Hydrocarbons in Basement Formations

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Publishers at ScrivenerMartin Scrivener (martin@scrivenerpublishing.com)

Phillip Carmical (pcarmical@scrivenerpublishing.com)

Hydrocarbons in Basement Formations

M. R. Islam Dalhousie University; Emertec R&D Ltd.

M.E. HossainNazarbayev University

andA. O. Islam

Emertec R&D Ltd.

This edition first published 2018 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA and Scrivener Publishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA© 2018 Scrivener Publishing LLCFor more information about Scrivener publications please visit www.scrivenerpublishing.com.

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Dedication

This book is dedicated to Professor G. V. Chilingar of University of Southern California in recognition of his lifelong teaching that has touched the hearts

of thousands of researchers from around the world.

vii

Contents

Foreword xv

1 Introduction 11.1 Summary 11.2 Is Sustainable Petroleum Technology Possible? 21.3 Why is it Important to Know the Origin of Petroleum? 41.4 What is the Likelihood of an Organic Source? 51.5 What is the Implication of the Abiogenic Theory of

Hydrocarbon? 61.6 How Important are the Fractures for Basement Reservoirs? 81.7 What are we Missing Out? 81.8 Predicting the Future? 101.9 What is the Actual Potential of Basement Hydrocarbons? 10

2 Organic Origin of Basement Hydrocarbons 112.0 Introduction 112.1 Sources of Hydrocarbon 132.2 Non-Conventional Sources of Petroleum Fluids 292.3 What is a Natural Energy Source? 342.4 The Science of Water and Petroleum 392.5 Comparison between Water and Petroleum 422.6 Combustion and Oxidation 57

2.6.1 Petroleum 592.6.2 Natural Gas 602.6.3 Natural Gas Hydrates 622.6.4 Tar Sand Bitumen 632.6.5 Coal 652.6.6 Oil Shale 652.6.7 Wax 662.6.8 Biomass 67

viii Contents

3 Non-organic Origin of Basement Hydrocarbons 693.0 Introduction 693.1 Theories of Non-organic Origin of Basement Petroleum 703.2 Formation of Magma 72

3.2.1 Magma Escape Routes 733.2.2 Magma Chamber 743.2.3 Types of Magma 78

3.2.3.1 Mafic Magma 803.2.3.2 Intermediate Magma 803.2.3.3 Felsic Magma 81

3.3 The Composition of Magma 823.4 The Dynamics of Magma 853.5 Water in the Mantle 1033.6 The Carbon Cycle and Hydrocarbon 1083.7 Role of Magma During the Formation of Hydrocarbon

from Organic Sources 1183.8 Abiogenic Petroleum Origin Theory 119

3.8.1 Diamond as Source of Hydrocarbons 1283.8.2 Oil and Gas Deposits in the Precambrian

Crystalline Basement 1323.8.3 Supergiant Oil and Gas Accumulations 1383.8.4 Gas Hydrates – the Greatest Source of Abiogenic

Petroleum 142

4 Characterization of Basement Reservoirs 1474.0 Summary 1474.1 Introduction 1474.2 Natural and Artificial Fractures 151

4.2.1 Overall in Situ Stress Orientations 1614.3 Developing Reservoir Characterization Tools for

Basement Reservoirs 1624.4 Origin of Fractures 1714.5 Seismic Fracture Characterization 178

4.5.1 Effects of Fractures on Normal Moveout (NMO) Velocities and P-wave Azimuthal AVO Response 181

4.5.2 Effects of Fracture Parameters on Properties of Anisotropic Parameters and P-wave NMO Velocities 182

4.6 Reservoir Characterization During Drilling 1854.6.1 Overbalanced Drilling 1914.6.2 Underbalanced Drilling (UBD) 193

Contents ix

4.7 Reservoir Characterization with Image Log and Core Analysis 2024.7.1 Geophysical Logs 205

4.7.1.1 Circumferential Borehole Imaging Log (CBIL) 213

4.7.1.2 Petrophysical Data Analysis using Nuclear Magnetic Resonance (NMR) 220

4.7.2 Core Analysis 228 4.8 Major Forces of Oil and Gas Reservoirs 237 4.9 Reservoir Heterogeneity 255

4.9.1 Filtering Permeability Data 2634.9.2 Total Volume Estimate 2674.9.3 Estimates of Fracture Properties 268

4.10 Special Considerations for Shale 268

5 Case Studies of Fractured Basement Reservoirs 2735.0 Summary 2735.1 Introduction 2745.2 Geophysical Tools 282

5.2.1 Scale Considerations in Logging Fracture Rocks 2835.2.2 Fracture Applications of Conventional

Geophysical Logs 2845.2.3 Borehole Techniques 290

5.2.3.1 Borehole Wall Imaging 2915.2.4 Micro Log Analysis 294

5.2.4.1 High-definition Formation Microimager 2955.2.4.2 Micro-Conductivity Imager Tool (MCI) 2995.2.4.3 Multistage Geometric Analysis Method 300

