Distinguishing fizz gas from commercial gas reservoirs using multicomponent seismic data

Zhu, Fuxing; Gibson, Richard L.; Watkins, John J.; Yuh, Sung

doi:10.1190/1.1438514

Cited by 19 publications

(3 citation statements)

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“…Duffant et al (2000) extracted SEI from a North Sea dataset and showed how instantaneous   can be obtained by combining SEI and EI. Converted P-S waves have also been used in identifying elastic rock properties (Jin et al, 2000;González, 2000;Wu, 2000;Zhu et al, 2000;Ramos and Castagna, 2001;etc). In this chapter, the concept of converted ray impedance (CRI) derived from the pseudo quadratic approximation of Zoeppritz equations for the P-S converted waves (Wang, 1999) is proposed.…”

Section: Chaptermentioning

confidence: 99%

Seismic ray‐impedance inversion

Wang¹

2016

Seismic Inversion

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This thesis investigates a prestack seismic inversion scheme implemented in the ray parameter domain. Conventionally, most prestack seismic inversion methods are performed in the incidence angle domain. However, inversion using the concept of ray impedance, as it honours ray path variation following the elastic parameter variation according to Snell's law, shows the capacity to discriminate different lithologies if compared to conventional elastic impedance inversion.The procedure starts with data transformation into the ray-parameter domain and then implements the ray impedance inversion along constant ray-parameter profiles. With different constant-ray-parameter profiles, mixed-phase wavelets are initially estimated based on the high-order statistics of the data and further refined after a proper well-toseismic tie. With the estimated wavelets ready, a Cauchy inversion method is used to invert for seismic reflectivity sequences, aiming at recovering seismic reflectivity sequences for blocky impedance inversion. The impedance inversion from reflectivity sequences adopts a standard generalised linear inversion scheme, whose results are utilised to identify rock properties and facilitate quantitative interpretation. It has also been demonstrated that we can further invert elastic parameters from ray impedance values, without eliminating an extra density term or introducing a Gardner's relation to absorb this term.Ray impedance inversion is extended to P-S converted waves by introducing the definition of converted-wave ray impedance. This quantity shows some advantages in connecting prestack converted wave data with well logs, if compared with the shearwave elastic impedance derived from the Aki and Richards approximation to the Zoeppritz equations. An analysis of P-P and P-S wave data under the framework of ray impedance is conducted through a real multicomponent dataset, which can reduce the uncertainty in lithology identification.

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Section: Chaptermentioning

confidence: 99%

Seismic ray‐impedance inversion

Wang¹

2016

Seismic Inversion

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“…Techniques to evaluate reservoir density (e.g. Wu, 2000, Zhu, et. al, 2000 should help in gas saturation analysis.…”

Section: Density and Attenuation Estimatementioning

confidence: 99%

‘Fizz water’ and low gas saturated reservoirs

Han¹,

Batzle²

2001

SEG Technical Program Expanded Abstracts 2001

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Numerous dry holes have been drilled based on false hydrocarbon indicators (DHI) and have been attributed to 'fizz water' effects. However, this 'fizz water' concept is illdefined and misunderstood. Newly measured data show that dissolved gas has negligible effect on water velocity. In addition, gas bubbles exsolving from either water or oil have only a small effect on fluid properties at pressures higher than about 20 Mpa (about 3000 Psi). Gas at high in situ pressure and temperature conditions has similar properties to light oil. Realistic gas properties must be used to estimate the properties of gas-liquid mixtures. Trapped original gas distribution in situ may be patchy (in layers or packets), while the exsolved or leaked gas distribution is likely to be relatively homogenous. Although fluid properties and gas distributions are complicated in deep-water reservoirs, seismic evaluation of gas saturation is possible. Developing seismic techniques to quantitatively calibrate hydrocarbon indicators in addition seismic evaluation of rock density and attenuation should lead to new integrated techniques for better evaluation of hydrocarbon saturation.

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“…Use of P-to-S converted waves (PS) has been suggested as a source of additional information that can help in these two situations, for example, Engelmark (2000) in the case of imaging reservoirs with low-impedance contrast, and Wu (2000), and Zhu et al (2000) for distinguishing high vs. low gas saturation. However, those works propose using PP and/or PS reflectivity (Rpp, Rps), which are interface properties.…”

Section: Introductionmentioning

confidence: 99%

Far offset P‐to‐S “elastic impedance” for lithology and partial gas saturation (fizz water) identification: Applications with well logs

González¹,

Mukerji²,

Mavko³

et al. 2003

SEG Technical Program Expanded Abstracts 2003

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In this paper, we present a formulation of P-to-S "elastic impedance" (PSEI), assuming the validity of convolutional model for PS converted waves and weak contrast between layers. We show how, for a particular analytically defined angle, PSEI can theoretically give a direct density estimator. Two applications with real well logs are shown: PSEI as best lithology differentiator in an Orinoco Belt example (also applicable to reservoirs with small acoustic impedance contrast between sands and shales), and PSEI to discriminate between commercial gas saturations and fizz water.

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Distinguishing fizz gas from commercial gas reservoirs using multicomponent seismic data

Cited by 19 publications

References 0 publications

Seismic ray‐impedance inversion

Seismic ray‐impedance inversion

‘Fizz water’ and low gas saturated reservoirs

Far offset P‐to‐S “elastic impedance” for lithology and partial gas saturation (fizz water) identification: Applications with well logs

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