Outcrops Revitalized: Tools, Techniques and Applications Ole J. Martinsen, Andrew J. Pulham, Peter D.W. Haughton, and Morgan D. Sullivan, Editors
CONTENTS Dedication to Kristian Søegaard ................................................................................................................................................................................................... fmiii
Introduction Outcrops Revitalized—Tools, Techniques and Applications: An Introduction OLE J. MARTINSEN, ANDREW J. PULHAM, PETER D.W. HAUGHTON, AND MORGAN D. SULLIVAN......................... 3
Tools and Techniques Outcrops Revitalized: Past, Present, and Future Uses JOHN THURMOND .................................................................................................................................................................... 15 The Geometric Interrelationships of Outcrops and Rock Bodies: Setting Up and Testing Quantitative Hypotheses JOHN C. TIPPER ......................................................................................................................................................................... 21 Extending Digital Outcrop Geology into the Subsurface RICHARD R. JONES, JAMIE K. PRINGLE, KENNETH J.W. MCCAFFREY, JONATHAN IMBER, RUTH H. WIGHTMAN, JIULIN GUO, AND JONATHAN J. LONG................................................................................................................................... 31 Half-Graben-Scale Geocellular Outcrop Modelling of Rift Initiation Strata from LIDAR-Based Digital Outcrop Data: The Nukhul Syncline, Suez Rift, Egypt PAUL WILSON, DAVID HODGETTS, FRANKLIN RARITY, ROB L. GAWTHORPE, AND IAN R. SHARP ...................... 51 Seismic Modeling of Outcrop Analogues: Techniques and Applications KRISTINA BAKKE, STEEN AGERLIN PETERSEN, OLE JACOB MARTINSEN, TOR ARNE JOHANSEN, TROND LIEN, AND JOHN THURMOND ............................................................................................................................................................. 69 3-D Forward Seismic Model of an Outcrop-Based Geocellular Model XAVIER JANSON AND SERGEY FOMEL ................................................................................................................................. 87 The Automated Interpretation of Photorealistic Outcrop Models ERIK MONSEN, DAVID WILLIAM HUNT, AICHA BOUNAIM, BE´RENGE`RE SAVARY-SISMONDINI, TROND BRENNA, MICHAEL NICKEL, LARS SONNELAND, JOHN BERNARD THURMOND, AND PAUL GILLESPIE............................. 107 Fractures in Carbonates: From Digital Outcrops to Mechanical Models PAUL GILLESPIE, ERIK MONSEN, LAURENT MAERTEN, DAVID HUNT, JOHN THURMOND, AND DEAN TUCK .... 137 Numerical Modeling of Deepwater Channel Stacking Pattern from Outcrop and the Quantification of Reservoir Significance MICHAEL J. PYRCZ, TIMOTHY MCHARGUE, MORGAN SULLIVAN, JULIAN CLARK, NICHOLAS DRINKWATER, ANDREA FILDANI, HENRY POSAMENTIER, BRIAN ROMANS, AND MARGE LEVY .................................................. 149
Applications Event-Based Modeling of Turbidite Channel Fill, Channel Stacking Pattern, and Net Sand Volume TIM MCHARGUE, MICHAEL J. PYRCZ, MORGAN D. SULLIVAN, JULIAN CLARK, ANDREA FILDANI, MARJORIE LEVY, NICHOLAS DRINKWATER, HENRY POSAMENTIER, BRIAN ROMANS, AND JACOB COVAULT ................... 163 Characterization of Fault-Related Dolomite Bodies in Carbonate Reservoirs Using LIDAR Scanning JULIETTE LAMARCHE, JEAN BORGOMANO, BRUNO CALINE, FRANCK GISQUET, SYLVAIN RIGAUD, STEFAN ¨ DER, AND SOPHIE VISEUR ........................................................................................................................................ 175 SCHRO Numerical Outcrop Geology Applied to Stratigraphical Modeling of Ancient Carbonate Platforms: The Lower Cretaceous Vercors Carbonate Platform (SE France) RE´MY RICHET, JEAN BORGOMANO, ERWIN W. ADAMS, JEAN-PIERRE MASSE, AND SOPHIE VISEUR ............... 195 Application of Terrestrial LIDAR to Upper Silurian, Shallow-Marine Outcrops, Southern Libya—Implications for Subsurface Exploration DIRK RADIES, MICHAEL SCHERER, AND ROBERT KOEHAZY....................................................................................... 