Smart Fractured Reservoir Development

Strategies

TUROGE Event, 9th & 10th April 2014

Dr Mark Cottrell (mcottrell@golder.com)

FracMan Technology Group

Golder Associates Europe

Introduction

Introduction

Presentation describes a strategy that can provide insight into the

improved assessment of unconventional fractured hydrocarbon plays

(e.g. shales, tight gas, coal gas, and fractured carbonates), and also for

renewables (e.g. deep geothermal);

The strategy provides integration of key geological data that can be

used to provide rational descriptions of the fractured rock conditions,

which are normally more complex than those needed for conventional

porous flow systems;

The approach provides a scalable/verifiable approach for understanding

the effects and influences of the natural fracture network, in terms of

specific well trajectories, compartmentalization, completions,

potential hydraulic fracture stimulation and environmental risk. 2

(c) Golder Associates, 2013

14 April 2014

Presentation Overview

Presentation Overview

Questions & Why?

Mechanical Units

The DFN Method

Hydraulic Fracturing

Microseismicity

Simulating Production

Going from Well to Field Scale

Use for Environmental Drivers?

Conclusions

14 April 2014

(c) Golder Associates, 2013

3

Key Questions to Smart Fractured Reservoir

Development

What would we like to be smarter about in our fractured reservoir?

What are the Fracture geometries? –Directionality of properties

Are the fractures conductive, closed or sealing? – Contribution to Production

How many & how big? – Volumetrics

What is their spatial distribution? - Layer bound, Pervasive? – Connectivity

How well do they connect? – Drainage volumes, well planning – Optimisation

Fracture Kh? – Flow rate impacts

Do different populations behave differently? Faults, joints? – Heterogeneity

Mechanical sensitivity of properties? –Stress, strength, etc.

14 April 2014

(c) Golder Associates, 2013

4

Why are Fractures Important?

FMI Fractures/m Fracture KHWhat the FMI sees…..

What the PLT sees…..

PLT inflows don’t have to coincide

with high fracture frequency

well

well

14 April 2014

(c) Golder Associates, 2013

5

Not All Rocks are Similarly Fractured

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Shales: Few natural fractures

Bakken

Shales: Natural fractures but some are healed

Eagle Ford

Barnett

Niobrara

Shales: Persistent, open, natural fractures

Marcellus

Utica

Monterey

Niobrara

Coals: Butts and Face Cleats

Surat Basin Australia

SE Piceance Basin

Niobrara

Utica

(c) Golder Associates, 2013

Surat BasinPiceance Basin

Mechanical Units

Mechanical Units and Natural

Fracturing

Natural fracturing is from the

combined effect of mechanisms

related to material layering and

in situ conditions;

Mechanisms related to layering

are often considered responsible

for both naturally occurring and

hydraulic fracture development

Example of mechanical layering in marly shales;

Fractures intensities can vary significantly across small boundaries; and

Arresting of fractures from crossing between mechanical layers can

effectively inhibit vertical connectivity in the reservoir/play.

14 April 2014

(c) Golder Associates, 2013

Upper

Mechanical

Layer

Lower Mechanical

Layer

7

Discrete Fracture Network (DFN) Model

April 14, 2014 8

+ Major Faults

+ Matrix

+ Natural Fractures

Modern DFN Analysis Workflow

Model Frame-

work & LoadingFracture

Characterisation

Fracture Model

Building

Static-Dynamic

Analysis

DFN Upscaling

& Dynamic

AnalysisAll

Units0

10.0

20.0

30.0

40.0

50.0

60.0

EquivRadius

0

10

20

30

40

50

60

Fre

quency

Orientation

Size analysis

Intensity

analysis

Layered fracture systems

Regular fracture systems

Full field models

Matrix block size analysis

Hydraulic fracture simulation

Volumetrics & TDV

Permeability upscaling

Oil or Gas flow simulation

Geomechanical analysis &

upscaling

Data from:

well logs,

surfaces, grids,

geological,

geomechanical,

geophysical

models

14 April 2014

(c) Golder Associates, 2013

9

Example Well Data to DFN Model (Vertical)

Cumulative Fracture Intensity Plot

0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

Percent of Total Fractures

40.0

50.0

60.0

70.0

80.0

90.0

100.0

110.0

120.0

Measu

red D

epth

Well_1_Intersecting Fractures_Log

Orientation: Orientation

data taken from image log.

Care needed to correct for

bias

Fracture intensity data taken

from well data

Cumulative intensity graph showing two

lower thicker but lower intensity layers

around thinner higher intensity layer

Final DFN model

of outcrop

Intersecting fractures seen

organised within three main

layers of the reservoir

Conceptual Model: Synthesising intensity

data, orientation and structural knowledge

helps develop a conceptual picture of how to

assemble DFN model.

DFN model from well data requires greater

conceptual push (driven from structural

knowledge & concepts) and results in higher

uncertainty than a model built from outcrop

14 April 2014

(c) Golder Associates, 2013

10

Example Well Data to DFN Model (Lateral)

Intensity data from Image logs

Trace Length Exercise

0.0001

0.001

0.01

0.1

1

10

1 10 100 1000 10000

Trace Length (meters)

No

rm

ali

zed

Nu

mb

er

Outcrop Data

Lineament Map Data

Fracture size data from

seismic, well and

outcrop data

14 April 2014

(c) Golder Associates, 2013

11

Orientation data from Image logs

Stage 1: Connected Volume

Stage 1 “hydraulic fracture” with top

reservoir layer trace map superimposed

14 April 2014

(c) Golder Associates, 2013

12

3D Hydraulic Fracture

Inside Overall Natural

Fracture Network

• The pumped stimulation fluid preferably flows into the connected natural network; and

• If the natural fractures cannot accommodate the pumped water volume, the ‘new’

hydraulic fracture develops further (perpendicular to minimum stress).