5.2.5 Fracture Identifications using Neural Networks 3035.3 Petro-physics in Fracture Modeling, Special Logs and

their Importance 3035.3.1 Measurement While Drilling (MWD) 303

5.3.1.1 Formation Properties 3055.3.2 Mud Logging 306

5.3.2.1 Objectives of Mud Logging 3065.3.2.2 Mud Losses into Natural Fractures 307

5.3.3 Conventional Logging 3085.3.3.1 Resistivity Logging 3085.3.3.2 Porosity Logging 3085.3.3.3 Combination Tools 3085.3.3.4 Cased-Hole Logging 309

x Contents

5.3.4 Magnetic Resonance Imaging (MRI), Nuclear Magnetic Resonance (NMR), Ultra Sonography 3095.3.4.1 Magnetic Resonance Imaging 3095.3.4.2 Nuclear Magnetic Resonance 3105.3.4.3 Ultra-Sonography 311

5.4 Case Study of Vietnam 3125.5 Case Studies from USA 323

5.5.1 Tuning/Vertical Resolution Analysis 3275.5.2 Conclusion on Case Study 3295.5.3 Geological Techniques 329

5.5.3.1 Data and Methods 3305.5.3.2 Distinguishing Natural Fractures

from Induced Fractures and their Well-Logging Response Features 333

5.5.3.3 Analysis of well-Logging Responses to Fractures and Establishment of Interpretation Model 334

5.5.3.4 Distribution of Natural Fracture 335

6 Scientific Characterization of Basement Reservoirs 337 6.1 Summary 337 6.2 Introduction 338 6.3 Characteristic Time 342 6.4 Organic and Mechanical Frequencies 349 6.5 Redefining Force and Energy 351

6.5.1 Energy 351 6.6 Natural Energy vs. Artificial Energy 362 6.7 From Natural Energy to Natural Mass 368 6.8 Organic Origin of Petroleum 397 6.9 Scientific Ranking of Petroleum 4036.10 Placement of Basement Reservoirs in the Energy Picture 414

6.10.1 Reserve Growth Potential of Basement Oil/Gas 4246.10.2 Reservoir Categories in the United States 425

6.10.2.1 Eolian Reservoirs 4276.10.2.2 Interconnected Fluvial, Deltaic,

and Shallow Marine Reservoirs 4346.10.2.3 Deeper Marine Shales 4406.10.2.4 Marine Carbonate Reservoirs 4436.10.2.5 Submarine Fan Reservoir 4466.10.2.6 Fluvial Reservoir 446

6.10.3 Quantitative Measures of Well Production Variability 451

Contents xi

7 Overview of Reservoir Simulation of Basement Reservoirs 4597.1 Summary 4597.2 Introduction 460

7.2.1 Vugs and Fractures Together (Triple Porosity): 4657.3 Meaningful Modeling 4667.4 Essence of Reservoir Simulation 468

7.4.1 Assumptions behind Various Modeling Approaches 4697.4.1.1 Material Balance Equation 4717.4.1.2 Decline Curve 4737.4.1.3 Statistical Method 4827.4.1.4 Finite Difference Methods 487

7.5 Modeling Fractured Networks 4937.5.1 Introduction 4937.5.2 Double Porosity Models 493

7.5.2.1 The Baker Model 4957.5.2.2 The Warren-Root Model 1963 4967.5.2.3 The Kazemi Model 496

7.5.3 The De Swaan Model 4977.5.4 Modeling of Double Porosity Reservoirs 4977.5.5 Dimensionless Variables 4987.5.6 Influence of Double-Porosity Parameters 501

7.5.6.1 Influence of ω: 5027.5.6.2 Influence of λ: 502

7.6 Double Permeability Models 5047.6.1 Basic Assumptions for Double Permeability Model 5057.6.2 Dimensionless Variables 5077.6.3 Double Permeability Behavior when the two

