气候变化领域集成服务门户(CCPortal): Prediction of Elastic Properties Within CO2 Plume at Sleipner Field Using AVS Inversion Modified for Thin-Layer Reflections Guided by Uncertainty Estimation

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DOI	10.1029/2020JB019782
	Prediction of Elastic Properties Within CO2 Plume at Sleipner Field Using AVS Inversion Modified for Thin-Layer Reflections Guided by Uncertainty Estimation
	Ghosh R.; Ojha M.
发表日期	2020
ISSN	21699313
卷号	125 期号:11
英文摘要	Existing amplitude variation with offset (AVO) and slowness (AVS) theories fail to interpret observed amplitudes in terms of actual elastic properties of the media for a reflection event resulting from a stack of thin layers. We propose a method to replace the stack of thin layers with an equivalent medium of elastic properties using the Backus averaging theory. Numerical examples show considerable deviation in intercept calculated from the modified AVO and AVS theories from the conventional methods. AVS theory is preferred as it can be applied irrespective of impedance contrast in both precritical and postcritical reflections, and no spherical divergence correction is required. P and S wave velocities, density, and thickness of thin layers are determined using the inversion scheme of very fast simulated annealing (VFSA). Uncertainty in prediction is evaluated using an approximate marginal posterior probability density function and a parameter correlation matrix. We demonstrate our methodology on synthetic and real seismic data from the Sleipner field, which is a good example of enhanced seismic amplitudes due to interference among reflections from thin layers. We select 11 common depth point (CDP) gathers for amplitude analysis of four identified reflectors along a line of 3-D seismic data acquired in 2008. Predicted mean models of CO2-saturated sand layers at all locations show that the thickness, density, and P and S wave velocities vary from 5–7 m, 1.8–2.0 g/cm3, and 1,460–1,490 and 630–650 m/s, respectively. Our analysis suggests that the model parameters are well constrained and independent except at a few locations. © 2020. American Geophysical Union. All Rights Reserved.
英文关键词	AVS/AVO; CO2 sequestration; elastic property; thin layer; uncertainty; VFSA
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187485
作者单位	CSIR-National Geophysical Research Institute, Hyderabad, India
推荐引用方式 GB/T 7714	Ghosh R.,Ojha M.. Prediction of Elastic Properties Within CO2 Plume at Sleipner Field Using AVS Inversion Modified for Thin-Layer Reflections Guided by Uncertainty Estimation[J],2020,125(11).
APA	Ghosh R.,&Ojha M..(2020).Prediction of Elastic Properties Within CO2 Plume at Sleipner Field Using AVS Inversion Modified for Thin-Layer Reflections Guided by Uncertainty Estimation.Journal of Geophysical Research: Solid Earth,125(11).
MLA	Ghosh R.,et al."Prediction of Elastic Properties Within CO2 Plume at Sleipner Field Using AVS Inversion Modified for Thin-Layer Reflections Guided by Uncertainty Estimation".Journal of Geophysical Research: Solid Earth 125.11(2020).