Generally sub-bottom profiling (SBP) systems are single-channel systems used to acquire shallow reflection seismic profiling. A variety of Sub-bottom profiling systems are available, these systems function at differing transmit frequencies and this has an effect on the resultant resolution and the depth of acoustic penetration below the seabed.
Lower frequency sound sources produce deeper acoustic penetration below the seabed however, as a consequence of low transmit frequency a lower resultant resolution is achieved. Higher frequency systems achieve less penetration but produce higher resolution data.
The sub-bottom profiling penetration depth is related to the transmit frequency, source energy and the nature of seabed geology, for example, layers of course sands or near seabed gas blanking will often severely limit penetration and with only one receiving channel available low amplitude reflected signals in these zones may be lost within the ambient noise created by the survey vessel its self and or the sea state.
Listed below are a number of most commonly used sub-bottom profiling equipment and their operational characteristics:
Multi-channel solutions offer the ability to significantly increase the signal to noise ratio and recover low amplitude signals buried within noise by stacking and processing data however, the survey industry today has moved towards digital multi-channel streamers which can provide better reliability than multi-channel analogue streamers of an earlier design.
There are a number of disadvantages in using digital streamer systems for ultra high resolution (UHR) data acquisition such as the purchase cost, physical size and the added cost and time required for post acquisition processing.
The ProSeis x16 reduces the costs of acquisition by employing purpose built short group analogue streamers and vessel side high specification analogue to digital conversion, system software acquires, stacks and processes data in near real time ready for interpretation by removing the need for onboard processing equipment and personnel.