New Methodologies for Fractured

Reservoir

Characterisation & Modelling

PPR-000-MAP-002-A

INTRODUCTION

GEOL. MODEL &

Maps, Cores, Logs, Tests,

etc

FORECAST TO

PPR-000-MAP-003-A

INTRODUCTION

TO WORK IN THE

TRANSVERSE WAY

IS THE BEST

METHOD

PPR-000-MAP-004-A

RESERVOIR CHARACTERISATION: data-base

EXPLORATION-APPRAISAL

1

Sedimentology

Dynamic Data

VIRGO VIRGO#2

1 0- 3 1 0- 2 1 0- 1 1 00 1 01

10-

41

0-3

10-

2

D T ( H R )

DP

+

D

ER

IV

AT

IV

E

(M

PS

I2

/C

P/

MS

CF

/D

)

E N D W B S

P D = 1 / 2

S m o o t h i n g C o e f = 0 . , 0 .

S k i n ( m e c h ) + D Q = 3 . 9 7

- x b o u n d a r y = 3 7 5 . F E E T ( 1 . 0 0 )

+ x b o u n d a r y = 1 0 6 . F E E T ( 1 . 0 0 )

P e r m - T h i c k n e s s = 1 3 9 0 . M D - F E E T

T u r b u l e n c e = 0 . 1 / M S C F / D

p e r m e a b i l i t y = 2 7 . 3 M D

S k i n ( m e c h ) = 3 . 9 7

w e l l . s t o r a g e = . 0 0 1 0 0 B B L S / P S I

* * S i m u l a t i o n D a t a * *

H o m o g e n e o u s R e s e r v o i r

1 9 9 7 / 0 5 / 3 0 - 1 4 5 9 : G A S ( P S E U D O - P w i t h M a t . B a l . )Petro-acoustic Geology Petrophysics

Well Data

Core analysis

INTEGRATED STUDY: Data integration for reservoir modelling

SCAL

RESERVOIR MODELSeismic

CROSSPLOT POR-Perm

0,01

0,1

1

10

100

0 2 4 6 8 10 12 14 16 18

Porosity (%)

Pe

rme

ab

ilit

y (

mD

)POR-Perm

PPR-000-MAP-005-A

RESERVOIR CHARACTERISATION: data-base

To analyse and to integrate fracture data from different sources at different scales (well, intra-well, reservoir)

To generate 3D Discrete Fracture Networks (DFN) according to different conceptual models

To make a screening of the DFN models by matching the available production and interference test data.

To compute equivalent parameters for charaterizing the Fracture System

Methodology Workflow

Whats a fracture ?

Rock Mechanics:

a break or rupture in a rock created by the action of the stress forces.

Petrophysics:

a discontinuity in a rock interrupting the capillary properties.

In general:

non-sedimentary mechanical discontinuity

RESERVOIR MODELING

A

B

C

Matrix :

< 2 %

K < 1

mD

Matrix :

high

low K

Matrix :

high

high K

Fracture system is

the storage

Fracture system increase

the K of the matrix

Fracture system

drain the matrix

Types of fractured reservoir

(Nelson 1982)

RESERVOIR MODELING

Modeling targets

Matrix System Fracture-network System

+ 1ma 2ma 3ma

1f 2f 3f

Reservoir Geologist

focus the attention to

the Petrophysical

Characterisation of

Reservoir

The final targets are:

the O.H.I.P (Original

Hydrocarbon In Place)

estimate

the Reserves estimate

Phi

K

Sw

Reservoir Geological Model

RESERVOIR MODELING

Dual Continuum Model

Dual

Continuum

Model

Matrix

Low Conductivity

Cap. pressure > 0

Fracture system

High Conductivity

Cap. pressure = 0

Matrix and Fracture Systems

are a Continuum

Where is the boundary

between the two?

RESERVOIR MODELING

Fractured

Reservoir

Warren-Root Dual Continuum

Conceptualization

Discrete Fracture Network

Conceptualization

Fractured Reservoir Modeling

RESERVOIR MODELING

Matrix cells are linked to the relevant fracture system cells

MATRIX

FRACTURE

CENTROID

Dual media simulation method

RESERVOIR MODELING

Fracture systems at different scales

Megascopic Scale

Reservoir Segments

Major Flow Paths

Mesoscopic Scale

Productive Network

Microscopic Scale

Fluids Storage

RESERVOIR MODELING

Warning !

