Ebook: Pitfalls in Seismic Interpretation

Society of Exploration Geophysicists, 1973. — 58 p. — (Geophysical Monograph Series, N2). — ISBN (print): 978-0-931830-11-2.Since current data processing and presentation yield seismic sections that resemble geologic cross-sections, geologists and geophysicists not experienced in seismic interpretation are often greatly tempted to read geology more or less directly from the seismic section. Where the geology is simple, this will not present a problem. However, in areas of complex structure, rapid changes in lithology or velocity, or irregular surface or near-surface conditions, serious errors may result from the literal interpretation of seismic sections.Interpretation pitfalls fit into one of the following three categories:
Pitfalls associated with velocity occur because seismic data are presented in traveltime rather than depth,
Pitfalls associated with geometry occur because reflections from a three-dimensional space are plotted in a two-dimensional section, and
Pitfalls associated with recording and processing occur because all recorded events are not of geologic origin, and improper processing can mask geology.We will discuss pitfalls associated with 23 features frequently seen on seismic sections. It is important that the reader note the order of presentation. First we will show a seismic profile and give a seemingly good geologic explanation of the features shown on the section. Then we will use a geologic model and its seismic expression to show that what seems to be straightforward geology is, in fact, a pitfall. Finally, we will present validity checks for spotting the pitfall so that correct interpretations can be made along with correction methods where applicable.