Logical, Systematic, Complete
IPCFR – Integrated Petrophysics for Carbonate and Fractured Reservoirs –
A Roadmap
Contents – 5 Day
Contents – 3 Day
The Central Role of the Petrophysicist is to INTEGRATE !
Day 1
COURSE OBJECTIVES
Course Objectives 1
Course Objectives 2
INTRODUCTION AND PRINCIPLES
Intro – Reservoir schematic
Intro – Reminder: Borehole, Invasion & Symbols
(Schl. Gen-3)
Intro – Aquifer, Transition Zone & Hydrocarbon Zone
Intro – Data Hierarchy and Upward Calibration:
Logs Provide a Vehicle for Data Integration
Intro – Data Hierachy Concept
Intro – Data Hierarchy Criteria
Intro – Calibration projects high value data into larger reservoir volumes using more continuous data
Intro – Adopt a problem solving philosophy
Course Structure & Evaluation Sequence
CARBONATES ARE DIFFERENT TO CLASTICS So don’t treat them like clastics
Contrasting Geological Origins – Clastics
Contrasting Geological Origins – Carbonates
Contrasting Geological Origins – Carbonates
Contrasting Geological Origins – Carbonates
Contrasting Geological Origins – Fractures
MICROPRACTICAL – QL Sw & k: invasion profiles
MICROPRACTICAL – QL Sw & k: Porosity vs Rt
Dominant Minerals – clastics, carbonates, fractures
Dominant Minerals – clastics
About clay minerals
Carbonates diagenesis – 1
Carbonates diagenesis – 2 Always look for dolomitic zones!
Diagenesis – carbonates more extreme
Carbonate Diagenetic Facies
Carbonate Diagenetic Effects on Permeability
Clastic-Carbonate differences:
Carbonate POROSITY: low, high, variable, extreme
Clastic-Carbonate differences:
Clastics PORE GEOMETRY usually simple
Clastic-Carbonate differences:
Carbonates PORE GEOMETRY extremely diverse
Clastic-Carbonate differences: Carbonates PORE GEOMETRY range
c:\data\courses\zzMRIL.avi Click to play
Clastic-Carbonate differences..
but Carbonate PORE GEOMETRY can also be uniform
Clastic-Carbonate differences: heterogeneity, mm-m
Carbonate porosity types are diverse (Choquette & Pray 1970)
Summary – Clastic – Carbonate matrix differences
Stress, Fracture Types & Petrophysical Features
Fracture Spacing “S” and Width “E”
Geologic Parameters Controlling “S” and “E”
Reservoir Character created by differences:
Fracture-Matrix Interaction, q
Day1 AM PRACTICAL: Physical Characteristics Questions
Reservoir Character created by differences
– oil wetness
Wettability: Wetting preferences dictate the distribution of oil & water within the pore network
Saturation Exponent vs. Fraction Oil Wet Surface
The link between resistivity and Sw becomes problematic with mixed n* 3.4 ? 1.8; EHC+48%
Wettability: Is your reservoir non-strongly water wet?
ARE CARBONATE GEOLOGICAL CLASSIFICATION SYSTEMS USEFUL FOR CARBONATE PETROPHYSICS?
Carbonate Classifications-Dunham: Grain support
Carbonate Classifications – petrophysics at last !
Lucia: rock-fabric classes
Carbonate Classifications – Lucia’s key concepts
Lucia – vug classes. Are vugs connected?
Lucia’s –
“Rock Fabric”
Lucia’s –
“Rock Fabric”
Lucia’s – “Rock Fabric”
Non-vuggy limestones & dolostones: Class1, 2 & 3
Fracture permeability
Parallel plate single fracture set
Lucia’s – “Rock Fabric” Separate vug permeability – difficult
c:\data\courses\zzSTAR.avi Click to play
Lucia’s – “Rock Fabric” generic inter particle off-the-shelf answers
In Defence of Lucia – from Ø to k & Sw without core Use, adapt, replace
Fractures – Fractured Reservoir Classification – Aguilera
Fractures – Fractured Reservoir Classification – Nelson
Fooled by Fractures
Course Structure & Evaluation Sequence
HOW DO THE PHYSICAL CHARACTERISTICS OF CARBONATES IMPACT RESERVOIR MEASUREMENTS?
Impact of Character on Measurement & Evaluation
Impact on Measurements – Conventional logs:
a Failure Point
Impact on Measurements – Matrix porosity
Impact on Measurements – Matrix porosity
Clastics vs Carbonates
Impact on Measurements – Matrix porosity
Matrix porosity measurements compared
Day1 PM PRACTICAL: Classification Systems and Petrophysics, Lucia
END DAY 1
Day 2
Recap Day1
Impact on Measurements – Fracture porosity
Impact on Measurements – Matrix saturation Swrt
Impact on Measurements – Matrix saturation Swpc
Impact on Measurements – Swpc
What is Capillary Pressure?
