Advanced Well Log Analysis & Interpretation
This course will teach you how to evaluate reservoirs and quickly identify flawed results. Robust reserves and simulation are achieved by the logical, systematic integration of all relevant data. A quality interpretation is extremely cost-effective compared with development mistakes and essential with today’s complex data sets. Proper core-log-test integration replaces the need to run expensive, irrelevant logs, explains data conflicts and provides the correct answer faster, strengthening your position as an operator and petrophysicist. By contrast, stand-alone log analysis results in wrong decisions and weakens your position as a competent petrophysicist.
This course, evolved over 25 years of technical petrophysical consulting and training, demonstrates how robust answers are achieved by the logical integration of core, special core, pressures, well-tests and other diverse data. Pay and reserves are addressed first by Quick Look Log Analysis and then by a disciplined, logical process to optimize the interpretation of lithology, porosity, saturation, permeability and fluid contacts – the basis of Reserves. Low Contrast Pay, clastics and carbonates are evaluated by straight forward integration techniques which outperform log analysis with direct, plain to see results.
The integration of mudlogs, LWD, wireline, facies/rock types, core, SCAL, NMR, dielectric, MDTs and well tests are explained via the author’s 30,000 core plug PetroDB and Interactive Petrophysics (IP) software. Finally, the critical Petrophysics to Geomodel Essential Checks are clearly set out.
This course is a condensed package of powerful integration techniques.
DAY 1
Introduction & Principles
- A Comprehensive Course Manual!
- Objective of Formation Evaluation
- Four log calibrations ensure correct HPV’s
- Reservoir schematic
- The Concept of Data Hierarchy
- Calibration projects high value data into larger reservoir volumes using more continuous data
- MICROPRACTICAL Logs, Core, Salinity & Rw
- Major Petrophysical Difficulties
- Hetrogeneous reservoirs require measurements at the required answer scale, or multiple finer scale measurements to describe them
- Improper core sampling for core-log calibration
- A Basic Problem for Petrophysics
- Deterministic vs. Probabilistic Petrophysics
Introduction & Principles
- Conventiona Logs: Caliper; Gamma Ray, Spontaneous
- Potential, MicroResistivity, Multi-depth Resistivity,
- Compressional Sonic, Density, Neutron
- Conventional Logs: Porosity, Sw, Perm, Pay
- Quick Look: Invasion profiles indicate mobile fluids & permeability – oil base mud
- Quick Look: Why porosity logs are plotted backwards
- Quick Look: Mudlog, rate shows and apply chromatograph ratios
- Quick Look: Compute Vsh; Ø; Sw; k
- Quick Look: Aquifer, Transition Zone and Hydrocarbon Zone
- Quick Look: Default Equation Sequence
RECOMMENDED EVALUATION SEQUENCE: A-Z Data Preparation
- Data Prep: Log Data Preparation
- Data Prep: Merge LWD and Wireline
- Data Prep: Log Normalisation
- Data Prep: Core Data Preparation & Vetting
Vshale And Lithology
- Vsh: Common Uses of Vclay, Vshale
- Vsh: Common Problems
- Vsh: Magnetic Resonance and other inputs
- Look Log Analysis Practical
- Vsh: Density-neutron
- Vsh: Some more equations. See Notes
- Vsh: Thomas-Stieber clay distribution. Assumes sand Øt is reduced by dispersed clay in pores, Tertiary clastics
- Lith: Litho scanner and spectral GR tools
- As a Reviewer of Petrophysics: Check Vshale
Porosity
- Ø: Objective of Log Derived Porosity
- Ø: Common Porosity Problems
- Ø: Pre-emptive action for Badhole
- Ø: Importance and Problems of Core Porosity
- Ø: Significance of grain density, rhog
DAY 2
Day 1 Recap, Questions, Debate
- Ø: RCA, typical laboratory process
- Ø: Recommended RCA procedure
- Ø: Gas expansion porosity Boyle’s Law Porosimeter
- Ø: Core Overburden Porosities
- MICROPRACTICAL: Which quicklook porosity?
