. Geochemical Model Assisted
Analysis
of

Solid
Mineral—Aqueous
Phase Interactions
and
Construction
of
Charts, 344. References, 372.
CHAPTER
14
Formation
Damage
by
Organic
Deposition
379
Summary,
379. Introduction, 379. Characteristics
of
Asphaltenic
Oils, 382. Mechanisms
of the
Heavy Organic
Deposition, 388. Asphaltene
and Wax
Phase Behavior
and
Deposition Envelopes, 392. Asphaltene Adsorption, 405.
Empirical Algebraic Model
for
Formation Damage

by
Asphaltene Precipitation
in
Single Phase,
410.
Simplified
Analytic
Model
for
Asphaltene-Induced Formation Damage
in
Single-Phase, 414. Plugging-Nonplugging Pathways Model
for
Asphaltene
Deposition
in
Single-Phase,
421.
Two-Phase
and
Dual-Porosity Model
for
Simultaneous
Asphaltene-Paraffin
Deposition, 428. Single-Porosity
and
Two-Phase Model
for
Organic Deposition, 438. References, 449.
PARTY

Assessment
of the
Formation
Damage
Potential
CHAPTER
15
Laboratory
Evaluation
of
Formation
Damage
456
Summary,
456. Introduction, 456. Fundamental Processes
of
Formation Damage
in
Petroleum Reservoirs, 458. Selection
of
Reservoir Compatible Fluids, 459. Experimental Set-up
for
Formation
Damage Testing, 459.
Special
Purpose
Core
Holders,
461.
Guidelines

and
Program
for
Laboratory Formation Damage
Testing, 470.
Core
Flood
Tests,
478
Laboratory
Procedures
for
Evaluation
of
Formation Damage Problems, 478.
The
Liquid
Block Problem,
481.
The Mud
Damage Problem, 482.
Evaluation
of
Drilling
Muds—Damage
Potential
and
Removal,
482. Evaluation
of

Hydraulic Fracturing Fluids, 488. Evaluation
of
Workover
and
Injection Fluids, 488. Evaluation
of
Workover
Damage
and
Remedial Chemicals,
491.
Critical Interstitial Fluid
Velocity
and pH for
Hydrodynamic
Detachment
of
Fines
in
Porous Media,
491.
Scaling
from
Laboratory
to
Bottom Hole,
499. Determination
of the
Formation Damage Potential
by

Laboratory Testing, 500. References, 522.
CHAPTER
16
Simulator
Development
528
Summary,
528. Introduction, 528. Description
of
Fundamental
Model Equations, 529. Numerical Solution
of
Formation
Damage
Models,
532. Ordinary Differential Equations, 533.
Partial Differential Equations, 538. References,
549
CHAPTER
17
Model
Assisted
Analysis
and
Interpretation
of
Laboratory
and
Field
Tests

552
Summary, 552. Introduction, 552. Measurement Error, 554.
Error
Analysis—Propagation,
Impact, Estimation, 556.
Sensitivity
Analysis—Stability
and
Conditionality,
561.
Model
Validation,
Refinement,
and
Parameter Estimation, 564.
Determination
of the
Formation Damage Potential
by
Simulation, 570. References, 603.
XI
PART
VI
Formation
Damage Models
for
Field
Applications
CHAPTER
18

Drilling
Mud
Filtrate
and
Solids
Invasion
and
Mudcake
Formation
60S
Summary, 608. Introduction, 608. Simplified Single Phase
Mud
Filtrate Invasion Model,
613.
Two-Phase Wellbore
Mud
Invasion
and
Filter Cake Formation Model, 617. References, 623.
CHAPTER
19
Interjectivity
of the
Water-flooding
Wells
627
Summary,
627. Introduction, 627. Injectivity Ratio, 628. Models
Separating
the

