##### A probabilistic model for ghost delay time estimation based on recording geometry

Authors:
J. Ricket and I. Cec´ılio

Journal name: Geophysical Prospecting

Issue: Vol 66, No 5, June 2018 pp. 964 - 974

DOI: 10.1111/1365-2478.12524

Organisations:
Wiley

Language: English

Info: Article, PDF ( 5.09Mb )

Summary:

In order to deconvolve the ghost response from marine seismic data, an estimate of
the ghost operator is required. Typically, this estimate is made using a model of inplane
propagation, i.e., the ray path at the receiver falls in the vertical plane defined
by the source and receiver locations. Unfortunately, this model breaks down when
the source is in a crossline position relative to the receiver spread. In this situation,
in-plane signals can only exist in a small region of the signal cone.
In this paper, we use Bayes’ theory to model the posterior probability distribution
functions for the vertical component of the ray vector given the known source–
receiver azimuth and the measured inline component of the ray vector. This provides
a model for the ghost delay time based on the acquisition geometry and the dip of the
wave in the plane of the streamer. The model is fairly robust with regard to the prior
assumptions and controlled by a single parameter that is related to the likelihood of
in-plane propagation.
The expected values of the resulting distributions are consistent with the deterministic
in-plane model when in-plane likelihood is high but valid everywhere in the signal
cone. Relaxing the in-plane likelihood to a reasonable degree radically simplifies the
shape of the expected-value surface, lending itself for use in deghosting algorithms.
The model can also be extended to other plane-wave processing problems such as
interpolation.

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