World-class training for the modern energy industry

Building a Reservoir Model, Pembrokeshire, UK (G055)

Tutor(s)

Mark Bentley: TRACS International and Langdale Geoscience.

Overview

This course offers a software-independent view on the process of reservoir model design and simulation model-building, addresses the underlying reasons why some models disappoint and offers solutions that support the building of more efficient, fit-for-purpose models. The thread through the week is a model design for the notional ‘Pembroke Field’ – a synthetic field constructed from reservoir analogue outcrops in South Pembrokeshire.  The Pembroke Field contains three contrasting reservoir types: continental clastics, shallow marine deltaics and naturally fractured carbonates, in both structurally deformed and undeformed settings. Data from producing oil and gas fields has been scaled to the synthetic models to create a realistic hydrocarbon field accumulation, ready for development.

Objectives

You will learn to:

  1. Create a fluid-sensitive conceptual model for a heterogeneous reservoir, built from a selection of elements and placed in a realistic architectural framework: the “sketch”.
  2. Guide the use of geostatistical tools intuitively, balancing deterministic and probabilistic components with awareness of the limits of the tools.
  3. Select appropriate methods for modeling of matrix properties, including the handling of net (cut-off’s vs total property modeling).
  4. Evaluate options for multi-scale modelling and the possible need for multi-scale approaches based on hierarchical understanding of Representative Elementary Volumes (REV).
  5. Understand issues surrounding permeability modeling and why this differs from the handling of other properties.
  6. Learn a rule of thumb (“Flora’s rule”) to help assess what level of static model detail matters to flow modeling and forecasting.
  7. Review how to use well test analysis to constrain models.
  8. Review options for model-based uncertainty handling (base case led, multi-deterministic scenarios, multi-stochastic ensembles), learn how to post-process the results and how to select an appropriate workflow which minimizes impact of behavioral bias.

Exertion Level

This class requires an EASY exertion level. Field stops require short walks along coastal paths, beaches and wave cut platforms. The longest walk is <5km (3 miles). Field stops are all at approximately sea level and some are tide dependent. Transport will be by coach.This class requires an EASY exertion level. Field stops require short walks along coastal paths, beaches and wave cut platforms. The longest walk is <5km (3 miles). Field stops are all at approximately sea level and some are tide dependent. Transport will be by coach.

Level and Audience

Intermediate. The course is aimed at geoscientists with knowledge of reservoir modeling software, petrophysicists who provide input to static reservoir models and reservoir engineers involved in simulation work who deal with the static-dynamic interface on a regular basis. The course is also of benefit to team leaders who wish to have a deeper understanding of the principles behind modeling and how to QC models made by others.

Duration and Logistics

5 days; a mix of field work (70%), and classroom exercises (30%).

Course Content

The central theme of the course is Reservoir Model Design, on the premise that it is design rather than software knowledge that typically distinguishes “good models” from “bad models”. Considerable time is dedicated to reservoir model and simulation exercises in many companies but the results often disappoint: the time taken to build models is often too long, the models too detailed and cumbersome and the final model is ultimately not fit-for-purpose. This course examines the reasons why and offers remedies to fix these problems.

Modelling and simulation software is not run live on the event – the emphasis is on good design. However, models and simulations of the Pembroke Field have been built at a number of scales and will be shown to quantify the impact of the observed field heterogeneities on fluid flow.

The course is organized around the following five themes, issues within which are often the cause of poor model outcome:

Model purpose
What is the question we are specifically trying to address? What do we really mean when we say “fit for purpose”?

Elements and architecture
How much detail should be incorporated into the models? From the rich spectrum of potential lithofacies, electrofacies, biostratigraphic and analogue data inputs, how do we select the “right” number of components (elements) to take forward into the modeling process? Once selected, how do these elements combine into a realistic description of length scales and reservoir architecture? How to capture this in an interpretative sketch that can be used as a cross-discipline communication tool.

Probability and determinism
Is the balance of probabilistic and deterministic components appropriate given the model purpose? Should heterogeneities be handled implicitly or explicitly in the static and dynamic models and if implicitly, then how should we average their properties? What are our expectations of geostatistics and how do we control the algorithms intuitively to replicate a sketched reservoir concept? This applies both to modeling of the matrix and also fractures, and we explore how we can use well test data to place deterministic constraints on our models.

Multi-scale modeling
What scale should we be modeling and simulating at, given the fluid type and model purpose? Can everything be modeled at one scale, or are static/dynamic multi-scale models required? We address the full spectrum of heterogeneity using the concept of Representative Elementary Volumes and conclude that traditional static-dynamic upscaling is only part of the story and not always the main part. Illustrations of fine-scale “Truth” models will be used to illustrate where we sometimes go wrong when we over-simplify a design.