Impact on Measurements – Swpc
WFTs Provide FWL, Mobile Fluid Type
& Actual Capillary Pressure = Excess Pressure = Saturating Pressure
Impact on Measurements – Matrix saturation Swmr
MICROPRACTICAL – Matrix porosity Error in
“tight” carbonates
Impact on Measurements – Matrix permeability
Impact on Measurements – Matrix permeability
Impact on Measurements – Fracture permeability
Impact on Measurements – Netpay thickness, h
Impact on Measurements – FWL
MICROPRACTICAL – Data Hierarchy drives Data Flow
CAUTION ! MISLEADING DATA IN CARBONATE AND FRACTURED RESERVOIRS
Misleading Data – fracture wells tests
Misleading Data – Access the matrix!
Misleading Data – routine core analysis
Misleading Data – biased RCA
Misleading Data
Use high sample density fixed spacing RCA
Misleading Data – inadequate pore throat size data
Misleading Data – missing Clay Bound Water
Misleading Data – Mercury capillary pressure data correction, for ClayBW only
Misleading Data – Rt
Misleading Data – Viscous oil shortens NMR T2
Carbonate & Fracture Major Petrophysical Difficulties
c:\data\courses\zzIFX.wmv Click to play
Day2 AM1 PRACTICAL: FWL from single WFT point
Day2 AM2 PRACTICAL: Classification Systems & Petrophysics, Fractures
Course Structure & Evaluation Sequence
USEFUL DATA – LOG IT, USE IT
Achieving Optimal Data Acquisition
Useful data – Drilling, Mudlogs, Chromatograph
Useful data – Rxo
Useful data – Whole core, Miniperm
Useful data – Core
Useful data – Sonic, Density
Useful data – Logged Water Zones
Useful data – a*Rw, m from Dielectric BVW and Rxo
Useful data – Analogs cheap!
Useful data – Analog superimposed RCA for SCAL
Useful data – Analog FZI for SCAL Pc data
Useful data – Stoneley Permeability
POWERFUL DATA – NICE IF YOU CAN GET IT!
Powerful data – Fracture Check & Managed Pressure
Drilling (MPD) Control swab/surge & detect permeable fracs
Powerful data – Fracture Test Design & analysis (1)
Powerful data – Fracture Test Design & analysis (2)
Dual porosity pressure build up vs. time characteristics
Powerful data – Image Logs
Powerful data – Image Logs
Powerful data – Image Logs
Powerful data – NMR: Principle
Powerful data – NMR: Think Sw-Ht
Powerful data – NMR: Convert T2 to Ht & BVW
Powerful data– NMR bins imply Sw for a given Pc (Ht)
Powerful data – NMR: Acquire Fast BFV, BVI
Day2 PM PRACTICAL: Impact of Physical Characteristics on Measurements
END DAY 2
Day 3
Recap Day2
Powerful data – Array Sonics e.g. SLB Sonic Scanner (MSIP)
Powerful data – What we need from Array Acoustics
Powerful data – Dielectric Tools:
SLB: ADT Array Dielectric Tool SPE116130 (Sep-08)
c:\data\courses\zzDieScanr.wmv Click to play
Powerful Data – Production Noise Log frequency distinguishes fracture vs matrix flow
Powerful data – Sigma Logs: BVW
Powerful data – Sigma Logs: BVWe
Powerful data – LWD Sigma log: BVW
MICROPRACTICAL Sw: Calculate Swi_mr from
Free Fluid and Øt, what assumptions?
Powerful data – FLEX, LithoScanner, ECS (Elemental Capture Spectroscopy)
c:\data\courses\zzLithoScanner.wmv Click to play
Powerful data – TypeC Fracture Well Tests
Well test + Image Log ? E ? Øf ? HCIIP !
Powerful… Core + Image Log + NMR + FWL
Powerful… Relative contribution to Formation Evaluation of different data types
Key Questions for the Data Acquisition program
Guide – Carbonate Wireline Logging (SLB mnemonics)
Course Structure & Evaluation Sequence
CARBONATES QUICK LOOK – DIFFERENT TO CLASTICS
QL – Fracture ID,
conventional logs
QL – Fracture Porosity indicated by Conventional Logs
QL Fracture ID – Key Points
Course Structure & Evaluation Sequence
General – Four calibrations ensure correct matrix HPV
..this is what we will do (Deakin & Smith 2003)
Carbonate Matrix Evaluation
Carbonate Matrix Evaluation – Key Elements
QL – Achieving Fit-For-Purpose Quick Look Results
QL – unseen rhog changes in low Ø rock will ruin Ød !
