Chapter 13: AVO Enigmas
Several case histories presented in this volume illustrate instances in which AVO has failed as a gas indicator. In the majority of cases, the drilling logs contain the evidence for the origin of the bright spot and/or AVO anomaly. The logs for the two case histories in this chapter contain no clue as to the origin of extremely attractive amplitude and AVO anomalies. We can only speculate as to the origin of the amplitude and AVO anomalies in these cases.
Figures & Tables
A cursory look at the contents of the book might lead the reader to belive that AVO is not a successful hydrocarbon indicator, as we show many examples of AVO predictions gone awry, and dry holes drilled based on AVO anomalies. However, a closer look at the pages will give the reader the message we are trying to convey: used properly and cautiously, AVO can be a valuable tool for direct detection. The preponderance of unhappy endings in the book is unavoidable, as the goal of this book is to provide information that may prevent other dry holes being drilled. Inevitably, the best lessons are learned from mistakes, a statement that applies to life in general as well as to seismic interpretation.