Model-based uncertainty-handling
How to really go wrong. What are the tools we can use to identify natural bias (heuristics) in the modeling process and select workflows that capture useful ranges in a practical way, minimizing bias in the process. We summarize the current range of stochastically and deterministically led options, including the current trend towards “ensemble” modeling and the use of machine learning and AI. We discuss which techniques are appropriate to use and when, and how to post-process the results and communicate them usefully to colleagues.

Itinerary

Day 0
Arrival. Evening course introduction and safety briefing
Overnight Saundersfoot

Day 1
Model purpose, elements and architecture
Fieldwork: Amroth, incised valley fill, delta front and delta plain depositional systems
Overnight Saundersfoot

Day 2
Rock modelling, probability and determinism, practical geostatistics
Fieldwork: Swanlake Bay and Manorbier, Lower Old Red Sandstone (Early Devonian) fluvial facies – sandbody types and palaoesols
Overnight Saundersfoot

Day 3
Property modelling, handling permeability and fractures
Fieldwork: Saundersfoot – folding
Overnight Saundersfoot

Day 4
Dealing with scale: upscaling, multi-scale modelling and the REV
Fieldwork: Stackpole – faulting and fractured carbonates
Overnight Saundersfoot

Day 5
Model-based uncertainty handling; completing the Pembroke model design and debriefing with reservoir and simulation models.
Fieldwork: Tenby – carbonates and structural features
Overnight Saundersfoot

Day 6
Departure

Geological Controls on Production in Unconventional Reservoirs (G052)

Tutor(s)

Bruce Hart: Department of Earth Sciences, Western University

Overview

This course classifies unconventional reservoirs from a petroleum systems perspective and leads participants through how depositional controls on reservoir architecture and mechanical stratigraphy affect development strategies.

Duration and Logistics

Classroom version: 3 days; a mix of lectures exercises. The manual will be provided in digital format and participants will be required to bring a laptop or tablet computer to follow the lectures and exercises.

Virtual version: Four 4-hour interactive online sessions presented over 4 days (morning sessions in North America, afternoon sessions in Europe). A digital manual and exercise materials will be distributed to participants before the course.

Level and Audience

Fundamental. Intended for subsurface professionals (geologists, geochemists, geophysicists, reservoir-, completion- and drilling engineers) who have some working knowledge of unconventional reservoirs but are looking to understand how multi-disciplinary integration can improve exploration and development decisions.

Objectives

You will learn to:

  1. Describe unconventional reservoirs based on all parts of their petroleum system’s character, and use that knowledge in a predictive way at all steps from exploration to development
  2. Maximize the benefit of common tools for unconventional reservoir characterization.
  3. Define stratigraphic and structural controls on development strategies: landing-zone definition, horizontal vs vertical wells
  4. Develop a common language that can be used to facilitate information exchange between various engineering and geoscience subdisciplines.

Course Content

This course classifies unconventional reservoirs from a petroleum systems perspective and leads participants through hands-on exercises (data from the Eagle Ford, Bakken, San Juan Basin and elsewhere) that reinforce the concepts of depositional controls on reservoir architecture and fractures.

The term “unconventional reservoirs” encompasses a wide range of reservoir types: tight-gas sandstones, naturally fractured reservoirs, source-rock (“shale”) plays, etc. The

common bond is that the reservoirs have permeabilities measured in the nano- to microDarcy range and require hydraulic fracturing and/or horizontal drilling for production to be economic. These reservoirs develop in a variety of different petroleum systems. In some, e.g., tight-oil sandstones, the source rock and reservoir are separate. In other cases, e.g., source-rock reservoirs, the source- and reservoir rocks are the same. Because of these and other genetic differences, exploration and development strategies need to be tailored to optimize economic return.

Goals of the course include:

  • Examine how a genetic classification of unconventional reservoirs, using concepts from petroleum systems analyses, can guide decision making from exploration to development stages of a play.
  • Illustrate how depositional controls on reservoir architecture and mechanical stratigraphy affect development strategies: the choice of horizontal vs vertical wells, landing zone definition, frack barrier identification, etc.
  • Characterize the positive and negative effects of natural fractures and faults and means for their identification.
  • Examine how to maximize the benefit of common tools (triple combo logs, core analyses, etc.) for identifying the potential of unconventional reservoirs.

