waterflooding ()
Post on 06-Jan-2017
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In the name of God
WATERFLOODING
Presentation Summary•Type of production•History of waterflooding•Why does (and doesn’t) waterflooding
work in various reservoir situations•What are the optimum conditions for
waterflooding•What are some common problems
associated with waterflooding•Waterflooding in Iran and Saudi
Arabia
Calculating Original Oil in Place (OOIP)• OOIP = 7,758*A*h* *(1-Sw)/Bo• Where:• OOIP = original oil in place, STB• 7,758 = factor converting acre-feet to barrels• A = reservoir area, acres• h = average reservoir thickness, feet• = average reservoir porosity, fraction bulk
volume• Sw = average water saturation, fraction pore
volume• Bo = oil formation volume factor, RB/STB
Primary Oil Production Methods•Oil Compression Drive (0.1-2% OOIP)
•Compaction Drive (0.1 – 2% OOIP)
•Solution gas drive (1-10% OOIP)
•Gascap drive (1-20% OOIP)
History of waterflooding•Accidental water injection in
1865(pennsylvania)• ’’Circle Flooding’’(Center injector,work
outward)•First 5 spot pattern,Bradford field in 1924•1930’s waterflood in Texas and Oklahama•Genral applicability in 1950’s
How does a waterflood work?•Certain oil wells are converted to water in
jection wells•Other oil wells remain as producers•The injected water displaces, or “pushes”
oil to the producing wells•Waterflooding performs two perimary
tasks:•To maintain the reservoir pressure•To drive the oil toward the wells
Waterflood Recovery(cold method)•Depends strongly on a number of factors
to be discussed•Can be as high as 60% of the OOIP in
place in some favorable situations•May be much lower in other cases•There are generally optimum reservoir
types, conditions and implementation strategies for waterflooding to maximize potential oil recovery
TYPES OF WATERFLOOD OPERATIONS
Natural Waterflooding
Infinite Aquifer Type Waterflood
1 m3Out
1 m3In
Limited Aquifer Type Waterflood
1 m3Out
0.5 m3In
Passive Aquifer Type Waterflood
1 m3Out
0 m3In
Modes of Natural Waterfloods•Vertical drive (most effective)
•Edge or horizontal drive (less effective)
Vertical Flood (Common in Reef Structures)
Edge Flood
‘Induced’ Waterfloods
Common Induced Waterflood Types•Edge drive (updip)•Bottom drive (gravity stabilized)•Line Drive•Advancing line drive•Staggered line drive•Pattern•Reservoir dictated
Updip Edge Drive
Vertically Stable Bottom Drive
Line Drive
Staggered Line Drive
Pattern Flooding – 5 Spot
Pattern Flooding – 7 Spot
Pattern Flooding – 9 Spot
Waterflood Requirements
#1 Suitable Reservoir
#2 Water!!!
