Advances in Oil and Gas Exploration & Production Hamid N. Alsadi Seismic Hydrocarbon Exploration 2D and 3D Techniques Advances in Oil and Gas Exploration & Production Series editor Rudy Swennen, Department of Earth and Environmental Sciences, K.U. Leuven, Heverlee, Belgium The book series Advances in Oil and Gas Exploration & Production pub- lishes scientific monographs on a broad range of topics concerning geo- physical and geological research on conventional and unconventional oil and gas systems, and approaching those topics from both an exploration and a production standpoint. The series is intended to form a diverse library of reference works by describing the current state of research on selected themes, such as certain techniques used in the petroleum geoscience business or regional aspects. All books in the series are written and edited by leading experts actively engaged in the respective field. The Advances in Oil and Gas Exploration & Production series includes both single and multi-authored books, as well as edited volumes. The Series Editor, Dr. Rudy Swennen (KU Leuven, Belgium), is currently accepting proposals and a proposal form can be obtained from our representative at Springer, Dr. Alexis Vizcaino ([email protected]). More information about this series at http://www.springer.com/series/15228 Hamid N. Alsadi Seismic Hydrocarbon Exploration 2D and 3D Techniques 123 Hamid N. Alsadi Data Processing Section Ministry of Oil Baghdad Iraq ISSN 2509-372X ISSN 2509-3738 (electronic) Advances in Oil and Gas Exploration & Production ISBN 978-3-319-40435-6 ISBN 978-3-319-40436-3 (eBook) DOI 10.1007/978-3-319-40436-3 Library of Congress Control Number: 2016942906 © Springer International Publishing Switzerland 2017 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. Printed on acid-free paper This Springer imprint is published by Springer Nature The registered company is Springer International Publishing AG Switzerland Preface The favorable reception of the first edition of this book (seismic Exploration, published by Birkhauser Verlag in 1980) stimulated my belief in the need of an updated book that includes the advances in the techniques which have taken place during the past three decades. In preparing the present updated volume, I have taken into consideration the remarks and suggestions of the users of the 1980 edition from both of the academic and industrial work domains. Since 1980, when the first edition of this book was published, great developments in the seismic exploration technology have taken place. These developments have occurred in all of the three exploration phases: acquisi- tion, processing, and interpretation techniques. The most prominent advances which have taken place in these years are the widespread implementations of the 3D surveying, pre-stack migration, and growing interpretation tech- niques in both structural and stratigraphic exploration. As it is familiar with the exploration geophysicists, this subject (seismic exploration) is fully dealt with in many original and authentic internationally known text books. In this publication, no new subjects added to those found in the other standard books which are well known in the geophysical library. In fact, these and other related scientific papers and research reports formed solid references for the present book. There are, however, differences in the design and presentation approach. In its design, the book is intended to be a comprehensive treatise of the seismic exploration tool, addressing audiences in both of the academic and industrial establishments. It is made up of 12 chapters covering the basic aspects of the seismic reflection exploration subject, starting with the basic theory, followed by the applied data acquisition technology, and ending with the processing and interpretation. In presenting the subject matter, emphasis is made on the practical aspects of the subject, using clear and simplified presentation, avoiding excessive descriptions and unnecessary lengthy comments. Numerous illustration figures (>390 figures) have been used throughout the book to aid in clarifying the concepts and procedures involved in any standard seismic exploration survey. In this way, the book can be considered as a very useful introductory teaching manual for university students taking seismic reflection exploration as part of a postgraduate