Introduction

  • Petroleum systems to completion design: the wholistic view
  • What are petroleum systems?
  • Conventional vs unconventional plays (petroleum systems perspective)
  • Unconventional play types
  • Pressure systems
  • Horizontal drilling, hydraulic fracturing and factory drilling

Source-Rock Reservoirs (“Shale Plays”)

  • Petroleum systems characterization of source-rock reservoirs
  • Source-rock characterization
  • Mineralogy and mechanical properties of source-rock reservoirs
  • Pore systems and reservoir quality
  • Eagle Ford case study & exercise

Tight-Oil Reservoirs

  • Petroleum systems characterization of tight-oil reservoirs
  • Shaley sandstones: petrophysical evaluation, pore-system characterization
  • Bakken and Cardium case studies and exercises

Naturally Fractured Reservoirs

  • Petroleum systems characterization of naturally fractured reservoirs
  • Fracture characterization
  • Fractures and fluid flow
  • Drilling naturally fractured reservoirs
  • Mesaverde Group (San Juan and Piceance Basin) case studies and exercises

Synthesis

  • Beginning with the end in mind: Thinking “development” during exploration
  • The Unconventional-Conventional Spectrum: hybrids, haloes & headaches
  • Stratigraphic controls on unconventional reservoir potential
  • Structural controls on unconventional reservoir potential
  • Full integration, from start to finish

Cretaceous Lacustrine Carbonate Reservoirs of the South Atlantic (G045)

Tutor(s)

Paul Wright: Independent Consultant.

Overview

This course provides a description of the highly unusual carbonate reservoirs deposited in the Santos Basin (offshore Brazil) during the rift to sag stages of Atlantic opening, and a discussion of the controversies surrounding their origin. Particular emphasis will be given to the Aptian so-called microbialite reservoirs (Barra Velha Formation and equivalents), reviewing both of the main models for their development and evaluating the seismic and sedimentological models. A practical approach to characterizing these complex rock types will be provided. The course will include an introduction to non-marine carbonate systems in extensional settings, as well as a review of the South Atlantic coquina reservoirs.

Duration and Logistics

Classroom version: A 2-day classroom course. The manual will be provided in digital format and participants will be required to bring a laptop or tablet computer to follow the lectures and exercises.

Virtual version: Four 3-hour interactive online sessions presented over 4 days (mornings in North America and afternoons in Europe). A digital manual will be distributed to participants before the course. Some reading is to be completed by participants off-line.

The course content and details can be altered to fill 1, 2 or 3 days for in-house delivery.

Level and Audience

Advanced. Intended for technical staff and managers who are involved in exploration for or exploitation of carbonates along the margins of the South Atlantic, or are interested in furthering their understanding of carbonate reservoirs in general.

Objectives

You will learn to:

  1. Recognize the range of carbonate systems that develop in extensional settings.
  2. Describe the highly unusual and prolific Aptian carbonate reservoirs of the Santos Basin.
  3. Contrast the models for the formation of these chemogenic rocks and discuss their differences.
  4. Evaluate the strikingly different reservoir characteristics that emerge from the two models.

Course Content

Themes to be covered are:

  • Introducing non-marine carbonate systems in extensional settings
    • the continuum from lacustrine carbonates through to hydrothermal travertines
    • microbial carbonates
  • The tectonic settings of the pre-salt lacustrine carbonates
  • The Barra Velha and its equivalents
    • facies, cyclicity, porosity formation, clay mineral diagenesis, reservoir rock characterization and rock fabric classification
    • isotopic data and its significance
  • Evaluating the seismic evidence for Barra Velha platforms
  • Age equivalent Barra Velha facies and microbialites in Brazil (onshore and offshore) and West Africa
  • Current models for the coquinas reservoirs of Brazil and West Africa

Key Concepts in Clastic Reservoir Performance (G044)

Tutor(s)

Mike Boyles: Retired Shell Oil and Affiliate Faculty, Colorado School of Mines

Overview

This course presents the concepts and terms used to describe the sedimentology, stratigraphy and structure of clastic units, and introduces the environments of deposition of clastic sediments. The awareness of these topics and their heterogeneities allows participants to understand their role in predicting reservoir performance in exploration projects, in development planning and in managing field performance.

This course presents a stand-alone overview of clastic reservoirs and would be beneficial for any subsurface team member. It also serves to provide the framework for the geologic concepts that are examined in Clastic Reservoirs Field Seminar: Stratigraphic and Structural Heterogeneities That Impact Exploration and Production Reservoir Performance (G012). Attending G044 will allow G012 participants to maximize the benefit of spending time in the field. For a more detailed approach to the subject in the classroom, consider the 5-day Introduction to Clastic Reservoirs: Stratigraphic and Structural Heterogeneities That Impact Performance (G047).

Duration and Logistics

Classroom version: A 1-day classroom course comprising a mix of lectures (75%) and hands-on exercises (25%). The manual will be provided in digital format and participants will be required to bring a laptop or tablet computer to follow the lectures and exercises.