Layers are Producing 5087.6.4 Influence of Double Permeability Parameters 508

7.6.4.1 Influence of κ and ω: 5087.6.4.2 Influence of λ: 511

7.6.5 Double Permeability Behavior when only One Layer is Producing 511

7.7 Reservoir Simulation Data Input 5147.8 Geological and Geophysical Modeling 5167.9 Reservoir Characterization 518

7.9.1 Representative Elementary Volume, REV 5207.9.2 Fluid and Rock Properties 523

7.9.2.1 Fluid Properties 5237.10 Risk Analysis and Reserve Estimations 524

7.10.1 Special Conditions of Unconventional Reservoirs 524

xii Contents

7.10.1.1 Fluid Saturation 5257.10.1.2 Transition Zones 5257.10.1.3 Permeability-Porosity Relationships 5257.10.1.4 Compressibility of the

Fractured Reservoirs 5267.10.1.5 Capillary Pressure 526

7.10.2 Recovery Mechanisms in Fractured Reservoirs 5287.10.2.1 Expansion 5287.10.2.2 Sudation 5307.10.2.3 Convection and Diffusion 5327.10.2.4 Multiphase Flow in the

Fracture Network 5327.10.2.5 Interplay of the Recovery Processes 5337.10.2.6 Cyclic Water Injection 5337.10.2.7 Localized Deformation of

Fluid Contacts 5347.10.3 Specific Aspects of a Fractured Reservoir 535

7.10.3.1 Material Balance Relationships 5357.10.4 Migration of Hydrocarbons in a Fractured

Reservoir and Associated Risks 5387.10.4.1 The Case of Fracturing Followed by

Hydrocarbon Migration 5387.11 Recent Advances in Reservoir Simulation 542

7.11.1 Speed and Accuracy 5427.11.2 New Fluid Flow Equations 5437.11.3 Coupled Fluid Flow and Geo-Mechanical Stress

Model 5457.11.4 Fluid Flow Modeling under Thermal Stress 5477.11.5 Challenges of Modeling Unconventional Gas

Reservoirs 5477.12 Comprehensive Modeling 556

7.12.1 Governing Equations 5567.12.2 Darcy’s Model 5577.12.3 Forchheimer’s Model 5587.12.4 Modified Brinkman’s Model 5617.12.5 The Comprehensive Model 564

7.13 Towards Solving Non-Linear Equations 5687.13.1 Adomian Domain Decomposition Method 5697.13.2 Governing Equations 571

7.14 Adomian Decomposition of Buckley-Leverett Equation 5737.14.1 Discussion 576

Contents xiii

8 Conclusions and Recommendations 5818.1 Concluding Remarks 5818.2 Answers to the Research Questions 582

8.2.1 Is Sustainable Petroleum Technology Possible? 5828.2.2 Why is it Important to Know the Origin

of Petroleum? 5828.2.3 What is the Likelihood of an Organic Source

for Basement Fluids? 5838.2.4 What is the Implication of the Abiogenic Theory

of Hydrocarbon? 5838.2.5 How Important are the Fractures for Basement

Reservoirs? 5838.2.6 What are we Missing Out? 5848.2.7 Predicting the Future? 5848.2.8 What is the Actual Potential of Basement

Hydrocarbons? 584

9 References and Bibliography 587

Index 619

xv

Foreword

The great Western philosopher, Jean-Jacques Rousseau once wrote: “I would rather be a man of paradoxes than a man of prejudices,” as if we are faced with only two options that are: man of uncouth ignorance (who else would entertain paradoxical thinking?) and man of deliberate ignorance (who else would entertain prejudices?) The fact is, modern age is full of examples of such paradoxical and prejudicial thoughts. We are constantly bombarded with fundamentally absurd notions that can be deconstructed with simplest of logic, yet few if any dare question the incessant proclama-tions of these nonsensical theories as ‘laws’. Take, for instance, the centu-ries old teaching that resources are finite, whereas needs are infinite. Where does that put any engineering solutions of pre-Industrial age era that is based on the principle zero-waste? Yes, it makes the time-tested principle of nature-based approach an absurd concept. Yet, we go ahead and define sustainability as the target for any technology development. Is it possible that we don’t understand there is no sustainability without zero-waste or is it that we like to use the word sustainability just because it is fashionable to do so. Then, the case of ad hominem fear mongering that population explosion is the biggest threat to humanity. Before we can catch the breath, we are then told that humans are the greatest creation of all. Then take the case of “grim climate concerns” due to the production of fossil fuel. Why is the fossil fuel all of a sudden a villain. Ah, it’s carbon dioxide, we are told. It’s as if we are to forget that carbon is the most essential component of plants – the very same plants that is in the core of sustainability of the ecosystem.

