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Geophysics 210 September 2008
Geophysics 210 September 2008 Geophysics 210 - Physics of the Earth A1: What is geophysics Geophysics: Application of physics to understand the structure and working of the Earth. Geophysics can be divided into exploration geophysics and geodynamics. Exploration geophysics is the process of imaging what is inside the Earth. Direct sampling in the Earth with drilling can only reach depths around 10 km so indirect methods are needed. Often used to describe commercial exploration, but includes investigations to depths of the mantle and core. All geophysical methods can be divided into active and passive techniques. In an active technique, it is necessary to generate a signal (e.g. in seismic studies sound waves are generated with an explosion or an earthquake). In a passive technique a naturally occurring signal is detected (e.g. the pull of gravity of a buried object). Geodynamics is the study of how the Earth works, and considers questions such as: -what drives plate motion? -what triggers earthquakes? -how is the Earth’s magnetic field generated? -how do continent-continent collisions build mountains? This field depends heavily on information derived from geophysical imaging. Advances in computer power now allow simulations of these processes in ever increasing detail and realism. A2 : Basic structure of the Earth • Radially symmetric to first order. • Crust – mainly silicate minerals, enriched in lighter elements (Na, Al) • Mantle – silicate minerals with more heavy elements (Fe and Mg) magnesium. Divided into upper and lower mantle (dashed line) • Outer core - liquid iron that convects rapidly. • Inner core – Lump of solid iron roughly the size of the moon • Crust and mantle are defined in terms of their distinct chemical compositions. -
Ten Years of Marine CSEM for Hydrocarbon Exploration
GEOPHYSICS, VOL.75, NO. 5 ͑SEPTEMBER-OCTOBER 2010͒; P.75A67–75A81, 15 FIGS. 10.1190/1.3483451 Ten years of marine CSEM for hydrocarbon exploration Steven Constable1 years of the first survey three contracting companies had been ABSTRACT formed for the express purpose of providing commercial marine CSEM services to the exploration industry. Now, almost 10 years af- Marine controlled-source electromagnetic ͑CSEM͒ sur- ter the Girassol survey, marine CSEM is a broadly used, if not main- veying has been in commercial use for predrill reservoir ap- stream, geophysical technology, with over 500 surveys reportedly praisal and hydrocarbon exploration for 10 years.Although a having been carried out and several custom-built survey vessels in recent decrease has occurred in the number of surveys and operation. The 75th anniversary of GEOPHYSICS and the 10th anni- publications associated with this technique, the method has versary of commercial marine CSEM seem to constitute an appro- become firmly established as an important geophysical tool priate occasion to review the marine CSEM method: where we have in the offshore environment. This is a consequence of two im- been, where we are today, and where we might be going. portant aspects associated with the physics of the method: The aim of this paper is to provide a technical review, which is ac- First, it is sensitive to high electrical resistivity, which, al- cessible to the nonexpert, of the marine CSEM method. However, to though not an unambiguous indicator of hydrocarbons, is an illustrate some of the important issues, original calculations have important property of economically viable reservoirs. -
Summary of the New W4300 Course in DEES: “The Earth's Deep Interior” Instructor: Paul G
