geocompletion

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INNOVATIVE ENGINEERING SYSTEMS LIMITED14 RUBISLAW TERRACE LANE ABERDEEN AB10 1XF UK

TEL: +44 (0)1224 658695 FAX:+44 (0)1224 658696E-MAIL [email protected]

INNOVATIVE ENGINEERING SYSTEMS LIMITED

IESL

Geo -COMPLETION

Well Engineering

Technical Brochure

MAY 2005


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TABLE OF CONTENTS

This document contains CONFIDENTIAL and PROPRIETARY INFORMATION of Innovative Engineering Systems Limited (IESL). This document and the information disclosed herein shall

not be reproduced in whole or in part to others for any purpose including conceptual design, engineering, manufacturing or construction without the written permission of IESL. IESL 2005

REV A Geo-COMPLETION - Technical Brochure MAY 2005 3

1. INTRODUCTION........................................................................................... 5

2. TECHNOLOGY BACKGROUND................................................................ 9

2.1 Impact of geomechanical properties on reservoir performance ........... 9

2.2 Field conditions and reservoir properties............................................ 10

2.3 Relationship of stress & permeability.................................................11

3. GEO-COMPLETION FUNDAMANTALS ............................................. 15

3.1 Computational models ........................................................................ 15

3.2 Features & characteristics of the models ............................................ 16

4. SYSTEM STRUCTURE............................................................................... 17

4.1 Reservoir module ................................................................................ 17

4.2 Interface module ................................................................................. 18

4.3 Wellbore module................................................................................. 18

5. CONTACT INFORMATION....................................................................... 21

APPENDIX A OUTPUT GRAPHICS.................................................................23


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Table of Content


not be reproduced in whole or in part to others for any purpose including conceptual design, engineering, manufacturing or construction without the written permission of IESL IESL 2005

4 MAY 2005 Geo-COMPLETION - Technical Brochure REV A


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Section 1

INTRODUCTION 1




1. INTRODUCTION

P R O B L E M S

Well and reservoir deliverability impairment is commonly attributed to skindevelopment

Well integrity deteriorates with depletion and changes in the fluid and

production conditions resulting in poor productivity

Solids production and loss of well integrity is commonly identified late

resulting in loss of production and poor hydrocarbons recovery

In field re-development projects the assumption that rock and reservoir

properties have not changed significantly normally leads to costly

B E N E F I T S Coupled flow and geomechanics improves the understanding of well and

reservoir performance resulting in better completions and higher production

Changes in reservoir mechanical properties can be beneficial to improve

production and extend life of the field

Field re-development projects can be enhanced from timely identification of the

rock mechanical affecting productivity therefore, allowing to improve well

design reduce risk

Geo-COMPLETION is a system that integrates Reservoir and Completion Engineering

principles with Geomechanics in order to enhance productivity and reservoir deliverability

through an improved well design and evaluation process. The system is structured so it

addresses the main issues of the completion design process for initial reservoir conditions as

well as accounting for the changes that take place through the life of the field. The system is

composed of three main modules as depicted below

Reservoir module

Interface (Reservoir/Wellbore) module

Wellbore module


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Introduction1




Figure 1.1 Geo-COMPLETION - Areas of Expertise

The Reservoir module addresses productivity issues previously ignored by current

approaches. These include inflow, skin, invasion and mechanical integrity of the rock. The

integration of Geomechanics contributes to a better understanding of these issues enhancing

the well design process and long-term productivity. For instance, withGeo-COMPLETION,

formation permeability changes as a function of depletion are determined on a foot-by-foot basisby taking into consideration how the rock integrity evolves during the life of the field. Also the

rocks fabric is determined and changes in grain arrangement are predicted in order to quantify

its impact on productivity. The well design process is enhanced by:

Determining rocks permeability changes as a function of pressure depletion therefore,

contributing to MAXIMIZING long-term productivity


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Introduction 1

This document contains CONFIDENTIAL and PROPRIETARY INFORMATION of Innovative engineering Systems Limited (IESL). This document and the information disclosed herein shall



Determination of solids invasion and formation damage on a foot-by-foot basis

resulting in more accurate inflow contribution, which ENHANCES well completion

design and REDUCES risk and cost Determination of the critical BHFPs for wellbore or perforation tunnels stability,

MINIMIZING the risk of solids production and Enhancing long term production

Identification of the impact on productivity of the different parameters such as BHFPs,

GOR, WOR and depletion for both Sandstones and Carbonates which AIDS in the

completion design and equipment selection processes

The Interface module covers all the aspects that link the reservoir with the Wellbore such as

casing design, cementation, perforation and stimulation programs. Integrated with the results ofthe Reservoir module, the Interface module allows detailed evaluation of the interface and how

the interaction between the reservoir and the wellbore can be maximized for improved well

productivity. This permits

IMPROVED hole size selection and casing design to minimise operational risk and

cost.

