QC and use Fracture

Attribute Data

Fracture Modeling – Petrel 2010

Initial Data

Analysis

Modeling Fracture

Parameters

Building Fracture

Model

Upscaling Fracture model with

Multiple Fracture Drivers

Import/Display

Simulation

Fracture Modeling

Intro

Theorethical

Background

Fracture Modeling Course Course Content

Day 1 Day 2

Introduction

Optional: Background theory

Import & display fracture data

QC and use fracture attributes

Initial data analysis

Modeling fracture parameters

Building a Fracture model

Upscaling fracture attributes

Fracture drivers

Dual porosity simulation setup

Fracture Modeling Course

Introduction Overview

What is Fracture Modeling?

Naturally Fractured Reservoirs

Fluid Flow Simulation Models

Fracture Modeling approaches

Fracture Modeling Workflow

Data Set - Location

Data Set - Geological description – Stratigraphy/Mechanical zones

– Fractures

Data Set - Comparative Outcrop studies

What is Fracture Modeling? Purpose and Process

Purpose Create simulation properties for matrix and fractures to

be able to predict reservoir behavior

Why? Many reservoirs are dual porosity/dual permeability

(Naturally fractured); leading to high flow zones not representative of the matrix flow capacity

Flow simulators have problems simulating these kind of reservoirs.

Process Multi-disciplinary approach;

Use analyzed fracture data from wells

Building a Fracture model (DFN+IFM)

Upscale fracture permeability, porosity and connection factor between matrix and fractures from the Fracture model

These data can subsequently be simulated

Naturally Fractured Reservoirs Simple Classification of Reservoir types

I. Fractures provide essential Porosity and Permeability – Requires large reservoir tank or thick pay zones to be economical (no matrix porosity)

II. Fractures provide essential reservoir Permeability – Most reservoirs with storage in matrix but low matrix permeability

III. Fractures assist Permeability in already producible reservoir – Higher porosity lithologies

IV. Fractures provide no additional Porosity/Permeability – Fractures act as Flow Barriers

% o

f To

tal P

erm

.

% of Total Poro.

I II

III

IV

100% ΦF

100% KF

Naturally Fractured Reservoirs Example of Reservoir types

I. Fractures provide essential Porosity and

Permeability

II. Fractures provide essential reservoir

Permeability

– Fluid communication from Matrix to

Fractures is important

– Fracture Morphology essential !

III. Fracture assist Permeability in already

producible reservoir

IV. Fractures provide no additional

Porosity/Permeablity

• Morphology

M to F communication

• Good Recovery Factor

• Good waterflood

sweep efficiency

• Morphology

Restricted communication

• Poor Recovery Factor in

tight Matrix

• Poor waterflood sweep

efficiency

MATRIX

DISCHARGE

M

F

Crossflow No Crossflow

M

Fluid Flow Simulation Models How to approximate nature?

Reality Approximation

In Place Reserves

Recovery

Well Productivity

Field Connectivity

Reality captured in 3D Models

Ideally hydrocarbon flow takes place in a Single Porosity / Permeability system

However in Dual Porosity reservoirs, fluids exist in two interconnected systems (matrix and fractures). This must be accounted for in Simulation models.

Fra

ctu

re

Mat

rix

Fluid Flow Simulation Models Dual Porosity (DP) models

Real Reservoir

Match Stick Model Layered Model Sugar Cube Model

Dual Porosity idealization A simplification of the real reservoir is done when creating a dual porosity model

Fluid flow and transport exist in both the connected fractures and matrix blocks

Two overlapping continua, where both are treated as porous media

Dual Porosity model types Simple layer model (sheet of parallel fracture sets)

Matchsticks model (2 orthogonal fracture sets)

Sugarcube model (3 orthogonal fracture sets)

Fluid Flow Simulation Models DFN vs. Dual Porosity models

DFN Model – Non Uniform Geometry – Variable Fracture Orientation – Variable Fracture Length – Variable Aperture - -> Variable Intensity and Interconnectivity

Dual Porosity Model – Fixed Geometry – Continuous Fractures – Equal spacing – Constant Aperture

DFN Model

Layered Model

Real Fractured

Medium

Fluid Flow Simulation Models Standard approaches to fracture modeling

Equivalent Continuum – Bulk response for equivalent porous media

Dual Porosity (DP) – Separate Matrix and Fracture blocks

Discrete Fracture Network (DFN) – Physical fracture representation – Upscaled to Dual porosity properties

Real Fractured

Medium

Equivalent Non-Fractured

Medium

Layered Model

DFN Model

Fluid Flow Simulation Models Petrel 2010 approach to fracture modeling

Implicit Fracture Model (IFM) – Yields directly fracture porosity and permeability as properties – Upscaled to Dual porosity properties