Summary of the new W4300 course in DEES: “The Earth's Deep Interior” Instructor: Paul G. Richards ([email protected]) This course emphasizes the geophysical study of Earth structure below the crust, drawing upon geodesy, geomagnetism, gravity, thermal studies, seismology, and some geochemistry. It covers the principal techniques by which discoveries have been made in deep Earth structure, and describes particular features of the mantle, and fluid and solid cores, such as: • the upper mantle beneath old and young oceans and continents • the transition zone in the mantle between about 400 and 700 km depth (within which density and elastic moduli increase anomalously with depth), • the lowermost mantle and core/mantle boundary (across which density doubles and sound speed halves), and • the outer core/inner core boundary (discovered by seismology, and profoundly affecting the Earth's magnetic field). The course is part of the core curriculum for graduate students in solid Earth geophysics and marine geophysics, is an elective for solid Earth geochemistry and geology, and is accessible to undergraduate science majors with adequate math and physics. The course, together with EESC W 4950x (Math Methods in the Earth Sciences), replaces the previous W 4945x – 4946y (Geophysical Theory I and II). It includes parts of previous courses (no longer listed) in seismology, geomagnetism, and thermal history. Emphasis is on current structure, rather than evaluation of dynamic processes (such as convection). Prerequisites calculus, differential -
Modeling for Inversion in Exploration Geophysics A
MODELING FOR INVERSION IN EXPLORATION GEOPHYSICS A Dissertation Presented to The Academic Faculty By Mathias Louboutin In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the School of CSE in the College of Computing Georgia Institute of Technology February 2020 Copyright c Mathias Louboutin 2020 MODELING FOR INVERSION IN EXPLORATION GEOPHYSICS Approved by: Dr. Felix J. Herrmann, Advisor School Computational Science and Engineering Dr. Tobin Isaac Georgia Institute of Technology School of Computer Science Georgia Institute of Technology Dr. Umit Catalyurek School Computational Science and Dr. Zhigang Peng Engineering School of Earth and Atmospheric Georgia Institute of Technology Sciences Georgia Institute of Technology Dr. Edmond Chow School Computational Science and Date Approved: March 1, 2020 Engineering Georgia Institute of Technology ACKNOWLEDGEMENTS Before anything else, I would like to thank my supervisor Dr Felix J. Herrmann for giv- ing me the opportunity to work with him. Thanks to his leadership I had the opportunity to work and scientifically challenging problems in a collaborative and motivating atmosphere. I would also like to thank Professor Gerard Gorman at Imperial college. And large part of my research was kick-started by a visit at Imperial College and Dr. Gorman’s support and guidance made me achieve my research objective. I would like to thank Professor Umit Catalyurek, Professor Edmond Chow, Professor Tobin Isaac and Professor Zhigang Peng for agreeing to be on my Ph.D. committee at Georgia Tech, for reviewing my thesis, for making time for my proposal and defense and for your valuable input on my work. I would also like to thank my former Ph.D. -
Results of the Application of Seismic- Reflection And
RESULTS OF THE APPLICATION OF SEISMIC- REFLECTION AND ELECTROMAGNETIC TECHNIQUES FOR NEAR-SURFACE HYDROGEOLOGIC AND ENVIRONMENTAL INVESTIGATIONS AT FORT BRAGG, NORTH CAROLINA ByM.T. Meyer and Jason M. Fine U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 97-4042 Prepared for the Department of the Army Fort Bragg, North Carolina Raleigh, North Carolina 1997 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Gordon P. Eaton, Director The use of firm, trade, and brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. For additional information write to: Copies of this report can be purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Branch of Information Services 3916 Sunset Ridge Road Box 25286 Raleigh, NC 27607 Denver Federal Center Denver, CO 80225-0286 CONTENTS Page Abstract.................................................................................. 1 Introduction.............................................................................. 2 Background ....................................................................... 3 Purpose and scope ................................................................. 3 Physiographic and geologic settings .................................................. 4 Acknowledgments .............................................................. 6 Surface-geophysical methods ............................................................... 7 Shallow seismic reflection -
