Microsoft PowerPoint 1 RCM INTRODUCTION Final .pdf

RESERVOIR CHARACTERIZATION
AND MODELING







Geological model vs Reservoir model
• Vocabulary, Reservoir model: The key to production
• Reservoir model definition (Why a reservoir model ?)
• Example of history matching from a reservoir model
• Specificity of reliable cellular models
• Dynamic simulation to reduce reserves uncertainties
• Simples rules modeling for optimal

Cellular models
• Example of geological model
• Example of field
• Image parameters an hydrocarbon field
• Definition of a cellular model

Objectives
• Objectives of your company
• The reservoir engineer’s job
• Integrated reservoir studies: objectives
• Reservoir characterization and modeling: objectives
• Work with your colleagues

Geological modeling introduction: Presentation summary

Raphaël LALOU

1. Introduction

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Objectives of your company
After the discovery of a new reservoir, the goal is to set up a field development
project that will attempt to optimize hydrocarbons recovery as part of an
overall economic policy.
During the reservoir’s life, the company will continue to study its behavior
throughout the life of the field to determine the information required for
optimal production.
The proper way goes through the reservoir model. The right man is the
Reservoir Engineer

The optimal profitability of a project requires the knowledge of the
hydrocarbons in place, the recoverable reserves (estimated on the basis of
several alternative production methods) and the wells potential productivity.

The proper way goes through the geological model. The right man is the
Reservoir Geologist

A good reservoir model integrates geological constraints

These activities are based on digital reservoir modeling

The aim of these predictions is to dimension the future
production facilities, check-up economical interest of the field,
optimize the development scheme and establish a long term
development plan.

Evaluation of production forecasts through the knowledge of
Oil/Gas/Water production, the evolution of reservoir pressure
and the management of the field operations (number of wells,
water and gas injection, type of production method).

The reservoir engineer’s job

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Integrated reservoir studies: Objectives

Why performing an integrated field study ?

• To calculate hydrocarbon accumulation in a reservoir
• To estimate reserves and predict production
• To optimize field development

• To evaluate the relative impact of uncertainties

• To understand the reservoir heterogeneities’ impact on its dynamic
behavior

• To integrate geologic and dynamic constraints

• To develop a global understanding of integrated reservoirs studies

Cellular models are built to reach previous objectives, i.e :

Reservoir characterization and modeling objectives

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Work with your collegues
The log analyst (Quantitative interpretation from logs, OWC and
petrophysical parameters)
The lab petrophysicist (petrophysical measurements)

and



correlation

The geophysiscist (seismic data, faults, surfaces, seismic facies)
analysis,



(core

The geochemist (fluids and rocks analysis, organic matter)





The reservoir engineer (dynamic synthesis and flow simulation)

The sedimentologist
sedimentological model



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CELLULAR MODELS

The reservoir geologist verify data coherence during the modeling phase.
He must work with all actors of the study.
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Example of field

Example :
Geological model
in carbonates

Shaly limestone

Tight limestone

Porous limestone

Example of geological model

Monterralo anticline - Colombia

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Image parameters of an hydrocarbon field

External envelop
Iso contours top-base
Compartments

1. Shape and Volume

4 classes of questions to build a model
4.Fluids in place
Type of fluids, contacts
PVT, composition
Aquifer extension

2. Structural framework
Faults
Fractured areas
Micro fractures

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Definition of a cellular model

We need a cellular model:
to understand the complexity of reality
to quantify reality

A CELLULAR MODEL IS :
a schematic description of a reservoir that
represents its properties

Correlations, layering
Facies variation
Petrophysics
Drains, barriers

3.Internal organization

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GEOLOGICAL MODEL
Vs
RESERVOIR MODELS



Reservoir model = Dynamic model

Geological model = Geomodel = Static model

Cellular models



Vocabulary

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REALITY

Geomodel vs reservoir model (1)
GEOLOGICAL MODEL (STATIC)
for volume computation
• Phi (effective porosity)
• K (permeability)
• S (saturations: W, O, G)
• Net & Gross thickness

RESERVOIR MODEL (DYNAMIC)
for fluid flow simulation

Different objectives > Different cell size

PREDICT DYNAMIC BEHAVIOR

RESERVOIR MODEL
for dynamic simulation

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• Phi e
• K (Kx,Ky,Kz)
•S
• Kr
• Pc
• Net/Gross

- One model for each parameter
Not to predict the reservoir content
- Used to :
Understand spatial distribution
but to anticipate
of hydrocarbons
its dynamic behavior
Calculate accumulations in place

- A quantitative synthesis

• Phi e
•K
•S
• Net/Gross

GEOLOGICAL MODEL
for static simulation

CHARACTERIZE RESERVOIR

Geomodel vs reservoir model (2)

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Reservoir model : The key for hydrocarbon production

For optimal field development… …the key for success is:

…the reservoir model !

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Reservoir model: Definition

A reservoir model is a gridded model which allows to manage and properly represent:
• Key heterogeneities (main flow units)
• Lithofacies and petrophysical properties distribution consistency

The objective of a reservoir model is :

NOT to predict what we should find in the reservoir…

TO ANTICIPATE ITS DYNAMIC BEHAVIOR
(match and predict)

…BUT ….

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Why a reservoir model ?

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81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97

Moderate Water Prod.

General field match

Example of history matching from a reservoir model

•Well production
•Fluid movements inside reservoir
•Pressure evolution

A RESERVOIR MODEL is used to simulate the evolution of a field vs time

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Good match
for pressure
profile

Good match for
oil production
profile

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Dynamic simulation to reduce reserve uncertainties

Capex: Capital expenditure
Opex: Operational expenditure

NEED FOR STRONG INTEGRATION BETWEEN GEO DISCIPLINES
SPECIALISTS (Geophysicists, Geologists, Reservoirs engineers)

A reliable geological model takes into account dynamic data:
• Location of the main faults which impact fluid flow (barrier or
conductive faults)
• Stratigraphic barriers, if stacked or multiple reservoirs

• fluid-flow simulation is more realistic and reliable

A good reservoir model is strongly constrained with the geological
model:

Specificities of reliable cellular model

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(Reservoir grid: 200x200x5m)

Generally, reasonable cells dimension is 100x100x1 m

Simple rules modeling for optimal



Keep it below 10 millions cells per unit

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** Geological model = Geomodel = Geocellular model = Static model

* Reservoir model = Dynamic model

• integrates reservoir geometry and petrophysical properties
• takes into account dynamic information
• provides key heterogeneity modeling

The geomodel** represents one of the most important phases in
the workflow of an integrated reservoir study, because it:

• well production
• fluid displacements inside the reservoir
• pressure evolution

The reservoir model* construction is the main objective of an
integrated reservoir study. This model is used to simulate the
evolution of a field throughout time for:

General contexte – Key points

Details in excess is not a guaranty of precision or accuracy
• Uncertainties are additive!
• Restrict the number of facies

Only model the relevant faults that can impact the reservoir, i.e.:
• Fault with a significant impact on reservoir dynamic
• Fault with throw greater than flow unit thickness










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Thank you for your attention!

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