Abstract Although one of the most extensively surveyed areas on earth, there remains extensive debate on the origin, nature and evolution of the crust in the deep Gulf of Mexico (GoM). Key reasons include a lack of basement penetration by drilling (reflecting the thick sediment cover that makes the basin prospective), and inadequate deep imaging data from seismic refraction, magneto-tellurics, and other geophysical techniques. The interpretation of potential fields data is complicated but can provide important constraints on deep crustal structure when combined with analysis of the shape and stratigraphic fill of the basin. The geometry and the nature of the Mohorovicic Discontinuity (Moho) can be constrained using an integrated and iterative approach that considers lithospheric flexure and isostasy, melt generation as a function of crustal thinning, and dynamic topography while honoring the gravity and the refraction data.

Abstract Tor H. Nilsen, a red-haired Scandinavian who stood more than six feet tall, died October 9, 2005, at his San Carlos, California, home. This was after a valiant five-year fight with melanoma cancer. He was 63. His ashes were scattered at his family plot in Norway in 2006. He was born in New York City on November 29, 1941, to Mollie Abrahamson and Nils Marius Nilsen of Mandal, Norway, and was the first of their children to be born in the United States. After graduating from Brooklyn Tech, he earned his B.S. in geology from City College of New York in 1962. While there, his prowess on the basketball court impressed a scout from the New York Knicks, but Tor went on to graduate school and earned his M.S. and Ph.D. degrees in geology from the University of Wisconsin at Madison in 1964 and 1967, respectively. His M.S. thesis was a study of Precambrian metasedimentary deposits in the Lake Superior area, and his Ph.D. thesis was a study of Devonian alluvial-fan deposits of the Old Red Sandstone in western Norway. Dr. Nilsen’s principal expertise was in depositional systems analysis, stratigraphic analysis, and the relationships among tectonics, eustasy, and sedimentation. He began his industry career in 1967 as a research geologist with the Shell Development Company in Houston, Texas, and Ventura, California, where he worked on the tectonics and sedimentation of Tertiary shelf systems of coastal California. He subsequently spent two years with the U.S. Army Corps of Engineers as the Military

Abstract AAPG Studies in Geology 56, Atlas of Deep-water Outcrops, is a much-needed volume that provides a compendium of many of the world’s best outcrops of deep-water, clastic depositional systems. Outcrops have long been the “tool of the trade” for geologists trying to better understand the architecture, facies, and evolution of deep-water depositional systems. Most importantly, outcrops serve as accessible examples of deep-water systems that can be studied at a range of scales as analogs for the buried but economically important deep-water systems that are the targets of modern hydrocarbon exploration. Today, seismic studies of the sea floor and underlying sediments along modern deep-water continental margins in the Gulf of Mexico, Brazil, the North Sea, West Africa, Indonesia, and other key areas paint rather detailed pictures of basin- to reservoir-scale architecture of deep-water systems. Although one-dimensional cores and logs from these areas provide limited views of features at a fine scale, there remains a resolution gap that complicates predictions of deep-water lithofacies and heterogeneity at intrafield scales. General recognition of this gap, emphasized as early as the mid 1980s in the COMFAN (Committee on Fans) meeting volume (Normark et al., 1983-1984; Bouma et al., 1985) and coupled with the increased needs of the petroleum industry, catalyzed a flurry of academic and industry studies of deep-water outcrops that might provide appropriately scaled analogs for subsurface deep-water reservoir systems. These outcrop studies, conducted around the world, greatly enhance our understanding of deep-water processes and the reservoir-scale architecture of deep-water deposits. However, selecting and

Abstract The Atlas of Deep-Water Outcrops (AAPG Studies in Geology 56) is a collection of both qualitative and quantitative data on deep-water outcrops from around the world that includes all seven continents and 21 countries ( Figure 1 ; Table 1 ). These outcrops also span most of the geologic time scale ( Table 2 ). The Atlas includes both a hardcopy version and CD. The hardcopy version presents data on 103 separate outcrops as well as summary overview papers on those areas with multiple outcrops. Other papers are on selected topics that summarize the types of deep-water deposits, seismic modeling of outcrops, current outcrop study techniques, use of outcrop data in reservoir modeling, and special types of deep-water deposits such as injectites. The companion CD includes 38 journal-style articles on the overview topics and more detailed reviews of selected outcrops. There are many individual and summary publications on deep-water fields and reservoirs, outcrops, and on modern submarine analogs. The goal of this publication is to not repeat but to build on this previous work by providing new and consistent data that more fully describe the various architectures present in deep-water outcrop deposits. This Atlas provides the first collection of quantitative architectural data on deep-water outcrops that may be used for reservoir modeling. The hardcopy version is designed with a standard format for the presentation of key outcrop descriptive information (Executive Summary, location maps, geologic setting, photomosaics, etc.) and quantitative data (statistics in a spreadsheet format such as bed thicknesses, bed lengths, net-to-gross

