Direct hydrocarbon indications from fluid contacts - stop calling them 'flatspots'! ...

• Main Authors: Dunne, Jarrod, Parsons, James
• Format: Conference Object
• Language: English
• Published: Zenodo 2023
• Subjects: DHI; flatspot; quantitative interpretation; AvO.; Sakhalin
• Online Access: https://dx.doi.org/10.5281/zenodo.7955930; https://zenodo.org/record/7955930

So called 'flatspots' rarely have the appearance of flatness, even at proven gas and oil fields and on seismic data that has been converted to depth using best-practice methods. The appearance of fluid contacts on seismic reflection data is influenced by several controls, most notably, fluid type; burial depth; saturation; and the size of the 'flatspot' anomaly compared to the imaging velocity resolution. Many cases of non-flatness are caused by lateral velocity variation in the overburden. Often the structural form of the trap itself is the cause. Non-flat seismic hydrocarbon contacts are seen at shallow gas hazards in Sakhalin, Russia; at oil fields in the Santos Basin, Brazil; and at 'gas on oil' accumulations in the Browse Basin, Australia. So, it appears that non-flat 'flatspots' are ubiquitous, suggesting an urgent name change is needed for this form of DHI. The interpretation of DHIs is aided by a new 2D synthetic modelling method that characterizes the time-depth behaviour of a field or prospect ... : Open-Access Online Publication: May 22, 2023 ...