QL – Porosity density neutron, Ødn
QL – Porosity sonic (Wyllie Time Average), Øs
QL – Why sonic porosity? For vugs!
QL – (Ødn-Øs) indicates vugs, and m
Øs: approximate dt matrix
Øs: determine dt_fluid from dtf apparent (dtfa)
Øs: determine vugs & predict m with dtfa
Day3 PRACTICAL: Achieving Cost Effective Data Acquisition & Basic Carbonate Log Analysis – Questions
Course Structure & Evaluation Sequence
QL – Ro prediction a*Rw, m Archie: Sw^n = a*Rw / (Rt * Ø^m)
Impact of ‘m’ on Ro. Archie: Ø-m=Ro/Rw
Actual lab SCAL m variations caused by vuggy porosity – m impacts Ro and HPV
Is Water Zone ‘m’ related to Øvugs? If yes use Øvugs to predict m in HC zone
Ro prediction variable m
Saturation Archie, Swar
What is ‘n’? Archie: Sw-n = Rt/Ro
QL – HC detection, qualitative
QL – Saturation. Resistivity ratio: Swrr
QL – Saturation: Swrr problems
QL – Sw resistivity ratio: Swrr
QL – Reconcile Swar, Swrr
FULL CARBONATE MATRIX EVALUATION
Average m’s: Interparticle 1.99; Vuggy/moldic 2.28
Average m’s: Non vuggy Lucia Classes
Whole rock m: vugs increase, fracs decrease
Carbonate matrix evaluation – vugs increase m
Carbonate matrix evaluation – reality is complex
Carbonate matrix – Determine vugs: Image logs
Carbonate matrix – Determine vugs: NMR logs
Carbonate matrix – summary variable m (mv) determination from Øvug
Carbonate matrix – vugs and HPV
Day3 PRACTICAL: Basic Carbonate Log Analysis: Platform Carbonate, Gas – Questions
END DAY 3
Day 4
Recap Day3
Carbonate matrix evaluation –
Rock Fabric Identification
MICROPRACTICAL Ro: Compute m apparent in Sw100 zone
Carbonate matrix – Porous plate apparatus used for air-brine capillary pressure data, Sw – Pc
Carbonate matrix –
Wetting phase (water) desaturation with increasing Pc
Carbonate matrix –
Height positions the Pc-Sw data in the reservoir
Carbonate matrix –
Use RCA to project cap.press data into the reservoir
Carbonate matrix –
Capillary Pressure Measurement techniques
Carbonate matrix – Core Overburden Electrical Properties combined with porous plate Pc
Carbonate matrix – Capillary Pressure Saturations,
4 controls on Sh
Carbonate matrix – Interfacial Tension IFT
Do Perched Water contacts violate capillary pressure Saturation-height assumptions?
Carbonate matrix – Mercury injection data reveals PTSD
Carbonate matrix – Different Reservoir Qualities yield Different TZ thickness
Carbonate matrix – In Transition Zones Pc is low and Sw>Swi Water and oil are both mobile
MICROPRACTICAL Cutoff: Relative Perm SCAL data demonstrates the Netpay permeability cutoff
Carbonate matrix –
Summary of J Function Sw from Pc data, Swj
Swpc: J Bundles Ø, k and Ht to correlate with Sw
Fitting Pc data: FOIL, Lambda, Modified J, Johnson, Skelt
Carbonate matrix –
Converting Laboratory Pc to reservoir Height
Carbonate matrix –
Swj (predicted) vs core plug measured Sw
Carbonate matrix –
QuickLook Swpc: arrange your Pc data like this,
per rocktype, facies
Carbonate matrix – Redisplay lab Pc results as a simple Sw-Ht grid
Carbonate matrix – Bulk Volume Water > Cap.Press BVWi Indicates Fluid Zone = Transition Zone; Residuals or Water
Carbonate matrix: Oil and Water mud core Sw compared
to reservoir true Sw
Swobm: Partial Invasion of an Oil Mud Core leaving an un-invaded center
Carbonate matrix –
Dean Stark apparatus used in the determination of oil mud Swcore
Carbonate matrix:
Check OBM 3days before coring
Day4 PRACTICAL: Achieving Fit For Purpose QL Results 1/2
RESERVOIR ROCK TYPES (RRTs)
Carbonate matrix – Characterise EACH RRT:
NMR T2 distribution may indicate Pore Throat Size distribution
Carbonate matrix – Characterise EACH RRT:
will the pore system unload it’s oil?
