Oil and Gas

Oil and Gas | Petrophysics

Uncertainty in Petrophysics: Shaly-Sands, Carbonates, and other Problem Areas

Course Code: N064
Instructors:  Martin Kennedy
Course Outline:  Download
Format and Duration:
5 days

Summary

This course looks at the fundamental reasons for errors and uncertainty and the tools and techniques used to handle them. The concepts are illustrated with examples from a range of different reservoirs that are known to cause problems. These include tight gas sands, carbonates,shaly sands, thin bed pay, and fractured reservoirs.

Business Impact: For some plays, petrophysics can contribute a lot of uncertainty and even lead to gross errors. Attendance on this course will allow participants to better understand and quantify this uncertainty and more acurately calculate the range of petrophysical properties and hydrocarbons in place.

Duration and Training Method

This is a classroom course comprising lectures, discussions case studies, and practical exercises. Problems are designed to be tackled with calculators, charts, and graph paper and/or Excel.

Course Overview

Participants will learn to:

  1. Estimate the various sources of error and uncertainty in petrophysical data.
  2. Understand the reasons why conventional log analysis can fail to produce satisfactory answers in carbonates. Appreciate that petrophysical properties may be subject to much higher uncertainty in carbonates.
  3. Quantify and account for the effects of clay and/or shale in log analysis, particularly when computing saturation. Use special core analysis data to quantify excess conductivity.
  4. Appreciate tools and techniques that can be used to evaluate thin bedded reservoirs.

1. Introduction and administration

  • Revision of the petrophysical workflow and inherent assumptions
  • Sources and handling of errors and uncertainty in petrophysics
  • Tools and techniques (Image logs, NMR, geochemical logs, petrography)
  • Case Study: tight gas sands.

 

2. Case study on carbonates

  • Pore systems in carbonates
  • Heterogeneity
  • Porosity estimation
  • Saturation estimation
  • Permeability prediction

3. Classical shaly sand reservoirs

  • Total and effective porosity (Vshale estimation)
  • Excess conductivity
  • Waxman-Smits/cation exchange capacity
  • Permeability prediction

4. Thin bed pay

  • Recognition and characterisation
  • Total and effective porosity
  • Sand-shale ratio estimation (Vshale)
  • Thomas-Steiber methodology
  • Resistivity and saturation estimation
  • Resistivity modelling

5. Fractured reservoirs

  • Diagnostics
  • Characterisation
  • Tool response to fractures

6. Course wrap-up

  • Designing logging suites
  • Electrical vs. hydraulic conductivity
  • Real vs. artifact fractures in the borehole wall
  • Integrating petrophysical, drilling, and dynamic data
  • Closing comments

Geoscientists and engineers working with such problem reservoirs and petrophysicists seeking to extend their log analysis skills beyond well-behaved pore systems. Participants are expected to have experience or petrophysics and formatio evaluation.

Martin Kennedy

Background
Martin Kennedy, is a consultant petrophysicist based in Perth, Western Australia. He began his career as a wireline-logging engineer. After leaving the field, Kennedy worked in R&D, for government and for several mid-sized British independents before moving to Perth as Woodside’s Chief Petrophysicist in 2003. He left after six years to concentrate on training and consulting. His career has spanned everything from field studies to quick-look evaluations as well as managing the petrophysics skill-pool for two companies. Kennedy has worked on most of the classic petroleum provinces outside North America (and a few within) as well as some more exotic areas. He now consults for a wide range of companies ranging from small Independents to Majors and specializes in areas that do not readily yield to standard techniques. His particular interests are carbonates; the way logging tools interact with geology; image logs; and interpreting old logs, bad logs, and bad/old logs. Kennedy holds a degree in chemistry from Bristol U. and a PhD degree in electrical engineering from Edinburgh U.

Affiliations and Accreditation
PhD Edinburgh University - Electrical Engineering
BSc Bristol University - Chemistry

Courses Taught
N003: Geological Interpretation of Well Logs
N030: Rocks & Fluids: Practical Petrophysics (Isle of Wight, England)
N360: Quantitative Log Analysis and Petrophysics

CEU: 3.5 Continuing Education Units
PDH: 35 Professional Development Hours
Certificate: Certificate Issued Upon Completion
RPS is accredited by the International Association for Continuing Education and Training (IACET) and is authorized to issue the IACET CEU. We comply with the ANSI/IACET Standard, which is recognised internationally as a standard of excellence in instructional practices.
We issue a Certificate of Attendance which verifies the number of training hours attended. Our courses are generally accepted by most professional licensing boards/associations towards continuing education credits. Please check with your licensing board to determine if the courses and certificate of attendance meet their specific criteria.