Observing fractures does not make a fractured

reservoir

Initially unfractured reservoirs become fractured

due to wrong diagnosis or fractures reactivated

Initially fractured reservoirs become unfractured due to

fractures closed and or uniform and intense fracturing

RESERVOIR MODELING

Fractured reservoir indications

High heterogeneity (differences between wells)

Complex well test responses (derivatives)

Localised flow (mudlosses, PLTs Production Logging

Tools)

Unexpected dry wells

Irregular production rate correlation between wells

RESERVOIR MODELING

Measuring the variations in pressure versus time and interpreting them gives data on the reservoir and the well.

RESERVOIR MODELING

Dynamic modelling

0.01

0.1

1

10

0.0001 0.001 0.01 0.1 1 10 100 1000

Elapsed Time (hrs)

Pre

ssu

re C

han

ge

an

d D

eriv

ati

ve

(ba

r)

TEST DERIVATIVE

TEST PRESSURE BI-LINEAR FLOW

Kh F stabilisation

DUAL POROSITY PSS

TRANSITION

MATRIX (AND MICRO-FRACTURES) &

MACRO-FRACTURE INTERACTION

( l, w)

DUAL POROSITY

TRANSIENT

FAULTS & MACRO-

FRACTURE

INTERACTION

1/4

1

0.001

0.01

0.1

1

0.001 0.01 0.1 1 10 100

Pre

ssure

C

hang

e

and D

eri

vative

(b

ar)

Elapsed time (hrs)

Log-Log Match - Flow Period 21

WELLBORE

STORAGE

DERIVATIVE END EFFECT

RESERVOIR MODELING

Data fracture analysis

Fracture Type

Orientation

Lenght

Type of Filling

Spacing (fracture intensity)

Interconnection Degree

RESERVOIR MODELING

Fractured Reservoir Characterization

Structure

Petrophysical properties of the matrix

Geometrical properties of the fractures

Average dimensions of the matrix block

Petrophysical properties of the fractures

Matrix-fracture exchange phenomena

Fracture Connectivity

RESERVOIR MODELING

Available Data 2D and 3D seismic

Outcrops mapping

NMR and X-ray techniques / Thin sections

Oriented core analysis

Microlosses

Well bore image logs (FMI-FMS,UBI)

Production data (Well test, Interference test etc..)

RESERVOIR MODELING

3D Model at Field Scale

The 3D model takes into account only the largest

structural features (from 2D 3D seismic).

Modeling is carried out by integrating the results form

different disciplines :

seismic interpretation

structural modeling

reservoir internal geometry modeling

When integrating the data, the overall model

consistency is tested.

RESERVOIR MODELING

3D Model

Reservoir layering

Structural model

Seismic interpretation

Author: G.Rea W.Gatti

1

2

3

Fractured Reservoir Characterization & Modeling 3D Model structural model

RESERVOIR MODELING

Fracture data analysis from outcrops

Fracture type

Orientation

Lenght

RESERVOIR MODELING

Fracture Analysis Well scale

RESERVOIR MODELING

Fracture analysis from oriented core

Oriented core Unrolled core image Fracture picking

N W S E N

RESERVOIR MODELING

It is possible to detect:

open fractures (fluorescent)

cemented fracture

stilolytes

It is possible to estimate:

fracture lenght

fracture orientation

fracture aperture

Input Data

Fracture analysis at core scale

RESERVOIR MODELING

X-Ray and NMR techniques on core full size

Nuclear Magnetic

Resonance

core holder

Core sample sleeve

distribution

plug

X- Ray

RESERVOIR MODELING

Imaging log tools

FMI (Resistivity Image)

UBI (Acoustic Image)

RESERVOIR MODELING

Fracture detection from imaging log

RESERVOIR MODELING

Monitoring of mud losses

RESERVOIR MODELING

3845

3846

3847

3848

3849

3850

0 75 150 225

Q LOSS (l/min)

Pro

fon

dit

(

m)

Dep

th (

m)

Mud losses monitoring

Tuning log image

interpretation on core data

FMI UBI core

image

Main

fracture

Input data (well scale) Borehole

RESERVOIR MODELING

Data Integration for Fracture Network Modelling

3845

3846

3847

3848

3849

3850

0 75 150 225

Q LOSS (l/min)

Pro

fond

it (m

)

Mud Losses

Production Tests

Imaging Logs

Outcrops

Seismic Coherency

Core Full Size

Core Thin Sections

3D Core Imaging

Fracture modeling workflow

Layering

Fracture network

Stress field

Log interpretation

Breakout analysis

Core analysis

Sedimentological model

3D structural model

Outcrop study

Geomechanic data and

interpretation (Poly 3D)

Static model

(FRED)

Production data

Validation of static model

(MAFIC OIL)

Dynamic model

(ECLIPSE)

Well test simulation

Interference between Gorgoglione and Perticara simulation

Whole field interference test simulation

Conceptual models

Thank you for your Attention