The world contains abundant energy resources. The challenge is extracting and utilizing these resources affordably, in an environmentally responsible way, and in a dense enough form to be useful to humans. The link between energy, the environment, and the economy is unavoidable and involves the geosciences at its core. Carbon-based fuels such as wood, hay, and coal powered human society for millennia. Then, in the early twentieth century, petroleum in various refined forms came into use for lighting, heating, and early combustion engines. Today, fossil fuels—coal, petroleum products, and natural gas—represent an important 85% of the global energy mix, but they are not without challenges. Coal's greatest challenges are environmental: the impact of surface mining; water contamination; discharge of airborne pollutants including sulfur, nitrogen, and mercury; and the emission of CO 2 . The emerging technologies of carbon capture and sequestration may offer the prospect (such as coal-fired of solving one of coal's problems; large, stationary sources of CO 2 power plants) are the most efficient targets for carbon capture. However, capturing CO 2 is expensive. Oil and, to a much lesser degree, natural gas also produce CO 2 and other emissions when combusted. Oil and natural gas require drilling, entailing the associated environmental impacts of oil-field operations; yet there remain considerable global oil and natural gas resources. The current frontiers for conventional oil and natural gas production include ultra-deep water, the Arctic, sediments deposited beneath major salt formations, and other extreme operational environments. As existing and new conventional oil and natural gas reserves decline, unconventional reservoirs—shale gas, coal bed natural gas, tight gas, shale oil, oil shale, oil sands, and perhaps eventually natural gas hydrates—will represent a growing part of the fossil-fuel mix. Nuclear energy—today fission, and tomorrow, perhaps, fusion—is very dense, has no emissions, is highly efficient, and is very affordable on a kilowatt-hour basis. Adoption of nuclear energy is limited by the high initial cost of building a power plant, public perception, issues of waste handling, the fear of proliferation, and the very real need to make reactors safe from natural and human-caused disasters. “Renewable” forms of energy—those that are generated by “renewable” motion such as wind and moving water; or “renewable” sources of heat such as geothermal and solar; or those that are grown such as biofuels—will increase as a proportion of the energy mix. These sources are currently limited in growth rate by their lower energy density and, for some, their intermittency. Intermittency—the wind does not always blow and the sun does not always shine—must be addressed by significant improvements in energy storage technologies: in chemical batteries; as pumped water or compressed air; as heat stored in molten salt, buildings, and other forms; as kinetic energy in flywheels; as electrons in advanced capacitors; or by various other technologies. But these energy storage technologies need to be made efficient, affordable, and scalable before they will be deployed broadly. Because the transition from a fossil-energy present to an alternate-energy future involves the interplay between energy, environment, economy, and policy, almost without exception all forms of energy involve the geosciences. Coal mining requires geologic understanding. Large-scale geologic carbon sequestration, which might someday make coal more environmentally friendly, will rely on a whole new discipline involving advanced subsurface characterization and monitoring. The subsurface understanding and technology required for conventional and unconventional oil and gas exploration and extraction are substantial. From the scale of nanopores to tectonic plates, the use of advanced seismic imaging, ever more-quantified field and laboratory experimentation, airborne remote sensing, and much more is required to unlock the fossil-fuel resources that remain trapped in the Earth. Nuclear energy relies on sources of uranium, plutonium, thorium, and many other mined products. And eventually, geologic repositories will be required to store the waste products of nuclear power generation. In terms of renewable energy, production of biofuels involves soil science, hydrogeology, fertilizers, weather, and climate. Harnessing geothermal energy involves the ability to characterize the subsurface geothermal resource. Generating power from tides and waves involves oceanography and analysis of coastal change. Utilizing wind depends on weather pattern studies and geomorphology for the siting of turbines, as well as the mining of copper, carbon, and other materials. Producing solar energy involves the geosciences, with the need for silicon, gallium, cadmium, copper, and other materials. As large-scale energy-storage solutions become necessary, input from the geosciences will range from characterizing the subsurface for compressed-air storage to mining rare-earth elements for chemical batteries. The involvement of geosciences in energy does not stop with subsurface understanding or the construction of a power plant. “Above-ground” environmental and policy challenges covering the full lifecycle of any form of energy are as great as the “below-ground” technical challenges. Environmental geologists, biologists, energy economists, and policymakers must come together to develop sensible policies and regulatory rules that make it possible for industry, government, academe, and nongovernmental organizations (NGOs) to work together to deliver balanced solutions.