Discrete Fracture Network (DFN) – Physical fracture representation – Upscaled to Dual porosity properties

Real Fractured

Medium

Property Model

DFN Model

Combined Model

Fracture Modeling Workflow Petrel – Overall Fracture modeling workflow

Well data Data

Analysis

Model

Parameters

Create

Fracture model

Upscale

& Simulate

Fracture Modeling Workflow Petrel – Specific Fracture modeling processes

DFN

IFM

Fracture intensity

Hybrid

IFM / DFN

model

Data Set Teapot Dome – Wyoming (USA)

USA

Achnowledgements:

Thanks to Rocky Mountain Oilfield Testing Center and

U.S. Department of Energy for using Teapot data

Teapot Dome is located in central Wyoming. A comprehensive Data Management

project has been conducted to digitize and compile all available data. Data is

available e.g. for research and software testing/training.

0 1 km

N

Quaternary

Alluvium

Mesaverde Fm

Undifferentiated

NPR3 Boundary

1

2

3

4

51 Section

Location,Number

Unit 5: Fluvial Ss

Unit 4: Non-Marine Carb.

Sh with localized

coal

Unit 3: White Beach

Ss

Unit 2: Shoreface/Beach

Ss

Unit 1: Shallow Marine

Interbedded Ss

and Sh 10m

0

Data Set – Stratigraphy (Outcrops @ Alcova anticline)

Reworked from:

S.Raeuchle et al, 2006 and Cooper, S. 2000

East West

Cretaceous

Measverde Fm

Teapot Sandstone

Parkman Sandstone

Carboniferous

Tensleep Fm

0 1 km

N

Quaternary

Alluvium

Mesaverde Fm

Undifferentiated

NPR3 Boundary

1

2

3

4

51 Section

Location,Number

Unit 5: Fluvial Ss

Unit 4: Non-Marine Carb.

Sh with localized

coal

Unit 3: White Beach

Ss

Unit 2: Shoreface/Beach

Ss

Unit 1: Shallow Marine

Interbedded Ss

and Sh 10m

0

Data Set – Mechanical Zones (Mesaverde Fm. Outcrops)

Generalized Stratigraphic column

– Parkman Sandstone Mb. (Mesaverde Fm.)

Mechanical zones

Separating units according to mechanical properties is important due

to mechanical influences on fracture characteristics.

Compiled from Mallory et al., 1972; Spearing, 1976, and

Rocky Mountain Oilfield Testing Center field data.

From: Cooper, 2000; Cooper et al., 2001, 2003.

Data Set – Mechanical Zones (Tensleep Sst. Outcrops)

Stratigraphic systems

Separating units according to stratigraphic architecture is also important for

prediction of complex fracture development in low-complex reservoir facies.

Compiled from Zahm & Hennings, 2009 (AAPG Bulletin)

Data Set – Fracture Intensity (Tensleep Sst. Outcrops)

Fracture intensity at multiple scales

High variability in fracture intensity was demonstrated, caused by original depositional

architecture, overall structural deformation and diagenetic alteration of the host rock.

Fracture intensity depends on stratigraphic scale.

1. Throughgoing fractures

2. Sequence Bound fractures

3. Facies Bound fractures

4. Lamina Bound fractures

Compiled from Zahm & Hennings, 2009 (AAPG Bulletin)

Data Set – Faults at Teapot Dome (Outcrops)

Map of faults and representative

hinge-perpendicular fractures

Map of faults and representative

hinge-parallel fractures

Modified from: Cooper et al., 2006

Data Set – Fractures at Teapot Dome (Outcrops)

N

covered

0 1 m

Throughgoing fractures Cross fractures

Illustrations from: Cooper, 2000

Fracture map of a pavement surface Illustrating

the nature of throughgoing fractures and cross

fractures at the top of a single sandstone bed at

Teapot Dome Conceptual 3D model of fracture outcrop patterns

developed at Teapot dome.

Data Set – Fractures related to Lithology (Outcrops)

Unit 5: Fluvial SsUnit 4: Non-Marine Carb.

Shwith localized

coalUnit 3: White Beach

Ss

Unit 2: Shoreface/BeachSs

Unit 1: Shallow MarineInterbedded Ssand Sh 10m

0

0 1 km

N

QuaternaryAlluvium

Mesaverde Fm

Undifferentiated

NPR3 Boundary

n = 24

N

n = 23

Charted Locality

Illustrations from: Cooper, 2000

A

B

Throughgoing

fractures

Rotation to

Fold Hinge

Surface outline

(boundary) of

subsurface 3D grid

Overthrust

Tensleep Fm top

Data Set – Infer Outcrop observations to subsurface 3D models?

EXERCISES Module 1

P.42 - 49