2D CMP seismic acquisition is carried out using conventional single-vessel technology with towed streamer as long as 3,000-6,000 m and within the range of 240-480 number of channels. All recording, signal excitation equipment and QC group are located on the same vessel-carrier. PGS-Khazar LLC has developed and successfully applies the unique technology, which makes it possible to perform seismic acquisition using the streamer as long as 4500m within up to 3,5m depth. The total make of such works, which were performed in the waters of the Caspian Sea (the Kazakh sector) is more than 5000 linear km at depths of 3,5-6m.
The number of air-guns (GGun, MiniGGun, BOLT) and their volume in an array is calculated and experimentally selected taking into account the required acquisition depth, sea depth and environmental restrictions.
2D HRS CMP and 2D UHRS CMP acquisition for detailed splitting of the near-surface section (performed for soil survey) is carried out using the similar technology. The length of seismic cables is usually equal to 300-1200 m and the channel interval and hydrophone group length are 3,125m or 6.25 m.
Bolt 2800 LLX HR or MiniGGun air-guns are used as energy sources for HRS survey ensuring wide frequency band in the range 20-450 Hz.
The specially designed ultra-high frequency air sources Malysh-UHF are used as UHFSenergy sources ensuring wide frequency band in the range 100-750 Hz. |