Abstract The global energy marketplace is undergoing a predictable transition from coal in the 19 th century, to oil in the 20 th century, to natural gas and other non-fossil fuels in the 21 st century. Oil as a percentage of total global energy “peaked” in 1979, and thus the 20 th century will undoubtedly be remembered as the golden age of oil. The expansion of natural gas and other lower and non-carbon forms of energy in the 21 st century has far-reaching implications and brings with it a number of favorable outcomes. Natural gas is abundant and is found in more regions than oil; this illustrates energy diversity and security of supply. With substantial growth expected in worldwide LNG in the coming decades, natural gas will have a global delivery infrastructure that will help stabilize energy prices, benefiting the macro-economies of most nations. A global natural gas infrastructure will help make the transition to alternatives smoother. Increased use of natural gas—to replace coal in power generation and oil in transportation—would help reduce atmospheric emissions. A subtle but important corollary to the long-term trend toward natural gas shows an ever greater percentage of natural gas production coming from unconventional resources. One need only look to the United States, where coal-bed methane, shale gas and tight gas now represent over 50% of annual production (a benchmark achieved several years earlier than the Tinker forecast published in a 2004 Oil and Gas Investor article), and estimated unconventional natural gas resources have more than tripled the conventional gas resource base. As in the United States, a significant portion of the world’s remaining natural gas resource is probably unconventional—tight gas, coal-bed gas, shale gas representing technologically proven unconventional resources; and methane hydrates, ultra deep (15,000 to 30,000 ft), and brine gas resources as possible future unconventional components. The bulk of the global unconventional natural gas has not yet been developed, and it represents an enormous untapped resource.

Abstract South Dagger Draw (SDD) field, located in southeast New Mexico, produces hydrocarbons from complex sigmoid-oblique clinoforms of the Pennsylvanian Canyon and Cisco Formations. South Dagger Draw field, a combination structuralstratigraphic trap, represents the northern extension of the Indian Basin field. Through February 2001, the Indian Basin and SDD fields together had produced nearly 23 million bbl of oil and 2 tcf of gas from Marathon Oil Company-held acreage. Vuggy porosity, formed dominantly in algal biostromes and bioherms located at the rampmargin position of each clinoform, represents the primary reservoir. Vugs were formed by acidic hydrothermal fluids that migrated upward along joints and were baffled beneath shales, resulting in dissolution zones that are controlled by the interplay between structural joints and stratigraphic shales and carbonates. Data used in the study include logs, cores, modern wire-line log suites, borehole image logs, and three-dimensional (3-D) acoustic impedance values from inversion of seismic data. Seismic data provide interwell information helpful for determining the present-day structure of the field but not particularly useful for interpreting the stratigraphy. High-frequency sequence-stratigraphic interpretation, guided by a depositional model derived from description of cores and outcrops, was accomplished using a necessary combination of well logs, cores, and seismic data. The sequence-stratigraphic interpretation served as input for multiple iterative seismic inversions and provided the framework for the integrated 3-D geologic model.

