The use of seismic amplitude for fluid detection dates back to the 1960s where Mike Forrest observed the first bright spot associated with gas in seismic data. With the improved understanding of fluid effect on seismic amplitude, fluid detection using seismic data has taken further steps. Subsequently, by the 1970s and early 1980s, a number of published papers proposed explanations for the amplitude expressions related to fluid. The papers also documented the occurrence of these amplitude expressions in different areas such as Gulf of Mexico, California, Louisiana, Alberta in Canada, and Middle East. All this has contributed to the introduction of Amplitude Variation with offsets (AVO) analysis methods for fluid detection. In the late 1980s and early 1990s, fluid indicators became a common practice in oil and gas exploration; and computer programs were been developed for that purpose. Today, a long list of fluid indicators is available for interpreters and AVO practitioners, for example: the product of AVO Intercept and Gradient, Fluid Factor, scaled Poisson ratio, Far-Near partial stacks, and some other recent indicators such as Fluid Angle, Energy-weighted AVO, J attribute among many others. The list has even extended from reflectivity-based indicators to impedance-based indicators. In this lecture, a number of the above fluid indicators will be explored and discussed. Then, two new fluid indicators will be introduced and compared with the existing indicators. The first indicator will combine the Gradient and scaled-Poisson reflectivity to highlight fluid responses. The second will be extracted from Amplitude Decomposition with Offset (ADO). The ADO is used to search for amplitude expressions related to fluids in a way similar to the well-known Spectral Decomposition. The indicators will be then examined on real dataset from Offshore Australia to help identify gas-saturated zones.
Speaker: Mohammed Farfour, Sultan Qaboos University
Mohammed Farfour has received an M.Sc. degree in geophysics from Boumerdes University in Algeria, and a PhD degree from Chonnam National University, South Korea. He worked as Postdoc researcher at Chonnam University and as a reservoir geophysicist at the National Company of Geophysics in Algeria before joining Sultan Qaboos University. At Sultan Qaboos University’s Earth Science Department, he teaches courses and conduct researches related to seismic interpretation and reservoir characterization. He has given a number of technical presentations in numerous SEG events and other international events. He published several papers in different scientific and professional journals. He is an applicant for two patents for fluid detection and reservoir characterization and developed free software programs for AVO analysis and interpretation (MAVO) and Borehole geophysics (MVSP). He is a reviewer in The Leading Edge, and Geophysics and an associate editor in the Arabian Journal of Geosciences. Mohammed received Schlumberger Award for young geoscientists in 2013 and best teacher Award in 2020. Mohammed is a member in SEG since 2008 and in AAPG and EAGE since 2011.
Dr. Ali Al-Naamani is currently the head of the Quantitative Interpretation (QI) team in PDO. He did both BSc and PhD in Geophysics from UK. His PhD thesis was on 4D analysis of multi-component seismic data. He joined the QI team in PDO after receiving his PhD in 2004. Then moved to the study centre providing seismic support to the integrated team. He then moved to Brunei as a senior production seismologist on a 4 year assignment. On completion of his assignment, he returned to PDO as a senior reservoir geophysicist rejoining the QI team. His technical expertise include 4D seismic, AVO, seismic inversion, neural net technologies for facies classification and property prediction and seismic modeling. His previous leading roles include leading the appraisal campaign for a number of fields in PDO and leading the WRFM opportunity realization team.