211 Outcrop-Based GPR Tomography Through Braided-Stream Deposits GINNY L. RUST, GARY S. WEISSMAN, ULRIKE WERBAN, JEDEDIAH D. FRECHETTE, AND TIMOTHY F. WAWRZYNIEC.......................................................................................................................................................................... 227 Processing of Outcrop-Based LIDAR Imagery to Characterize Heterogeneity for Groundwater Models ELIZABETH M. NICHOLS, GARY S. WEISSMAN, TIMOTHY F. WAWRZYNEIC, JEDEDIAH D. FRECHETTE, AND KATHERINE A. KLISE............................................................................................................................................................. 239 A High-Resolution Study of Depositional Facies and Architecture of Fords Branch Outcrop: A Middle Pennsylvanian Sedimentary Sequence near Pikeville, Kentucky, U.S.A. SUMANTA K. CHATTERJEE, ARTHUR D. COHEN, AND CHRISTOPHER G. ST. C. KENDALL .................................... 249
OUTCROPS REVITALIZED: PAST, PRESENT, AND FUTURE USES JOHN THURMOND Statoil Research Center Bergen, Bergen, Norway e‐mail:
[email protected] ABSTRACT: The ultimate goal of collecting outcrop data is to be able to understand the underlying physical controls on the formation of the rock record, and these techniques provide an essential step in the right direction towards this goal. In particular, development of new techniques for acquiring data from outcrops has led to an ongoing evolution in how outcrop data can be analyzed and utilized in the petroleum industry. Understanding which technique to use depends strongly on the problem being addressed, as the choice of techniques provides different cost‐benefit outcomes to different problems. The key to adopting these techniques successfully is to understand their limitations and where the successes have been in applying them. This brief review defines the problems being addressed in collecting outcrop data, examines the role of the ‘‘digital’’ geologist and the collection, application, and deployment of three‐dimensional data, and the future of outcrop studies. Reference is made to case studies described in other contributions in this volume.
THE GEOMETRIC INTERRELATIONSHIPS OF OUTCROPS AND ROCK BODIES: SETTING UP AND TESTING QUANTITATIVE HYPOTHESES JOHN C. TIPPER Institut für Geowissenschaften—Geologie, Albert‐Ludwigs‐Universität, Freiburg in Breisgau, Germany e‐mail:
[email protected]‐freiburg.de ABSTRACT: An outcrop’s geometry will always have an effect on how data from that outcrop are interpreted; therefore those data should be used only when the implications of that geometry have been taken fully into account. Problems inevitably arise whenever the geologist attempts to do this, the greatest of which stems from the uncertainty that necessarily exists in the position and orientation of the outcrop relative to the underlying rock body. This problem is best handled by means of a hypothesis‐ based approach for outcrop interpretation, for instance by using one of the three techniques outlined in this paper. The first of these techniques—the use of geometric probability arguments—is illustrated here in the context of recognizing clinoforms in outcrop. It is shown that clinoforms will rarely be seen as sigmoid‐shaped curves on randomly positioned and randomly oriented outcrop faces; they are more likely to be seen as simple convex‐up or concave‐up curves. The second technique—the use of Monte Carlo methods—is illustrated in the context of interpreting dog‐legged outcrops in flat‐lying sedimentary successions. It is shown that the probability of failing to recognize simple features on the face of dog‐ legged outcrops can be high, and that this failure probability is highest for relatively long and sinuous outcrops with relatively many segments. This result conflicts totally with conventional geological wisdom. The third technique—the use of standard statistical tests—is illustrated by showing how isolated outcrops can be used to test correlation hypotheses in areas of broken exposure. The paper warns of the danger of conflating rock body and outcrop, then finally offers guidance on hypothesis selection.