Virtual version: Two 4-hour interactive online sessions presented over 2 days (mornings in North America and afternoons in Europe). A digital manual and exercise materials will be distributed to participants before the course. Some reading and an exercise are to be completed by participants off-line.

Level and Audience

Fundamental. This is a refresher course for geoscientists and an overview of geologic basics for reservoir engineers, petrophysicists, managers and support staff.

Objectives

You will learn to:

  1. Understand the basic terminology of sedimentology, stratigraphy and sequence stratigraphy.
  2. Describe key characteristics of eolian, coastal plain, delta and deepwater reservoirs.
  3. Understand how subsurface reservoirs can be divided into flow units that capture key reservoir flow characteristics.
  4. Describe heterogeneities that can impact flow unit properties.
  5. Understand how sequence stratigraphic concepts are applied in a practical and predictive way.

Course Content

  1. Basic tools used in subsurface interpretation
    • Sedimentology
    • Stratigraphy
    • Sequence stratigraphy
  2. Introduction to clastic facies
    • Eolian
    • Coastal plain
    • Deltas
    • Turbidites
  3. Structural Heterogeneities

An Introduction to Mudrock Reservoirs: Basin Setting, Stratigraphy, Sedimentology and Rock Properties (G042)

Tutor(s)

Jeff May: Geological Consultant and Affiliate Faculty, Colorado School of Mines

Overview

The evaluation of shale reservoirs presents a unique challenge: whereas some of the approaches applied are the same as for conventional reservoirs, many new methodologies and tools have been developed for the assessment of this unconventional resource. In this seminar, participants are exposed to the latest concepts of mudrock sedimentation and how it relates to reservoir properties. The development of mudrock successions, including depositional processes and stratigraphic cycles, is highlighted. Goals of the course include:

  • Providing practical techniques for assessing reservoir heterogeneity during play reconnaissance (‘data mining’) and regional evaluation (‘sweet spot’ mapping).
  • Interpreting and correlating well logs within a sequence-stratigraphic framework.
  • Learning what components are fundamental to core description and interpretation, including observations on composition, texture, sedimentary structures and fractures.
  • Developing an understanding of the factors that control reservoir quality: mineralogy, lithologic components, cements, fabric, fractures and pore systems. Methods used to investigate these rock properties also will be discussed.

Duration and Logistics

Classroom version: A 2-day classroom course comprising a mix of lectures (80%) and hands-on exercises (20%). The manual will be provided in digital format and participants will be required to bring a laptop or tablet computer to follow the lectures and exercises.

Virtual version: Four 4-hour interactive online sessions presented over 4 days (mornings in North America and afternoons in Europe). A digital manual and exercise materials will be distributed to participants before the course. Some reading and several exercises are to be completed by participants off-line.

Level and Audience

Fundamental. Intended for all subsurface professionals involved in the evaluation of unconventional resources. Geologists, geophysicists, petrophysicists and engineers who want to understand mudrock deposition relative to reservoir properties will benefit from the concepts and techniques presented. Participants should have a basic familiarity with resource plays. Some understanding of depositional processes and sequence stratigraphy is recommended.

Objectives

You will learn to:

  1. Determine the key geologic parameters that affect the attributes of shale reservoirs.
  2. Identify the components of basin analysis required when scoping a new shale play.
  3. Integrate a variety of data types necessary to identify and map optimum drilling locations and targets.
  4. Evaluate the variety of depositional processes and changes in environmental conditions recorded in a shale succession and tie that information back to well log character.
  5. Assess the basic stratigraphic framework of shale reservoirs and understand how systematic vertical changes relate to fabric, composition, texture and, ultimately, reservoir quality.
  6. Interpret and correlate well logs utilizing a sequence stratigraphic framework.
  7. Understand the observations and methodology necessary when describing and interpreting mudrock cores.
  8. Define the key rock parameters that control reservoir quality and mechanical properties.
  9. Describe the latest methodologies of pore-scale imaging for shale evaluation.

Course Content

Introduction

  • Mudrock definition
  • Lithologic heterogeneity
  • Critical play element

Data mining (play reconnaissance)

  • Published literature
  • Existing production
  • Mud log shows and tests
  • Core, cuttings and outcrop samples

Regional evaluation (sweet spot identification)

  • Basin analysis
  • Isopach and isolith mapping
  • Rock quality mapping
  • Hydrocarbon saturation mapping
  • Structure mapping
  • Pressure compartments and thermal anomalies
  • Organic geochemistry
  • Geophysical attribute mapping

Stratigraphic framework

  • Basinal setting
  • Depositional processes
  • Organisms and organic matter
  • Stratigraphic cyclicity
  • Sequence stratigraphy and well log patterns
  • Regional correlations and variations