Typical Water Sources•Produced water(s) (Native and non native
to formation)•Surface water (Rivers, lakes, etc)•Shallow ground water•Waste water streams•Often a mixture of some of the above
Surface Water
Shallow Aquifer
ProducingFormation
Deep Aquifer
Surface Water - Direct Intake
Surface Water
Shallow Aquifer
ProducingFormation
Deep Aquifer
Surface Water - Infiltration Gallery
Surface Water
Shallow Aquifer
ProducingFormation
Deep Aquifer
Shallow Aquifer
Surface Water
Shallow Aquifer
ProducingFormation
Deep Aquifer
Formation Water
Surface Water
Shallow Aquifer
ProducingFormation
Deep Aquifer
Deep Aquifer
Injection Water Quality Issues•Sufficient volume for future
requirements?•Reliable year round source?•Total suspended solids content (TSS)•Oil and Grease Content (OGC)•Total dissolved solids content (TDS)•Scaling indexes•Specific ionic composition•salinity
Waterflood Progression
Waterflood Progression
Waterflood Progression
Waterflood Progression
Factors Impacting the Displacement Effectiveness of a Waterflood
MACROSCALE EFFECTS•Heterogeneity•Permeability contrasts•Reservoir continuity•Faults and fractures
MICROSCALE EFFECTS•Pore size distribution and geometry
•Capillary pressure•Wettability•Relative permeability character•Advance rate•Injection fluid induced damage
Factors Affecting Waterflood Success• Timing of flood – earlier is betterHigher primary depletion (lower pressure) increases
gas saturation High gas saturation decreases oil recovery• Well spacing Tighter well spacing is better Increases Ea and Ev accelerates waterflood recovery• Pattern selectionBalanced patterns improve Ea and WOR performance
MACROSCALE ISSUES
Reservoir Heterogeneity
Reservoir Heterogeneity
Permeability Contrasts
Reservoir Continuity
Reservoir Continuity
Natural Fractures Parallel to the Line of Flow
Microscale IssuesPrimarily Dominated by Wettability Effects
What is Wettability?•Preferential Attraction of a fluid to a solid
surface in the presence of one or more other immiscible fluids
Wettability Types•Water Wet•Oil Wet•Neutral Wet•Mixed Wet•Spotted Wet
Mixed Wettability•A fairly common wettability type in which
tight microporosity is water saturated and water wet, while oil saturated macropores are oil wet
Impact of Wettability on Relative Permeability to Water and Oil
Impact of Wettability on Relative Permeability to Water and Oil
Relative Permeability
Water Saturation - Fraction
Rel
ativ
e P
erm
eabi
lity
- Fra
ctio
n
Swi 10%Crossover 22% SwKrw = 0.88
Swi approx 25%Crossover approx 68% Krw = 0.08
General Impact of Wettability on Rel Perm
Factor WaterWet
Oil Wet Neutral Wet
Mixed Wet
Swi >15% <15% 10-20% >15%
CrossoverPoint
> 50% Sw < 50% Sw Approx 50% Sw
< 50% Sw
Krw at Sor <0.2 >0.5 0.2-0.5 >0.5
Specific Impact of Wettability on Waterflood Performance
Favorable vs. Unfavorable Mobility Ratio
Factors Improving Mobility
M = x Krw
w x K ro
Low Oil Visc Low Krw / Krg
High Displacing Phase Visc
High Kro
Example – Waterflood in a Favorable Mobility System (M=0.5)
Example – Waterflood in a Unfavorable Mobility System (M=20)
Given this – What are the Optimum Reservoir Wetting Conditions for a Waterflood?
For Maximum Ease of Water Injection
OilWet!
For Maximum Oil Recovery and Lowest Residual Oil Saturation
Neutral/MixedWet
For Most Rapid Oil Recovery and Minimum Water Production
WaterWet!
Optimum Conditions?•In most cases, optimum economic recovery efficiency is achieved when the wetting condition is a strongly water wet as possible
Does This Mean if my Reservoir is NOT Water Wet Waterflooding Will NOT be Economic?
To Flood?
To Not to Flood?
???
Many Successful Waterfloods have been Conducted in Oil Wet and Mixed Wet Reservoirs
•Overall economic benefit may be less than if the reservoir had been strongly water wet, but may still represent substantial improvement over straight primary depletion
Waterflood Screening and Evaluation Process
General ProcessMacroscaleScreening
MicroscaleScreening
Water SourceAnd QualityEvaluation
Simulation,Implementation
Conclusions•Waterflooding can result in significant
additional incremental oil recovery in many reservoir situations
•Not all reservoirs are prime waterflood candidates
•Macroscale features may control the effectiveness of a waterflood
•Mobility dominates microscale sweep efficiency
•A detailed protocol for evaluation has been presented
Part 2:Waterflooding in Iran and Saudi Arabia
waterflooding in iranمیانگیIن تزریIق آIب بIه میدانهای دورود، سIلمان، بالل، سIیوند، دنIا و اسفند در •
هزار بشکIه در روز بوده که از ایIن میزان بیشتریIن حجم ٢٩۶ حدود 93سIال تزریق آب به ترتیب به میدانهای دورود، اسفند و سلمان بوده است.