ENHANCED stimulation treatment design and implementation by allowing a more

accurate diagnosis of invasion and formation damage.

ENHANCEDwell perforating design and interval selection by taking into account the

stress conditions and rocks integrity through the entire life of the reservoir.

OPTIMIZEDcementing through the reservoir section by using reservoirs rock integrity

and strength to avoid slurry losses and enhance placement and zonal isolation.

The Wellbore module covers all the aspects of selecting the optimum equipment and

completion options. Geo-COMPLETION allows optimum design for reservoirs prone to

solids production for both sandstones and carbonates. Conditions to optimize completionselection permits:

OPTIMUMequipment selection for wells requiring solids management or their control

can be implemented based on a better understanding of the reservoir and the

expected operating conditions.


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Introduction1




In the cases where a solids production strategy is selected, Geo-COMPLETIONallows the

identification and minimisation of equipment damage ENHANCING productivity and long-term

performance.


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Section 2

TECHNOLOGY BACKGROUND 2




2. TECHNOLOGY BACKGROUND

Current well completion design has traditionally taken very little notice of the Geomechanical

issues that affect reservoir performance over the life of the field. Geomechanical issues aremost commonly considered only in order to determine the likelihood of solids production. At

this point a decision is made as to whether to implement a completion that will include a solids

control method or not.

A similar situation exists in terms of reservoir engineering and analysis where the overhead of

Geomechanics is just an extra hassle in addition to the existing obstacles encountered in

defining and analysing reservoirs performance.

The fact is that the prevalent geomechanical conditions in a particular field such as in-

situ stresses and rock mechanical properties have a significant impact on productivity at

all stages of the field life. Even worst, these parameters change in time and are not

adequately accounted while designing new completions or evaluating future reservoir

performance.

The lack of understanding and utilisation of geomechanical principles in current well design and

reservoir evaluation results in leaving unexploited the real well and reservoir production

potential at all stages of the fields life.

2.1 IMPACT OF GEOMECHANICAL PROPERTIES ONRESERVOIR PERFORMANCE

Geomechanical conditions in a field have a significant effect on the reservoir properties and

rocks fibre through the life of the field. Changes in properties such as permeability, porosity and

pressures are the most common ones encountered. It is accepted in engineering terms that

permeability changes that commonly are not accounted for in conventional well completion

design are the results in local or field wide changes of the earth stresses. In most cases we

attribute this changes to the appearance of a skin that we are unable to neither define nor

quantify properly.

This is illustrated in the following graph, which illustrates a reservoir sequence in South East

Asia and how rocks integrity varies for different stages of depletion during the life of the field.


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Technology Background2




Figure 2.2 - Geomechanical Efficiency

The strength of the various layers (both sandstones and shales) that compose the reservoir

responds differently as a result of changes in reservoir pressures. These changes are

presented in this figure as when the individual layers start to deform plastically as the depletion

takes place.

It can be seen that this changes occur within the first 100 psi drop in reservoir pressure. As the

layers go from elastic to plastic state then all their original properties such as porosity and

permeability will change resulting in a new set of properties mainly in the near Wellbore area.

This are not accounted for in conventional completion design or reservoirs productivity

evaluation. In other words, the permeability of the reservoir is assumed constant and anychanges on its IPR are the result of the other parameters and properties such as viscosity, skin

and fluid saturations instead of the actual fabric of the rock matrix.

2.2 FIELD CONDITIONS AND RESERVOIR PROPERTIES

The following graph illustrates the relationship that exists between the Geomechanical

properties and the rock properties and how the latter are affected by changes in the conditions.


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Technology Background 2




Figure 2.2 Impact of Geomechanics on Reservoir Properties & Long-Term Performance

As can be seen the effects in terms of productivity and reservoir performance are significant and

eventually will lead to

Higher cost for new wells to be drilled in the field

Production rates that are below the capability of the reservoir

Higher workover frequency

Higher uncertainty hence risk

More expensive and complex surface facilities

Overall project cost will increase and field life might be limited

2.3 RELATIONSHIP OF STRESS & PERMEABILITYThe relationship between Geomechanical conditions such as stress and rock properties such as

permeability has long been established (Rhett and Teufel, 1992). The strain caused by changes

in the reservoir conditions such as those created by depletion will result in changes in

permeability. It must be noted that these changes might be an increase or a decrease in

permeability depending on the original rock properties and the magnitude of the change in the

Geomechanical conditions.


