摘要
In Oilfield A, of south Bohai, the large area (20km^2) of gas in the shallow layer of the main structure makes a "gas cloud" effect in the seismic section. It makes the seismic migration imaging of the deeper aim layer inconsistent with the actual features of a geologic structure. But, the converted waves,PS waves, containing effective information of incident compressed (P) waves, can create converted S waves. The S wave is affected little by the shallow layer screen, allowing better imaging of the deeper layer. So, 4C seismic acquisition was carried out on the structure. Through geologic reconnaissance on the site, shallow layer drilling analysis and multicomponent seismic experiments, the offshore acquisition flows are designed. Choosing appropriate processing flows for converted waves and paying attention to the key tache of processing, a high quality 2D converted wave section was obtained. By identifying the character of the seismic wave correctly, making use of the full wave logging, producing synthetic converted wave seismogram, and identifying horizon, we can carry out structure interpretation and reserve evaluation of the oilfield.
In Oilfield A, of south Bohai, the large area (20km2) of gas in the shallow layer of the main structure makes a “gas cloud” effect in the seismic section. It makes the seismic migration imaging of the deeper aim layer inconsistent with the actual features of a geologic structure. But, the converted waves, PS waves, containing effective information of incident compressed (P) waves, can create converted S waves. The S wave is affected little by the shallow layer screen, allowing better imaging of the deeper layer. So, 4C seismic acquisition was carried out on the structure. Through geologic reconnaissance on the site, shallow layer drilling analysis and multicomponent seismic experiments, the offshore acquisition flows are designed. Choosing appropriate processing flows for converted waves and paying attention to the key tache of processing, a high quality 2D converted wave section was obtained. By identifying the character of the seismic wave correctly, making use of the full wave logging, producing synthetic con- verted wave seismogram, and identifying horizon, we can carry out structure interpretation and reserve evaluation of the oilfield.