درصIد نفت مخازن فالت قاره ۴٠مطالعات جدیIد نشان مIی دهIد کIه بیIش از •را در حوزه خلیIج فارس مIی توان بIه روش تزریIق آIب (بIا توجIه بIه منابIع آبی
فراوان و دسترسی آسان) برداشت کرد.(حدود • شرکIت ایIن تولیIد از توجهIی قابIل ١بخIش طریق ۵ از درصIد)
فرازآوری گاز در چاهها انجام می شود.هIم اکنون تزریIق گاز و تزریIق آIب، دو روش اصIلی ازدیاد برداشت از مخازن •
نفتIی کشور اسIت؛ اگرچIه در مناطIق خشکIی کشور، تزریIق گاز به عنوان برخی (در گیرد مIی قرار اولویIت در برداشIت ازدیاد روش تریIن اصIلی میدانهای نفتIی مناطIق نفIت خیIز جنوب، تزریIق آIب همچنان ادامIه دارد) اما در فالت قاره ایران بIه دلیIل دسIترسی آسIان بIه آIب، تزریIق آIب در اولویت
قرار می گیرد.
Waterflooding in Saudi Arabia آرامکIو در • اعالم کرد کIهI نرخ افت ۲۰۰۶س�ال سIخنگوی شرکIت
۸توليIد مياديIن نفتIی بالIغ عربسIتان را بدون انجام هيچ اقدام جديدی، کاهش درصد ۲است که فعاليت های آرامکIو اين ميزان را به درصد
خواهد داد. در واقع عربستان سIعی می کنIد تا از دو طريق، تأثيIر افت توليIد بر روی ظرفيIت توليIد خود را کاهIش دهIد؛ نخست به کارگيری دوم و توليدی ميادين در تکنولوژی های موجود جديدتريIن و بهتريIن
توسعه ميادين جديد. جهIت حفIظ فشار ميادين توليدی، ۱۹۵۰ايIن کشور از اواسIط دهIه •
شروع بIه تزريIق گاز همراه نفIت کرد. اوليIن واحIد تزريIق گاز در سال در ميدان عين دار ۱۹۵۹ در ميدان آبقيق و دوميIن واحد در سال ۱۹۵۴
احداث شد. پIس از چندی بIه دليIل اينکIه تزريIق گاز نتوانسIت به طور کامل از افت فشار مخازن جلوگيری کند، به تزريق آب روی آوردند.
Waterflooding in Saudi Arabia در ميدان آبقيIق باز می گردد کIه به ۱۹۵۶اوليIن تجربIه تزريIق آIب بIه سIال •
کار تزريIق به ۱۹۶۰ بودن ايIن عمليات، در اوايIل دهIه موفقيت آميIزدليIل معادل ۱۹۹۸ميدان قوار قبIل از افIت فشار ايIن ميدان آغاز شد. در سIال
ميليون بشکه در روز به دو ميدان قوار و آبقيق آب تزريق مي شد. ۱۲ ۱۲بر اسIاس گزارش های شرکIت سIعودیI آرامکIو،I در حال حاضIر روزانIه •
بIه ميليون بشکIه آبقيIق و بری تزريIق می شود که ۳آIب I،۷ ميدان قوار I،اIدري آIب تصIفيه از آIن بشکIه واحدهای ۳ميليون از بشکه ميليون
ميليون بشکIه نيIز از سIفره های آIب زيرزمينی ۳جداسIازی نفIت و گاز و تأمين می شود.
ميليون ۴ ميليون بشکIه به ميدان قوار و ۸ ميليون بشکIه، ۱۲از مجموع •با وجود آرامکIو آبقيIق تزريIق می شود. شرکIت بIه مياديIن بری و بشکIه
اين ۴گذشIت از هIم هنوز I،یIنفت مخازن بIه آIب تزريIق از شروع دهIه عمليات درس می گيرد.
Thanks for Your Attention!
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