Pseudo-gamma ray volume from extended elastic impedance inversion for gas exploration

Neves, Fernando; Mustafa, Husam M.; Rutty, Patrick M.

doi:10.1190/1.1766237

Cited by 16 publications

(1 citation statement)

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“…This would require the integration of seismic and well data for enhanced vertical and lateral resolution for quantitative interpretation. Seismic inversion is a sophisticated tool used by the oil and gas companies to integrate 3D seismic data with petrophysical measurements from wells to improve spatial resolution, reduce risk in exploration and enhance development plan (Neves et al 2004;Avseth et al 2005;Alfaro et al 2007;Suslick et al 2009;Adeoti et al 2017). Since reflected seismic wave amplitudes are functions of acoustic/ elastic impedance, it becomes necessary to analysis seismic data stacked at various offset and angle of incidence ranges to exploit AVO (amplitude variation with offset)/ AVA (amplitude variation with angle) information in the data.…”

Section: Introductionmentioning

confidence: 99%

Hydrocarbon reservoir delineation using simultaneous and elastic impedance inversions in a Niger Delta field

Adesanya

Adeoti

Oyedele

et al. 2021

J Petrol Explor Prod Technol

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The global energy demand is increasing while production from mature fields is drastically reducing consequently, oil and gas industries are expanding activities into more challenging areas. The inability of the traditional seismic data to properly delineate hydrocarbon reservoirs from subtle seismic features in ‘Sandfish’ field located offshore, Niger Delta informed the use of simultaneous and elastic impedance inversion. The elastic and derived volumes from seismic inversion would reduce risk, enhance hydrocarbon discovery and optimize development plans in the study area. Four ‘Sandfish’ (Sfn) wells (Sfn-01, Sfn-02, Sfn-04 and Sfn-05), check-shots and 3D seismic data of five angle stacks (6–12°, 12–18°, 18–26°, 26–32° and 32–42°) were used in the study. Low frequency (0–2 Hz) models were generated from interpolation of high-cut-filtered compressional wave velocity log (P-sonic), shear wave velocity log (S-sonic) and density log guided by interpreted four seismic horizons. The low frequency models broaden the spectrum of the elastic volumes and also served as inversion constraints. The five partial angle stacks varying from 6–42° were simultaneously inverted using Jason’s Rock-Trace® inversion software which iterated trial inversions until the model sufficiently matched the seismic data. The near (6–12°) angle and far-far (32–42°) angle stacks were also inverted and compared with the inverted volumes from the simultaneous inversion. This was carried out to determine the effectiveness of near and far-far elastic impedance volume in delineating hydrocarbon reservoirs. The inverted elastic volumes P-impedance (ZP), S-impedance (ZS), density (ρ), near and far-far elastic and derived volumes lambda-rho (λρ), mu-rho (µρ), Poisson’s-ratio (σ) reveal vertical and lateral continuity of the reservoirs identified (K01, N01 and P01) at 2179 m, 2484 m and 3048 m, respectively. The delineated reservoirs showed good match with the sand tops away from the well control validated by a blind well test. The cross-plot of inverted ZP from simultaneous inversion and well ZP gave correlation coefficient of 86% indicative of high quality inverted volume which will reduce exploration risk. The plot of inverted ZP from simultaneous inversion and inverted far-far elastic volume reflected 82% correlation coefficient indicating that this method could be adopted in other fields with limited data and similar geological setting. Hence, the study has shown the efficacy of elastic volumes in delineating hydrocarbon reservoirs which can help locate optimum region for development wells.

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Section: Introductionmentioning

confidence: 99%