Publications

We present the results of a feasibility study performed to asses the benefits of a broadband acquisition in the characterization of a gas field located in a slope channel environment. Reason behind this work was the need to give an answer to the following questions: what is the expected maximum resolution achievable and how to “fit” the 3D acquisition to elastic inversion? First question, resolution, is related to wavelet bandwidth, the broader the bandwidth the higher the resolution. To have a broadband seismic dataset we have to acquire and process the data in broadband of course, however a key factor to be evaluated is the earth response, and in particular attenuation. During the study different methodologies were adopted to compute the Q factor, leading to a concordant value. The knowledge of the attenuation of the earth allowed the estimation of the maximum achievable frequency content at target level both for a conventional and a broadband acquisition. First result of the study is quite obvious a posteriori: no increase in the high frequency can be expected in a low pass earth system, and this was our case. However we estimated that the low end of the frequency spectrum could be significantly enlarged, up to one octave, with a broadband acquisition. How this spectrum broadening can results in tangible benefits in the interpretation and characterisation of the gas field? To answer, a visco-elastic modelling of conventional and broadband CMP gathers at wells location was performed and the modelling was validated by conventional real data comparison. Moreover the