Calibrated Marine Source (CMS) System

Time-lapse (4D) acquisition

Shot-to-shot variations reduce the resolution and repeatability of seismic data. Q-Marine technology uses the notional source method, (Ziolkowski et al., 1982), to compute the source array output for each shot from nearfield hydrophone recordings, ensuring that an accurate signature can be derived for every shot. Measurement and compensation for variations in the source signature between phases of a 4D study remove a major perturbation from the time-lapse signal and bring new confidence to amplitude interpretation.

A deterministic operator is derived for each individual shot in a survey allowing determination of a common target signature. Once the vertical signature has been stabilized, a second pass of directional de-signature can be applied to ensure amplitude fidelity as a function of offset.

The example (right) illustrates how the calibrated marine source system can compensate for shot-to-shot variations in the source array output. On the left are the data before application of the shot-to-shot calibration and, on the right, the data after deconvolution.