Internal
and
External Filtration
Processes,
632.
Diagnostic-Type Curves
for
Water Injectivity Tests, 639. Models
for
Field Applications,
641.
Models Coupling
the
Internal
and
External Filtration
Processes,
643. References, 644.
CHAPTER
20
Reservoir
Sand
Migration
and
Gravel-Pack
Damage:
Stress-Induced
Formation
Damage,
Sanding

Tendency,
Prediction,
and
Control
647
Summary,
647. Introduction, 647. Sand Control, 648. Gravel
Design Criteria,
651.
Prediction
of
Sanding Conditions, 655.
Massive Sand Production Model, 658. Sand Retention
in
Gravel-Packs, 664. References, 665.
CHAPTER
21
Formation
Damage
by
Scale
Deposition
669
Summary,
669. Introduction, 669.
Sulfur
Deposition Model, 669.
Calcite
Deposition Model, 674. References, 677.
xn

PART
VII
Diagnosis
and
Mitigation
of
Formation
Damage
CHAPTER
22
Field
Diagnosis
and
Measurement
of
Formation
Damage
680
Summary,
680. Introduction, 680. Diagnosis
and
Evaluation
of
Formation Damage
in the
Field,
681.
Pseudo-Damage Versus
Formation
Damage, 684. Measures

of
Formation
Damage,
684.
Flow
Efficiency,
691. Depth
of
Damage, 693. Model-Assisted
Estimation
of
Skin Factor, 694.
Model-Assisted
Analysis
of the
Near-Wellbore
Permeability Alteration using Pressure Transient
Data,
694. Continuous Real Time Series Analysis
for
Detection
and
Monitoring
Formation
Damage
Effects,
698.
Formation
Damage Expert System, 702. References, 703.
CHAPTER

23
Formation
Damage
Control
and
Remediation
706
Summary,
706. Introduction, 706. Selection
of
Treatment Fluids,
710. Clay Stabilization, 711.
pH-Buffer
Solutions, 714. Clay
and
Silt
Fines,
715.
Bacterial
Damage, 716. Inorganic
Scales,
717. Organic Deposits,
717.
Mixed
Organic/Inorganic
Deposits,
718.
Formation Damage Induced
by
Completion-Fluids

and
Crude-Oil
Emulsions,
718.
Wettability Alteration
and
Emulsion
and
Water Blocks, 718. Intense Heat Treatment, 719.
Stimulation
by
Hydraulic Fracturing, 719. References, 725.
Index
730
About
the
Author
741
Xlll
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Preface
Formation damage
is an
undesirable operational
and
economic problem
that
can
occur during
the

various phases
of oil and gas
recovery
from
sub-
surface
reservoirs including production, drilling, hydraulic
fracturing,
and
workover operations.
Formation
damage assessment, control,
and
remediation
are
among
the
most important issues
to be
resolved
for
efficient
exploitation
of
hydrocarbon
reservoirs.
Such
damage
is
caused

by
various adverse pro-
cesses, including chemical, physical, biological,
and
thermal interactions
of
formation
and
fluids,
and
deformation
of
formation under stress
and
fluid
shear. Formation damage indicators include permeability impairment, skin
damage,
and
decrease
of
well performance.
The
properly designed experi-
mental
and
analytical techniques presented
in
this book
can
help understand-

ing, diagnosis, evaluation, prevention
and
controlling
of
formation damage
in
oil and gas
reservoirs.
This book provides
an
understanding
of the
fundamentals
of the
relevant
processes causing formation damage
and
reducing
the
flow
efficiency
in the
near-wellbore
formation during
the
various phases
of oil and gas
production;
an
update review

of the
various
approaches
used
in the
modeling
and
simula-
tion
of
formation damage
for
model assisted analysis
and
interpretation
of
laboratory
core
tests,
and for
prediction
and
control
of
formation damage;
and
the
techniques used
for
assessment, diagnosis, minimization,

and
control
of
formation
damage
in
petroleum
reservoirs.
It
focuses
on the
modeling
and
simulation
of the
rock,
fluid,
and
particle interactions,
fluid and
particle inva-
sion,
filter
cake, in-situ mobilization, migration,
and
deposition
of
fines,
or-
ganic