Abstract Exploration and production (E&P) in deep water (500-2000 m [1640-6560 ft]) and ultra-deep-water (>2000 m [>6560 ft]) settings have expanded greatly during the past 20 years, to the point at which they are now major components of the petroleum industry’s upstream budgets. Most exploration and production activity has concentrated in only three areas of the world: the northern Gulf of Mexico, offshore Brazil, and offshore West Africa, although activity is increasing in several new areas. Globally, deep water remains an immature frontier, with many deep-water sedimentary basins being only lightly explored. Although deep-water discoveries account for less than 5% of the current worldwide oil-equivalent resources, the amount is increasing rapidly. Importantly, these resources are primarily oil; gas exploration is immature, reflecting infrastructure and economic limitations. There have been at least 42 giant fields (>500 million BOE) discovered in deep water. By year end 2003, approximately 78 billion BOE of total resources had been discovered in deep water from 18 basins on six continents. This total consists of 48 BBO and condensate and 174 TCFG. Deep water contains 85% of the reserves and ultra-deep water has 15%. The immaturity of the play is illustrated by the fact that >50% of the reserves have been discovered since 1995, with 31% being developed and 5% produced. The exploration success ratio, particularly in basins such as the northern Gulf of Mexico and offshore West Africa, has been increasing. Most of these successes are in settings with younger (Cenozoic, mostly Neogene) sandstone reservoirs with direct

Abstract Since initial exploration success more than a century ago in onshore California, more than 872 discoveries with total reserves >137 billion barrels oil equivalent (BBOE) have been made in deep-water deposits. A rapid increase in such discoveries began in the 1970s and more than 350 are expected in this decade based on historic trends. More than 80% of these discoveries are in offshore basins. North America dominates the number of total discoveries as well as reserves but there is an increasing number of African and Brazilian discoveries and fields. Reservoir rocks range in age from Ordovi-cian to Pleistocene. However, more than 90% are in Cretaceous or younger rocks. Passive margins have been the setting for most of these accumulations, and most are in slope depositional environments. However, recent technological advances allowing drilling in deeper waters will lead to more discoveries in lower slope to basin depositional environments. Further statistics on hydrocarbons, reservoir drive, trap types, porosity, and hydrocarbon column heights are discussed from a commercially available database compiled by Cossey and Associates Inc.

Abstract In this study, our aim is to show that new measuring and visualization techniques can have large implications for the future application of outcrop data. First, we review different techniques that can be used to collect digital outcrop data. We especially focus on outcrop capture methods such as photorealistic, 3-D digital outcrop models. These models can be rendered with stunning verisimilitude even on laptop computers. We show some of the applications of photorealistic outcrop models, focusing on how the models can be used directly in a virtual reality (VR) environment to produce sophisticated reservoir models with high accuracy. Finally, we show how the captured digital rocks can be visualized synchronously with the modeled ones. The benefits of visualizing the real world and the model at the same time and in an immersive visualization environment are significant, particularly as a platform for multidisciplinary discussions. A part of this study is based on the Eocene Ainsa Turbidite System in the Spanish Pyrenees. More details of this turbidite system are provided in this Atlas in other papers. The outcrops are located along two flanks of a syncline (the Buil Syncline), and are basically two-dimensional. Therefore, one is forced to make a number of conceptual interpretations on the location and nature of the turbidite system in the subcrop between these two flanks. Other workers have contrasting views on this turbidite system. The aim here is not to claim a perfect model of the studied outcrops (which is impossible due to their nature), but to

Abstract Seismic forward models of turbidite outcrop sections have been created to illustrate how reservoir architecture details may be expressed within the scale of resolution of commonly available, marine seismic data. These can be instructive for refining seismic interpretations and recognizing uncertainties inherent in those interpretations. Outcrop sections having sufficient length and thickness were digitized at a bed scale to generate models (Table 1). These cover a variety of sheet, channel, and mixed architecture styles. The outcrop sections were derived from various sources (Table 1) ; additional outcrops are discussed in the full-length version of this paper on the CD-ROM in the back of this book (chapter 119). The sections were digitized at the finest resolution possible. This usually approximated bed scale; however, very thin, heterolithic laminae were usually lumped together as thin-bed facies. The models are relatively simple, noise-free, normal-incidence, synthetic seismograms. Velocity and density were assigned by facies and given values typical of oil-saturated sands in Gulf of Mexico Tertiary minibasin settings (Table 2). The geometries are, therefore, geologically realistic. However, in real subsurface reservoirs there is likely to be more rock property variation within facies, and also more noise in the seismic response. Shear-wave rock properties or amplitude vs. offset are not considered in the models shown here. The workflow is illustrated in Figure 1. Testing the seismic response of a single geometry assuming different acoustic contrast and velocity can be instructive. We looked at the seismic response of outcrop sections

