Shear‐wave velocity and density estimation from <i>PS</i>-wave AVO analysis: Application to an OBS dataset from the North Sea

Jin, Side; Cambois, Guillaume; Vuillermoz, C.

doi:10.1190/1.1444833

Cited by 48 publications

(18 citation statements)

References 17 publications

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“…Valenciano and Michelena (2000) used a small-offset approximation to equation (1) to develop an inversion procedure for stacked P-S data. Jin et al (2000) applied an AVO inversion technique to an OBS data set from the North Sea. They illustrated the practical use of AVO inversion for S-wave velocity and density for seismic reservoir characterization; in particular, for fluid contact detection and pore fluid change.…”

Section: P-s Data Processingmentioning

confidence: 99%

Converted‐wave seismic exploration: Methods

Gaiser²,

et al. 2002

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Multicomponent seismic recording (measurement with vertical-and horizontal-component geophones and possibly a hydrophone or microphone) captures the seismic wavefield more completely than conventional single-element techniques. In the last several years, multicomponent surveying has developed rapidly, allowing creation of converted-wave or P-S images. These make use of downgoing P-waves that convert on reflection at their deepest point of penetration to upcoming S-waves. Survey design for acquiring P-S data is similar to that for P-waves, but must take into account subsurface V P /V S values and the asymmetric P-S ray path. P-S surveys use conventional sources, but require several times more recording channels per receiving location. Some special processes for P-S analysis include anisotropic rotations, S-wave receiver statics, asymmetric and anisotropic binning, nonhyperbolic velocity analysis and NMO correction, P-S to P-P time transformation, P-S dip moveout, prestack migration with two velocities and wavefields, and stacking velocity and reflectivity inversion for S-wave velocities.Current P-S sections are approaching (and in some cases exceeding) the quality of conventional P-P seismic data. Interpretation of P-S sections uses full elastic ray tracing, synthetic seismograms, correlation with P-wave sections, and depth migration. Development of the P-S method has taken about 20 years, but has now become commercially viable.

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Section: P-s Data Processingmentioning

confidence: 99%

Converted‐wave seismic exploration: Methods

Gaiser²,

et al. 2002

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“…Density appears poorly resolved by AVA analysis when using P‐wave data (Fig. 3, top right; see also Tarantola 1986; De Nicolao et al 1993; Debski and Tarantola 1995; Jin et al 2000; Castagna 2004). This is mainly because P‐wave reflection coefficients only become sensitive to density variations at very large angles of incidence.…”

Section: Resultsmentioning

confidence: 99%

“…One potential way of obtaining reliable information about density is through the amplitude‐versus‐angle analysis of converted waves (Jin et al 2000). In their pioneering work, Jin et al (2000) imaged 2D maps of shear‐wave velocity and density remarkably well from near‐surface P‐S data collected with an ocean‐bottom cable. This helped in detecting fluid contacts and delineating the extent of a reservoir sand in the North Sea.…”

Section: Introductionmentioning

confidence: 99%

Borehole‐guided AVO analysis of P‐P and P‐S reflections: Quantifying uncertainty on density estimates

Djikpesse

Meghirbi

Nizkous

et al. 2006

Geophysical Prospecting

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A B S T R A C TSeismic properties of isotropic elastic formations are characterized by the three parameters: acoustic impedance, Poisson's ratio and density. Whilst the first two are usually well estimated by analysing the amplitude variation with angle (AVA) of reflected P-P waves, density is known to be poorly resolved. However, density estimates would be useful in many situations encountered in oil and gas exploration, in particular, for minimizing risks in looking ahead while drilling. We design a borehole seismic experiment to investigate the reliability of AVA extracted density. Receivers are located downhole near the targeted reflectors and record reflected P-P and converted P-S waves. A non-linear, wide-angle-based Bayesian inversion is then used to access the a posteriori probability distributions associated with the estimation of the three isotropic elastic parameters. The analysis of these distributions suggests that the angular variation of reflected P-S amplitudes provides additional substantial information for estimating density, thus reducing the estimate uncertainty variance by more than one order of magnitude, compared to using only reflected P-waves.

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“…On the other hand, the inversion system for Q is more stable than the AVO (amplitude versus offset) analysis studied and practiced in the oil industry for the last 20 years. It is known that in AVO analysis, a 10% error in incident angles could result in a 40% error in reflection coefficients (Jin et al, 2000). Xia et al (2002c) used an algorithm (Menke, 1984) with a modification of introducing a damping factor to solve Q P and/or Q S from attenuation coefficients of Rayleigh waves.…”

Section: Near-surface Qmentioning

confidence: 99%

High-frequency Rayleigh-Wave method

Xia

Miller

et al. 2009

J. Earth Sci.

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High-frequency (≥2 Hz) Rayleigh-wave data acquired with a multichannel recording system have been utilized to determine shear (S)-wave velocities in near-surface geophysics since the early 1980s. This overview article discusses the main research results of high-frequency surface-wave techniques achieved by research groups at the Kansas Geological Survey and China University of Geosciences in the last 15 years. The multichannel analysis of surface wave (MASW) method is a non-invasive acoustic approach to estimate near-surface S-wave velocity. The differences between MASW results and direct borehole measurements are approximately 15% or less and random. Studies show that simultaneous inversion with higher modes and the fundamental mode can increase model resolution and an investigation depth. The other important seismic property, quality factor (Q), can also be estimated with the MASW method by inverting attenuation coefficients of Rayleigh waves. An inverted model (S-wave velocity or Q) obtained using a damped least-squares method can be assessed by an optimal damping vector in a vicinity of the inverted model determined by an objective function, which is the trace of a weighted sum of model-resolution and model-covariance matrices. Current developments include modeling high-frequency Rayleigh-waves in near-surface media, which builds a foundation for shallow seismic or Rayleigh-wave inversion in the time-offset domain; imaging dispersive energy with high resolution in the frequency-velocity domain and possibly with data in an arbitrary acquisition geometry, which opens a door for 3D surface-wave techniques; and successfully separating surface-wave modes, which provides a valuable tool to perform S-wave velocity profiling with high-horizontal resolution.

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Shear‐wave velocity and density estimation from PS-wave AVO analysis: Application to an OBS dataset from the North Sea

Cited by 48 publications

References 17 publications

Converted‐wave seismic exploration: Methods

Converted‐wave seismic exploration: Methods

Borehole‐guided AVO analysis of P‐P and P‐S reflections: Quantifying uncertainty on density estimates

High-frequency Rayleigh-Wave method

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