Abstract In any modern or ancient carbonate setting, one depositional environment eventually transitions into another, and facies change. Topography is a primary driver of lateral facies change. In a given shelf or ramp profile, carbonate facies tend to be more continuous along strike and more apt to change along dip. If topographic dip is steep, facies change in shorter distances than if topographic dip is gradual. Because facies (1) dictate original petrophysical properties and strongly influence diagenetic alteration, (2) strongly influence petrophysical properties and associated wireline log and seismic responses, and most importantly (3) change within a time-bound package of rock, it is highly unlikely that the correlation of similar wireline log signatures or the tracing of a continuous seismic reflector for great distances will result in an accurate chronostratigraphic interpretation. Although these concepts are widely understood and accepted today, and in spite of ever-improved seismic imaging technologies, accomplishing the feat of building realistic depositional topography into subsurface stratigraphic interpretation remains a difficult task. Even though sequence stratigraphy has revolutionized both exploration and exploitation in the oil industry by showing that chronostratigraphy improves the ability to predict the 3D distribution of reservoir, source, and seal strata, stratigraphers continue to hedge bets towards flat correlation by correlating similar log signatures and carrying continuous seismic reflectors. The only way to avoid this tendency toward the horizontal is to impose a facies-driven model of depositional topography onto the stratigraphic interpretation. An accurate assessment of depositional topography requires a sedimentologic analysis of core and outcrop analog data to determine reasonable water-depth ranges for component facies, and the definition of a hierarchy of stratigraphic cyclicity to determine longer term water-depth variation represented by component facies. Concepts of depositional topography are applied differently for each high-frequency cycle (cycle) as follows: Constructional cycle—Individual cycles should illustrate depositional topography that represents the water depth of the included facies ( i.e. , if a cycle contains a range of facies from tidal flat through 100-ft-water-depth outer ramp facies, then the bounding surfaces should illustrate that topography). Because of the relatively short time duration represented by an individual cycle, each cycle should allow reconstruction of paleobathymetry once compaction/subsidence are removed. Draped cycle—High-frequency cycles that drape preexisting topography will not necessarily show a simple facies to predicted water-depth correlation. Conformable high-frequency sequence (HFS) boundaries—are a composite stratigraphic record of short-term and long-term eustasy, subsidence, sedimentation rate, and compaction, and therefore may not show a direct relationship to facies that are found directly below them but will nonetheless control depositional topography of the facies in the overlying sequence. Disconformable (erosional) HFS boundaries—are not candidates for reconstruction of depositional topography of the underlying facies, but like conformable HFS boundaries, they will control depositional topography of the facies in the overlying sequence. Permian-age outcrops and subsurface datasets from West Texas and New Mexico, representing transitional icehouse-greenhouse systems, provide an excellent starting point to illustrate the importance of depositional topography on stratigraphic interpretation. Eustatic amplitude in transitional icehouse-greenhouse systems was neither too great nor too small, but just right to record a relatively complete stratigraphic signal along the depositional profile. Examples include ramp to steep-rimmed profiles.