I know of no other scientist that has done so much in deconstructing the myths of modern era than Prof. Islam, the lead author of this book. His pioneering work includes the introduction of zero-waste engineering and green petroleum – the terms that were considered to be oxymoron when he first introduced them over a decade ago. In this book, he, along with his co-authors, delve into one of the most controversial topics in petroleum

xvi Foreword

engineering. It was long known, basement reservoirs and everything about them cannot be explained with conventional diagenesis models. However, no one dared take on the problem with an approach that would answer all the questions and solve all the paradoxes. Instead, in line with what has become the hallmark of New science, everyone agreed to disagree and settle for a particular branch of the dogmatic process. Prof. Islam charac-teristically takes an entirely different approach. This book gets to the root of the problem by advancing an option radically divergent from both the ‘petroleum is of organic origin no matter what’ and the ‘petroleum is of non-organic origin – no matter what’. With this approach, people would no longer be reduced to “choosing” between the equally paradoxical paths.

This is a unique book that describes Geology with the logic of math-ematics and engineering with the lucidity of fine arts. There is no fallacy, no resorting to dogma and most importantly there is not a single statement that would lead to a paradox. This book gives a great hope in restoring the time-honoured fact that nature’s bounty is infinite and as long human greed is in check, we don’t have to worry about energy needs of mankind.

If there is any shortcoming of this book, it is in the fact that it covers only basement reservoirs. One can envision the theories advanced in this book will be able to explain many phenomena, the scientific explanation of which have eluded all scientists – none of whom has been able to answer all the questions, without resorting to dogma. This book is a masterpiece that belongs to every scientist and engineer that aspires to be educated about the most important energy source of human history.

G.V. ChilingarUniversity of Southern California

1

1Introduction

1.1 Summary

Hydrocarbons and their transformations play major roles in sustaining today’s civilization. Petroleum fluids are essential for providing chemical and energy sectors with raw materials that are needed for practically all aspects of modern living ranging from transportation to health and medi-cine. After water, crude oil is the most abundant naturally occurring fluid on earth. However, the modern era has few direct applications of crude oil and practically none of the produced petroleum is processed, either through refining or gas processing, prior to final use. Unfortunately, all modern techniques for refining are also known to be inherently damaging to the environment. In the information age, environmental sustainability has become the most important concern and there is a growing urge to find either an alternative to petroleum fluids or any technology that ‘mini-mizes’ the environmental impact. While some progress has been made in developing alternate energy sources, few, if any, present a truly sustain-able option. More importantly, no realistic alternate source, sustainable or

2 Hydrocarbons in Basement Formations

otherwise, for millions of tons of chemical raw materials for the chemi-cal/medical industries has been suggested. In this regard, basement res-ervoirs offer an unprecedented opportunity. However, the true benefit of the petroleum fluids produced from basement reservoirs cannot be appre-ciated without thorough scientific understanding of their nature. This is the first textbook that makes a scientific investigation into the nature of basement rock, the origin of the petroleum that impregnates these rocks and how to properly characterize the behavior of these rock/fluid systems. It is shown with clarity that basement fluids are amenable to sustainable petroleum usage and with careful management skills they can become the hallmark of a sustainable source of both energy and chemical raw materi-als. This textbook explains the fundamental features of the hydrocarbons in the basement, geological aspects of fractures and types of fractures, and a novel reservoir characterization technique. Two dominant theories of the origin of basement fluids are presented in detail and arguments made in supporting the validity of these theories within a specific domain. It covers almost all seismic techniques including geological techniques, geophysical tools, micro log analysis and borehole techniques, with a focus on fracture networks. A guideline for scientific characterization is presented in order to determine the ranking of petroleum fluids. This book deals with the interpretation and modeling of the fracture network as well as risk analysis and reserve estimation of these kinds of reservoirs.

1.2 Is Sustainable Petroleum Technology Possible?

Even though petroleum continues to be the world’s most diverse, efficient, and abundant energy source, due to “grim climate concerns”, global initia-tives are pointing toward a “go green” mantra. When it comes to defining ‘green’, numerous schemes are being presented as ‘green’ even though all it means is the source of energy is not carbon. In fact the ‘left’, often embold-ened with ‘scientific evidence’, blames carbon for everything, forgetting that carbon is the most essential component of plants. The ‘right’, on the other hand, deny climate change altogether, stating that it is all part of the natural cycle and there is nothing unusual about the current surge in CO2 in the atmosphere. Both sides ignore the real science behind the process. The left doesn’t recognize the fact that artificial chemicals added during the refining process make the petroleum inherently toxic.