and
inorganic precipitation
and
scale formation, alteration
of
porosity,
permeability,
and
texture
in
laboratory cores
and
reservoir formations,
and
the
effects
of
single
and
multi-phase
fluid
systems.
Formation damage
is an
interesting interdisciplinary
subject
that attracts many
researchers.
This
book

is a
recapitulation
of the
present state-of-the-art knowl-
edge
in the
area
of
formation damage.
It is
intended
to be a
convenient source
of
information, widely spread over
different
sources.
I
have tried
to
cover
the
relevant
material with
sufficient
detail, without overwhelming
the
readers.
This
book

can be
used
by
those
who are
engaged
in the
various
aspects
of
xv
formation
damage problems associated
with
the
production
of
hydrocarbons
from
subsurface reservoirs.
It may
serve
as a
useful
reference
and
provides
the
knowledge
of the

theoretical
and
practical
aspects
of
formation damage
for
various purposes, including model assisted interpretation
of
experimental
test
data, prediction
and
simulation
of
various formation damage scenarios,
evaluation
of
alternative strategies
for
formation damage minimization,
and
scientific
guidance
for
conducting laboratory
and
field
tests.
Exhaustive

effort
has
been made
to
gather, analyze,
and
systematically
present
the
state-of-the-art knowledge accumulated over
the
years
in the
area
of
formation damage
in
petroleum reservoirs. This book
is
intended
to
provide
a
quick
and
coordinated overview
of the
fundamentals,
and the
experimental

and
theoretical approaches presented
in
selected publications.
However,
it
should
not be
viewed
as a
complete
encyclopedic
documentation
of
the
reported studies.
It
discusses processes causing formation damage
and
reducing
the
productivity
of
wells
in
petroleum reservoirs
and
systematically
presents various approaches used
in the

diagnoses, measurement, production,
and
simulation
of
formation damage.
The
techniques
for
assessment, minimiza-
tion, control,
and
remediation
of the
reservoir formation damage
are
described.
This book
is
intended
for the
petroleum, chemical,
and
environmental
engineers, geologists, geochemists,
and
physicists involved
in
formation dam-
age
control,

and for the
undergraduate senior
and
graduate petroleum engi-
neering students. Therefore, this book
can be
used
in
industry
training courses
and
undergraduate
senior
and
graduate level petroleum engineering
courses.
It is
recommended
for
formation
damage courses
and as a
companion
for
drilling,
production,
and
stimulation courses. Readers will:
•
Learn

the
mechanisms
and
theoretical background
of the
common for-
mation damage
processes
• Be
familiar with
the
testing, modeling
and
simulation techniques avail-
able
for
formation damage assessment,
and
• Be
able
to
develop strategies
for
better management
of the
adverse pro-
cesses
to
minimize
and

avoid formation damage
in
petroleum reservoirs.
The
material presented
in
this book originates
from
my
industry short
courses
and
curriculum courses
at the
School
of
Petroleum
and
Geological
Engineering
at the
University
of
Oklahoma.
I am
indebted
to the
researchers
who
have contributed

to the
understanding
and
handling
of the
various
issues
and
aspects
of
formation damage
and
miti-
gation. Their
efforts
have
led to the
accumulation
of a
substantial amount
of
knowledge
and
expertise
on
formation damage
and
helped develop techniques
and
optimal strategies

for
effective
detection, evaluation,
and
mitigation
of
formation
damage
in
subsurface reservoirs. Their works have been published
in
various literature.
I am
pleased
to
have
had the
opportunity
to
analyze,
xvi
integrate, transfer,
and
present
the
state-of-the-knowledge
of
formation dam-
age in a
consistent manner

in one
source
for the
readers
of
this book. Many
of
the
figures,
tables,
and
other relevant materials used
in the
preparation
of
this
book were extracted
from
the
literature published
by
various researchers, com-
panies,
and
organizations. These include
the
following: Academic
Press;
AAPG—American
Association