Core description

  • Mudrock classification
  • Composition and texture
  • Sedimentary structures and depositional processes
  • Fracture types and styles
  • Mechanical stratigraphy

Rock description (reservoir quality)

  • Mineralogy and lithologic components
  • Fabric
  • Pore systems
  • Cements
  • Fractures
  • Fluids

Exercises conducted during the course include:

  • Mowry Shale Sequence Stratigraphy – core interpretation and regional well log correlation
  • Niobrara Formation – well log sequence stratigraphy
  • Graneros and Greenhorn Formations – well log sequence stratigraphy

Characterization of Clastic Reservoirs: Workflows for Reservoir Evaluation (G035)

Tutor(s)

Vitor Abreu: President, ACT-Geoscience; Adjunct Professor, Rice University

Overview

Reservoir mapping at production scale has to be performed with an understanding of clastic depositional systems, with full integration of core, core-plugs, well logs, seismic and production and engineering data. The variation in reservoir architecture of most common deposition-system morphotypes strongly influences development and production strategies, as well as in mapping techniques for not only the field scale but also to increase chances of finding near-field opportunities. The workshop examines common reservoir facies in transitional-marine to deep water systems, from fluvio-, wave- and tidal-dominated deltas, incised valleys, deep water channel systems and distributary channel lobe systems (deep water fans). Discussions include dimensional data of sand bodies in the different environments and recognition criteria in cores, well logs and seismic. The class will present optimized workflows for reservoir mapping, including the definition of the deliverables that need to be achieved in different business stages, focusing on when, why and how to develop them.

Duration and Logistics

Classroom version: 3 days; a mix of lectures (55%), core observation (10%) and hands-on exercises (35%). The manual will be provided in digital format and participants will be required to bring a laptop or tablet computer to follow the lectures and exercises.

Virtual version: Five 4-hour interactive online sessions presented over 5 days (morning sessions in North America and afternoon sessions in Europe). A printed manual and exercise materials will be distributed to participants before the course and several exercises are to be completed by participants off-line.

Level and Audience

Advanced. This course is intended for geologists, geophysicists and petrophysicists with basic training in sequence stratigraphy and basic clastic facies.

Objectives

You will learn to:

  1. Recognize different environments of deposition (EoDs) in cores, emphasizing typical facies stacking in common transitional marine and deep marine reservoirs.
  2. Classify facies and stacking in typical transitional marine to deep marine EoDs.
  3. Mechanisms for sediment transport in different EoDs and impact on reservoir rock properties.
  4. Integrate core and core plug information in reservoir analysis, tying to well log and seismic data.
  5. Recognize typical log patterns in different depositional systems.
  6. Recognize typical seismic map views and cross-sectional views of sand-rich EoDs.
  7. Apply mapping techniques for well logs and seismic with emphasis on identification of EoDs.
  8. Make pre-drill predictions based on understanding of EoDs and seismic response.
  9. Understand dimensional data for sandbodies in different EoDs
  10. Implement reservoir mapping workflows that emphasize data integration and focus on deliverables in different business stages.

Course Content

  • Classification of clastic depositional environments.
  • How to recognize different environments of deposition (EoDs) in cores, emphasizing typical facies stacking in common transitional marine and deep marine reservoirs.
  • Facies classification and stacking in typical transitional marine to deep marine EoDs.
  • Sediment transport mechanisms in different EoDs and impact in reservoir rock properties.
  • Typical log patterns in different depositional systems.
  • Typical seismic map views and cross-sectional views of sand-rich (EoDs).
  • How to properly integrate core and core plug information in reservoir analysis, tying to well log and seismic data.
  • Mapping techniques for well logs and seismic with emphasis on identification of EoDs.
  • Pre-drill prediction based on understanding of EoDs and seismic response.
  • Dimensional data for sandbodies in different EoDs.
  • Reservoir mapping workflows emphasizing data integration and main deliverables in different business stages.

Applied Concepts in Fractured Reservoirs with Discussions on Production, EOR, CO2 Sequestration and Geothermal Energy (G039)

Tutor(s)

John Lorenz and Scott Cooper: FractureStudies LLC

Overview

This course explores the wide range of structures that fall under the term ‘fracture’ and examines the effects of different fracture types on permeability in conventional and unconventional hydrocarbon reservoirs, and for EOR, CO2 sequestration and geothermal energy applications. The course establishes an understanding of natural fractures by explaining fracture mechanics and the origins of fractures, and then presents practical approaches to analyzing and working with fractures. Topics will include: collecting fracture data; measuring fracture attributes; differentiating natural from induced fractures; calibrating fracture data (from core, CT scans, outcrops, image logs and seismic); and determining in situ stresses. The course also describes how to predict fracture types in different structural domains and in different types of reservoirs, how the differences between extension and shear fractures control both individual fracture permeability and fracture network interconnectedness, and how to assess the interaction between natural and hydraulic stimulation fractures. Discussions of the applications to CO2 sequestration, geothermal energy, hydrocarbon reservoirs and enhanced recovery are included.