An Introduction to Geophysical Exploration, 3E
An Introduction to Geophysical Exploration Philip Kearey Department of Earth Sciences University of Bristol Michael Brooks Ty Newydd, City Near Cowbridge Vale of Glamorgan Ian Hill Department of Geology University of Leicester THIRD EDITION AN INTRODUCTION TO GEOPHYSICAL EXPLORATION An Introduction to Geophysical Exploration Philip Kearey Department of Earth Sciences University of Bristol Michael Brooks Ty Newydd, City Near Cowbridge Vale of Glamorgan Ian Hill Department of Geology University of Leicester THIRD EDITION © 2002 by The right of the Authors to be distributors Blackwell Science Ltd identified as the Authors of this Work Marston Book Services Ltd Editorial Offices: has been asserted in accordance PO Box 269 Osney Mead, Oxford OX2 0EL with the Copyright, Designs and Abingdon, Oxon OX14 4YN 25 John Street, London WC1N 2BS Patents Act 1988. (Orders: Tel: 01235 465500 23 Ainslie Place, Edinburgh EH3 6AJ Fax: 01235 465555) 350 Main Street, Malden All rights reserved. No part of MA 02148-5018, USA this publication may be reproduced, The Americas 54 University Street, Carlton stored in a retrieval system, or Blackwell Publishing Victoria 3053,Australia transmitted, in any form or by any c/o AIDC 10, rue Casimir Delavigne means, electronic, mechanical, PO Box 20 75006 Paris, France photocopying, recording or otherwise, 50 Winter Sport Lane except as permitted by the UK Williston,VT 05495-0020 Other Editorial Offices: Copyright, Designs and Patents Act (Orders: Tel: 800 216 2522 Blackwell Wissenschafts-Verlag GmbH 1988, without the prior -
Bore Hole Ebook, Epub
BORE HOLE PDF, EPUB, EBOOK Joe Mellen,Mike Jay | 192 pages | 25 Nov 2015 | Strange Attractor Press | 9781907222399 | English | Devizes, United Kingdom Bore Hole PDF Book Drillers may sink a borehole using a drilling rig or a hand-operated rig. Search Reset. Another unexpected discovery was a large quantity of hydrogen gas. Accessed 21 Oct. A borehole may be constructed for many different purposes, including the extraction of water , other liquids such as petroleum or gases such as natural gas , as part of a geotechnical investigation , environmental site assessment , mineral exploration , temperature measurement, as a pilot hole for installing piers or underground utilities, for geothermal installations, or for underground storage of unwanted substances, e. Forces Effective stress Pore water pressure Lateral earth pressure Overburden pressure Preconsolidation pressure. Cancel Report. Closed Admin asked 1 year ago. Help Learn to edit Community portal Recent changes Upload file. Is Singular 'They' a Better Choice? Keep scrolling for more. Or something like that. We're gonna stop you right there Literally How to use a word that literally drives some pe Diameter mm Diameter mm Diameter in millimeters mm of the equipment. Drilling for boreholes was time-consuming and long. Whereas 'coronary' is no so much Put It in the 'Frunk' You can never have too much storage. We truly appreciate your support. Fiberscope 0 out of 5. Are we missing a good definition for bore-hole? Gold 0 out of 5. Share your knowledge. We keep your identity private, so you alone decide when to contact each vendor. Oil and natural gas wells are completed in a similar, albeit usually more complex, manner. -
Imaging Through Gas Clouds: a Case History in the Gulf of Mexico S
Imaging Through Gas Clouds: A Case History In The Gulf Of Mexico S. Knapp1, N. Payne1, and T. Johns2, Seitel Data1, Houston, Texas: WesternGeco2, Houston, Texas Summary Results from the worlds largest 3D four component OBC seismic survey will be presented. Located in the West Cameron area, offshore Gulf of Mexico, the survey operation totaled over 1000 square kilometers and covered more than 46 OCS blocks. The area contains numerous gas invaded zones and shallow gas anomalies that disturb the image on conventional 3D seismic, which only records compressional data. Converted shear wave data allows images to be obtained that are unobstructed by the gas and/or fluids. This reduces the risk for interpretation and subsequent appraisal and development drilling in complex areas which are clearly petroleum rich. In addition, rock properties can be uniquely