Anthony Day

A Robust Strategy for Processing 3D Dual-sensor Towed Streamer Data

A dual-sensor streamer records not only the pressure field but additionally the vertical component of the particle velocity field. Properly matched records may be used to separate the total wavefield into up- and down-going parts. In this paper, we presen

Conventional Versus Dual-sensor Streamer Data De-ghosting; A Case Study From the Haltenbanken Dual-streamer Acquisition.

Recent developments in the field of marine towed streamer acquisition technologies have brought about new data information that needs to be assessed and compared to conventional data. Dual-sensor towed streamer acquisition, with its wave-field decomposition capabilities, is one such recent development. The present work compares conventional data with dual-sensor data acquired simultaneously at 2 different depths. The two streamers were towed vertically under each other, the conventional at 8m depth and the dual-sensor at 15m depth. To facilitate comparison the data from the two streamers have been processed optimally and in the same manner, i.e. wave field decomposition was also conducted on the conventional streamer data. The resulting up-going pressure field was compared to the up-going pressure field derived from the dual-sensor data. The comparison shows a clear advantage for the dual-sensor wave field decomposition result. Since the comparison is mostly limited to the low frequencies in this case, the superior result from the dual-sensor streamer data is attributed to better signal-to-noise ratio due to a deeper towing depth.

Space‐frequency domain processing of irregular dual‐sensor towed streamer data

When combining pressure and particle velocity sensor records obtained using a dual-sensor streamer, it is convenient to perform a number of processing steps in the frequency-wavenumber domain. This approach assumes that the recording surface is flat, and if this assumption is violated errors will be introduced. In this paper, we present a space-frequency domain method for processing dualsensor streamer data that removes the need to make this assumption. The method is illustrated using synthetic and field data examples.

Increased streamer depth for dual-sensor acquisition - Challenges and solutions

The towing depth applicable to dual sensor streamer acquisition has hitherto been limited by operational challenges associated with maintaining the fronts of the streamers at a deeper tow position, which creates additional drag, and noise recorded by the vertical particle velocity sensor. These restrictions have limited 3-D acquisition to a maximum towing depth of 20 m whilst 25 m towing depth is routinely used for 2-D acquisition. In July 2013, a field trial was performed with a slanted streamer, from 15m depth at the front to 30m at larger offsets. Since the front of the streamer is deployed at a depth routinely used for dual sensor streamer acquisition, such a slanted streamer profile is no more operationally difficult to achieve and has comparable noise performance to a horizontal streamer. Wavefield separation can be performed for arbitrary streamer profiles and the up-going wavefield output at a horizontal datum, thereby presenting no additional difficulties for subsequent processing steps. The benefit of deploying a substantial proportion of the streamer at greater depth is increased low frequency signal-to-noise ratio (less than 16 Hz). This uplift was demonstrated by comparing the data acquired using a slanted streamer profile to that obtained using a horizontal streamer.