A unified framework for the deconvolution of traces of nonwhite reflectivity

Geophysics ◽  
2000 ◽  
Vol 65 (5) ◽  
pp. 1660-1676 ◽  
Author(s):  
M. M. Saggaf ◽  
Enders A. Robinson

One of the fundamental assumptions of conventional deconvolution methods is that reflection coefficients follow the white‐noise model. However, analysis of well logs in various regions of the world confirms that in the majority of cases, reflectivity tends to depart from the white‐noise behavior. The assumption of white noise leads to a conventional deconvolution operator that can recover only the white component of reflectivity, thus yielding a distorted representation of the desired output. Various alternative processes have been suggested to model reflection coefficients. In this paper, we will examine some of these processes, apply them, contrast their stochastic properties, and critique their use for modeling reflectivity. These processes include autoregressive moving average (ARMA), scaling Gaussian noise, fractional Brownian motion, fractional Gaussian noise, and fractionally integrated noise. We then present a consistent framework to generalize the conventional deconvolution procedure to handle reflection coefficients that do not follow the white‐noise model. This framework represents a unified approach to the problem of deconvolving signals of nonwhite reflectivity and describes how higher‐order solutions to the deconvolution problem can be realized. We test generalized filters based on the various stochastic models and analyze their output. Because these models approximate the stochastic properties of reflection coefficients to a much better degree than white noise, they yield generalized deconvolution filters that deliver a significant improvement on the accuracy of seismic deconvolution over the conventional operator.

2013 ◽  
Vol 7 (0) ◽  
pp. 991-1018 ◽  
Author(s):  
B. T. Szabó ◽  
A. W. van der Vaart ◽  
J. H. van Zanten

Author(s):  
Sheng Xu ◽  
Chun-yan Ji ◽  
C Guedes Soares

In this article, a novel mooring system with side-mooring lines is proposed for a traditional shape semi-submersible platform with four columns. To obtain the dynamics of moored system, model tests were carried out at a wave basin, including free-decay model tests, white noise model tests and irregular model tests. The natural periods in heave, roll and pitch models were measured and compared with numerical results. The motion response amplitude operators under 90° and 135° waves were obtained from white noise model tests and then compared with numerical simulations. A 100-year sea state in South China Sea was simulated in the wave basin by the JONSWAP spectrum, and the 6-degree-of-freedom motion responses of semi-submersible and mooring tensions were recorded in beam and quartering seas. The effects of the side-mooring lines on the floating platform motion response, mooring tensions and mooring fatigue damage are evaluated by comparing the results with and without side-mooring lines installed.


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