f Amplitude Extraction and Rock Properties Calibration (AVO Analysis)

Seismic reflections are used in oil business to locate geological structures that have the potential to trap hydrocarbons. Geophysicists discovered that the presence of gas/oil often coincided with the presence of high amplitude reflections known as “bright spots.” The bright spot technique was found to have limitations in that factors other than gas or oil, could cause bright reflections. Wells drilled into “Bright spots” have encountered igneous intrusions, carbonates, hard streaks and wet sands. A more definitive test rather than bright spots detection on a stacked seismic section was sought for the direct detection of gas on seismic records. One such test is the analysis of amplitude variation with offset (AVO). Amplitude versus offset or AVO analysis has played an increasing role over time and is now becoming a routine part of exploration studies. The aim is to minimise the uncertainty associated with the prospect and improve the chance of drilling successful exploration wells. The overall objectives of the AVO analysis are as follows: