Characterization of gas-charged sediments from joint inversion of Qp and Qs

Xiong Lei, Eugene C. Morgan

Research output: Contribution to journalConference article

2 Citations (Scopus)

Abstract

Seismic attenuation is an effective indicator of the presence of gas. However, quantitatively inverting rock physics models of attenuation is difficult because of large errors in attenuation estimates, the nonlinearity of these models, and their generally large number of input parameters (high dimensionality). In this paper, we propose to estimate properties of gas-charged sediments by jointly inverting P- and S-wave quality factors, which are inversely proportional to attenuation. We use the Dvorkin-Mavko attenuation model to functionally link Qp and Qs to key sediment properties of interest, such as water saturation and porosity. At first, the centroid-frequency-shift method is used to estimate the quality factor from OBS data of Finneidfjord, Norway, since it is a statistic-like method that can be used for broad bandwidth and high attenuation seismic data. Then, forward modeling is constructed as Dvorkin-Mavko attenuation model, which is sensitive to the gas saturation at different frequency bands. Lastly, we use a generic algorithm to do a joint Qp and Qs inversion process, computing the distribution of various parameters. The advantage of applying generic algorithm is its good performance on global optimization and feasibility of imposing a relatively realistic constraint on the search. We find good performance and agreeable values for gas saturation. But the ambiguity problem of the solution still needs to be further researching.

Original languageEnglish (US)
Pages (from-to)2765-2770
Number of pages6
JournalSEG Technical Program Expanded Abstracts
Volume34
DOIs
StatePublished - Jan 1 2015
EventSEG New Orleans Annual Meeting, SEG 2015 - New Orleans, United States
Duration: Oct 18 2011Oct 23 2011

Fingerprint

Sediments
sediments
attenuation
inversions
saturation
Gases
gases
gas
sediment
seismic attenuation
Saturation (materials composition)
sediment property
forward modeling
Global optimization
Q factors
nonlinearity
Frequency bands
estimates
P-wave
S-wave

All Science Journal Classification (ASJC) codes

  • Geotechnical Engineering and Engineering Geology
  • Geophysics

Cite this

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title = "Characterization of gas-charged sediments from joint inversion of Qp and Qs",
abstract = "Seismic attenuation is an effective indicator of the presence of gas. However, quantitatively inverting rock physics models of attenuation is difficult because of large errors in attenuation estimates, the nonlinearity of these models, and their generally large number of input parameters (high dimensionality). In this paper, we propose to estimate properties of gas-charged sediments by jointly inverting P- and S-wave quality factors, which are inversely proportional to attenuation. We use the Dvorkin-Mavko attenuation model to functionally link Qp and Qs to key sediment properties of interest, such as water saturation and porosity. At first, the centroid-frequency-shift method is used to estimate the quality factor from OBS data of Finneidfjord, Norway, since it is a statistic-like method that can be used for broad bandwidth and high attenuation seismic data. Then, forward modeling is constructed as Dvorkin-Mavko attenuation model, which is sensitive to the gas saturation at different frequency bands. Lastly, we use a generic algorithm to do a joint Qp and Qs inversion process, computing the distribution of various parameters. The advantage of applying generic algorithm is its good performance on global optimization and feasibility of imposing a relatively realistic constraint on the search. We find good performance and agreeable values for gas saturation. But the ambiguity problem of the solution still needs to be further researching.",
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Characterization of gas-charged sediments from joint inversion of Qp and Qs. / Lei, Xiong; Morgan, Eugene C.

In: SEG Technical Program Expanded Abstracts, Vol. 34, 01.01.2015, p. 2765-2770.

Research output: Contribution to journalConference article

TY - JOUR

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AU - Lei, Xiong

AU - Morgan, Eugene C.

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