Abstract In any modern or ancient carbonate setting, one depositional environment eventually transitions into another, and facies change. Topography is a primary driver of lateral facies change. In a given shelf or ramp profile, carbonate facies tend to be more continuous along strike and more apt to change along dip. If topographic dip is steep, facies change in shorter distances than if topographic dip is gradual. Because facies (1) dictate original petrophysical properties and strongly influence diagenetic alteration, (2) strongly influence petrophysical properties and associated wireline log and seismic responses, and most importantly (3) change within a time-bound package of rock, it is highly unlikely that the correlation of similar wireline log signatures or the tracing of a continuous seismic reflector for great distances will result in an accurate chronostratigraphic interpretation. Although these concepts are widely understood and accepted today, and in spite of ever-improved seismic imaging technologies, accomplishing the feat of building realistic deposi-tional topography into subsurface stratigraphic interpretation remains a difficult task. Even though sequence stratigraphy has revolutionized both exploration and exploitation in the oil industry by showing that chronostratigraphy improves the ability to predict the 3D distribution of reservoir, source, and seal strata, stratigraphers continue to hedge bets towards flat correlation by correlating similar log signatures and carrying continuous seismic reflectors. The only way to avoid this tendency toward the horizontal is to impose a facies-driven model of depositional topography onto the stratigraphic interpretation. An accurate assessment of depositional topography requires a sedimentologic analysis of core and outcrop analog data to determine reasonable water-depth ranges for component facies, and the definition of a hierarchy of stratigraphic cyclicity to determine longer term water-depth variation represented by component facies. Concepts of depositional topography are applied differently for each high-frequency cycle (cycle) as follows: Constructional cycle—Individual cycles should illustrate depositional topography that represents the water depth of the included facies ( i.e ., if a cycle contains a range of facies from tidal flat through 100-ft-water-depth outer ramp facies, then the bounding surfaces should illustrate that topography). Because of the relatively short time duration represented by an individual cycle, each cycle should allow reconstruction of paleobathyme-try once compaction/subsidence are removed. Draped cycle—High-frequency cycles that drape preexisting topography will not necessarily show a simple facies to predicted water-depth correlation. Conformable high-frequency sequence (HFS) boundaries—are a composite strati-graphic record of short-term and long-term eustasy, subsidence, sedimentation rate, and compaction, and therefore may not show a direct relationship to facies that are found directly below them but will nonetheless control depositional topography of the facies in the overlying sequence. Disconformable (erosional) HFS boundaries—are not candidates for reconstruction of depositional topography of the underlying facies, but like conformable HFS boundaries, they will control depositional topography of the facies in the overlying sequence. Permian-age outcrops and subsurface datasets from West Texas and New Mexico, representing transitional icehouse-greenhouse systems, provide an excellent starting point to illustrate the importance of depositional topography on stratigraphic interpretation. Eustatic amplitude in transitional icehouse-greenhouse systems was neither too great nor too small, but just right to record a relatively complete stratigraphic signal along the depositional profile. Examples include ramp to steep-rimmed profiles.

Abstract Three-dimensional geologic models are often described as “products” of the reservoir characterization process, when in fact they might better be considered “tools” for reservoir management. For a 3-D geologic model to be used as a reservoir management tool, it must be a reasonably accurate representation of the rock and fluid system in the earth volume of interest. Integrated 3-D geologic modeling is a highly iterative, hierarchical process. Each step of the workflow builds and is dependent upon prior steps. Each data type used in reservoir characterization results from a unique experiment measuring different volumes of rock. Sophisticated, calculation intensive algorithms, designed to run on powerful hardware systems, are now available to help integrate these different data types. However, hardware and software are only tools, and effective 3-D reservoir modeling must involve an iterative process of geological interpretation, petrophysical analysis, seismic processing and inversion, and application of mathematical algorithms. The iterative reservoir characterization process involves several significant challenges, including defining and adhering to a reasonable workflow, handling multiple data types to fill the interwell volume with petrophysical data that describe reservoir behavior accurately, and testing the 3-D model interpretation. South Dagger Draw field is presented as a case study to demonstrate our reservoir characterization workflow. South Dagger Draw is a Pennsylvanian reservoir located in southeast New Mexico. It produces from vuggy porosity formed along fractures and dominantly in algal mound complexes located at the ramp margin. A detailed sequence-stratigraphic interpretation of logs, cores, predicted facies, and 3-D acoustic impedance data, guided by a depositional model derived from description of cores and outcrops, defined a series of complex sigmoid-oblique, prograding clinoforms. This stratigraphic framework is the input for 3-D geologic modeling. Seismic and log data were integrated into a 3-D Geologic Model using a new approach based on rock physics rather than geostatistics. The approach recognizes that acoustic impedance (AI) values, derived from accurate, iterative inversions of 3-D seismic data, represent the only true measurements of the complete earth volume of interest. Therefore, instead of treating the AI measurements as “soft” data and conditioning the model results to the limited earth sample measured by well logs, the AI data are treated as valid, and the log data are conditioned to the seismic using nonlinear rock and fluid physical equations. The result is a 3-D Geologic Model that acknowledges the error and scale differences inherent in the subsurface data (core description, core analysis, wireline logs, and 3-D seismic), attempts to integrate the data on the basis of physical principles, and provides a forward modeling approach to test the result.

