2Integrated Formation Evaluation

PGE385MSpring 2002 Semester

Lecture Presentation, January 17

INTEGRATED FORMATION EVALUATION

Carlos Torres-Verdín, Ph.D.Assistant Professor

The University of Texas at Austin

Formation Evaluation

Formation Evaluation Flowchart

Density: Influence of Porosity and Saturation

Equations and Tools

Linear Equations and Volumetric Models

Linear Equations and Volumetric Models

Formation Evaluation: Basic Data

250 cm 200 150 100 50 0 cm

80 cm

80 cm

40 cm30 cm 20 cm

60 cm

5 cm 2 cm 0 cm

INDUCTION LOG

LATEROLOG

NEUTRONGAMMA RAY

DENSITY

SONICMICRO RESISTIVITY

MICROLOGDIPMETER

DEPTH OF INVESTIGATION

RES

OLU

TIO

NRESISTIVITY

RADIOACTIVITY

RESISTIVITY

ACOUSTIC

Logging Tools

MUD-FILTRATEINVASION

EXPERIMENT

Mud-Filtrate Invasion Experiment

Open-Hole Logging Environment

Dynamic Mud Filtrate Invasion and Mud Cake Buildup

Source: Oilfield Review, Schlumberger

NOMENCLATURE

Porosity

GENERALIZED COMPARISON

DensityMeasurements

in the Borehole

Typical Borehole Density Tool Configuration

COMPENSATED NEUTRON LOG

A SIMPLE EXPERIMENT

NEUTRON POROSITY TRANSFORMS

NEUTRON PHENOMENA AS A FUNCTION OF ENERGY

POROSITY AND LITHOLOGY

PULSED NEUTRON THEORY

PorosityLogs:

Neutron,Density,

NMR

Laminated Clean Gas Sand

SONIC LOGGING: BASIC PRINCIPLES

Single Transmitter-Dual Receiver Tool

SONIC LOGGING

Static and Dynamic Deformation

Monopole in a Fast Formation

SONIC POROSITY: Intuitive Model

Sonic Porosity: Theory and Measurements

Acoustic Log: Core Calibration

LWD/Wireline Neutron-Density Comparison

Effects of Drilling Muds on Log Responses

Shale, Silt, and Clay

Low-Resistivity Sand

Pore-Filling Kaolinite

Pore-Lining Chlorite

Chlorite

Pore-Bridging Illite

Vshale DETERMINATION

Electrical Response of Rock Formations

POROSITY

• TOTAL WATER SATURATION?

• BOUND-FREE (MOVABLE) WATER?

• IRREDUCIBLE WATER SATURATION (i.e. clay-bound water and capillary-bound water)?

WATER SATURATION

• TOTAL POROSITY?

• EFFECTIVE POROSITY?

ARCHIE’S “Clean Sand” EquationEffective DC Resistivity Response

RESISTIVITY: Influence of Water Saturation

Water-Wet Hydrocarbon-Bearing Rock Formation

Wilcox SandOklahoma City

1 cm

Close-Up

Clay

ELECTRICAL PROPERTIES OF SHALY SANDS

Shale-Free Electrical Model

•• Archie (1942)Laminated Shale Electrical Model

•• Poupon-Leveaux (Indonesian))

“Double-Layer” Dispersed Clay Electrical Models

•• Waxman-Smits

•• Dual-WaterMixed Dispersed-Clay / Laminar-Shale Electrical Model

•• Patchett-Herrick

Several Water Saturation Models

Water Adsorption by Clays[Cation-Exchange-Capacity (CEC) Mechanism]

Shale Distribution

MULTIPLE SHALE VOLUME MODELS

WAXMAN-SMITS “Dispersed Clay” Equation

Effective DC Resistivity Response

POUPON “Laminar Sand-Shale” Equation

Effective DC Resistivity Response

PATCHETT-HERRICK (Poupon + Waxman-Smits) EquationEffective DC Resistivity Response

GR & Caliper

Permeability & Resistivity Archie T2

SpectraWaxman

SmitsDual Water

Poupon -Leveaux

Patchett -Herrick

Formation Volumetrics

MULTIPLE WATER SATURATION INTERPRETATIONS

Mineralogy Determination

Imaging Thin Beds

Formation Testing

Pressure-Drawdown Analysis

Fluid Gradients

Fluid Contacts and Density

Permeability

Fractured Reservoirs

Photograph courtesy of Prof. Jon Olson

WHEN DOES THEORY BREAK DOWN?

Example of Microfracturing

SUMMARY

Acknowledgements

• Baker Atlas

• Schlumberger

• Halliburton