Duration and Logistics

Classroom version: A 3-day classroom course comprising a mix of lectures (80%) and hands-on exercises (20%). The manual will be provided in digital format and participants should bring a laptop or tablet computer to follow the lectures and exercises. A highlight of the classroom version is the inclusion of a hands-on, 65-plus piece teaching collection of natural and induced fractures in core.

Virtual version: Five 4-hour interactive online sessions presented over 5 days (mornings in North America and afternoons in Europe). A digital manual and exercise materials will be distributed to participants before the course. Some reading and exercises are to be completed by participants off-line.

Level and Audience

Advanced. Intended for geoscientists, reservoir and completion engineers, and petrophysicists, who wish to characterize and understand fracture systems and their effects on reservoir permeability and fluid flow. The class includes assessing how fracture permeability is affected by the in-situ stress system, and the interaction of natural fractures with hydraulic stimulation fractures.

Objectives

You will learn to:

  1. Appreciate how different fracture types have different effects on reservoir permeability and fluid flow.
  2. Assess how fracture types can vary by lithology within the same structural setting.
  3. Establish how fracture types can vary by structural setting within the same lithology.
  4. Assess fracture permeability and how it can be sensitive to changes in the in-situ stress during production and injection.
  5. Recognize fracture type using the small sampling of a reservoir offered by core and how this can provide a conceptual model for differentiating radial from anisotropic drainage, or flow away from the well during injection.
  6. Appreciate the interaction of natural fractures with hydraulic stimulation fractures as utilized in hydrocarbon, sequestration and geothermal industries, depending on fracture type and orientation relative to the in-situ stresses.
  7. Use insights into fracture mechanics and the origins of fractures, and gain an understanding of natural fractures and their potential effects on fluid flow.

Course Content

Part 1: Understanding natural fractures – types, dimensions and origins

  • Nomenclature and fracture classification systems
  • Fracture characteristics and dimensions – individual fractures, fracture populations and fracture systems
  • Identifying natural fracture types
  • The geologic origin of stress systems capable of fracturing rock
  • The mechanics of fracturing rock in extension and shear
  • The essential importance of pore pressure in fracture mechanics
  • Correlating laboratory and outcrop fracture observations to theoretical fracture mechanics
  • Mechanical stratigraphy: fracturing in carbonates vs sandstones vs shales
  • Fractures related to faults and anticlines: the characteristics of fracture corridors and sweet spots
  • Additional fracture types

Part 2: Measuring and analyzing natural fractures

  • Planning a fracture study: getting the most out of fracture measurements
  • Fracture data sources: core, CT scans, outcrops, image logs and seismic data
  • Fracture data from engineering tests
  • Techniques, methodologies and work flows
  • Coring and core processing protocols
  • Logging core for optimum fracture characterization
  • Distinguishing natural from drilling-induced fractures
  • Analyzing fracture data for use in fluid-flow models
  • Case studies: estimating fracture effectiveness from core data

Part 3: The effects of natural fractures

  • Fractured-reservoir classification
  • Effects of fractures on drilling and coring
  • Fracture volumetrics
  • Case studies: the Midale Field, the Rulison Field and the Spraberry Formation
  • The permeability behavior of individual fractures
  • The permeability and flow behavior of fracture systems
  • The sensitivity of individual fractures and fracture-system permeability to changing stresses during production and injection
  • The effects of fault and fracture-controlled sweet spots and barriers
  • Completions: the interaction between natural and hydraulic fractures

Reservoir Engineering Fundamentals: The Essentials in a Day (G037)

Tutor(s)

Associate Reservoir Engineer at TRACS International Ltd and Independent Engineer at Delta-T Energy Consultancy

Overview

Have you been on reservoir engineering classes in the past, heard the terms, seen the equations but not used any of it directly yourself? Would you like someone to run over the basics and just pick out the essentials, the parts everyone really needs to know? This short, focused class is designed to explain how reservoir engineers make subsurface interpretations, use these to build models to make forecasts and use these in turn to influence significant investment decisions. The course will cover what types of models the reservoir engineer uses, from simple analytical (graphical and spreadsheet) tools to more complex numerical simulators. It will put in context the key fundamentals of rock and fluid properties, reservoir deliverability, well performance and process design. The course will also illustrate how these fundamentals and the commercial E&P context place constraints on forecasts, and why a significant associated range of uncertainty results. This will be done in plain language accessible to those working outside reservoir engineering with the aim of giving you what you need to know to understand the subject – just the essential details.

