- Copyright © 2003 Society of Exploration Geophysicists
Rapid advancements in multicomponent acquisition methods and processing techniques have led to numerous applications for converted wave (C-wave) data that are increasingly used for exploration and exploitation of oil and gas. However, the increased prevalence of multicomponent seismic applications means that interpreters must face many difficult challenges: how to register P-wave time to C-wave time, determine the best methodology for interpreting C-wave data, and/or how to apply the C-wave interpretation in assessing the risks of exploration and exploitation prospects. This paper addresses these issues and attempts to guide the interpreter through the multicomponent data interpretive process with numerous examples from two East Cameron gas fields in the Gulf of Mexico.
In the fall of 1999, PGS acquired the first commercial multicomponent 3D survey in the Gulf of Mexico. BP licensed the data in early 2000. The survey, approximately 80 km2 full fold, covers BP's East Cameron 261 and East Cameron 265 fields. The primary purpose of the survey was to address data degradation due to the presence of gas in the shallow sediments. Seismic imaging over these fields, which have more than 30 gas-bearing reservoirs in depths of less than 1000 ft to over 15 000 ft, has been hampered by severe velocity push-downs and gas cloud effects in the conventional P-wave data. The new 4C data, particularly the C-wave data, have unquestionably improved imaging in and below gas cloud areas. The fields were subsequently re-evaluated, and interpretation of new data resulted in a much more improved understanding of the hydrocarbon-bearing reservoirs which led to five consecutive successful exploitation wells in East Cameron 261.
Acquisition and processing
While it is not the intent of this paper to go into the details of acquisition and processing, the reader may be interested in how the survey was acquired and processed in order to compare …