The University of Southampton
University of Southampton Institutional Repository

Characterization of the slope-destabilizing effects of gas-charged sediment via seismic surveys

Characterization of the slope-destabilizing effects of gas-charged sediment via seismic surveys
Characterization of the slope-destabilizing effects of gas-charged sediment via seismic surveys
Finneidfjord, Norway has a history of submarine slope failure and hosts areas of buried, gas-charged sediment. Using shipboard seismic survey data from Finneidfjord, we illustrate how novel seismic data processing techniques can yield estimates of geotechnical properties of this gas-charged sediment. This data processing involves two steps: 1) estimate the amount of seismic attenuation that a gas-bearing layer creates, and 2) fit a wave attenuation model to the observed attenuation. We accomplish the first step using a wavelet-based spectral ratio approach, and find the seismic quality factor (inversely related to attenuation) from the change in amplitude spectra across the gas layer. The novelty of this paper really comes in the second step, where we create a Bayesian hierarchical model that combines a wave attenuation model with a spatial random (Gaussian) process model. The advantage of this combination is that our estimates of the gas properties not only must conform to the observations of attenuation (quality factor), but must also smoothly vary over space, as one would expect of any natural process. Ultimately, we end up with posterior distributions of gas properties at points throughout our gas-bearing layer. We use these posterior distributions to probabilistically evaluate the role that gas plays in slope failures in Finneidfjord. This method has other applications in natural gas resource exploration and carbon sequestration.
OTC-25196
Offshore Technology Conference
Morgan, Eugene
bf724358-8351-4c0e-99ce-cb2254b5e54d
Vanneste, Maarten
6ca23aee-5aa7-4dca-9f86-791e5c4a6d82
Vardy, Mark E.
8dd019dc-e57d-4b49-8f23-0fa6d246e69d
Morgan, Eugene
bf724358-8351-4c0e-99ce-cb2254b5e54d
Vanneste, Maarten
6ca23aee-5aa7-4dca-9f86-791e5c4a6d82
Vardy, Mark E.
8dd019dc-e57d-4b49-8f23-0fa6d246e69d

Morgan, Eugene, Vanneste, Maarten and Vardy, Mark E. (2014) Characterization of the slope-destabilizing effects of gas-charged sediment via seismic surveys. In Proceedings of the Offshore Technology Conference 2014. Offshore Technology Conference. OTC-25196 . (doi:10.4043/25196-MS).

Record type: Conference or Workshop Item (Paper)

Abstract

Finneidfjord, Norway has a history of submarine slope failure and hosts areas of buried, gas-charged sediment. Using shipboard seismic survey data from Finneidfjord, we illustrate how novel seismic data processing techniques can yield estimates of geotechnical properties of this gas-charged sediment. This data processing involves two steps: 1) estimate the amount of seismic attenuation that a gas-bearing layer creates, and 2) fit a wave attenuation model to the observed attenuation. We accomplish the first step using a wavelet-based spectral ratio approach, and find the seismic quality factor (inversely related to attenuation) from the change in amplitude spectra across the gas layer. The novelty of this paper really comes in the second step, where we create a Bayesian hierarchical model that combines a wave attenuation model with a spatial random (Gaussian) process model. The advantage of this combination is that our estimates of the gas properties not only must conform to the observations of attenuation (quality factor), but must also smoothly vary over space, as one would expect of any natural process. Ultimately, we end up with posterior distributions of gas properties at points throughout our gas-bearing layer. We use these posterior distributions to probabilistically evaluate the role that gas plays in slope failures in Finneidfjord. This method has other applications in natural gas resource exploration and carbon sequestration.

This record has no associated files available for download.

More information

Published date: 8 May 2014
Venue - Dates: OTC 2014, Houston, United States, 2014-05-05 - 2014-05-08
Organisations: Geology & Geophysics

Identifiers

Local EPrints ID: 364844
URI: http://eprints.soton.ac.uk/id/eprint/364844
PURE UUID: a53fd4c8-8405-4c0a-9405-cf9b5380e325

Catalogue record

Date deposited: 13 May 2014 08:31
Last modified: 14 Mar 2024 16:42

Export record

Altmetrics

Contributors

Author: Eugene Morgan
Author: Maarten Vanneste
Author: Mark E. Vardy

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×