Publication Name: Australasian Exploration Geoscience Conference 2018
Authors: Sebastian Nixon, Tony Hallam, Andrew Constantine
Date Published: February 2018
Number of Pages: 8
Abstract:
The first evidence of seismic brightening linked with gas charged reservoirs was recognised by Shell in the very late 1960s in the Gulf of Mexico. Since that time the terms bright spots, flat spots, amplitude versus offset (AVO) anomalies or gas anomalies have been used interchangeably (and often loosely) to imply positive evidence for gas charge. Collectively known as Direct Hydrocarbon Indicators (DHI), they have reduced risk and driven the successful exploration of many hydrocarbon discoveries. However, DHIs are not infallible and misinterpretation can lead to disappointment. We contend that it is very difficult to misinterpret a genuine DHI anomaly but easy to falsely characterise a seismic anomaly as a genuine DHI. In our experience, it is a combination of fundamental seismic attributes within the context provided by a sound geological and structural model that derives the most value in DHI assessment.