Abstract The spectacular mixed siliciclastic/carbonate exposures of the Guadalupe Mountains include 30 high-frequency sequences (HFS) that stack together to form six composite sequences (CS), the CS9 through CS14. These sequences include carbonate ramps and reef-rimmed platforms as well as basin-restricted lowstand sequences. The Capitan Formation represents the shelf-margin and slope facies tracts of the upper 12 HFS. The Capitan is examined in the context of this late Leonardian-Guadalupian ramp-to-rimmed-shelf system by focusing on extrinsic controls on platform development. Eustatic changes initiate and punctuate larger scale changes in platform evolution. Rapid shifts of large magnitude, such as the latest Leonardian (L7-L8 HFS) eustatic rise, are a first-order control on platform architecture and reef formation. The model for the late Permian eustatic curve based on the present stratigraphic framework suggests that by the time the Capitan was established, eustatic amplitudes were in the range of 20 m or less. This amplitude variation does not cause major shifts in the shelf-margin location but is sufficient to affect critical accommodation factors that influence reef depth and faunal composition. Antecedent topography, whether of tectonic, depositional, erosional, or compactional origin, is the critical parameter in controlling the timing and development of the Capitan and other buildups in the Leonardian-Guadalupian sequences, as well as the primary control driving the ramp-to- rimmed-shelf transition. The shelf-slope break, whether a ramp or rimmed shelf, is only one of numerous geometric parameters that can be used to describe the dynamic evolution of carbonate platforms. Changing styles of carbonate-platform progradation and aggradation, which are responses to changes in platform and basin accommodation and sediment-supply, can be captured using P/A (ratio of progradation to aggradation for a given chronostratigraphic unit) and SMP/A (shelf-margin progradation/aggradation ratio) ratios. P/A values > 25 are characteristic of ramps and lowstand wedges, whereas P/A values < 25 are indicative of either transgressive-dominated ramps or reef-rimmed margins. SMP/A values within the Capitan- equivalent sequences can be used to document the complex but systematic and predictable progradational-aggradational-progradational response of the shelf margin to changing base level. Within the high-frequency sequence framework, other analytical tools, including facies tract substitution and facies proportions, can be used to better constrain interpretations of the dynamic water-depth setting of the Capitan margin and factors controlling its position on the profile. This holistic approach, which draws on relationships from outer-shelf and shelf-crest facies tracts in the interpretation of the Capitan margin, demonstrates the power of a stratigraphic framework for sedimentologic analysis.

Abstract Dip-oriented profiles of the Yates-Capitan shelf margin were independently constructed from exceptional outcrops in McKittrick and Slaughter Canyons in the Guadalupe Mountains of west Texas and southern New Mexico. Comparison of the two profiles reveals significant similarities in the position and character of high-frequency sequence boundaries, the internal architecture of facies tracts and cycle-stacking patterns, and offlap angles of both the shelf and reef. The evolution of the Yates-Capitan shelf margin is recorded by systematic long-term trends in key depositional variables measured on individual high-frequency sequences in each canyon. This comparison of the two profiles, located along strike 25 km apart, provides a three-dimensional model of the extent and variability of genetic components of the Late Permian margin of the Northwest shelf of the Delaware basin. Comparison of the sequence stratigraphic models for the Yates Formation in McKittrick and Slaughter Canyons indicates that four complete high-frequency sequences can be confidently correlated along strike. Fundamental architectural characteristics of the Yates-Capitan shelf margin are evident in the comparative profiles from each canyon. (1) The Yates Formation in both canyons exhibits initial aggradational geometries followed by strong progradational patterns. The volume of the shelf-crest pisolite complex in the Yates progressively expands through time in concert with a reciprocal contraction of the outer-shelf facies tract. The time-equivalent Capitan reef in both canyons exhibits remarkably similar patterns of stepwise alternations of aggradational and progradational growth that relate to changes in high-frequency sequence architecture through time. (2) The thickness of the Yates varies considerably both across the dip of the shelf margin and along strike between the two canyons. The 240%—600% increases in downdip thickness primarily reflect the inherited depositional topography. The thickness variation along the 25-km strike distance may indicate significant lateral variability in subsidence and/or accumulation rate along the Yates-Capitan shelf margin. (3) Several individual siliciclastic beds can be correlated between each canyon, and the distribution of siliciclastics within individual high-frequency sequences exhibits similar patterns of retrogradation, aggradation, and progradation. Correlative facies-stacking patterns integrated with long-term variations in progradation:aggradation ratio and derived offlap angle act as sensitive indicators of relative changes in base level. Comparison of our integrated field observations with subsurface data from the northern Northwest shelf (65–90 km away), Central Basin platform (approximately 150 km away), and Eastern shelf (>300 km away) reveals a consistent, basin-wide pattern of the internal architecture of the high-frequency sequences that compose the Yates Formation. These widespread similarities provide compelling evidence for regional sea-level control on sequence development around the Permian basin.

