Avo Analysis
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AVO Principles, Processing and Inversion
AVO principles, processing and inversion AVO principles, processing and inversion Hong Feng and John C. Bancroft ABSTRACT In this paper, we will review the basic principles of AVO and introduce some amplitude preserving algorithms. Seismic data processing sequences for AVO analysis and some algorithms for AVO inversion will be discussed. Topics related to AVO, such as rock physics, AVO modeling, AVO interpretation, and AVO pitfalls are beyond the scope of this report. INTRODUCTION The AVO (amplitude variation with offset) technique assesses variations in seismic reflection amplitude with changes in distance between shot points and receivers. AVO analysis allows geophysicists to better assess reservoir rock properties, including porosity, density, lithology and fluid content. Around 1900, Knott and Zoeppritz developed the theoretical work necessary for AVO theory (Knott, 1899; Zoeppritz, 1919), given the P-wave and S-wave velocities along with the densities of the two bounding media. They developed equations for plane-wave reflection amplitudes as a function of incident angle. Bortfeld (1961) simplified Zoeppritz’s equation, making it easier to understand how reflection amplitudes depend on incident angle and physical parameters. Koefoed (1955) described the relationship of AVO to change in Poisson’s ratio across a boundary. Koefoed’s results were based on the exact Zoeppritz equation. The conclusions drawn by Koefoed are the basis of today’s AVO interpretation. Rosa (1976) and Shuey (1985) did breakthrough work related to predicting lithology from AVO, inspired by Koefoed’s article. Ostrander (1982) illustrated the interpretation benefits of AVO with field data, accelerating the second era of amplitude interpretation. Allen and Peddy (1993) collected seismic data, well information, and interpretation from the Gulf Coast of Texas and published a practical look at AVO that documented not only successes but also the interpretational pitfalls learned from dry holes. -
Feasibility of Multi-Component Seismic for Mineral Exploration
Western Australian School of Mines: Minerals, Energy and Chemical Engineering Feasibility of Multi-component Seismic for Mineral Exploration Pouya Ahmadi This thesis is presented for the Degree of Doctor of Philosophy of Curtin University December 2018 Declaration To the best of my knowledge and belief, this thesis contains no material previously published by any other person except where due acknowledgement has been made. This thesis contains no material, which has been accepted for the award of any other degree or diploma in any university. Signature: …………………………………………. Date: …………………………07/12/2018 To my wife, parents and sister. iii Abstract The mineral industry traditionally uses potential field and electrical geophysical methods to explore for subsurface mineral deposits. These methods are very effective when exploring for shallow targets. As shallow deposits are now largely depleted, alternative technologies need to be introduced to discover deeper targets or to extend known resources deeper. Only the seismic reflection method can reach the desired depths as well as provide the high-definition images of the subsurface that are required. Conventional seismic reflection methods make use of only one component (vertical) of the wave field (P-wave) which is very effective in resolving complex structural shapes but less so for rock characterisation. The proposition of this work is that the utilisation of the full vector field (3 component seismic data (3C)) could provide additional information that will help in rock identification, classification and detection of subtle structures, alteration and lithological boundaries that are of crucial importance for mineral exploration. Shear wave splitting, polarisation changes and velocity differences between polarised modes have at present undefined potential in resolving lithological changes, internal composition of shear zones, subtle faults and fractured zones. -
Calculation of a Synthetic Gather Using the Aki-Richards Approximation to the Zoeppritz Equations
University of New Orleans ScholarWorks@UNO University of New Orleans Theses and Dissertations Dissertations and Theses Fall 12-15-2012 Calculation of a Synthetic Gather using the Aki-Richards Approximation to the Zoeppritz Equations Graham Ganssle [email protected] Follow this and additional works at: https://scholarworks.uno.edu/td Part of the Geophysics and Seismology Commons Recommended Citation Ganssle, Graham, "Calculation of a Synthetic Gather using the Aki-Richards Approximation to the Zoeppritz Equations" (2012). University of New Orleans Theses and Dissertations. 1566. https://scholarworks.uno.edu/td/1566 This Thesis is protected by copyright and/or related rights. It has been brought to you by ScholarWorks@UNO with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights- holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/or on the work itself. This Thesis has been accepted for inclusion in University of New Orleans Theses and Dissertations by an authorized administrator of ScholarWorks@UNO. For more information, please contact [email protected]. Calculation of a Synthetic Gather using the Aki-Richards Approximation to the Zoeppritz Equations A Thesis Submitted to the Graduate Faculty of the University of New Orleans in partial fulfillment of the requirements for the degree Master of Science In Applied Physics By Graham R. Ganssle B.S. University of New Orleans, 2009 December, 2012 Table of Contents List of Figures ............................................................................................................................................ -
Msc Thesis Justin Lo 1047357.Pdf (12.23Mb)
A Modern Reinvestigation of the 1987 Moutere Depression Seismic Survey Justin Chen Lo A thesis submitted for the degree of Master of Science At the University of Otago, Dunedin, New Zealand. Table of Contents Abstract .................................................................................................................................................. iv Acknowledgements ................................................................................................................................ vi 1.0 Introduction ...................................................................................................................................... 1 1.1 Project Aim .................................................................................................................................... 1 1.2 Geological Background ................................................................................................................. 2 1.2.1 Moutere Depression .............................................................................................................. 2 1.2.2 Moutere Gravels & Glen Hope Formation ............................................................................. 2 1.2.3 Western Province ....................................................................................................................... 3 1.2.4 Eastern Province .................................................................................................................... 3 1.2.5 South of Nelson .....................................................................................................................