of
Petroleum Geologists;
ACS—American
Chemical Society;
AIChE—American
Institute
of
Chemical Engineers;
American Institute
of
Physics;
API—American
Petroleum Institute;
ASME—
American
Society
of
Mechnical Engineers; A.A. Balkema Publisher; Baroid
Drilling
Fluids, Inc.; Canadian Institute
of
Mining, Metallurgy
and
Petroleum;
Chemical
Processing magazine; Chemicky
Prumysl;
Computational Mechan-
ics, Inc.; Elsevier Science, Geological Society,
IEEE—Institute

of
Electrical
and
Electronics Engineers, Inc.; International Institute
for
Geothermal
Research, Italy; Ilinois State Geological Survey; John Wiley
&
Sons Limited;
Marcel
Dekker,
Inc.,;
M-I
L.L.C.; Plenum Press; Sarkeys Energy Center
at
the
University
of
Oklahoma;
SPE—Society
of
Petroleum Engineers;
SPWLA—Society
of
Professional Well
Log
Analysis; Transportation Research
Board; National Academies, Washington, D.C.; Turkish Journal
of Oil and
Gas;

and the
U.S. Department
of
Energy.
In
addition,
G.
Atkinson,
T.
Dewers,
A.
Hayatdavoudi,
I. B.
Ivanov,
P. R.
Johnson,
P. A.
Kralchevsky,
R.
Philip,
T. S.
Ramakrishnan,
M. M.
Reddy,
G. W.
Schneider,
H.
Tamura,
and K. J.
Weber

allowed
the use of
materials
from
their publications.
B.
Seyler
of the
Illinois
State Geological Survey provided
the
photographs included
in the
book.
The
permission
for use of
these materials
in
this book
is
gratefully
acknowledged.
I am
also
grateful
to
Gulf Publishing Company, Timothy
W.
Calk,

and
Execustaff
Composition Services
for
their support
in the
preparation
and
real-
ization
of
this book. Special thanks
are due to
Susan Houck
for her
care
in
typing
the
manuscript.
Any
comments, corrections,
and
suggestions
by the
readers
to
improve this
book
are

welcomed.
Faruk
Civan, Ph.D. P.E.
University
of
Oklahoma
Norman,
Oklahoma
xvn
This page intentionally left blank
Chapter
1
Overview
of
Formation
Damage
Summary
A
comprehensive review
of the
various types
of
formation damage
problems
encountered
in
petroleum
reservoirs
is
presented.

The
factors
and
processes causing these problems
are
described
in
detail.
The
design
of
a
team
effort
necessary
for
understanding
and
controlling
of the
for-
mation
damage
problems
in the
field
is
explained.
The
motivation

for the
writing
of
this book
and the
specific objectives
are
stated.
The
approach
taken
in the
presentation
of the
materials
in
this book
is
explained.
A
brief
executive summary
of the
topics covered
in the
book
is
given.
The
roles

played
by
different
professionals,
such
as the
petroleum
and
chemical engi-
neers, chemists, physicist, geologists,
and
geochemists,
are
described.
Introduction
Formation damage
is a
generic terminology referring
to the
impairment
of
the
permeability
of
petroleum bearing formations
by
various adverse
processes. Formation damage
is an
undesirable operational

and
economic
problem
that
can
occur during
the
various phases
of oil and gas
recovery
from
subsurface
reservoirs including production, drilling, hydraulic
fractur-
ing,
and
workover operations.
As
expressed
by
Amaefule
et
al.
(1988)
"For-
mation
damage
is an
expensive headache
to the oil and gas

industry."
Bennion
(1999)
described
formation
damage
as:
"The
impairment
of the
invisible,
by the
inevitable
and
uncontrollable, resulting
in an
indeter-
minate
reduction
of the
unquantifiable!"
Formation damage assessment,
control,
and
remediation
are
among
the
most important issues
to be