Abstract A 3-D geological model was constructed from a 3-D outcrop for reservoir flow simulation that can address the effects of small-scale (subseismic), interwell heterogeneities on production in analog deep-water oil and gas reservoirs. The dimensions of the Hollywood Quarry, Arkansas (Figure 1) , are 380 x 250 x 25 m (1247 x 821 x 83 ft) ( Figures 2 , 3 ). The quarry exposes in 3-D the upper Jackfork Group turbidites, which ate often used as an outcrop analog for deep-water reservoirs in the Gulf of Mexico and elsewhere. A variety of turbidite facies are present: lenticular, channelized sandstones, pebbly sandstones, and conglomerates within shales (CI); laterally continuous, interbedded thin sandstones and shales (SI, S2); and thicker, laterally continuous shales (Ml, M2). Sandstone and shale beds are folded and cut by strike-slip faults with a vertical component. These combinations of structural elements and facies have resulted in a stratigraphic interval that is highly compartmentalized, both horizontally and vertically. The quarry is used here as an analog to a variety of subsurface reservoir types. Techniques used to characterize the quarry include behind-outcrop coring, outcrop gamma-ray (GR) logging, measured stratigraphic sections, sequential photography of the quarry walls, Digital Orthophoto-Quadrangle (DOQ) mapping, Ground Penetrating Radar (GPR), Global Positioning System (GPS), shallow, high-resolution seismic reflection, and GPS laser-gun positioning of geologic features in 3-D space. The west wall has been quarried back within 0.5 m (1.6 ft) of the first inline of an earlier 3-D GPR survey and coring operation. The

Abstract The occurrence of sand injectites is well documented in many hydrocarbon-bearing, deep-water clastic reservoirs. In some fields, injectite sand bodies, and depositional sand bodies that have been modified by liquefaction and fluidization, hold major reserves. These fields were not drilled as sand injectite prospects, but the significance of the injectites became apparent during field appraisal and/or development. However, the first exploration well that deliberately targeted a sand injectite was drilled as recently as 2004 ( Rawlinson et al., 2005 ). Thus, sand injectites (intrusive traps sensu Hurst et al., 2005) constitute a virtually unexplored trapping style. We believe that many sand injectites are routinely overlooked and/or misinterpreted in subsurface studies. Further, if identified, their significance is frequently underestimated and, except where we know their significance, are not incorporated into static or dynamic models of reservoir performance. We provide illustrations of some of the most spectacular known outcrops of sand injectites, which may be analogs for subsurface reservoir and intrareservoir-scale occurrences.

Abstract During the Mesozoic, the present-day Antarctic Peninsula was the site of an active volcanic arc related to the eastwards subduc-tion of proto-Pacific oceanic crust. Alexander Island is the largest of the many islands that lie on the western (forearc) side of the Antarctic Peninsula. The island is comprised of a greenschist facies, accretionary prism complex (LeMay Group), unconformably overlain and faulted against the forearc sedimentary deposits of the Fossil Bluff Group. The Fossil Bluff Group ranges in age from Middle Jurassic to latest Early Cretaceous and has a stratigraphic thickness of 7 km (4.4 mi). Aalonian-Tithonian clastic units are derived from the accretionary complex, recording the transition from trench-slope to forearc basin sedimentation. The upper formations represent a large-scale, shallowing-upwards cycle of Kimmeridgian to Albian age, with a volcanic arc provenance. The Himalia Ridge Formation is a 2.2 km (1.4 mi)-thick sequence of Late Jurassic to Early Cretaceous conglomerates, immature arkosic sandstones, and mudstones, derived from an andesitic volcanic arc, and deposited in a north-south elongate forearc basin. At the type locality (Himalia Ridge on Ganymede Heights), the formation was deposited as a series of migrating, conglomerate-filled, innet-fan channels and associated overbank-crevasse-splay sheet sands, thin-bedded levees, and interchannel mudstones flanking the basin matgin. The basin was inverted within a strike-slip regime in the middle Cretaceous, and the sttata deformed into a broad monocline with associated thrusting. At Himalia Ridge, the formation is exposed as a continuous section dipping southeast at about 30°. The upper part of the formation is repeated