Summary – Reservoir Rock Typing (RRT)
World’s Largest Tanker: JahreViking 4.1mm bbls crude
Ultra Large Crude Carrier (ULCC). Planet Earth consumes 20 of these per day
Carbonate matrix – Magnetic Resonance Swi for ‘n’
Carbonate matrix – A better way to display NMR data
Carbonate matrix – Four calibrations ensure correct matrix HPV ..this is what we have done (Deakin & Smith 2003)
Course Structure & Evaluation Sequence
CARBONATE MATRIX PERMEABILITY EVALUATION
k matrix QL: Adapt Chart K-4
c:\data\courses\zzMRIL.avi Click to play
Carbonate matrix –
SDR permeability equation, T2 cutoff not used
Carbonate matrix – Coates permeability
Carbonate matrix – determine vug connectivity
p = f.(Øvug)
Carbonate matrix – Bound Fluid Volumes and logs
Carbonate matrix –
Why the Coates Equation is so powerful
Carbonate matrix – Coates equation vs Core
Carb matrix – What is an Acoustic Stoneley Wave?
Carb matrix – Stoneley waves: Attenuation, Slowness & Mobility
Carb matrix –
Stoneley waves Slowed & Attenuated by Mobility
FWL – Supercharging: WFT measured pressures may be above formation if permeability is low
FWL Excess Pressure plots clarify FWLs and show actual reservoir capillary pressure
c:\data\courses\zzRCI.avi Click to play
Carb matrix – Diverse data with the same result creates confidence in the result.. especially in complex reservoirs
Carbonate Matrix – Key Points
Day4 PRACTICAL: Achieving Fit For Purpose QL Results 2/2
END DAY 4
Day 5
Recap Day4
Course Structure & Evaluation Sequence
FRACTURES
Fractured Reservoir Evaluation process
Fractures – Basement High & Porosity Distribution, TypeC
Fractures – Fracture POROSITY is SMALL!
Fractures – Limited storage: HPV per GRV << Intergranular
Fractures – Porosity: Outcrop studies
Fractures – Porosity: Core + Image logs
Fractures – Porosity: Well Tests TypeC and TypeB if kf>>km
Fractures – Fracture PERMEABILITY is BIG!
Fractures – Useful calculators
Frac Ø & HPV, from DST kh and Deterministic. Type C and B if kf>>km
Fractures – Finding & Evaluating Fracs Data, Ranked
Fractures –
Acoustic Stoneley Wave Reflection Coefficient
Fractures – Acoustic Stoneley Wave response
Fractures – Stoneley Attenuation and Fracture Aperture
Fractures –
What is Acoustic Shear Wave Splitting?
Fractures –
Acoustic Wave Shear Anisotropy
Fractures – Conjugate fractures & Smax
QL – Fracture ID: special logs 1
QL – Fracture ID: special logs 2
Fractures –
Orientation: Acoustic & Image
c:\data\courses\zzXMAC.avi Click to play
Fractures – Circumfrential Acoustic Scanner Tool (CAST) amplitude displayed as dipping planes (fracs) with known orientation
Fractures – Comparison of Fracture Imaging Logs
Fractures – Mechanical Properties Log
Fractures – Production Logging Techniques
Fractures – S, E, Orientation and Length?
Any other data?
Fractures –
Lithology may influence fracture spacing, S
Determine Fracture-Matrix Interaction
Fractures – Plan view: vertical fractures & horizontal well
Fractures – Size, Density & Orientation
Fracture Orientation + Stress Orientation ? Drill
Fracture Indicator Scores – exhaustive and definitive but slow
Fractures – Surprising Fluid Distributions after Production
Fractures – Some Key Points
Course Structure & Evaluation Sequence
CARBONATE GEO-MODEL INPUT
A Consistent Geological Model
Imagine your reservoir as a road cutting..
Geo-model Checksums
EHC & kh must be equal at all scales of reservoir description!
Course Structure & Evaluation Sequence
10 Systematic errors which will ruin your
carbonate/fracture geo.model (chronological)
Day5 PRACTICAL How to Use Capillary Pressure Data – Questions
THE END
BACKUP
Twice Daily Practical work sessions
Morning coffee – Your considered questions and debate
100+ Critical Equations in MSExcel format
Abbreviations
Key C&F technical papers
References
Charts
Together we recognise, understand and treat all the critical issues which threaten the Carbonate & Fracture petrophysicist. The structured process detailed in this course will arm you with fresh confidence, knowledge and enthusiasm for your work as a Carbonate geoscientist.
If you love petrophysics you will love this course. Guaranteed !
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