The study of sustainability is a complex science as it involves subsur-face and surface, natural and artificial materials, with very high ratio of unknowns over known information (Figure 1.1). Any false step in the

Introduction 3

process shown in Figure 1.1 can trigger unsustainability. Both the science and the mathematics of the process have been deficient at best.

In 2010, we (Islam et al., 2010) used detailed pathway analysis to iden-tify flaws of various energy production schemes, including petroleum resource development. The source of alteration of CO2 quality that renders the CO2 unabsorbable by the ecosystem was identified for each case. CO2 emission data from the pre-industrial age all the way to the current era are then analyzed, showing a clear correlation between CO2 concentration in the atmosphere with ‘corrupt’ CO2 emission, which itself was a func-tion of the fuel source, the path it travels, isotope numbers, and age of the fuel source. Various energy technologies were ranked based on their long-term sustainability. It was shown that petroleum is the most environmen-tally benign among the energy sources investigated, followed by biofuel, solar, wind, and nuclear. When the artificial chemicals are replaced with natural substitutes at various phases of petroleum processing, petroleum wastes become useful materials that can be recycled in the ecosystem in a zero-waste mode. Not only the by-products, including CO2 emissions, are benign, they are in fact beneficial to the environment. Each of these wastes can then become raw materials for value-added new products. Finally the paper offers guidelines for ‘greening’ of petroleum operations as well as the economics of zero-waste petroleum production and long-term envi-ronmental sustainability. So, if petroleum products are benign and offer

Figure 1.1 Various steps involved in petroleum technology.

TransportationDrilling

Sustainabletechnology

Mystery anduncertainity cloud Reservoir modeling

Necessity ofMathematicalbackground

FormulationDiscretizationLinearization

Avoiding complexityIgnoring role of viscosity

Ignoring time dependency

Revisit riskanalysis

Consideration of complex rheologyUse of “memory”

Addition of 4th

dimension, time

Reservoir formationHydrocarbonproduction

and end user

4 Hydrocarbons in Basement Formations

the greatest hope for sustainable technology, which type of petroleum res-ervoirs are the best of the best? In this book, we disclose the facts about basement reservoirs and demonstrate that basement reservoir fluids are the most beneficial with the greatest possibility of value addition, as long as their processing is done targeting a particular application, uniquely suited for these fluids. Such a study was only possible after scientific characterization of the rock and fluid system.

1.3 Why is it Important to Know the Origin of Petroleum?

Petroleum fluids are synonymous with ‘fossil fuel’ or any fluid with organic origin. It turns out, invoking such a premise limits the ability of properly characterizing petroleum fluids, including the true source. This is partic-ularly true for basement reservoirs that are known to have little resem-blance to conventional fossil fuel. It is no surprise that oil and gas fields in crystalline basement are discovered mostly by accident, usually when the unassuming operator notices hydrocarbon shows. Yet, these reser-voirs can be prolific and the overall estimate of petroleum reserve can go up with revamping of techniques to track basement reservoirs. The stan-dard definition of crystalline basement by petroleum geologists is any metamorphic or igneous rock unconformably overlain by a sedimentary sequence. A somewhat more ‘scientific’ definition is given by Lartdes et al. (1960): “the only major difference between basement rock and the overly-ing sedimentary rock oil deposits is that in the former case the original oil-yielding formation (source rock) cannot underlie the reservoir.” This definition extends the limit of exploratory geological and geophysical stud-ies significantly. However, this definition is still limiting as it suggests that a basement reservoir may be the result of hydrocarbon migration from sedimentary rock to older porous metamorphic or igneous rocks to form a basement reservoir, the likes of which were found in Japan, Mexico and the Maracaibo Basin of Venezuela (Schutter, 2003). As pointed out by Petford & McCafrey (2003), this narration is a mistake. The 1999 Gulf discovery of Suban gas field after penetration sufficiently deeply in the basement rocks proved this point. Similarly, literature is deficient in giving sufficient consideration to mixed convection heating from igneous rocks that can contribute to the maturation process in sediments that have been heated rapidly by magmatic intrusion (e.g., Saxby & Stephenson 1987; Stagpoole & FunnelI 200I; Schutter 2003), making excellent cap rocks (Chert et al., 1999).