Abstract Fjords can become so overdeepened below sea level during protracted glaciations that they fill with hundreds of meters (>1000 ft) of seawater when glacioeustatic rise occurs during and following deglaciation. Fjords, therefore, can host true deep-water environments, which are commonly laterally confined but longitudinally extensive. Outcrops of ancient paleofjord sediments offer three-dimensional views of the evolution of these deep-water, confined sedimentary environments, where the factors controlling sediment supply are both climatic (deglaciation and eustasy) and tectonic (isostatic rebound). Quebrada de las Lajas, near San Juan, western Argentina, preserves a Pennsylvanian glacial to postglacial succession that was deposited in an over-deepened paleofjord. The sedimentary succession exposed in the paleofjord is divided into four evolutionary stages: Stage I was an ice-contact delta and proglacial lake, Stage II was a relatively quiet, deep-water marine environment punctuated by turbidity currents, Stage III was an aggradational confined sheet system, and Stage IV was the subaqueous portion of a progradational, coarsening- and shoaling-upward fan delta. The entire sedimentary succession comprises approximately 350 m (1150 ft) of remaining exposed thickness. Each of the four evolutionary stages has distinct architectural characteristics associated with its depositional environment. Stage I is chatacterized by predominandy lobe-shaped, sheetlike conglomerate and sandstone bodies associated with the ice-contact delta and a subaqueous fan. Stage I also preserves several small, turbidite channel bodies and a small-scale, highly aggradational channel-levee system with a conglomeratic channel axis and thin-bedded sandstone and siltstone levees. Stage II is characterized by thin beds of shale and siltstone punctuated by medium

Abstract The Cambrian Donkey Bore Syncline exposes a salt-withdrawal minibasin filled with more than 500 m (1640 ft) of clastic sediments in the northern part of the Flinders Ranges, South Australia. The minibasin formed in the Early Cambrian as the Adelaide geosyncline passive margin was inverted. Analysis of salt geometries within the Flinders Ranges suggests that the Delamerian orogeny may have commenced during the latest Proterozoic (Mark G. Rowan and Bruno C. Vendeville, personal communication, 2006). If true, movement of the Willouran-aged Callanna Group salt would have been enhanced by shortening-induced folding and diapir squeezing. The doubly folded syncline exposes shallowly dipping sediments along its three limbs across an area of approximately 21 km 2 (8 mi 2 ) next to the Wirrealpa Diapir. The minibasin was situated on the upper slope, most likely below storm wave base. It was flanked to the south by a shallow-marine clastic depositional environment during deep-water sandstone (Bunkers Sandstone) deposition. Paleocurrent data within the basin as well as the axes of slumped sandstone beds indicate sediment input from the south. The main deep-water sediments of the Bunkers Sandstone are up to 350 m (1150 ft) thick. They have an overall net-to-gross of approximately 30% and form a transgressive package with each unit becoming successively less sand-rich. Three classes of architectural elements, ranging in thickness from 50-90 m (164-295 ft), are present in outcrop. These include 1) sandstone-rich sheets with a net-to-gross of up to 70% (Unit A), 2) sandstone-rich thin beds with net-to-gross of up to 60%

Abstract The West Crocker Formation is a major, basin-floor, submarine-fan complex that was deposited in an accretionary foredeep basin during the Oligocene to early Miocene (20–37 Ma) in the South china Sea and adjacent onshore Borneo (Figure 1) . This sandstone-dominated succession is several kilometers thick (2.0 m), but may be up to 10 km (6.2 mi). It is more than 25,000 km 2 (9652 mi 2 ) in extent, and is exposed across a large part of the coastal ranges of Sabah, east Malaysia ( Figures 2 , 3 ). In terms of its size and extent, the West Crocker deep-water turbidite system, which forms part of the Crocker-Rajang fold belt, is comparable to other world-class modern and ancient turbidite systems. However, it is relatively poorly known (Stauffer, 1976; Tongkul, 1987 ; Crevello, 2002 ). This study focuses on the nature of the sedimentary facies and high-frequency depositional sequences. It is based on inland outcrops (quarries and road sections) in the vicinity of Kota Kinabalu (Figure 3) , where the West Crocker Formation occurs as a series of steeply dipping, north-northeast- to south-southwest-trending, thrust-bounded outcrops. Although thrust faults typically define the bases and tops of the individual outcrop segments, the vertical sections that have been logged for this study are extensive (-150–300 m [492–984 ft] long) and contain only minor internal faulting. Hence, the latter has negligible impact on the interpretation of the stratigraphic elements. The outcrops are aligned along regional strike for -100 km (-62 mi), from north to south,