Estimating gas saturation in a thin layer by using frequency‐dependent amplitude versus offset modelling

Jin, Zhaoyu; Chapman, Mark; Wu, Xiaomin; Papageorgiou, Grigorios

doi:10.1111/1365-2478.12437

Cited by 20 publications

(15 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Combined seismic data and prior information can be integrated into the Bayesian inversion theory framework and has been widely used in seismic inversion and other algorithms (Buland and Omre 2003;Rabben et al 2008;Alemie and Sacchi 2011;Bachrach 2015;Zhou et al (2017a, b); Wu et al 2014;Jin et al 2017Jin et al , 2018. When using Bayesian theorem to construct an objective function, the likelihood function of the data can be expressed: (b) (a) T represents the model parameters vector where , , , and are interested parameters (two vertical velocities, density and two Thomsen anisotropic parameters; each of them is a vector with N elements, and N is the size of model parameters).…”

Section: Prestack Ava Inversionmentioning

confidence: 99%

Nonlinear amplitude versus angle inversion for transversely isotropic media with vertical symmetry axis using new weak anisotropy approximation equations

Zhou

Chen

et al. 2020

Pet. Sci.

View full text Add to dashboard Cite

In VTI media, the conventional inversion methods based on the existing approximation formulas are difficult to accurately estimate the anisotropic parameters of reservoirs, even more so for unconventional reservoirs with strong seismic anisotropy. Theoretically, the above problems can be solved by utilizing the exact reflection coefficients equations. However, their complicated expression increases the difficulty in calculating the Jacobian matrix when applying them to the Bayesian deterministic inversion. Therefore, the new reduced approximation equations starting from the exact equations are derived here by linearizing the slowness expressions. The relatively simple form and satisfactory calculation accuracy make the reduced equations easy to apply for inversion while ensuring the accuracy of the inversion results. In addition, the blockiness constraint, which follows the differentiable Laplace distribution, is added to the prior model to improve contrasts between layers. Then, the concept of GLI and an iterative reweighted least-squares algorithm is combined to solve the objective function. Lastly, we obtain the iterative solution expression of the elastic parameters and anisotropy parameters and achieve nonlinear AVA inversion based on the reduced equations. The test results of synthetic data and field data show that the proposed method can accurately obtain the VTI parameters from prestack AVA seismic data.

show abstract

Section: Prestack Ava Inversionmentioning

confidence: 99%

Nonlinear amplitude versus angle inversion for transversely isotropic media with vertical symmetry axis using new weak anisotropy approximation equations

Zhou

Chen

et al. 2020

Pet. Sci.

View full text Add to dashboard Cite

show abstract

“…Even in post-stack seismic data, the existence of noise will affect interpretation result which directly links the seismic images with subsurface oil & gas reservoirs (Wang et al 2011;Chen 2015bChen , 2016Gan et al 2016e;Ren & Tian 2016;Zhang et al 2016e). A successful separation between useful reflection signals and unwanted noise is a long standing problem in the area of seismic data processing and greatly affects the fidelity of subsequent seismic imaging and geophysical inversion, like amplitude-variation-with-offset (AVO) inversion, full waveform inversion, attenuation estimation and geological interpretation (He & Wu 2015;Li et al 2016a;Lines et al 2016;Liu et al 2016a;Mousavi & Langston 2016a,b;Mousavi et al 2016;Qu & Verschuur 2016;Qu et al 2016a;Zhang et al 2016f;Jin et al 2017;Li et al 2017;Ebrahimi et al 2017;Mousavi & Langston 2017). Effectively rejecting the cross-talk interference caused in the simultaneous-source seismic acquisition also plays a significant role in tremendously saving the data recording cost (Berkhout 2008;Qu et al 2014Qu et al , 2015Qu et al , 2016bAbma et al 2015;Chen 2015a;Zu et al 2015Zu et al , 2017aZhou 2017).…”

Section: Introductionmentioning

confidence: 99%

Seismic noise attenuation using an online subspace tracking algorithm

Zhou

Zhang

et al. 2020

Geophysical Journal International

View full text Add to dashboard Cite

SUMMARY We propose a new low-rank based noise attenuation method using an efficient algorithm for tracking subspaces from highly corrupted seismic observations. The subspace tracking algorithm requires only basic linear algebraic manipulations. The algorithm is derived by analysing incremental gradient descent on the Grassmannian manifold of subspaces. When the multidimensional seismic data are mapped to a low-rank space, the subspace tracking algorithm can be directly applied to the input low-rank matrix to estimate the useful signals. Since the subspace tracking algorithm is an online algorithm, it is more robust to random noise than traditional truncated singular value decomposition (TSVD) based subspace tracking algorithm. Compared with the state-of-the-art algorithms, the proposed denoising method can obtain better performance. More specifically, the proposed method outperforms the TSVD-based singular spectrum analysis method in causing less residual noise and also in saving half of the computational cost. Several synthetic and field data examples with different levels of complexities demonstrate the effectiveness and robustness of the presented algorithm in rejecting different types of noise including random noise, spiky noise, blending noise, and coherent noise.

show abstract

“…() and Jin et al . () attempted to estimate gas saturation using frequency‐dependent AVO analysis. Jin et al .…”

Section: Introductionmentioning

confidence: 99%

Frequency‐dependent PP and PS reflection coefficients in fractured media

Pang

Stovas

2019

Geophysical Prospecting

View full text Add to dashboard Cite

A B S T R A C TWhen a porous layer is permeated by mesoscale fractures, wave-induced fluid flow between pores and fractures can cause significant attenuation and dispersion of velocities and anisotropy parameters in the seismic frequency band. This intrinsic dispersion due to fracturing can create frequency-dependent reflection coefficients in the layered medium. In this study, we derive the frequency-dependent PP and PS reflection coefficients versus incidence angle in the fractured medium. We consider a two-layer vertical transverse isotropy model constituted by an elastic shale layer and an anelastic sand layer. Using Chapman's theory, we introduce the intrinsic dispersion due to fracturing in the sand layer. Based on the series coefficients that control the behaviour of velocity and anisotropy parameters in the fractured medium at low frequencies, we extend the conventional amplitude-versus-offset equations into frequency domain and derive frequency-dependent amplitude-versus-offset equations at the elastic-anelastic surface. Increase in fracture length or fracture density can enlarge the frequency dependence of amplitude-versus-offset attributes of PP and PS waves. Also, the frequency dependence of magnitude and phase angle of PP and PS reflection coefficients increases as fracture length or fracture density increases. Amplitude-versus-offset type of PP and PS reflection varies with fracture parameters and frequency. What is more, fracture length shows little impact on the frequencydependent critical phase angle, while the frequency dependence of the critical phase angle increases with fracture density.

show abstract

Estimating gas saturation in a thin layer by using frequency‐dependent amplitude versus offset modelling

Cited by 20 publications

References 59 publications

Nonlinear amplitude versus angle inversion for transversely isotropic media with vertical symmetry axis using new weak anisotropy approximation equations

Nonlinear amplitude versus angle inversion for transversely isotropic media with vertical symmetry axis using new weak anisotropy approximation equations

Seismic noise attenuation using an online subspace tracking algorithm

Frequency‐dependent PP and PS reflection coefficients in fractured media

Contact Info

Product

Resources

About