- Ø: The Ideal Model. Full core-log integration. Uses Øt & Øe linked via Qv, salinity (Juhasz 1988)
- Ø: What is Effective Porosity? Øe
- Ø: Porosity measurements compared
- Ø: Carbonates: Density-Sonic porosity can indicate vugs, Øv
- Ø: Log Integration. rhog variations cause error in Density Porosity
- Ø: Log Integration. Core-log plot determines apparent fluid density, rhof
- Ø: Magnetic Resonance Porosities, Ømrt, Ømre
- Ø: Neutron Porosity, Øn
- Ø: Advantages of Ødn and recap
- Ø: Gas Zone Porosities
- Reviewers of Petrophysics: Check Ø
Rw, Formation Water Resistivity
- Rw: Formation Water Resistivity
- Rw: The Rw we Want and The Rw we Get
- Rw: Sources of Rw *=@Swi
- Rw: Use WFT water samples to calibrate log Rwa’s
- Rw: Archie Rwa from clean 100% water zones
- MICROPRACTICAL Compute Rwa, Rwrr
- Rw: NaCl apparent (NaCla), a useful curve during exploration
- Rw: Identify & Flag “Sw100” zones for Rwa, NaCla, ma, BQva etc
- Rw: Rwpc, Rwssp, Rwgrad
- Reviewers of Petrophysical Results: Check Rw
- Day 2 1100h BEGIN Practical Ques2 Core-Log
- Workshop: Reconciliation
Ro, Water Saturated Formation Resistivity & m
- Ro: Water Saturated Resistivity, Objective and Problems
- Ro: Function of ‘m’
- Ro: Ø^-m = Ro/Rw. Core-log common format ‘m’ definition plot
- Ro: Pickett Plot: determines m, a*Rw and Sw from logs
- Ro: How to pick SCAL plugs
- Ro: Sw100 Zone Log Analysis ‘m’
- Ro: Determining m and m* from Sw100zone log data
- Ro: Carbonates: Is Water Zone ‘m’ related to Øvugs?
- Ro: ‘m’ Log Integration
- Reviewers of Petrophysical Results: Check Ro
- Resume Practicals with Water Zone “m”
- Ro: Water Saturated Resistivity, Objective and Problems
- Ro: Function of ‘m’
- Ro: Ø^-m = Ro/Rw. Core-log common format ‘m’ definition plot
- Ro: Pickett Plot: determines m, a*Rw and Sw from logs
- Ro: How to pick SCAL plugs
- Ro: Sw100 Zone Log Analysis ‘m’
- Ro: Determining m and m* from Sw100zone log data
- Ro: Carbonates: Is Water Zone ‘m’ related to Øvugs?
- Ro: ‘m’ Log Integration
- Reviewers of Petrophysical Results: Check Ro
- Resume Practicals with Water Zone “m”
DAY 3
Day 2 Recap, Questions, Debate
- n: Function of ‘n’
- n: Sw^-n = Rt/Ro Core-log common format ‘n’ definition plot
Wettability
- Wettability: Wetting preferences dictate the distribution of
- oil and water within the pore network
- Wettability: The link between resistivity & w becomes
- problematic with mixed wettability n* 3.4 Þ 1.8; EHC+48%
- Wettability: Is your reservoir non-strongly water wet?
- MICROPRACTICAL Sw equations predict Ro first. -
- Then compare with Rt
Shaly Sand Evaluation
- Shaly sands: Ro is suppressed in Shaly Sands for a given Ø
- Shaly sands: Rt is suppressed in Shaly Sands for a given Sw
- Shaly sands: Multiple Salinity Core Tests for Excess Conductivity, B*Qv and Waxman Smits Fws
- Shaly sands: Waxman & Smits, Swt
- Shaly sands: Core Cation Exchange Capacity for Qv
- Shaly sands: NMR logs provide Qv estimate
- Shaly sands: Archie m = f.(Ø, Vsh) for apparent Qv. no core (Qvm)
- Shaly sands: Equivalent Conductivity of Exchange Cations, B plot
- Shaly sands: Is ‘m’ a Function of Vshale? Sw100zone diagnostic plot
- Shaly sands: Are ‘clean’ sands really clean? Does it matter ?
- Popular Sw Equations
- Shaly sands: Selecting parameters for the Juhasz Qvn Eqn, 1 No core
- Shaly sands: Getting the right answer, cross calibration
- Day 3: 1100h BEGIN Practical: EVALUATION: Ø, Rw, ‘m’, ‘n’, Sw
- n: ‘n’ as a core-log matching parameter
Sw Oil Base Mud Core
- Swobm: Oil and Water mud core Sw compared to reservoir true Sw
- Swobm: Dean Stark apparatus used in the determination of oil mud Swcore
- Swobm: How to get Sw OBM core
Sw Capillary Pressure
- Swpc: What is Capillary Pressure?
- Swpc: WFTs Provide FWL, Mobile Fluid Type and Actual Reservoir Capillary Pressure
- Swpc: Porous plate apparatus used for air-brine capillary pressure data, Sw – Pc
- Swpc: Capillary Pressure Measurement techniques
- Capillary Pressure Saturations – 4 controls on Sh
- Have Anomalous plugs been identified?