determined from the compressional and shear data, allowing for improved reservoir characterization and lithologic prediction. Data acquisition and processing of multicomponent 3D datasets involves both similarities and differences when compared to conventional techniques. Processing for the compressional data is the same as for a conventional OBC survey, however, asymmetric raypaths for the converted waves and the resultant effects on fold-offset-azimuth distribution, binning and velocity determination require radically different processing methodologies. These issues together with methods for determining the optimal parameters of the Vp/Vs ratio (γ) will be discussed. Finally, images from both the compressional (P and Z components summed) and converted shear waves will be shown to illuminate details that were not present on previous 3D datasets. Introduction Multicomponent 3D surveys have become one of the leading areas where state of the art technology is being applied to areas where the exploitation potential has not been fulfilled due to difficulties in obtaining an interpretable seismic image (MacLeod et al 1999, Rognoe et al 1999). -
Gji-Keyword-List-Updated2016.Pdf
COMPOSITION and PHYSICAL PROPERTIES Composition and structure of the continental crust Composition and structure of the core Composition and structure of the mantle Composition and structure of the oceanic crust Composition of the planets Creep and deformation Defects Elasticity and anelasticity Electrical properties Equations of state Fault zone rheology Fracture and flow Friction High-pressure behaviour Magnetic properties Microstructure Permeability and porosity Phase transitions Plasticity, diffusion, and creep GENERAL SUBJECTS Core Gas and hydrate systems Geomechanics Geomorphology Glaciology Heat flow Hydrogeophysics Hydrology Hydrothermal systems Instrumental noise Ionosphere/atmosphere interactions Ionosphere/magnetosphere interactions Mantle processes Ocean drilling Structure of the Earth Thermochronology Tsunamis Ultra-high pressure metamorphism Ultra-high temperature metamorphism GEODESY and GRAVITY Acoustic-gravity waves Earth rotation variations Geodetic instrumentation Geopotential theory Global change from geodesy Gravity anomalies and Earth structure Loading of the Earth Lunar and planetary geodesy and gravity Plate motions Radar interferometry Reference systems Satellite geodesy Satellite gravity Sea level change Seismic cycle Space geodetic surveys Tides and planetary waves Time variable gravity Transient deformation GEOGRAPHIC LOCATION Africa Antarctica Arctic region Asia Atlantic Ocean Australia Europe Indian Ocean Japan New Zealand North America Pacific Ocean South America GEOMAGNETISM and ELECTROMAGNETISM Archaeomagnetism -
The Future of Onshore Seismic
VOL. 15, NO. 2 – 2018 GEOSCIENCE & TECHNOLOGY EXPLAINED geoexpro.com GEOTOURISM TECHNOLOGY EXPLAINED Aspen: Rocky Mountain High The Future of Onshore Seismic EXPLORATION Awaiting Discovery? The US Atlantic Margin GEOEDUCATION Resources Boosted by Billions GEOPHYSICS A Simple Guide to Depth Conversion Get Ready for the 2018 Egypt West Med License Round Unlock this frontier region with GeoStreamer seismic data for detailed subsurface information Benefit from true broadband depth imaging covering an area of more than 80 000 sq. km over the Herodotus/West Egypt Shelf. In partnership with: Meet our Egypt experts at EAGE in Copenhagen from 11–14 June 2018. Contact us for more information: [email protected] Ministry of Petroleum Ministry andof Petroleum Mineral Resources and Mineral Resources A Clearer Image | www.pgs.com/DataLibrary Previous issues: www.geoexpro.com Contents Vol. 15 No. 2 This edition of GEO ExPro focuses on North America; integrating geoscience for GEOSCIENCE & TECHNOLOGY EXPLAINED exploration; and reserves and resources. i 5 Editorial Egorov The underexplored US 6 Regional Update Atlantic margin may soon be open to exploration. 8 Licensing Update 10 A Minute to Read 14 Cover Story: Technology Explained: f Darts and Drones – The A simple guide to the parameters Future of Onshore Seismic involved in depth conversion. 18 Exploration: Awaiting Discovery? The US Atlantic Margin Earthworks Earthworks Reservoir 22 Industry Issues: Mind the Gaps v 24 GEO Physics: A Simple Guide Lasse Amundsen to Depth Conversion It is one of the oldest exploration areas in the world, but there is still plenty of potential in Central Europe. 26 Hot Spot: Renewed Excitement in Deepwater Gabon 28 Seismic Foldout: Exploring Papua New Guinea Y and Malvinas Become an expert at Finite 34 Exploration: Czeching it Out: Difference Modeling. -