Abstract This is a course about high-frequency carbonate sequence stratigraphy, and the dramatic impact that accurate stratigraphic interpretation has on the geologic characterization of subsurface carbonate reservoirs. The course, intended to be practical and applied, emphasizes process over theory. The objective of the course is to provide the participant with a set of sequence-stratigraphic tools and techniques that can be used to construct advanced stratigraphic reservoir models from subsurface data. Although there is no interpretive formula for sequence-stratigraphic interpretation, a logical process, or “work flow” for interpretation will be introduced, which can be applied to a variety of depositional and tectonic settings. The process stresses integration, as ultimately it is the integration of all available data that results in a sequence-stratigraphic framework interpretation useful for geologic description at the reservoir scale. The integrated data sets presented in the course result from outcrop and subsurface reservoir studies that the authors participated in during the past decade.

Abstract Modern sequence stratigraphy is a direct outgrowth of the concept of unconformity bound stratigraphic units as proposed by Sloss (1963), with some very important variations. In simplest terms, Sloss’s (1963) sequence stratigraphy was a tool to identify major unconformity-bound packages (e.g., Sauk, Kaskaskia) for the purpose of correlation across large areas of the craton (Fig. 1.1). We now call these 2nd order sequences. The second major evolutionary step in the conceptual evolution to modern sequence stratigraphy was seismic stratigraphy. AAPG Memoir 26 (Payton et al. 1977) captures, in a series of manuscripts by Exxon geologists, a methodology for identifying Slossian type unconformity-bound sequences using reflection seismic data. The emphasis of this methodology was the use of seismic geometry and termination styles to delineate unconformity-bound seismic sequences (Fig. 1.2; Mitchum et al. 1977a, b), derivation of eustatic curves using coastal onlap (Vail et al. 1977a), and global sequence correlation based on biostratigraphic control (Vail et al. 1977b). Another key aspect of this research (Vail et al. 1977c), which was also echoed by Brown and Fisher (1977) among others, was the chronostratigraphic significance of seismic reflectors. The observation that a single shelf-to-basin reflector mimicked a depositional time-line opened the door for sedimentologic analysis of the internal make-up of seismic sequences (Fig. 1.3). This seismic chronostratigraphy led to the third key development, which was concept of sequence stratigraphy. The transition from seismic stratigraphy to sequence stratigraphy represents a major conceptual jump. Focus shifted from global mapping of unconformity-bound packages to the interpretation of

Abstract There are two goals of 1-D analysis, which are somewhat related. The first goal is to use the available wellbore data to establish an initial cycle framework. To interpret a cycle framework, lithofacies data are almost always required, and cores represent the only true source of lithofacies data. The second goal of 1-D analysis is to quantify, integrate, and analyze the available wellbore data. Wireline logs, which represent the vast majority of the 1-D data in a reservoir, must be calibrated with quantified core data before being used for 2-D stratigraphic framework interpretation and in 3-D geologic models.

