Petrophysics Workflow - IHS · PDF filePetrophysics Workflow Petra® User Group Session Series Armin Schafer Technical Sales Executive PETRA/PetraSeis/GeoSyn Encana Amphitheatre Oct

Petrophysics WorkflowPetra User Group Session Series
Armin Schafer
Technical Sales Executive
PETRA/PetraSeis/GeoSyn
Encana Amphitheatre
Oct 20, 2011
noon 1 pm

Copyright 2011 IHS Inc. All Rights Reserved. 2
Petra User Session Agenda
News and Announcements
Petrophysics Workflow Intro what is Petrophysics
Importing Digital Data
Digital Logs QA/QC
Log Calculations
Log Generation
Refine / Reiterate
Questions

PETRA User Session Agenda
News and Announcements
Petrophysics Workflow
Questions

Petrophysics Defined
What is Petrophysics?
Petrophysics (petro is Latin for "rock" and physics is the study of nature) is the study of the physical and chemical properties that describe the occurrence and behavior of rocks, soils and fluids. Petrophysicists evaluate the reservoir rock properties by employing well log measurements, core measurements, and sometimes seismic measurements, and combining them with geology and geophysics. (Wikepedia)

Reservoir petrophysical properties
Most petrophysicists are employed to compute what are commonly called
reservoir petrophysical properties. These are:
Lithology : What type of rock is it. When combined with local geology and core study, geoscientists can use log measurements such as natural gamma, neutron, density, Photoelectric,
resistivity or their combination to determine the lithology downhole.
Porosity : The amount of pore (or fluid occupied) space in the rock. This is typically measured using an instrument that measures the reaction of the rock to bombardment by neutrons
or by gamma rays. Sonic wave speed and NMR logs are also measured to derive rock porosity.
Water saturation Sw: The fraction of the pore space occupied by water. This is typically measured using an instrument that measures the resistivity of the rock.
Permeability: The quantity of fluid (usually hydrocarbon) that can flow from the rock as a function of time and pressure. Formation testing is so far the only direct downhole permeability
measurement. In case of its absence, which is common in most cases, permeability estimation is
derived from other measurements, such as porosity, NMR, sonic, by empirical correlations.
Net Pay: Thickness of rock that can deliver hydrocarbons to the well bore at a profitable rate.

Petrophysics Wireline logs
Example from Wikepedia (author Andy May)
Petra example

Petra Petrophysical Workflow Goals
Automate petrophysical analysis and speed up
interpretation
Biggest challenge is data handling Best KISS principle
Log mnemonics reduced to minimal/optimal numbers
Smart use of filtering, renaming and merging of normalized curves
Workflows will be different based on work styles, areas of
expertise & allocated resources
Ideal vs. practical
Available HR and time

Petra Petrophysics Workflow
1. Import Relevant Digital Data
2. Verify Data QA/QC
3. Log Generation
4. Log Calculations
5. Refine / Reiterate

1) Import Relevant Digital Data
Digital Curves (via Direct Connect, Single LAS or Batch LAS)
Directional Surveys (via Direct Connect, Well-by-Well or Batch Ascii)

Importing Digital logs
Single or Batch LAS Direct Connect

Skip Duplicates

Resample / Rename if Curve Exists

Convert Units

Curve Translation File

Directional Surveys Well-by-Well CSV
If possible, import Azimuth and Inclination data as this cannot be back-calculated within PETRA.

Copyright 2011 IHS Inc. All Rights Reserved.
If possible, import Azimuth and Inclination data as this cannot be back-calculated within PETRA.
16
Directional Surveys Import tabular ASCII File

2 Verify Data QA/QC
Garbage in = Garbage out
Log Aliasing
Checking Units/Scales
Log Histogram & Statistics
Normalization
Advanced Log Transforms
Log Merging

Corporate or Project based strategy for data
imports
Companies often have best practices eg use decimal vs percentage for porosities, use .1 for sample rate
Key is to be consistent
Be aware of who is doing the updates and what data is being updated
where did the data come from define source field of data.
Add remarks or descriptions wherever possible.
Always keep a copy of the original data, save changes to a new copy

Data QA/QC
Check tool calibration and log quality
Use correct type of curve eg SS vs LS
Log quality year of log
Service provider variation in naming

Data QA/QC
Resampling under Advanced Log Transforms

Data QA/QC
Resampling under Advanced Log Transforms
Keep in mind that decimating can lose data and interpolating creates new data points.

Data QA/QC
Statistics and Log Histogram

Data QA/QC
Statistics and Log Histogram
Data Statistics
Log Histogram

Data QA/QC
Log Histogram

Data QA/QC
Run statistics on curves
Stats useful for picks, cutoffs and normalization

Data QA/QC
Check Scales and units
Check m vs feet and sample rate throughout the main module

Data QA/QC
Merging in Log Transformations

Data QA/QC
Merging Curves in the Log Previewer

Data QA/QC
Log Normalization

Data QA/QC
Log Normalization Percentile Range

Data QA/QC
Log Normalization Restrict Depths/Wells

3) Log Generation
Log Equation Expression (Vshale, Water Saturation, Effective Porosity, etc.)
Crossover and Pay Flag Curves
Advanced User Models

Log Generation
Log Equation Expression - SW

Log Generation
Log Equation Expression preloaded equations

Log Generation
Log Equation Expression VSH

Log Generation
Log Equation Expression write your own
Can save this and share with others

Log Generation
Advanced Transforms - Archie Water
Saturation

Log Generation
Advanced Log Transform Fortran scripts

Log Generation
Advanced Log Transform View Model

Log Generation
Advanced Log Transform Input and Output
Variables

Log Generation
Compute from Logs - Crossover

Log Generation
Compute from Logs Pay Flag Curves

Log Generation
Compute from Logs Pay Flag Curves
Output Curve Tab

4) Log Calculations
Log Footage Summations
Payflag Continuity

Log Calculations Log Footage
Summation (Reservoir Properties)

Log Calculations Zone Field Name
Descriptions
Gross - Gross footage is computed using one of two methods sel

Documents

Petrophysics Workflow - IHS · PDF filePetrophysics Workflow Petra® User Group Session Series Armin Schafer Technical Sales Executive PETRA/PetraSeis/GeoSyn Encana Amphitheatre Oct