Introduction 5

The accurate knowledge of the source of the basement oil is pivotal for two reasons. First, this would create an impetus for broadening the exploration base for basement reservoirs. Secondly, the quality of oil will likely be linked to the source and thereby would open up different oppor-tunities for processing for environmental integrity. The possible sources of basement fluids are investigated for both organic (Chapter 2) and non-organic (Chapter 3) origins. Even more significant discussion is presented in Chapter 5 that shows scientific characterization of these reservoirs must include the accurate source of these fluids, in order to properly identify long-term pathways of various components present as well as applicability of the hydrocarbons in question.

1.4 What is the Likelihood of an Organic Source?

Not long ago, an organic source was the only one considered for defining petroleum fluids. Even though igneous rocks posed an interesting dilemma in terms of how organic matters accumulated there, there was no shortage of dogmatic interpretation of geologic history. However, more questions arise than answers exist concerning hydrocarbons in and around igneous rocks. Figure 1.2 shows the distribution of hydrocarbons in and around igneous rocks. This figure shows that the highest reported occurrences are in basalts, followed by andesite and rhyolite tufts and lavas. Although vol-canic rocks in this survey constitute close to three-quarters of all hydro-carbon-bearing lithotypes, the majority of production and global reserves appears to be confined predominantly to fractured and weathered granitic rocks (Petford & McCafrey, 2003).

In order to make a non-controversial conclusion regarding the source of this hydrocarbon, one would need to have more data on magma com-position as well as the process of hydrocarbon generation in an inorganic setting. However, logical inference allowed us to determine with moderate certainty how much oil is organic in the basement reservoirs.

Chapter 2 establishes a systematic framework for the study of the sources of basement hydrocarbons practical applications that arise. This should include consideration of the relationship to possible source rocks, the mat-uration history, the possible migration pathways, the possible reservoir characteristics and the type of traps likely to be present. In Chapter 2, the fundamental features of the hydrocarbons in basement reservoirs are dis-cussed, along with the source of hydrocarbon, mechanism of formation and types of basement reservoirs are defined and discussed. Logical explanations are provided for each aspect of the theories presented. Finally, the framework

6 Hydrocarbons in Basement Formations

of scientific investigation of the origin of hydrocarbons is laid out in order to facilitate the study of sustainability and the true nature of hydrocarbons.

1.5 What is the Implication of the Abiogenic Theory of Hydrocarbon?

As stated earlier, maturation of organic-rich sediments was considered to be the only source of hydrocarbons in all types of petroleum reservoirs. As early as 1988, Abrajano et al. (1988) discussed an alternate origin in con-junction with natural gas seeps in an ophiolite in the Philippines. Under some circumstances, the serpentinization of ultramafic rocks may pro-duce hydrogen from the reaction of olivine with water; if carbon is also present, methane may be the product. The reaction resembles the Fischer-Tropsch reaction for generating synthetic hydrocarbons (Szatmari 1989). Even though this knowledge existed among scientists of the former Soviet Union for many decades, the notion of non-organic origin of oil was dis-missed in the West as marginal, ‘conspiracy theory’-like notions (Gold and Soter, 1980). Abiotic hydrocarbons from serpentinization or from the mantle may be identified by the anomalous distributions of carbon iso-topes and helium isotope ratios (Abrajano et al. 1988). Giardini & Melton (1981) stated that hydrocarbons with a d13C value more depleted than -18 %o may be abiogenic in origin. This rediscovery of abiogenic hydrocarbons led a series of studies. Sherwood et al. (1988) discussed the origin of CH4

Figure 1.2 The distribution of hydrocarbons in and around igneous rocks according to lithology (from Schutter 2003).

Mixedvolcaniclastic

Granite

Kimberlite

Serpentenite

Peridotite

Syenite/Trachyte Rhyolite(tuffs & lavas)

Andesite

Basalt

Introduction 7

found in the Precambrian crystalline rocks of the Canadian Shield. They noted that the CH4 lacked the characteristic isotopic signature of either organic matter or a mantle source. Some of the CH4 was strongly depleted in deuterium, and some was accompanied by H2, leading the way to theo-rize about serpentinization.

Then came the discoveries of the presence of a huge amount of water in the mantle (Guardian, 2014) leading Islam (2014) to theorize the for-mation of hydrocarbon under numerous conditions, virtually making it a continuous process. Islam (2014) argued that the notion of ‘clean’ energy has to be revised in view of natural processing time for various energy sources. Scientists are still grappling with the origin of the Earth or the universe, some discovering only recently that water was and remains the matrix component for all matter (Pearson et al., 2014). Figure 1.3 shows this depiction. As pointed out by Islam (2014), natural evolution on Earth involved a distinctly different departure point not previously recognized. Pearson et al. (2014) observed a ‘rough diamond’ found along a shallow riverbed in Brazil that unlocked the evidence that a vast “wet zone” deep inside the Earth that could hold as much water as all the world’s oceans put together. This discovery is important for two reasons. Water and carbon are both essential for living organisms. They also mark the beginning and end of a life cycle. All natural energy sources have carbon or require carbon to transform energy in usable form (e.g., photosynthesis).