PEAT8002 - SEISMOLOGY Lecture 13: Earthquake Magnitudes and Moment
PEAT8002 - SEISMOLOGY Lecture 13: Earthquake magnitudes and moment Nick Rawlinson Research School of Earth Sciences Australian National University Earthquake magnitudes and moment Introduction In the last two lectures, the effects of the source rupture process on the pattern of radiated seismic energy was discussed. However, even before earthquake mechanisms were studied, the priority of seismologists, after locating an earthquake, was to quantify their size, both for scientific purposes and hazard assessment. The first measure introduced was the magnitude, which is based on the amplitude of the emanating waves recorded on a seismogram. The idea is that the wave amplitude reflects the earthquake size once the amplitudes are corrected for the decrease with distance due to geometric spreading and attenuation. Earthquake magnitudes and moment Introduction Magnitude scales thus have the general form: A M = log + F(h, ∆) + C T where A is the amplitude of the signal, T is its dominant period, F is a correction for the variation of amplitude with the earthquake’s depth h and angular distance ∆ from the seismometer, and C is a regional scaling factor. Magnitude scales are logarithmic, so an increase in one unit e.g. from 5 to 6, indicates a ten-fold increase in seismic wave amplitude. Note that since a log10 scale is used, magnitudes can be negative for very small displacements. For example, a magnitude -1 earthquake might correspond to a hammer blow. Earthquake magnitudes and moment Richter magnitude The concept of earthquake magnitude was introduced by Charles Richter in 1935 for southern California earthquakes. He originally defined earthquake magnitude as the logarithm (to the base 10) of maximum amplitude measured in microns on the record of a standard torsion seismograph with a pendulum period of 0.8 s, magnification of 2800, and damping factor 0.8, located at a distance of 100 km from the epicenter. -
Small Electric and Magnetic Signals Observed Before the Arrival of Seismic Wave
E-LETTER Earth Planets Space, 54, e9–e12, 2002 Small electric and magnetic signals observed before the arrival of seismic wave Y. Honkura1, M. Matsushima1, N. Oshiman2,M.K.Tunc¸er3,S¸. Baris¸3,A.Ito4,Y.Iio2, and A. M. Is¸ikara3 1Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551, Japan 2Disaster Prevention Research Institute, Kyoto University, Kyoto 611-0011, Japan 3Kandilli Observatory and Earthquake Research Institute, Bogazic¸i˘ University, Istanbul 81220, Turkey 4Faculty of Education, Utsunomiya University, Utsunomiya 321-8505, Japan (Received September 10, 2002; Revised November 14, 2002; Accepted December 6, 2002) Electric and magnetic data were obtained above the focal area in association with the 1999 Izmit, Turkey earthquake. The acquired data are extremely important for studies of electromagnetic phenomena associated with earthquakes, which have attracted much attention even without clear physical understanding of their characteristics. We have already reported that large electric and magnetic variations observed during the earthquake were simply due to seismic waves through the mechanism of seismic dynamo effect, because they appeared neither before nor simultaneously with the origin time of the earthquake but a few seconds later, with the arrival of seismic wave. In this letter we show the result of our further analyses. Our detailed examination of the electric and magnetic data disclosed small signals appearing less than one second before the large signals associated with the seismic waves. It is not yet solved whether this observational fact is simply one aspect of the seismic dynamo effect or requires a new mechanism. Key words: Izmit earthquake, seismic dynamo effect, seismic wave, electric and magnetic changes 1.