Stage 2: Microseismicity in Shales

14 April 2014

(c) Golder Associates, 2013

13

Microseismicity Inside

Fracture Network

• Based on critical stress conditions, the timing and locations of microseismicity can be

simulated; and

• Microseismicity maps can be compared with observed, and can also help understand

the combined effect of in situ stress and natural fracture conditions.

Critical Stress Calculation

Stage 3: Stimulated Rock Volume

14 April 2014

(c) Golder Associates, 2013

14

Static Prediction of Stimulated

Rock Volume (SRV) • Stimulated Rock Volume

provides poor 1st order

estimate of drainage

volume per stimulation;

• Can help guide treatment

design and well spacing;

• Helps understand

interference.

Stage 4: Simulation of Production

15

Pressure derivative curves may not

have distinct fracture and matrix flow

regimes, but may produce

derivatives with slopes between a

half and one, similar to actual

deconvoluted production data; and

Can help predict long term

production characteristics.

14 April 2014

(c) Golder Associates, 2013

Answering Well Scale to Field Scale Question

14 April 2014

(c) Golder Associates, 2013

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Fracture ParametersCumulative Fracture Intensity Plot

0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

Percent of Total Fractures

9600.0

9800.0

10000.0

10200.0

10400.0

10600.0

10800.0

11000.0

Mea

sure

d D

epth

Duncan_5-13A2_Log_Duncan_5-13A2_LGROpenBOF ...Duncan_5-13A2_LGRBedding

P10=0.227

P10=0.610

P10=0.127

P10=0.934

Segment ID Starting Depth Ending Depth P10 C31 P32

1 9677.35 9966.11 0.23 3.37 0.76

2 9997.05 10394.11 0.13 3.37 0.43

3 10409.58 10564.27 0.93 3.37 3.14

4 10563.536 10771.271 0.61 3.37 2.05

LGR only

1

-41•10

-31•10

-21•10

0.1

-51•10

Perc

entile

102

1•103

1•104

1•105

1•10

Trace Length

CCDF Graph

PowerLaw Distr. parameters selected by user

minimum = 600 exponent = 2.4858

K-S statistics 0.173649

signif. level 0

0.01

0.1

1

0.1 1 10 100

Rate

-no

rm

ali

zed

P

ressu

re D

eriv

ati

ve (p

si(

a)/

bb

l/d

ay)

Time (hour)

Ute Tribal Test #2

Ute Tribal Test 1

Chevron Hatch 1-5B1 Test 1

Chevron Hatch 1-5B1 Test 2

Gulf Campbell Ute 1-7B1 Test 1Gulf Campbell 1-7B1 Test 2

T=2,100 md-ft/cP

T=720 md-ft/cP

T=400 md-ft/cP

T=430 md-ft/cP

T=280 md-ft/cP

T=200 md-ft/cP

T=290 md-ft/cP

Well Test Fracture Property

Fracture Hydraulic Properties

Orientation

Size

Local Intensity

Seismic Attributes

3D DFN Model, can then be either

a) Well scale

b) Sector scale, or

c) Field scale

All Units

Geomechanical Upscaling

Flow Solver Upscaling

Drainage Volume

Drill Here Map

Hydro-frac Simulation

Attribute Analysis

Field Scale Fracture Intensity Map

Well Scale Correlation

Example CFI correlation between

observed and predicted

Good correlation between seismic

attributes & well control fracture intensity

Field Scale Prediction

Using CFI correlations for multiple wells,

and 3D seismic it is possible to produce

fracture intensity map “drill here map”

Intensity in unexplored locations can be

proven in future appraisal wells.

April 14, 2014 17

Observed Well Scale CFI Log

derived from

Predicted CFI Log (Combined

Stiffness & Density)

Predicted CFI Log

(Stiffness only)

(c) Golder Associates, 2013

Question of Field Compartmentalization?

April 14, 2014

(c) Golder Associates, 2013

18

Oil/Gas that is not in a large

compartment may be difficult or

uneconomic to produce

Drainage is not a

simple ellipse!

E&P Models For Environmental Protection

Not just in E&P that such

approaches can help answer

questions and reduce risk

These approaches can help

minimise environmental

requirements and risk:

1) water requirements for

hydraulic fracture stimulation

2) hydraulic fracturing induced

seismicity on fault structures

3) deep injection strategies for

waste water disposal

April 14, 2014 19

(c) Golder Associates, 2013

Some Clients and Fracture Project Locations

April 14, 2014 20

Conclusions

Conclusions

We’ve presented an approach that can be used to provide smarter

assessment of naturally fractured reservoirs, e.g. shale's; fractured

carbonates, coals, volcanic basements;

Strategy provides integration of key geological data to provide a rational

and representative description of the fractured rock conditions and

importantly the connectivity;

Provides a scalable and verifiable approach for understanding the

effects and influences in terms of fracture connectivity, specific well

trajectories, compartmentalization, completions, and potential

effectiveness for hydraulic fracture stimulation.

Thank you for your attention! mcottrell@golder.com

April 14, 2014 21

(c) Golder Associates, 2013

Smart Fractured Reservoir Development

Strategies

TUROGE Event, 9th & 10th April 2014

Dr Mark Cottrell (mcottrell@golder.com)

FracMan Technology Group

Golder Associates Europe