World petroleum reserve takes on a different meaning if the possibility of abiogenic hydrocarbon is added to the equation.

The resource picture becomes even more interesting when the recent discovery of cyanobacteria that may have been active in all known epochs of life on Earth (Sarsekeyeva et al., 2015) is added. All these considerations and discoveries had to be integrated in a logical discussion. This is done in Chapter 3.

Figure 1.3 Water plays a more significant role in material production than previously anticipated (from the Guardian, March 12, 2014).

2 3

21Ocean

Continent Lowermantle

OuterCore

Water-richzone

Water-richzone

Inner core

Transitionzone

4

5

8 Hydrocarbons in Basement Formations

1.6 How Important are the Fractures for Basement Reservoirs?

Fractures are very common objects in geological systems. This is particu-larly true for basement reservoirs. When open, fractures can account for 99% of the fluid flow through the reservoir, whereas closed fractures make a reservoir unproductive, despite use of massive hydraulic fracturing. There has been tremendous progress over the last decades in terms of remote sensing, with a superflux of new techniques in more recent years. In this, the role of seismic data has been phenomenal. For instance, Freudenreich et al. (2005) used 3D maps of orientation and density derived from seis-mic observations. Other authors use geomechanical models in which the fractures grow during the deformation process – a process that can help reconstitute geologic history. There has been a large number of remote sensing tools that can allow detection of fractures. However, an integrated reservoir characterization technique is still lacking. Chapter 4 presents a comprehensive fracture characterization technique that is also practical. It avoids using statistical processing or linearization of data, instead applying scientifically accurate non-linear filters. All available data are integrated in order to create the most likely picture of the fractured formation.

Chapter 5 consolidates the reservoir characterization technique with case studies. It is shown that the practical reservoir characterization tool can help unlock the mysteries of many basement reservoirs and open exploratory opportunities in previously unknown target areas.

1.7 What are we Missing Out?

It is well known that New science has numerous contradictions and unfounded premises that make it difficult to include a new synthesis. If that is the case, how can we trust the currently used reservoir characteriza-tion tools that are based on New science?

This aspect needs some elaboration. We used the term, ‘New science’ innumerable times in our books. The word ‘New science’ refers to post-Newtonian era that is marked by a focus on tangibles and short-term. In essence, new science promotes a myopic vision, for which the historical background of any event is ignored in favour a time slot that fits the desired outcome of a scientific process. Even though not readily recognized, new science is actually rooted in Dogma science – the ones the likes of Thomas Aquinas introduced. We have demonstrated in our recent books (e.g. Islam et al., 2013, 2015, 2016, 2016a; Islam and Khan, 2012, 2016) how dogmatic notions were preserved by Newton, who claimed to have answers to all

Introduction 9

research questions. First premises of Newton were not more logical than first premises of Thomas Aquinas, yet Newton as well as post-Newton Newtonian fanatics considered Newton’s work as the standard of real sci-ence and proceeded to claim the ultimate knowledge has been achieved for everything. In essence, New science added only ignorance and arrogance of the so-called scientists who were no closer to scientific facts and true knowledge than the likes of Thomas Aquinas.

Figure 1.4 demonstrates how the process worked in the Eurocentric culture. In this transition, Albert Einstein and his notion of Quantum mechanics added another level of hubris. Whatever couldn’t be explained by Newtonian ‘laws’ now was claimed to be crystal clear with the arrival of the concept of Quanta. Yet, none of the claims of quantum mechanics could be verified with experiments or even logical discourse. Instead, a great deal of false confidence is added in order to create an illusion that we are climbing the knowledge ladder, while in fact we only thing we are climbing is the arrogance/ignorance curve at a ever increasing faster rate.

Islam (2014) as well as Khan and Islam (2016) introduced a series of discussions of the fundamental science of mass and energy that enables readers to grasp the concept of natural energy and mass. This forms a back-ground for characterizing basement reservoirs with true science without resorting to dogmatic assumptions. Scientific characterization involves ranking in terms of energy contents as well as diversity of applications.

