) Main Technical Benefits of 3D OBC Acquisition

In offshore streamer operations, the surveying, receiver, source and the recording process is synchronous. In 3D Ocean Bottom Cable acquisition, this process is more comparable to the desynchronized process of onshore operations. This explains the higher cost of such operations, compounded by the difficulty involved in deploying equipment in obstructed or very shallow waters and hence the large amount and variety of specialized heavy-duty and waterproof equipment required. Despite this cost drawback, 3D OBC acquisition offers many geophysical and technical advantages over regular surface marine streamer acquisition which include: Fixed receiver spread compared to moving marine streamer, reducing noise level. Land type split spread and wide azimuth 3D geometries.; Patch or swath type shooting with shot lines either in line or cross line.; Source energy adaptable to water depth.; Possible continuous connection from land to sea over shore.; Receiver deghosting with dual sensor summation of hydrophone and vertical geophone signals recorded at the same position.; Coupling of sensors adapted to sea bottom conditions.; Options of recording converted waves with 4C sensors (one hydrophone and 3 orthogonal geophones) and processing the shear wave data to increase reservoir knowledge.This presentation will detail these different topics and show some examples of parameters and the current state of the art of OBC marine and geophysical equipment