In petroleum exploration, the geophysicist's task is to look beneath the earth's surface in the search for new deposits of oil and natural gas. Subsurface geologic structures of interest can be several miles deep. Geophysicists use the seismic reflection method in their search for oil and natural gas. The exploration geophysicist illuminates the earth's subsurface by means of an energy source that generates seismic waves. The subsurface rock layers transmit and reflect those seismic waves. A seismic survey consists of collecting seismic reflection data over a selected geographic area, called the prospect. The seismic reflection method, when considered as an instrument for remote detection, has much in common with other disciplines that are based on noninvasive techniques for finding the structure of an inaccessible body, such as medical imaging and nondestructive testing.
What is seismic acquisition? The essential features of seismic data acquisition are as follows: (1) At a fixed point on the surface of the earth, a source of energy — such as an array of dynamite charges or air guns or swept-frequency vibrators (as in vibroseis) — is activated. Such an activated source is called a shot. (2) Seismic waves from the shot propagate downward from the source point and go deep into the earth (Bois, 1968). (3) Eventually, the waves are reflected from geologic interfaces and propagate upward from those interfaces. A primary reflection is a reflection that travels directly down to the interface and then directly back up to the surface. A multiple reflection
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Digital Imaging and Deconvolution: The ABCs of Seismic Exploration and Processing
Digital Imaging and Deconvolution: The ABCs of Seismic Exploration and Processing (SEG Geophysical References Series No. 15), covers the basic ideas and methods used in seismic processing, concentrating on the fundamentals of seismic imaging and deconvolution. Most chapters are followed by problem sets. Some exercises supplement textual material; others are meant to stimulate classroom discussions. Text and exercises deal mostly with simple examples that can be solved with nothing more than pencil and paper. The book covers wave motion; digital imaging; digital filtering; various visualization aspects of the seismic reflection method; sampling theory; the frequency spectrum; synthetic seismograms; wavelets and wavelet processing; deconvolution; the need for continuing interaction between the seismic interpreter and the computer; seismic attributes; phase rotation; and seismic attenuation. The last of the 15 chapters gives a detailed mathematical overview. Digital Imaging and Deconvolution, nominated for the Association of Earth Science Editors award for best geoscience publication of 2008–2009, will interest professional geophysicists, graduate students, and upper-level undergraduates in geophysics. The book also will be helpful to scientists and engineers in other disciplines who use digital signal processing to analyze and image wave-motion data in remote-detection applications. The methods described are important in optical imaging, video imaging, medical and biological imaging, acoustical analysis, radar, and sonar.