1. Geologic Analysis of Naturally Fractured Reservoirs 2nd Edition, R. A
Geologic Analysis of Naturally Fractured Reservoirs 2nd Edition, R.A. Nelson (2001)
Gulf Professional Publishing
a subsidiary of
Butterworth-Heinemann, Boston, MA

2. Geologic Analysis of Naturally Fractured Reservoirs 2nd Edition, R. A
Geologic Analysis of Naturally Fractured Reservoirs 2nd Edition, R.A. Nelson (2001)
The following contains renditions of the figures included within the book as well as additional figures used by the author to teach industry courses on the subject.
Also included is Appendix D of the book.

3. Ronald A. Nelson Discipline Structural Geology & Rock Mechanics
Location BP Amoco, Upstream Technology, Geology Team, Houston
History 26 years with BP Amoco as
Specialist & Manager
Education BS (Northern Illinois), MS, PhD
(Texas A&M) all in Geology
Skills Fractured Reservoirs, Technology
Management, Peer Assists,
Recruiting, Structural Interpretation
in Thrust Belts and Rifts
Publications 75 citations; including a textbook
“Geologic Analysis of Naturally
Fractured Reservoirs” eds. 1&2.

4. Liesegang
Banding in
Aztec Ss,
Nevada

5. Work Builds On:
Nelson, R. A., 1985, Geological Analysis of Naturally Fractured Reservoirs: Contributions in Petroleum Geology & Engineering, Gulf Publishing Co., Houston, TX, 320 p.
Material presented in the AAPG Fractured Reservoir Analysis School,

6. Courtesy of Gulf Professional Publishing, Boston

7. General Outline Introduction Fracture Origin Fracture Morphology
Fracture Porosity
Fracture Permeability
F/M Interaction
Fracture Intensity
Intensity Prediction
9. Orientations
10. Reservoir Types
11. Well Directions
12. Simulation
13. Fracture Reservoir Production
14. Reservoir Screening
15. Summary
(Field Examples)

8. Reasons Why We Look at Natural Fractures
Delineate Structure
Determine Mode & Path of Deformation
Define Mechanics of Fracture
Determine Paleo-stress Directions
Determine Velocity Anisotropy
Determine Mechanical Anisotropy
Predict Reservoir Properties & Potential

9. Total Integration Includes:
Fracture system characterization
Stratigraphic interpretation & modeling
Structural geology
Petrophysics
Seismic mapping & attribute analysis
Well testing, inc. production logs
Production history matching
Reservoir engineering, inc. dual porosity flow behavior
Fracture scaling and reservoir simulation
Drilling and completion technology

10. Modeling in Fractured Reservoirs SPE Forum, Sept. 2000
Static Conceptual
Model
Dynamic Conceptual
Simulation
Static Description
Dynamic Description
Upscaling
Subsurface
Outcrop
Wellbore
Geophysics
Pressure
Temperature
Fluid Types
Energy
Full Static &
Dynamic Simulation
Sanction, Recovery Planning, Flood Design, etc.
Statistical & Geomechanical
Representation
Well Test Data &
Well Histories
Modeling in Fractured Reservoirs SPE Forum, Sept. 2000
Oil
Water
Hansen
Peng
Rawnsley
Derivative
Experience & Analogs
Discrete Model
Continuous Model
Nelson

11. Fundamental Approach after Nelson (1985)
Determine fracture system origin(s) in 3-d
Allows for predictability away from wellbore
Tectonic, regional, cleat, diagenetic, sequence
Determine reservoir properties & var. in 3-d
Quantifies porosity, permeability, etc.
Morphology, width, spacing/intensity, stress affects
Fracture/matrix communication
Linkage in dual porosity system
Cross flow, connectivity, recovery

12. Fundamental Approach (cont.)
Determine reservoir type
Defines relative contribution of fractures and problems
Simulation, production character, management
Locate optimum drill locations & well paths
Quantifies “sweet spots” & maximizes wellbore surface
Intensity, azimuth, directional drilling, seismic attributes
Develop reservoir management strategies
Control the reservoir to efficiently balance rate & recovery and reduce well costs
Fracture closure, well patterns, sweep

13. Recent Advancement Areas
Log Characterization
Spacing Estimates
Fracture Zone Identification
Reservoir Simulation
Azimuth Predictions
Reservoir Analogs
Effects of Fracture and Diagenetic History

14. Impacts on Fractured Reservoir Studies

15. Fracture
A macroscopic planar discontinuity in rock which is interpreted to be due to deformation or physical diagenesis
It may be due to compactive or dilatent processes, thus having either a positive or negative effect on fluid flow
Its characteristics may have been modified by subsequent deformation or diagenesis

16. Fractured Reservoir
Any reservoir in which naturally occurring fractures have, or are predicted to have, a significant effect of flow rates, anisotropy, recovery, or storage.

17. Avoid “Fracture Denial”

18. “Fracture Denial” Keeps Us From:
Gathering important static data early
Optimizing our well locations & paths
Designing our secondary recovery patterns correctly
Accurately predicting field rates & recovery
Economically depleting our field