Duration and Logistics

Classroom version: A 1-day classroom course comprising a combination of lectures and exercises. The manual will be provided in digital format and participants should bring a laptop or tablet computer to follow the lectures and exercises.

Virtual version: Two 4.5-hour interactive online sessions presented over 2 days (mornings in North America and afternoons in Europe). A digital manual and exercise materials will be distributed to participants before the course. Some reading and several exercises are to be completed by participants off-line.

Level and Audience

Fundamental. Designed for those who interface with reservoir engineering professionals and need to understand the language, techniques and assumptions they make in forecasting reservoir performance under various development schemes. The class will provide an opportunity for learning, inspiration and discussion.

Objectives

You will learn to:

  1. Understand the principles of fluid flow in porous media (reservoirs).
  2. Recognize how fluid properties influence reservoir, well and processing performance.
  3. Distinguish the benefits and limitations of well testing.
  4. Understand how engineers decide on reservoir development methods, predict recovery factors and production profiles for oil and gas reservoirs.
  5. Appreciate that not all reservoir models need to be complex and understand when simple models suffice and when complex numerical simulation models are justifiable.
  6. Recognize tools used for reservoir monitoring and standards for reporting reserves.

Course Content

he course will cover six fundamental principles of reservoir engineering that everyone working with resource estimations and production forecasts should understand fully:

  1. The influence of reservoir fluid properties on phase behavior during production.
  2. What well testing really tells us about the reservoir.
  3. How reservoir fluids are displaced on a macroscopic and microscopic scale, ranging from the influence of reservoir architecture down to core plug scale heterogeneities.
  4. How to choose appropriately scaled models to select an appropriate production mechanism for oil and gas fields.
  5. How to monitor reservoir performance and production forecasting and how these change through the field life.
  6. How we manage uncertainty in reserves and resource booking.

How to Make a Good Reservoir Model: It’s Not the Software, It’s the Design (G036)

Tutor(s)

Mark Bentley: TRACS International Ltd and Langdale Geoscience

Overview

How can you tell the difference between a ‘good’ reservoir model and a ‘bad’ one? This short, focused class is designed to draw out the common reasons for ‘good’ and ‘bad’ outcomes, under the premise that models add value only when they add clear value to business decisions. The theme throughout the event will be the overriding issue of model design and the five areas of common error: model purpose; selection of elements; use of determinism and probability; model scale; and uncertainty handling. Advice will be given on how to review models, what questions to ask the model builders, and how to determine whether the output from models can be relied upon and used to support decisions. The course will close with a set of questions to ask yourself and others, suitable for reference in peer reviews or assists.

Duration and Logistics

Classroom version: A 1-day course comprising a mix of lectures, case studies and exercises. The manual will be provided in digital format and participants will be required to bring a laptop or tablet computer to follow the lectures and exercises.

Virtual version: Two 4-hour interactive online sessions presented over 2 days (mornings in North America and afternoons in Europe). A digital manual and exercise materials will be distributed to participants before the course. Some reading and several exercises are to be completed by participants off-line.

Level and Audience

Fundamental. Designed for people who want an update or refresh on working with reservoir models without having to spend a week out of the office. The class will provide an opportunity for learning, inspiration and discussion with other modelers.

Objectives

You will learn to:

  1. Explain the common causative factors for modelling ‘disappointments’.
  2. Define model purpose and explain the use of framing.
  3. Understand the fluid sensitivity to selection of model elements.
  4. Describe techniques for handling small-scale detail in large models.
  5. Be able to select between techniques for quantifying uncertainty.
  6. Implement QC tips to evaluate your (and other people’s) models.

Course Content

The five reasons why many models fail, and how to avoid them:

  1. Model purpose
    • Why model at all? What do we understand by ‘fit for purpose’?
  2. Elements and architecture
    • Getting the building blocks right
  3. Determinism and probability
    • Concept-driven (intuitive) geostatistics
    • Balancing probabilistic and deterministic tools>
    • The importance of trends
  4. Scaling
    • Beyond upscaling – pitching the models at the correct scale
    • Multi-scale modelling
    • The REV
  5. Uncertainty
    • Overcoming heuristics
    • Modelling – what you don’t know

Characterization, Modeling, Simulation and Development Planning in Deepwater Clastic Reservoirs, Tabernas, Spain (G076)

Tutor(s)

Mark Bentley: TRACS International Ltd and Langdale Geoscience

Ed Stephens: TRACS International

Overview

This course is led by a production geologist and reservoir engineer involved in deepwater reservoir development, and is presented as a practical reservoir discussion rather than purely a traditional geological field trip. The objective of this field course is to explore the reservoir modelling and petroleum engineering aspects of deepwater clastic reservoirs. The discussions highlight the linkage from depositional processes to geological architecture and flow heterogeneity in development planning. The Tabernas outcrops are very well exposed and offer examples of sand-rich and debris-flow-dominated reservoirs, high net:gross fan systems and classic mud-dominated facies. In particular, they give excellent insights into the reservoir heterogeneities occurring within apparently continuous ‘sand lobes’ and major channels.