EXTENDING DIGITAL OUTCROP GEOLOGY INTO THE SUBSURFACE RICHARD R. JONES Geospatial Research Ltd, Department of Earth Sciences, University of Durham, Durham, DH1 3LE, U.K. e‐mail: richard@geospatial‐research.com JAMIE K. PRINGLE School of Physical Sciences & Geography, Keele University, Keele, Staffs. ST5 5BG, U.K. KENNETH J.W. MCCAFFREY Geospatial Research Ltd, Department of Earth Sciences, University of Durham, Durham, DH1 3LE, U.K. JONATHAN IMBER Department of Earth Sciences, University of Durham, Durham, DH1 3LE, U.K. RUTH H. WIGHTMAN Department of Earth Sciences, University of Durham, Durham, DH1 3LE, U.K. Present address: Midland Valley Exploration Ltd, 144 West George Street, Glasgow, G2 2HG, U.K. JIULIN GUO Department of Earth Sciences, University of Durham, Durham, DH1 3LE, U.K. Present address: BP Exploration, Farburn Industrial Estate, Dyce, Aberdeen, AB21 7PB, U.K.
AND
JONATHAN J. LONG Department of Earth Sciences, University of Durham, Durham, DH1 3LE, U.K. ABSTRACT: Digital survey methods, including terrestrial laser scanning (LIDAR) and differential GPS, allow geological and topographic data from outcrops to be recorded very rapidly, in 3D, at detailed resolutions and with high spatial precision. Geological interpretations of outcrop datasets (e.g., fault or bedding traces) can be extended into the subsurface using geometric, probabilistic, or deterministic methods. Geometric methods based on interpolation and extrapolation of observed surfaces and surface traces are generally associated with high uncertainty. This can be reduced in areas of highly irregular topography. Another approach is to use geological heuristics to constrain the subsurface interpretation. This approach can help to limit the number of possible interpretations when creating multiple realizations. Deterministic methods encompass both invasive and non‐invasive approaches. Invasive methods include mining and quarrying, as well as small‐scale excavation of unconsolidated sediments. Behind‐the‐outcrop boreholes are only slightly invasive, and can provide very useful constraint of the subsurface. In contrast, geophysical methods such as near‐surface seismics and ground penetrating radar (GPR) allow indirect imaging of the subsurface and are non‐invasive.
Excellent coastal exposures of Namurian turbidites near the Bridge of Ross in County Clare, western Ireland, provide a case study in which several different types of digital outcrop data are combined and co‐visualized in a 3D model. In vertical sections on opposite sides of the outcrop a small‐scale turbidite channel is marked by an erosional base and inclined interbedded sandstones and mud‐clast conglomerates. The observed channel margins can be traced through the subsurface using 3D GPR.
HALF‐GRABEN‐SCALE GEOCELLULAR OUTCROP MODELLING OF RIFT INITIATION STRATA FROM LIDAR‐BASED DIGITAL OUTCROP DATA: THE NUKHUL SYNCLINE, SUEZ RIFT, EGYPT PAUL WILSON, DAVID HODGETTS, AND FRANKLIN RARITY Basin Studies and Petroleum Geoscience, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Williamson Building, Oxford Road, Manchester, M13 9PL, U.K. e‐mail:
[email protected] ROB L. GAWTHORPE Department of Earth Science, University of Bergen, P.O. Box 7803, Bergen, N‐5020, Norway
AND
IAN R. SHARP Statoil Research Center, Sandsliveien 90, Bergen, N‐5020, Norway ABSTRACT: The Nukhul Formation (Suez rift) consists of fluvial and tidally influenced shallow marine strata that were deposited in fault‐controlled seaways and tidal embayments during rift initiation. In this study, we create a half‐graben‐scale, high‐resolution (typical grid cell dimensions 20 m x 20m x 8 m) when the signal dissipated before reaching the receiver. Air‐ time arrivals that were observed compared favorably to model predictions based on LIDAR‐derived outcrop geometry, supporting the utility of LIDAR for constructing a digital, 3D outcrop. Furthermore, estimated values of radar velocity for this outcrop of 0.09 to 0.12 m/ns reasonably match known velocities for similar sediment. Had the GPR data acquisition been more successful at this outcrop site, we could have used detailed 3D facies architecture derived from the LIDAR data to assess the influence of sediment heterogeneity and anisotropy on GPR tomographic signals.
