Course Profile ERTH3021: Exploration and Mining Geophysics Semester 2, 2014 Course Outline: This course builds on the general introduction provided by ERTH2020, and examines common applied-geophysical techniques in more detail. In this course, there is a greater focus on the seismic method. The reciprocal method of refraction interpretation is reviewed and the seismic reflection technique is examined in detail, with discussion of acquisition, processing and interpretation. Selected topics in non-seismic geophysics are examined in detail, via practical exercises and a written assignment. In this course, the practical exercises are considered to be very important. Practical reports are given significant weighting (20% in 2014) and material covered in practicals is examinable. Staff: Coordinator: Steve Hearn Steele Building (3) Room 112 Email: steveh@geoph.uq.edu.au Consultation: Tues AM by email appointment Several classes will be run by guest: Stewart Fletcher (sfletcher@velseis.com) Class contact hours: Tues: 1pm - 6pm
ERTH3021 Exploration and Mining Geophysics 2 IMPORTANT INFORMATION FOR STUDENTS PLEASE ABSORB THIS Assumed background: The prerequisite for ERTH3021 is ERTH2020 (or ERTH3020). Please note that ERTH2020 itself has formal prerequisites (MATH1050, SCIE1000). Therefore this course (ERTH3021) assumes a background of Level-1 mathematics (algebra, calculus, trigonometry), as well as prior exposure to basic geology and geophysics, and computer programming (the python language is used). The technical content of ERTH3021 will be slightly higher than ERTH2020. Students who received less than a 5 in ERTH2020 should consult Dr Hearn before proceeding. Students from other institutions should only enrol in this course if they have done an introductory geophysics course with quantitative content. This course relies heavily on computational practical exercises and programming experience is assumed. Email Contact: From time to time, I will use student email to provide students with various course material, updates etc. Early in semester I will send a test email to all enrolled students. It is your responsibility to ensure that you are receiving mail, and to check your mail regularly. This can be very important around exam time. Web page: Various course download material will be placed on the web at the following address: www.geoph.uq.edu.au/erth3021. Calculators: Standard scientific calculators are essential for tutorial and examination work. Students are asked to perform interactive calculations in class. Programmable calculators are not to be used to store information for use in examinations. Summary of assessment tasks: In 2014 the breakup of marks for this course is: Exams 70% (Mid-Sem 30% Final 40%), Written Assignment 10%, Practical Exercises 20%. In order to pass this course, a passing mark (50%) must be achieved in the exam component, and the non-exam component. Details of the major written assignment are given later in this document, and will be discussed further in class. Detailed requirements for each practical exercise will be given at the start of each practical session. Material covered in practical exercises is examinable. Submission of Practical and Assignment Material: All practical and assignment material must be submitted in hard-copy form through the School of Earth Sciences office. Please ensure that you receive a receipt for your submission. Important Dates: Written Assignment Due: 4pm 26 August Practical Reports Due: Prior to next practical class. (i.e. 1pm on following Tuesday) Mid-Sem Exam: 09 September Late Submission Policy: Late submissions will incur a deduction of 20% of the available marks for each day beyond the deadline. For example, a student submits a component worth 10 marks 2 days late. Based on content he is awarded 8/10. Because the submission is 2 days late he incurs a penalty of 0.2 * 2 * 10 = 4 marks. The final mark is then 4/10.
ERTH3021 Exploration and Mining Geophysics 3 Indicative Course Content: 1. Lectures on Seismic Exploration The main focus of formal lectures will be to introduce the seismic reflection method of exploration. The material emphasises hydrocarbon exploration but is of increasing relevance in other mining and engineering applications, as well as in large-scale crustal studies. The course will draw from the following topics. The precise content list will be reviewed prior to exams. Review of Basic Seismic Concepts Common wave types (P, S, Surface). and their velocities Snell's law and the ray parameter Distinction between seismic reflection and refraction. The reflectivity concept and reflection coefficients. Examples of Practical Implications of these concepts Review of Seismic Refraction Review of the slope-intercept method of interpretation for horizontal and dipping layer. Review of the Reciprocal Method of interpretation. Relationship between time-depth and depth. Relationship between velocity-function and refractor velocity. Construction of extended spreads using multi-spread acquisition and offset shots. Reciprocal Method analysis using extended reversed spreads. Seismic Reflection Acquisition Seismic sources and detectors. Multi-channel recording, the roll-along technique, land and marine recording geometries, geophone groups. Survey and parameter design, 2D and 3D recording. Common Mid Point acquisition concepts in 2D and 3D. Production of Seismic Images Common Mid Point Processing (Normal Moveout, velocity analysis, CMP stacking). Basic processing techniques for image enhancement (amplitude equalisation, bandpass filtering, deconvolution, static correction, velocity filtering, migration). Seismic Modelling Forward modelling construction and use of synthetic seismograms. Inverse modelling seismic trace inversion, impedance mapping.
