We took advantage of an operational acquisition to record some test sail lines at the same location using a Conventional Flat Towed Streamer (CTS) configuration and a Variable-Depth Streamer (VDS) configuration, each configuration being acquired twice in order to enable a comparison in a 4D sense.
This dataset has been used to assess the impact of such acquisition modes and related broadband processing over the potential recovery of a 4D signal.
Since the area of acquisition is not a producing field and the time lapse between acquired sequences is counted in hours or days, the expected 4D difference is expected to be close to zero.
Preliminary results of our analysis show that VDS (baseline or monitor) over CTS (baseline or monitor) gives similar or slightly worse results than CTS (baseline) over the CTS (monitor). The repeated VDS sail line pairs tend to give an acceptable result within the conventional frequency bandwidth and far better results when considering the lower frequencies. However, we also observe that the current condition (feathering) and the sea state (swell noise) have impacted the results and the conclusions need to be mitigated with these limitations.
In terms of processing, we acknowledge that, today, broadband processing is more complex than conventional processing (whatever the broadband acquisition is: Variable Depth Streamer or Multi-Sensor Streamer). This is even truer for 4D processing. Deghosting, matching and absorption compensation is much trickier and needs higher levels of testing and QC in addition to a more appropriate de-noising phase.
Presentation Date: Tuesday, September 26, 2017
Start Time: 2:40 PM
Location: 351F
Presentation Type: ORAL