Chapter 6 introduces a scientific characterization technique that uses paradigm shift in its real sense. The outcome is a refreshing new approach that is practical and prepares one for in-depth understanding of the mech-anisms involved in petroleum reservoirs in general and basement reser-voirs, in particular. The technique relies heavily on whatever is available during the course of the reservoir development and minimizes spending on expensive tools that have little validity in basement reservoirs.

Figure 1.4 New science only added more arrogance, blended with ignorance to Dogma science.

Ignorance/Arroganceblend

Dogmascience

Newscience

New agescience

Time

10 Hydrocarbons in Basement Formations

1.8 Predicting the Future?

Everyone wants to predict the future, but how good is the prediction? In reservoir simulation, the principle of GIGO (garbage in and garbage out) is well known (Rose, 2000). This principle implies that the input data have to be accurate for the simulation results to be acceptable. The petroleum industry has established itself as the pioneer of subsurface data collection (Abou-Kassem et al., 2006). Historically, no other discipline has taken so much care in making sure input data are as accurate as the latest technol-ogy would allow. The recent superflux of technologies dealing with sub-surface mapping, real-time monitoring, and high-speed data transfer is an evidence of the fact that input data in reservoir simulation are not the weak link of reservoir modeling. However, for a modeling process to be meaningful, it must fulfill two criteria, namely, the source has to be true (or real) and the subsequent processing has to be true (Islam et al., 2016). Even though not commonly perceived, modeling comes before execution of any engineering project. The petroleum engineering industry is a cham-pion of modeling. Today, it has the ability to model a reservoir with no less than trillion cells and solve the governing equation within minutes. Only a decade ago, such performance was unthinkable even from supercomput-ers. The problem is not with the speed or the ability to model billions of grid blocks. The problem is not in collecting data and processing them. In fact, Saudi Arabia has set up massive 4D seismic in reservoirs that don’t even employ waterflooding. The problem lies within the fact that none of the unconventional or basement reservoirs follows Darcy’s law – the only equation petroleum engineers have used in the last 160 years. Chapter 7 shows how people tried to cope with this crisis and presents a way out, with practical advice on how to model basement reservoirs.

1.9 What is the Actual Potential of Basement Hydrocarbons?

All the chapters lead to answering this question. It places basement reser-voirs within the big picture of petroleum resources and provides one with a guideline for exploration, exploitation and final environmental impact of basement reservoirs.

The book closes with a list of references and bibliography. This list con-tains hundreds of entries spanning over 40 pages.

11

2Organic Origin of Basement Hydrocarbons

2.0 Introduction

The majority of hydrocarbons found on Earth naturally occur in the form of crude oil or natural gas. After water, petroleum fluids are the most abundant compounds on Earth (Islam, 2014). When organic matters are decomposed naturally they provide for an abundant source of hydrocar-bons.. It is recognized in the literature that there are several specific forms of hydrocarbons:

Dry gas: contains largely methaneWet gas: contains ethane propane, butane.Condensates: Hydrocarbon with a molecular weight such that they are gas in the subsurface where temperatures are high, but condense to liquid when they reach cooler, surface temperatures.Liquid hydrocarbons: commonly known as oil, or crude oil before refining

12 Hydrocarbons in Basement Formations

Plastic hydrocarbons: asphaltSolid hydrocarbons: coal and kerogen, matter in sediments that is insoluble in normal petroleum solvents.Gas hydrates: Solids composed of water molecules sur-rounding gas molecules, usually methane, but also H2S, CO2, and other less common gases.

More than 100,000 types of hydrocarbons are known. The main reason for this diversity is that carbon atoms can unite in many different ways to form complex chains or ring frameworks. Different arrangements of atoms yield different molecules.

Basement reservoirs can be found all over the world, but the follow-ing countries have significant proven reserve in the basement reservoirs (Figure 2.1).

Algeria, Argentina, Brazil, Canada, Chile, China, Egypt, Former USSR, India, Indonesia, Japan, Korea, Libya, Malaysia, Mexico, Morocco, New Zealand, Peru, Thailand, United Kingdom, United States, Venezuela, Vietnam, and Yemen.

Basement rock can be very old, up to 2.5 billion years of age. It is largely hard rock such as granite. The basement rocks are often highly metamor-phosed and complex, with many different types of rock – volcanic, intru-sive igneous and metamorphic. They are considered to be older than the time frame of formation of hydrocarbons in petroleum reservoirs. There are several theories on how hydrocarbons ended up in the basement rocks. Each theory has its shortcomings that will be discussed in this chapter.

Figure 2.1 Basement reservoirs are distributed around the world.