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The following figure present a conceptual view (After Wong et al 1997) of the various stages of

changes in the rock properties and fabric as a result of stress changes.

Figure 2.3 - Conceptual View of Main Events During Rock Deformation

In essence, changes in reservoir properties are the result of a need for the grains and fabric of

the rock to re-organise itself in order to accommodate the stresses and deformation of its

various mineral components. These re-organization and development of a new rock matrix

particularly in the near Wellbore area will go from displacements of the grain in the elastic

region up to hydrostatic compactation and pore collapse as a result of yielding and rock failure.

As a result, then we have a continuously changing permeability and porosity of a particular rock

as the reservoir is produced through the life of the field. Current methods of reservoir evaluation

only attempt to determine the magnitude and impact of these changes in cases where abnormal

events or conditions have been identified such as subsidence, Wellbore and casing collapseand other mechanical problems associated with changes in Geomechanical conditions.

The following figure illustrates a re-organisation of quartzs grains in a sandstone matrix as a

result of stress and its impact on permeability


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Technology Background 2




Figure 2.4 - Effect of Stress on Permeability in a High Porosity Sandstone


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Section 3

GEO-COMPLETION FUNDAMENTALS 3




3. GEO-COMPLETION FUNDAMANTALS

Geo-COMPLETIONis a new and advanced system that integrates Geomechanical physics

and reservoir engineering principles. The system is to be used for the timely prediction andquantification of reservoir properties and well performance changes through the life of the field.

Geo-COMPLETION is composed of three modules as described in previous sections and

has been developed for used with:

Both sandstone & carbonate reservoirs producing oil, gas or heavy crudes (< 12 API)

Accurate Inflow prediction through the life of the field

Enhanced formation damage identification/prediction

Determination of the risk of solids production and Wellbore collapse

Design and evaluation of completion options and their performance

Design and evaluation of perforating performance

3.1 COMPUTATIONAL MODELS

Geo-COMPLETION is based on a number of established disciplines and principles; five of

them form the main computational engine of the system. These are:

A pseudo 3D poro-elastoplastic geomechanical model

A formation impairment model based on flow of solids through porous media

Conventional reservoir engineering principles

IPR model for reservoirs producing heavy crudes (i.e. < 12 API)

All of them have been validated extensively and independently have formed the core of IESL

well engineering capability for many years. New components such as the perforating design and

formation damage system have been developed and integrated in order to create this advanced

system.


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Geo-COMPLETION Fundamentals3




3.2 FEATURES & CHARACTERISTICS OF THE MODELS

IESL has successfully used for many years a Pseudo 3D geomechanical model to identify and

resolve geomechanical issues affecting well and reservoir performance. This model has formed

the basis of IESLs SPMSand GeoDRILLsystems for the identification of sand production

and Wellbore stability problems. This model is continuously upgraded in order to introduce

advanced science concepts to allow accurate representation of field problems. Recent

developments include SynCAL, which is used in the prediction of hole sizes in order to

minimise the risk in wells using expandable tubulars and screens. Addition of a plasticity

element allows quantification of problems associated with the post yield state of reservoir rock

such as compactation and shale deformation and the resulting impact on well productivity. On

this basis IESL introduces Geo-COMPLETION, an advance system for the solution of well

completion and production problems at the wellbore.

Figure 3.2 Geo-COMPLETION Structure


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Section 4

SYSTEM STRUCTURE 4




4. SYSTEM STRUCTURE

Geo-COMPLETION structure allows delivery of key well design and evaluation as well as

reservoir performance based on its three modules. A description of the output for each modulethe system is described below

4.1 RESERVOIR MODULE

The reservoir module has been designed to deliver parameters and diagnosis on a foot-by-foot

basis. These parameters such as Inflow predictions, formation damage profiles, BHFP and

solids production prediction are oriented to maximise productivity and long term reservoir

performance. Detailed outputs are described below:

Permeability profile through the reservoir (on a foot by foot) for initial conditions and

through the life of the field. An Inflow Profile Log or IPL is generated highlighting the

main contributing layers and the evolution of their permeability as a function of time

and depletion.