ERTH3021 Exploration and Mining Geophysics 4 Structural Interpretation of Seismic Sections Tieing to synthetics. Picking a survey. Use of 2D versus 3D data. Horizon contour maps and depth conversion. 3-D seismic volumes and time-slices. Aspects of Sequence Stratigraphic Interpretation Significance of sea-level rise and fall. Identification of seismic sequence boundaries. Reflection configurations within seismic sequences. Systems tracts and their significance to hydrocarbon exploration. Note: Depending on staff availability there may be a number of lectures on nonseismic topics. 2. Seismic Practical Exercises: A number of seismic practicals will be given, designed to explore the formal lecture material listed above. Indicative topics are: Review of reciprocal method of seismic refraction interpretation. Geometry of 2D seismic acquisition Geometry of 3D seismic acquisition Introduction to Seismic Processing Seismic reflectivity modelling Understanding seismic field records Introduction to seismic interpretation
ERTH3021 Exploration and Mining Geophysics 5 3. Non-Seismic Practical Exercises Although the main focus of formal lectures is on the seismic method, a number of extension exercises will be given, relating to non-seismic geophysics. These practicals build on the material introduced in ERTH2020, and are aimed at extending the student's geophysical thought processes and skills. Indicative practical exercises are: General: Review of scientific programming using Python. This exercise is available online for revision purposes only. All students will have had some experience with the concept of programming, via programmable calculators, or using the formula tool in Excel. These are useful for very simple tasks, but for real-world data handling more complete tools are needed. It is assumed that students have had prior exposure to Python programming via ERTH2020 and/or SCIE1000. This practical provides a brief review of simple python programming skills, and provides analysis tools for use in subsequent practicals. Potential Field Methods: Variations in the earth's gravitational acceleration with latitude. In ERTH3020 we noted that several factors can cause observable variations in gravitational acceleration (g) from place to place. For example, g varies as a function of latitude. Here we will examine this idea in more detail, using Python to compute and plot the various components of this variation. Gravity Meters and the Zero-Length Spring One of the features of the gravity method is that the anomalies being measured are extremely subtle. High-accuracy devices are required. The Zero-Length spring is an interesting device which is central to most modern gravity meters. This practical is designed to examine the relative sensitivities of a simple mass-on-spring device and a beam device incorporating a 'Zero-Length' spring. It also provides a refresher in basic applied calculus. Dependence of magnetic anomalies on geometric relationships between field and structures. The ERTH3020 Crystal Mtn field trip detected a number of significant magnetic anomalies. The appearance of the anomaly is dependent not only on the magnetic susceptibilities of rocks, but also geometric interaction between magnetic field and geological structures. Here we will examine the feasibility of modelling some of the anomalies detected in the field. We also utilise our Python skills to calibrate the Berkeley modeller against a known theoretical magnetic anomaly.
ERTH3021 Exploration and Mining Geophysics 6 Electrical Methods: Convolution, the Resistivity Transform, and Interpretation of Schlumberger sounding curves In this exercise we demonstrate the concept of convolution, which is widely used in geophysical modelling and data processing. We will introduce the idea with simple examples including data smoothing and construction of synthetic seismograms. The concept of convolution will then be applied to the problem of building electrical sounding curves, via convolution of a Schlumberger array filter with the Resistivity Transform. References: There is no set text for this course. The following general references may assist understanding: On Line References Everett, Mark E. Near-Surface Applied Geophysics (ebook: PSE Library) Berkeley Course in Applied Geophysics http://appliedgeophysics.lbl.gov/ Lanza and Meloni: The Earth's Magnetism: an introduction for geologists (ebook: PSE Library) References: Sheriff, R.E., Encyclopedic Dictionary of Geophysics, 3 rd Edition, SEG. Sheriff, R.E. and Geldart, L.P., Exploration Seismology. Cambridge University Press. Telford, W., Geldart, L., Sheriff, R., Applied Geophysics, Cambridge University Press. Yilmaz, O., Seismic Data Processing, Society of Exploration Geophysicists. A number of additional references (web and hard-copy) will be given in class.
ERTH3021 Exploration and Mining Geophysics 7 Written Assignment Additional Information Aim The aim of this exercise is to provide experience at literature research and scientific writing. This skill is imperative for higher-level study, and subsequently in the workplace. Topic To investigate and discuss the impact of geophysics on resource exploration. You can choose to address either: (i) a particular non-seismic geophysical technique applied to a number of different exploration projects within Australia or overseas; or (ii) a range of geophysical techniques used in a particular exploration project. Assessment Criteria It is expected that the assignment will be maximum 2000 words, plus figures. The marking criteria (with an indicative breakdown) include: Technical content 40% Expression and grammar 30% Structure and logic 10% Figures and tables 10% Referencing 10% The document must indicate that you have carried out a reasonable literature search, and that you have achieved a reasonable technical understanding of the topic. Reports which are based on just one or two sources will not receive a strong mark for technical content. You are expected by now to be scientifically literate. If you are not then you need to get some help in this department. A very common error is to write several sentences as one. Remember that a sentence only has one verb. Avoid long and complex sentences (even if grammatically valid). Generally multiple short sentences are easier to read in a scientific article. The document must be logically subdivided, with logical titles for each section. Figures and tables should be clearly labelled, with captions, and referenced by figure/table number in the text.
ERTH3021 Exploration and Mining Geophysics 8 Technical sources must be correctly referenced. All sources referred to in the text must appear in the reference list at the end of the document. Do not list references for articles which are not referred to in the text. The general style of the document (Figures, Tables, References) should follow Geophysics or Exploration Geophysics. Source Material Some sources of information include the following journals (available online and from PSE): Exploration Geophysics Preview Geophysics The Leading Edge Geophysical Prospecting First Break A separate document (online_journals.pdf) which gives more detail on online access is available on the download site (www.geoph.uq.edu.au/erth3021) More detail relating to choice of topic and format will be given in class. Due Date: 4pm August 26 2014 Submit your assignment to the School office with appropriate cover sheet. Electronic Course Profile: The official course profile can be found online at http://uq.edu.au/study/course.html?course_code=erth3021