Abstract Two-dimensional stratigraphic analysis represents the bridge that joins the more familiar ground of 1-D data with the Star Wars genre 3-D reservoir model construction. Although products are coming onto the market as this book is being written that will allow geoscientists to interpret in 3-D space, the truth is that, for several years to come, the comfortable ruler of interpretation and comparison for most geologists will be a rather traditional combination of 2-D cross sections and maps. It is merely a matter of time before managers are sold well prospects using holograms, and fluvial geomorphologists examine the 3-D architecture of ancient river systems using 3-D images of complete channel belts. However, today it is difficult to shake the experience of decades of making structure and isopach maps when it comes down to bottom-line decision making. Symbolic of this phenomenon is STRATAMODEL™’s STRATAMAP™, a module that turns 3-D grid layers into 2-D maps in order that those accustomed to this format of presentation can relate more quickly. We recognize that currently our 3-D space-filling/model building is driven by a 2-D paradigm, and in this chapter we discuss a set of tools to carry out the interpretive process of framework building in 2D. The construction of a solid 3-D model starts with the conversion of 1-D data into 2-D panels of interpreted lithologies and petrophysical properties and mapped surfaces. This 2-D interpretation stage is a fundamental conceptual step that forms the skeleton that is subsequently “filled” in 3-D space using a variety

Abstract The 3-D geologic model is built first in the mind. Computer hardware and software are simply tools that allow for integration and analysis of massive amounts of data, and provide a visualization product for analysis; they are not a substitute for human interpretation and experience. The primary goal of 3-D geologic modeling is to capture the porosity, permeability, and saturation structure of the 3-D earth cube in order to derive a spatial understanding of the interwell heterogeneity. This requires an accurate stratigraphic framework, a reasonable method of data distribution, and a careful analysis of which stratal units actually control fluid flow. For example, a 1-foot thick shale, or a diagenetic carbonate cement barrier, may represent the most important feature to preserve in a 3-D model, but could easily be averaged out in the up-scaling process.

Abstract The construction of a stratigraphic framework for characterizing carbonate reservoirs is the first step in a series of interdependent analytical stages that ultimately yield a three-dimensional reservoir model. The stratigraphic layering scheme provides the constraining boundaries within which data is distributed away from the well bores into the interwell area. The positioning of these guiding surfaces has a primary effect on the quality and integrity of the reservoir model. High-frequency sequence stratigraphy is the methodology for integrating the core-wireline-seismic data into a genetically significant, testable 3-D framework. The emphasis in sequence stratigraphy on grouping genetically linked facies between chronostratigraphically significant surfaces is critical to the model construction process. This is because the sequence framework attempts to mimic the petrophysical layering, which is established in carbonate reservoirs by a cyclic alternation of more-or-less petrophysically-discrete layers. A grasp of the historical underpinning of sequence stratigraphy and an internally consistent terminology of sequences, cycles, and lithostratigraphic units is presented up-front to level the playing field and to help with communication. Good communication can make or break the integration of a new technology such as reservoir-scale sequence stratigraphy. No engineer is interesting in adjusting a simulation grid to capture a maximum flooding surface because this is part of the sequence framework. However, if MFS is a name for a laterally continuous low permeability barrier that extends across 90 percent of the reservoir, the chances that grids will be bent to account for this feature are increased substantially. The process of interpreting the reservoir volume

Abstract Sequence Stratigraphy and Characterization of Carbonate Reservoirs - Reservoir management is an important topic in the oil industry today. Conferences, forums, short courses, and technical papers, written and attended by engineers, geologists, geophysicists, petrophysicists, and managers discuss various aspects of reservoir management. A critical component of reservoir management is the accurate characterization of the hydrocarbon asset, called reservoir characterization. The topic of this course is the process of sequence-stratigraphic interpretation and characterization of carbonate reservoirs. Because of the overwhelming mass of information most reservoir geoscientists keep up with either some aspects of sequence-stratigraphy, or some aspects of reservoir characterization, but typically not both. The authors believe that the two disciplines are so intimately related that the sequence framework should be considered a critical piece of the integrated puzzle.