in seismic data processing there is a step of calculating the absorption represented By Q value which is Q factor , how we can estimate it from VSP ! thank you.
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$\begingroup$ Do you have a paper or reference that your question is based on? As with all things to do with Q values, I bet there are 101+ ways of approximating the forward and inverse problems, so it'd be helpful to know exactly what case you are looking at. $\endgroup$– ErikMar 24, 2020 at 8:54
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1$\begingroup$ You migth find it here. I think the paper is free if you join, but not sure. researchgate.net/publication/… $\endgroup$– user18590Mar 24, 2020 at 11:43
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$\begingroup$ i need just one way that can help me to estimate the value of Q using VSP data and if there is a way without VSP you can tell me about it too , thank you ! $\endgroup$– Djabri JosefMar 24, 2020 at 21:41
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1$\begingroup$ thank you @Universal_learner that paper was so helpful . $\endgroup$– Djabri JosefMar 24, 2020 at 21:43
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$\begingroup$ You are welcome. If you wish, you can write your own answer to help others facing the same problem. $\endgroup$– user18590Mar 25, 2020 at 11:40
1 Answer
The simplest method is the spectral ratio method where the frequency spectra at two different depth levels in the VSP are computed and divided i.e. the ratio of the spectra. IN theory the slope of this spectral ratio is related to the attenaution factor Q. However, this method is not very robust and the data needs careful preconditioning to remove reflections, multiples, conversions etc. There are many others methods that have been developed and are described in the literature e.g. Geophysics.