resolved
for
efficient
exploitation
of
hydrocarbon reservoirs (Energy High-
lights,
1990). Formation damage
is
caused
by
physico-chemical, chemi-
cal, biological, hydrodynamic,
and
thermal interactions
of
porous
formation,
particles,
and
fluids
and
mechanical deformation
of
formation
2
Reservoir
Formation
Damage
under

stress
and
fluid
shear.
These
processes
are
triggered during
the
drilling, production, workover,
and
hydraulic fracturing operations. For-
mation
damage indicators include permeability impairment, skin damage,
and
decrease
of
well performance.
As
stated
by
Porter (1989),
"Forma-
tion
damage
is not
necessarily reversible"
and
"What gets into porous
media

does
not
necessarily come out."
Porter
(1989)
called this phenom-
enon "the reverse
funnel
effect."
Therefore,
it is
better
to
avoid forma-
tion damage than
to try to
restore
it. A
verified formation damage model
and
carefully planned
laboratory
and
field
tests
can
provide
scientific
guidance
and

help develop strategies
to
avoid
or
minimize formation
damage. Properly designed experimental
and
analytical techniques,
and
the
modeling
and
simulation approaches
can
help understanding, diagno-
sis, evaluation, prevention, remediation,
and
controlling
of
formation
damage
in oil and gas
reservoirs.
The
consequences
of
formation damage
are the
reduction
of the oil and

gas
productivity
of
reservoirs
and
noneconomic operation. Therefore,
it
is
essential
to
develop experimental
and
analytical methods
for
under-
standing
and
preventing and/or controlling formation damage
in oil and
gas
bearing formations (Energy Highlights,
1990).
The
laboratory
experi-
ments
are
important steps
in
reaching understanding

of the
physical
basis
of
formation damage phenomena.
"From
this experimental basis,
realistic models which allow extrapolation outside
the
scaleable range
may
be
constructed" (Energy Highlights,
1990).
These
efforts
are
necessary
to
develop
and
verify
accurate mathematical models
and
computer simu-
lators that
can be
used
for
predicting

and
determining strategies
to
avoid
and/or mitigate formation damage
in
petroleum reservoirs
(Civan,
1994).
Confidence
in
formation damage prediction using phenomenological
models cannot
be
gained without
field
testing. Planning
and
designing
field
test
procedures
for
verification
of the
mathematical
models
are
important. Once
a

model
has
been validated,
it can be
used
for
accurate
simulation
of the
reservoir formation damage. Current techniques
for
reservoir characterization
by
history matching
do not
consider
the
alter-
ation
of the
characteristics
of
reservoir formation during petroleum pro-
duction.
In
reality, formation characteristics vary
and a
formation damage
model
can

help
to
incorporate this variation into
the
history matching
process
for
accurate characterization
of
reservoir systems and, hence,
an
accurate prediction
of
future
performance. Formation damage
is an ex-
citing, challenging,
and
evolving field
of
research. Eventually,
the
research
efforts
will
lead
to a
better
understanding
and

simulation
tools
that
can
be
used
for
model-assisted analysis
of
rock,
fluid, and
particle interac-
tions
and the
processes caused
by
rock deformation
and
scientific guid-
ance
for
development
of
production strategies
for
formation damage
control
in
petroleum reservoirs.
Overview

of
Formation
Damage
3
In
the
past, numerous experimental
and
theoretical studies have been
carried
out for the
purpose
of
understanding
the
factors
and
mechanisms
that govern
the
phenomena
involving formation
damage.
Although
vari-
ous
results were obtained
from
these studies,
a

unified
theory
and ap-
proach still does
not
exist.
Civan
(1996)
explains:
A
formation damage model
is a
dynamic relationship expressing
the
fluid
transport capability
of
porous medium undergoing various
alteration processes. Modeling formation damage
in
petroleum res-
ervoirs
has
been
of
continuing
interest.
Although many
models
have

been proposed, these models
do not
have
the
general applicability.
However,
an
examination
of the
various modeling approaches
re-
veals that these models share
a
common ground and, therefore,
a
general model
can be
developed,
from
which these models
can be
derived. Although modeling based
on
well accepted theoretical
analyses
is
desirable
and
accurate, macroscopic formation damage
modeling