PROCESSING OF OUTCROP‐BASED LIDAR IMAGERY TO CHARACTERIZE HETEROGENEITY FOR GROUNDWATER MODELS ELIZABETH M. NICHOLS, GARY S. WEISSMANN, TIMOTHY F. WAWRZYNIEC, AND JEDEDIAH D. FRECHETTE University of New Mexico, Department of Earth and Planetary Sciences, MSC03 2040, 1 University of New Mexico, Albuquerque, NM 87131, U.S.A.
AND
KATHERINE A. KLISE Sandia National Laboratories, National Security Applications Department, P.O. Box 5800 MS 0751, Albuquerque, NM 87185, U.S.A. ABSTRACT: Accurate representation of heterogeneity at varying scales is vital for modeling solute dispersion in groundwater aquifers and petroleum reservoirs. Dispersion, the result of varying velocities in a flow field, is, in part, due to material heterogeneity. In order to represent the influence of heterogeneity at the outcrop scale, a series of terrestrial LIDAR scans at millimeter‐scale point spacing were recorded in sediments located in braided stream exposures west of Albuquerque, New Mexico, and outside the Hanford Site in Washington. Scans are projected onto a vertical plane and converted to a high‐resolution TIFF image. Using the mean and standard deviation of the ‘‘stacked’’ images, the data are processed through a series of filters to enhance textural information and distinguish between lithologies. The product is converted to a grid with numerical color values for each lithology (e.g., sandstone, gravel). Each lithologic class is assigned reasonable values of hydraulic conductivity. Groundwater flow and transport time are simulated using MODFLOW and MODPATH, respectively. Simulations show that flow and solute transport are focused in the coarser‐grained laminae of cross‐ bedded units. Flow may be focused into some areas in finer‐grained beds as well, if the adjacent gravel bed has been cut. Thus, most of the flow may be focused into a smaller volume of the material making up the aquifer. This result shows that terrestrial LIDAR can be successfully applied to produce synthetic stratigraphy for use in fluid flow models.
A HIGH‐RESOLUTION STUDY OF DEPOSITIONAL FACIES AND ARCHITECTURE OF FORDS BRANCH OUTCROP: A MIDDLE PENNSYLVANIAN SEDIMENTARY SEQUENCE NEAR PIKEVILLE, KENTUCKY, U.S.A. SUMANTA K. CHATTERJEE, ARTHUR D. COHEN, AND CHRISTOPHER G. ST. C. KENDALL Department of Earth and Ocean Sciences, University of South Carolina, Columbia, EWS 617, 701 Sumter Street, Columbia, SC 29208, U.S.A. e‐mail:
[email protected] ABSTRACT: A Middle Pennsylvanian deltaic succession is exposed in the Fords Branch road cut located on US Highway 23, south of Pikeville, Kentucky, USA. The outcrop is 1.5 km long and 20 m in thickness and is oriented in an oblique strike orientation with respect to local paleoflow indicators and regional fluvio‐deltaic drainage directed broadly to the west in a late Paleozoic Appalachian foreland basin.
Sedimentological analysis of the outcrop and interpretation of a panoramic photo montage establishes that the succession in the road cut accumulated in three depositional episodes bounded by sequence stratigraphic surfaces. A basal complex of distributary‐ mouth bars, channels and levees is cut by and overlain by an incised‐valley fill. A capping unit of bay‐fill and distributary‐mouth‐bars sediments completes the exposed succession.
Both the basal and capping depositional episodes are interpreted as lower‐delta‐plain settings. The incised valley is dominated by fluvial channel deposits and exhibits an upward increase in fluvial channel amalgamation.
The focus of the study presented here is twofold: (1) the nature of delta‐front settings and how best analogs might be chosen, and (2) the evolution of fluvial channels in the outcrop panel, the architecture of which suggests a changing balance of sedimentation rate versus avulsion frequency over time.