Formation damage profile through the reservoir section (on a foot by foot) is presented

on a log format. The profile integrates identification of the main damaging mechanisms

as well as the most appropriate stimulation treatment for remedial. OPstim Log

A prediction of the likelihood of solids production is also produced for both sandstone

and carbonate reservoirs using the SPP log. Critical operating conditions such as

BHFP, WOR and their response to depletion are represented in the SPP.

An inflow profile and BHFP prediction is produced for reservoirs producing heavy

crudes. Using IESLs RhEPS technology a more accurate and realistic

representation of the ability of the reservoir to deliver fluids is produced and can be

presented as an IPL for heavy crudes. IPL- HC

All the above outputs and deliverables are produced for a number of variables and as

sensitivity analysis. The impact of GOR, WOR, depletion and rates can be simulatedfor a variety of operating conditions allowing evaluation of a number of possible

scenarios for well completion design and reservoir performance.

Graphical outputs as previously described above are included in the appendices.


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System Structure4




4.2 INTERFACE MODULE

The Interface module addresses the issues between the reservoir and the casing/Wellbore.

Issues such as stimulation, casing and perforation design are addressed in this module.

Detailed output of this module is described below:

Determination of critical loads affecting casing design and performance during the life

of the well. A critical identification of potential causes and factors affecting casing

collapse are presented based on the geomechanical conditions in the field.

Complete perforation design and performance analysis can be carried out taking into

account all the stresses and other factors affecting flow through the perforations.

Stability of the tunnels as well as their long-term performance can be simulated and

the output is presented in a numerical and log format. It permits selection of the

optimum perforating method and equipment as well as evaluation of perforations

performance.

This module includes the capability of designing the stimulation requirements for the

reservoir. In conjunction with the reservoir module this part of the system allows

proper identification of the stimulation requirements (i.e. damage removal or

permeability enhancement) and accurate location of the interval to be stimulated. As a

result, reservoir potential and fluids deliverability can be maximised.

4.3 WELLBORE MODULE

The Wellbore module of Geo-COMPLETION focuses on the completion design and

equipment requirements across the reservoir. To this effect, the module integrates output from

the previous modules in order to help with all the aspects of the reservoir face completion as

follows:

Completion options selection, recommendations for OH or cased/perforated well

completions are produced based on bore and perforation stability, solids production

potential, zonal isolation and reservoir deliverability / performance.

Once the fundamental completion alternative has been selected the system identifies

the long-term performance of a number of options using reservoirs mechanical

integrity and inflow performance principles. Completion options with and without solids

control methods are identified and every aspect reviewed to assess how suitable the

option and equipment will be to the long-term performance of the well and reservoir.


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System Structure 4




This capability is also implemented for fields with water injectors where issues such as

thermal effects on injectivity are evaluated in order to define the potential performance

of the injection wells over the life of the field. The Wellbore module allows evaluation and review of completion performance at any

time in the life of the field. Potential mechanical problems such as flow impairment;

fracture performance and screens/gravel pack efficiency in delivering maximum

amount of fluids can be identified.

Detail equipment specifications can be generated for each of the completion

components. Parameters such as dimensions, metallurgy, filter media sizing, pressure

drops and maximum mechanical and thermal loading can be specified for the option

selected.

Wellbore intervention and remedial options at any point in the life of the reservoir can

be identified from this module along with its operational characteristics for effective

deployment.


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System Structure4





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Section 5

CONTACT INFORMATION 5




5. CONTACT INFORMATION

U N I T E D K I N G D O M

14 Rubislaw Terrace Lane,Aberdeen AB10 1XF

Scotland

Telephone 01224 658695

Facsimile 01224 658696

Email [email protected]

U N I T E D S T A T E S

10375 Richmond Avenue

Suite 1300

Houston

TX 77042

USA

Telephone 713 974 0634

Facsimile 832 251 6691

Email [email protected]

L A T I N A M E R I C A

c/o Ingenieria y Technologica C.A.

PN-1068-0207, Av. Victoria

Edif. Meridional, P.B. entre calle Cuba y Centro America

Urb. Las Acacias Postnet

Caracas, Venezuela

Cellular 0414 1420045

Fax 0212 6932291

e-mail [email protected]


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System Structure4





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Appendix A

OUTPUT GRAPHICS A




Appendix A Output Graphics

IPL - Inflow Profile Log


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Output GraphicsA




OPStim - Operational Stimulation Log


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Output Graphics A




SPP - Sand Production Prediction

geocompletion

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