often
relies
on
some intuition
and
empiricism inferred
by
the
insight gained
from
experimental studies.
As
J.
Willard Gibbs stated
in a
practical manner: "The purpose
of a
theory
is
to
find
that viewpoint
from
which experimental observations appear
to fit the
pattern" (Duda,
1990).
Civan (1996) states:
The
fundamental

processes
causing damage
in
petroleum bearing
formations
are:
(1)
physico-chemical,
(2)
chemical,
(3)
hydrody-
namic,
(4)
thermal,
and (5)
mechanical. Formation damage studies
are
carried
out for (1)
understanding
of
these
processes
via
labora-
tory
and
field
testing,

(2)
development
of
mathematical
models
via
the
description
of
fundamental mechanisms
and
processes,
(3)
opti-
mization
for
prevention and/or reduction
of the
damage potential
of
the
reservoir formation,
and (4)
development
of
formation damage
control strategies
and
remediation methods. These tasks
can be

accom-
plished
by
means
of a
model assisted data analysis, case studies,
and
extrapolation
and
scaling
to
conditions beyond
the
limited test condi-
tions.
The
formulation
of the
general purpose formation damage model
is
presented
by
describing
the
relevant phenomena
on the
macroscopic
scale; i.e.
by
representative elementary porous media averaging.

As
stated
by
Civan
(1990):
Development
of a
numerical solution scheme
for the
highly non-linear
phenomenological model
and its
modification
and
verification
by
4
Reservoir
Formation
Damage
means
of
experimental testing
of a
variety
of
cores
from
geologi-
cal

porous media
are the
challenges
for
formation damage research.
As
expressed
by
Porter (1989)
and
Mungan (1989), formation dam-
age is not
necessarily reversible. Thus,
it is
better
to
avoid forma-
tion damage than
try to
restore formation permeability using costly
methods with uncertain successes
in
many cases. When
a
verified
generalized formation damage model becomes available,
it can be
used
to
develop strategies

to
avoid
or
minimize formation damage.
Finally,
it
should
be
recognized that formation damage studies involve
many
interdisciplinary knowledge
and
expertise.
An
in-depth review
of
the
various aspects
of the
processes leading
to
formation damage
may
require
a
large detailed presentation. Presentation
of
such encyclopedic
information
makes learning

of the
most important information
difficult
and, therefore,
it is
beyond
the
scope
of
this book. Instead,
a
summary
of
the
well proven, state-of-the-art knowledges
by
highlighting
the
impor-
tant
features,
are
presented
in a
concise manner
for
instructional purposes.
The
details
can be

found
in the
literature cited
at the end of the
chapters.
Common Formation Damage Problems, Factors,
and
Mechanisms
Barkman
and
Davidson
(1972),
Piot
and
Lietard (1987),
and
Amaefule
et
al.
(1987, 1988) have described
in
detail
the
various problems encoun-
tered
in the
field,
interfering with
the oil and gas
productivity.

Amaefule
et al.
(1988) listed
the
conditions
affecting
the
formation
damage
in
four
groups:
(1)
Type, morphology,
and
location
of
resident
minerals;
(2)
In-situ
and
extraneous
fluids
composition;
(3)
In-situ
tem-
perature
and

stress
conditions
and
properties
of
porous formation;
and
(4)
Well development
and
reservoir exploitation practices.
Amaefule
et al.
(1988) classified
the
various factors
affecting
forma-
tion
damage
as
following:
(1)
Invasion
of
foreign
fluids,
such
as
water

and
chemicals used
for
improved recovery, drilling
mud
invasion,
and
workover
fluids;
(2)
Invasion
of
foreign particles
and
mobilization
of
indigenous
par-
ticles, such
as
sand,
mud
fines,
bacteria,
and
debris;
(3)
Operation con-
ditions such
as