Duration and Logistics

A 5-day field course based in Almeria, Spain, comprising a mix of field activities and exercises. Transport will be by SUV on paved roads and unpaved tracks.

Level and Audience

Advanced. The course is largely aimed at geologists and reservoir engineers working on deepwater developments. The course is best suited to multidisciplinary team of geologists, geophysicists, petrophysicists and reservoir engineers.

Exertion Level

This class requires a MODERATE exertion level. There will be multiple walks of up to 1km (0.5 mile) most days. The longest walk of the class is approximately 2km (1 mile), with an ascent (and descent) of 75m (245 ft). The field area is in Europe’s only desert region and participants should expect high temperatures and an arid working environment. Participants should also be prepared for sudden and heavy rain showers.

Objectives

You will learn to:

  1. Assess the genetic processes that produce slumps, slides, debrites and high/low density turbidites, and explain why the concept of confinement underpins the description of heterogeneity in deepwater clastic systems.
  2. Evaluate the extent to which pay is under-/over-estimated in mud-rich/sand-rich systems, respectively, and the resulting errors in STOIIP and PI estimation.
  3. Organise a detailed sedimentological description into key reservoir elements and build an architectural model using those elements.
  4. Assess the basic principle of flow in porous media (Darcy) and describe how flow heterogeneity varies in layered and amalgamated clastic systems.
  5. Appraise the contrasting heterogeneities in sand- and mud-rich systems and determine how much detail is required in a reservoir description based on a consideration of fluid type and production mechanism.
  6. Evaluate how kv/kh impacts recovery in typical deepwater clastic architectures; optimally locate a well to optimize sweep for a range of architectural cases.
  7. Judge length scale variations for a typical deepwater clastic system, and discuss how this would be handled in a reservoir modelling and simulation context.

Course Content

This course covers the following topics:

  • Types of submarine fan systems
  • Influence of topography on reservoir distribution and quality
  • Reservoir heterogeneity
  • Reservoir modelling and simulation
  • Upscaling from core to simulation scale
  • Well selection and placement
  • Development planning for submarine fan reservoirs

Itinerary

Day 0: Arrival in Almeria

  • Evening course safety brief and introductory lecture.
  • Group dinner at the hotel.

Day 1: Overview of the Tabernas Basin

  • The class begins with overviews, orientation and scale of the Tabernas Basin, and a general introduction to deepwater clastic sedimentology and terminology
  • Visit to the basin margin to view coarse non-marine and shallow marine clastics which mark the initiation of sedimentation in the basin
  • Visit to the deepwater basin-fill succession to see the types of depositional environments in the basin – slumps, slides, debris flows, unconfined and confined turbidites

Day 2: Muddy Fan

  • Visit to a series of outcrop sections within a low net:gross submarine fan and typical geometries of those environments – thin-bedded turbidite sheet sands in confined and unconfined settings
  • Discuss thresholds of net:gross and the particular issue of thin bed pay
  • Use an outcrop-based model example to explore the concept of effective net from an engineering rather than a purely geological perspective

Day 3: Feeder Systems

  • Visit a series of outcrop sections to analyse the muddy feeder system and the sandy feeder system. Here we will study the individual architectures of the channelised units and discuss the facies, stacking patterns and evidence for their interpretation as feeder systems
  • Thin-skin sliding and soft sedimentary tectonics are also viewed in deeper, more distal sediments

Day 4: Sandy Fan

  • Visit a series of outcrop sections within a high net:gross submarine fan; high concentration, amalgamated sands in the lower fan, sheet-like tabular sands in the upper fan
  • Visit to the onlap margin of the body to view the overall geometries. Here we will conceive an overall sedimentological model for the outcrops and take a reservoir engineering perspective on the observed heterogeneity – does any of it matter? Outcome of this discussion will link through to a well design exercise
  • Outcrop-based permeability data will be used to support the observations on heterogeneity and to discuss how small-scale heterogeneity can be reasonably scaled into a simulation model

Day 5: Isolated Channel

  • Visit a series of outcrop sections to view Tabernas’ famous isolated channel and take the opportunity to describe and discuss intra-channel architectures and likely morphologies
  • Participants will carry out a modelling exercise on the channel based on their observations. A model developed for the class will be used as a basis for discussion of development planning in submarine fan systems

Day 6: Depart Almeria