- BEGIN PM Practical DAY 3 EVALUATION: Ø, Rw, ‘m’, ‘n’, Sw
- Swpc: Converting Laboratory Pc to Height
- Swpc: Use RCA to project cap.press data into the reservoir
- Swpc: Summary of J Function Sw from Pc data, Swj
- Swpc: The Reservoir Master Equation J predicts Sw (carbonate, poor fit)
- Swpc: Equation check: Plot Swj vs Sw measured
- Swpc: Capillary Pressure Sw and ‘n’
- Swpc: n from logged Rt and Cap. Pressure Data
DAY 4
Day 3 Recap, Questions, Debate
- Sw NMR, Sw Dielectric & Sw Other
- Swnmr: Magnetic Resonance Swi
- Swik4: Sw from log evaluation matches Swik4 from core Ø & k
- Dielectric movie
Sw Wrap Up
- Swrt: Do we use the Log Integrated ‘n’ value for Swrt or not?
- Sw: Consider cutting rotary side-wall cores for Ø, k & Sw in OBM wells
- Sw: One Common Use Equation Set – Log and Geo-model HPVs, kabs, koil Core = Log = Geomodel (black)
- Swrt: Other Sw checks
- Sw: Base case: The Sw Decision Tree
- Sw: Alternative Methods for Sw Equation Parameters
- Sw: Base case – Logical Constraints (reviewers)
- Sw: Logical constraint: At a given porosity, Swrt increases with increasing clays: the shaly sand equation (W&S) is not over compensating
- Sw: Logical constraint
- Sw: Swrt agrees with Swpc
- Recap. Calibrate Swrt with
- Four log calibrations ensure correct HPV’s.
- Moved Hydrocarbon Saturation, Shm
- Resistivity Ratio Sw, Swrr
- Reviewers of Petrophysical Results: Check Sw
- MICROPRACTICAL Core analysis indicates Swi
- What Rt = the maximum economic water cut?
Mobile Fluid Zones
- Mobile Fluid Zones
- Contacts, Fluid Zones & Capillary Pressure
- FZ: Fluid zone determination can be complex
- FZ: Common Fluid Zone Problems
- FZ: WFTs Provide Mobile Fluid Type, FWL and Capillary Pressure
- FZ: WFT Problems
- FZ: Supercharging: WFT measured pressures may be above formation if permeability is low
- FZ: Excess Pressure plots clarify FWLs and show actual reservoir capillary pressure
- FZ: Saturn Probe <2mD formation
- FZ: Mis-identified gradients from pressure barriers
- FZ: Movie
- FZ: Think of kicks as unplanned well tests
- FZ: Find gas, qualitative
- FZ: Bulk Volume Water, BVW = Ø*Swi (Buckles Number)
- FZ: Ø*Swi> Buckles Number indicates Fluid Zone = Transition Zone, Residual or Water
- FZ: Use Multiple Hydrocarbon Indicators!
- FZ: In Transition Zones Pc is low and Sw>Swi. Water and oil both mobile
- FZ: Different Reservoir Qualities yield Different TZ thickness
- Reviewers of Petrophysical Results: Check Fluid Zones
- DAY 4: 1100h BEGIN Practical. WFT Data Acquisition
k Permeability & Derivatives
- k: Permeability Objectives
- Compare your wells’ h or EHC like this
- k: Problem: Flow from Static Properties
- k: Other Permeability Prediction Problems
- k: Why core data rules (permeameter)
- k: Klinkenberg Permeability correction
- (gas slippage)
- k: The Effect of Oven Drying and Critical Point Drying on Illite Morphology
- k: RCA kair > k_in-situ
- k: Typical Relative Values for Various Measures of Permeability
- k: Well Test Permeability, kh
- k: The effective h may not be that at the well bore
- k: Reservoir Rock Typing (RRT) for klog: Facies, Image-log facies zonation
- k: Reservoir Rock Typing for klog
- k: Two Rocktypes: Same field, same well, same reservoir
- k: Rocktypes: J value vs. Sw trends help reveal separate rocktypes
- k: Rocktypes: Log linear J Function plot, two trends. Air/mercury data
- k: Rocktypes: Porosity-perm trend disturbed by diagenetic leaching
- k: Are Geo.Facies Useful for klog?
- K movie
- k: Permeability indicators, ranked
- k: Quick Look Permeability from cheap logs
- k: The ability of Sw to predict k exceeds Ø Same core plugs. (N.Sea cap.pres.data)
- k: kair from log derived Ø & Sw irreducible, Chart K4
- k: MICROPRACTICAL Hydrocarbon Pore Volume indicates permeability Chart K-4
- k: Advantages of HPV & Sw for klog
DAY 5
- k: Magnetic Resonance, kmr
- k: Timur Coates permeability equation
- k: Understanding Bound Fluid Volume BFV and logs
- k: Timur Coates adds what’s missing in Ø-k transforms
- k: Does your RE need stressed kbrine or kair? Ask
- kw ko kg: Swrt & SCAL rel.perm predicts kw, kg, pay, kh
- kw ko kg: inputs used to match summed log data kh to summed DST kh
- kw ko kg: Effective kg vs. kw, P10 and P90 versions and Linear kg-kw
- Reviewers of Petrophysical Results: Check Permeability
Net & Netpay
- Net: What is Netpay?