course. v vi Preface The chapters of the book are sequenced in the order of the activities normally executed in a standard seismic exploration survey: field acquisition, processing, and interpretation. Chapter 1 is an introductory chapter in which a brief historical note and short review of the geophysical exploration methods are given. This is followed by four chapters covering the theoretical aspect of the subject including basic principles and definitions of seismic waves, with a special chapter assigned for the seismic wave propagation velocity. The propagation phenomena, reflection, diffraction, transmission, and refraction, are dealt with in Chaps. 4 and 5. The following two chapters are devoted to the two main tools applied in seismic exploration, namely the 2D and 3D surveying techniques. Due to its important role in understanding of the processing steps applied in seismic data processing, a chapter (Chap. 8) is assigned solely for the seismic signal. This chapter is structured on the theme of considering the seismic reflection wavelet as a propagating signal in the same way as the electro- magnetic signal is treated by the communication theory applied in electro- magnetic wave propagation. Including a chapter on seismic signals, preceding the processing chapters, is a feature by which this book has deviated from other conventional publications. Data processing is presented under two headings: processing tools (Chap. 9) and the normally applied processing sequence (Chap. 10). Chapter 11 covers some specialized seismic exploration tools sometimes used in support of the conventional seismic reflection and refraction surveying. The book is concluded with Chap. 12 on interpretation. I would like to express my gratitude to my wife Asira and my sons (Eng. Majid, Ph.D., Eng. Muhannad, M.Sc., Thurayah, B.Sc., and Eng. Mahir, B.Sc.), for their continuous support and help throughout the past three years. My work in the writing of the book has incurred an additional burden to the family especially during the abnormally difficult times, which our country has experienced in the past twelve years. Baghdad, Iraq Hamid N. Alsadi December 2015 Contents 1 Introduction ................................... 1 1.1 Historical Review . 1 1.1.1 Elasticity and Seismic Waves (Båth 1979) . 1 1.1.2 Earthquake Seismology (Richter 1958). 2 1.1.3 Exploration Seismology (Telford et al. 1990) . 2 1.1.4 Summary of Exploration Seismology History (Sheriff and Geldart 1995) . 3 1.2 The Geophysical Exploration Project . 3 1.3 Geophysical Exploration Methods . 4 1.3.1 The Seismic Method . 4 1.3.2 The Gravity Method . 4 1.3.3 The Magnetic Method . 6 1.3.4 The Electical Method. 7 1.3.5 The Radioactivity Method . 9 1.4 Oil Well Drilling. 9 1.4.1 Drilling of the Exploration-Well . 10 1.4.2 The Oil-Well Rotary Drilling . 10 1.4.3 The Drill-Hole and Well Casing . 11 1.5 Well Geophysical Logging . 11 1.5.1 Electrical Logging . 12 1.5.2 Radioactivity Logging . 14 1.5.3 Acoustic Logging . 16 1.5.4 Log Interpretation . 19 1.6 Latest Developments in Well Logging . 19 1.6.1 Logging While Drilling Technique . 20 1.6.2 Borehole Imaging Tools. 20 1.7 Well Completion. 20 2 Seismic Waves ................................. 23 2.1 The Fundamental Conditions . 23 2.2 Theory of Elasticity . 23 2.2.1 Stress . 24 2.2.2 Strain . 26 2.2.3 Common Types of Strain . 26 2.2.4 The Volume-Changing Strain . 27 2.2.5 The Shape-Changing Strain . 28 2.2.6 The Cubical Dilatation. 28 vii viii Contents 2.2.7 Stress-Strain Relationship . 29 2.2.8 Hooke’s Law for Isotropic Media . 29 2.2.9 The Elastic Moduli . 30 2.2.10 The Elastic Moduli Interrelationships. 32 2.3 Wave Motion Equation . 32 2.3.1 One-Dimensional Scalar Wave Equation . 33 2.3.2 The Scalar and Vector 3D Wave Equations . 34 2.3.3 Plane Waves. 35 2.3.4 The P- and S-Waves . 36 2.4 Classification of Common Elastic Waves . 36 2.4.1 Body Waves. 37 2.4.2 Surface Waves . 38 2.4.3 Seismic Noise. 39 2.5 Propagation of Seismic Waves . 40 2.5.1 Elements of the Seismic Field. 41 2.5.2 Concepts of Wave-Fronts and Rays . 41 2.5.3 Huygens’ Principle . 42 2.5.4 The Concept of the Interface . 42 2.5.5 Changes of Propagation Direction at Interfaces . 43 2.5.6 Wave Conversion at Interfaces . 44 2.5.7 Energy Partitioning and Zoeppritz Equations . 45 2.5.8 Amplitude Variation with Angle of Incidence . 46 2.6 Effect of the Medium on Wave Energy .