well
flow
rates
and
wellbore pressures
and
temperatures;
and
(4)
Properties
of the
formation
fluids
and
porous matrix.
Figure
1-1 by
Bennion (1999) delinates
the
common formation damage
mechanisms
in the
order
of
significance.
Bishop
(1997)
summarized
the
seven formation damage mechanisms described

by
Bennion
and
Thomas
(1991, 1994)
as
following:
1.
Fluid-fluid incompatibilities,
for
example emulsions generated
between invading
oil
based
mud
filtrate
and
formation water.
Formation
Damage
s
ion
i
|
Phase
Trapping
1
^
Water-based
Fluids

r
Solids
Invasion
i
r
1
Oil-based
Fluids
r
Foamy
Oils
i
r
|
Perforation
Induced
Mechanica
Damage
i
r
Geomechanical
Induced
Dirty
Injection
Fluids
Rock-Fluid
Interactions
^
g
i

Wettability
Alterations
^
Clay
1
Defloculation
1
—
Adsorption
Fluid-Fluid
Interactions
i
^
D
araffins
1
Sc
En-
r
lids
1
Precipitates
Asphaltenes
Diamondoids
Figure
1-1. Classification
and
order
of the
common formation damage mechanisms (modified

after
Bennion, ©1999; reprinted
by
permission
of the
Canadian Institute
of
Mining, Metallurgy
and
Petroleum).
O
n>
CD'
o
O
3
O
£>
6
Reservoir
Formation
Damage
2.
Rock-fluid incompatibilities,
for
example contact
of
potentially
swelling
smectite

clay
or
deflocculatable
kaolinite
clay
by
non-
equilibrium
water based
fluids
with
the
potential
to
severely
re-
duce near wellbore permeability.
3.
Solids invasion,
for
example
the
invasion
of
weighting agents
or
drilled solids.
4.
Phase
trapping/blocking,

for
example
the
invasion
and
entrapment
of
water based
fluids in the
near wellbore region
of a gas
well.
5.
Chemical
adsorption/wettability
alteration,
for
example
emulsifier
adsorption changing
the
wettability
and fluid flow
characteristics
of
a
formation.
6.
Fines
migration,

for
example
the
internal movement
of
fine
par-
ticulates within
a
rock's pore structure resulting
in the
bridging
and
plugging
of
pore throats.
7.
Biological activity,
for
example
the
introduction
of
bacterial agents
into
the
formation during drilling
and the
subsequent generation
of

polysacharide polymer slimes which reduce permeability.
Team
for
Understanding
and
Mitigation
of
Formation Damage
Amaefule
et
al.
(1987, 1988) stated that formation damage studies
re-
quire
a
cooperative
effort
between various professionals.
These
and
their
responsibilities
are
described
in the
following:
(1)
Geologist
and
geochem-

ist
on
mineralogy
and
diagenesis
and
reservoir
formation
characterization
and
evaluation;
(2)
Chemist
on
inorganic/organic chemistry, physical
chemistry,
colloidal
and
interfacial sciences,
and
chemical kinetics;
and
(3)
Chemical
and
petroleum engineers
on
transport phenomena
in
porous

media, simulator development, interpretation
of
laboratory core tests,
scaling
from
laboratory
to
field,
interpretation
of
field
tests,
and
devel-
opment
and
implementation
of
strategies
for
formation damage control.
Objectives
of the
Book
The
focus
of
this book
is to
provide

sufficient
knowledge
for the
fol-
lowing purposes:
(1)
Understand relevant
processes
by
laboratory
and
field
testing;
(2)
Develop
theories
and
mathematical expressions
for
description
of the
fundamental
mechanisms
and
processes,
and
phenom-
enological mathematical modeling
and
obtain numerical solutions

for
simulator
development
and
computer implementation;
(3)
Predict
and
simulate
the
consequences
and
scenarios
of the
various types
of
forma-
tion damage
processes
encountered
in
petroleum reservoirs;
(4)
Optimize
for
prevention and/or reduction
of the
damage potential
of the
reservoir