- Net: Accurately determining the Net cutoff can be crucial
- Net: Gross Ratio Problems
- Net: Rt imported from Twin-well (200ft away) shows Water-flood Above and Below 1mD
- Misleading Data: How not to acquire SCAL data.
- Net: MICROPRACTICAL
- Relative Perm data demonstrates the Netpay permeability cutoff
- Net: Logs = non-pay or marginal, core = pay: Tested 11mmscfpd. This facies 35% Bulk Rock Vol.
- Net: NMR locates movable fluids and delineates netpay in laminated shaly sands (low contrast pay)
- Net: Log and Non-log Netpay, Netrock Indicators, ranked
- Net: Why Permeability as Cut-off criteria?
- Net: PASS FLUIDS measured by k – YES
- Net: Summary of Suggested Netpay / Netrock Method
- Reviewers of Petrophysical Results: Check Netpay
- Geo-Model Input Sensitivity Studies indicate what data to acquire and where to focus effort Geo-model: Input Uncertainties – strictly petrophysical Geo-model: Field Petrophysical Reference – The Results Table How much oil does each well have and how permeable?
- Geo-Model Input
- Sensitivity Studies indicate what data to acquire and where to focus effort
- Geo-model: Input Uncertainties – strictly petrophysical
- Geo-model: Field Petrophysical Reference – The Results Table
- How much oil does each well have and how permeable?
- Geo-model: A Consistent Geo model
- Geo-model: Checksums
- Ensure EHC & kh are equal at all scales
- Reviewers of Petrophysical Results
- 10 Systematic errors which ruin your geo models
- Well A Formation Fluid Pressures from FITs and DSTs
- Why does this plot miss the point?
- Well A: Key Findings1
- Well A: Key Findings2
What is Advanced Well Log Analysis & Interpretation training course objective?
- To understand the essential nature of petrophysics: it’s objectives, data and uncertainties
- To get the best possible answers from any given data set
- To review petrophysical studies effectively & quickly identify flawed results using a clear sequence of logical checks
- To identify and extract the key data channels from modern hi-tech logs which, when integrated with core, logs and well tests will answer the questions your team is asking (author specialty, see also IPSCAL)
- To identify and properly use what really matters in the increasingly complex barrage of modern petrophysical data
- To drill, core, log and test for clear formation evaluation results
- To avoid the 10 most common errors which ruin petrophysical results
- To use interactive software to reveal how your data can work together and impact results
Who should join Advanced Well Log Analysis & Interpretation training course by PetroSync?
Petrophysicists, geologists, operations geologists, geo-modellers, reservoir engineers, geophysicists, core analysts or anyone with a year’s experience with logs or formation evaluation. Bring your laptop with MS Excel.
Each day includes Daily Recap, Two theory and Two interactive practical sessions, Movies, Questions, Answers and Debates.
Mark Deakin, PhD
Mark Deakin is a consultant, author and course instructor in Petrophysical Data Integration. He holds a Ph.D. in ‘Integrated Petrophysics’ from London’s Imperial College, is an ex Amoco petrophysicist and has over 30 years’ experience, including 25 years as a course instructor. He has performed over 60 detailed reservoir studies worldwide; primarily in Southeast Asia’s low-contrast pay and carbonate & fractured reservoirs. Deakin’s approach is to identify and rank reserves uncertainties then guide companies towards defensible reserves and optimal development via the application of new technology, targeted data acquisition and the systematic, logical integration of all related data.
After his PhD Deakin authored the first public Integrated Petrophysics course in 1989 which evolved into the industry's benchmark petrophysics training course. This was followed by courses in Carbonate & Fracture petrophysics and three day focused modules on Quick Look Integration Techniques; How to use Modern Logs with SCAL; Low Resisivity Low Contrast Pay; Laminates & Thin Beds; How to use PetroDB effectively and a Renewable Energy.
Deakin's special interest has been using PetroDB (a generic, rock typed petrophysical database) and SCAL Digital Rock Physics with logs to identify Missed Pay and EOR. Since 2010 he has been drawn to the inevitability of Renewable Energy, writing the course Renewable Energy Primer in 2015. He is an active member of SPWLA and occasional lecturer at Curtin University and his consulting company PETROPHYSICS Pty Ltd has offices in Perth, Australia.
