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Volume 68, Issue 6
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

An inclusion model, based on the Kuster–Toksöz effective medium theory along with Gassmann theory, is tested to forward model velocities for fluid‐saturated rocks. A simulated annealing algorithm, along with the inclusion model, effectively inverts measured compressional velocity () to achieve an effective pore aspect ratio at each depth in a depth variant manner, continuously along with depth. Early Cretaceous syn‐rift clastic sediments at two different depth intervals from two wells [well A (2160–2274 m) and well B (5222–5303 m)], in the Krishna–Godavari basin, India, are used for this study. Shear velocity () estimated using modelled pore aspect ratio offers a high correlation coefficient (>0.95 for both the wells) with measured data. The modelled pore aspect ratio distribution suggests the decrease in pore aspect ratio for the deeper interval, mainly due to increased effective vertical stress. The pore aspect ratio analysis in relation to total porosity and volume of clay reveals that the clay volume has insignificant influence in shaping the pore geometry in the studied intervals. An approach based on multiple linear regression method effectively predicts velocity as a linear function of total porosity, the volume of clay and the modelled pore‐space aspect ratio of the rock. We achieved a significant match between measured and predicted velocities. The correlation coefficients between measured and modelled velocities are considerably high (approximately 0.85 and 0.8, for and , respectively). This process indicates the possible influence of pore geometry along with total porosity and volume of clay on velocity.

© 2020 European Association of Geoscientists & Engineers © 2020 European Association of Geoscientists & Engineers
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2020-05-13
2024-04-24

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Effective medium theory and multiple linear regression‐based velocity estimation in syn‐rift clastic sequence of the Krishna–Godavari basin, India
Geophysical Prospecting 68, 1793 (2020); https://doi.org/10.1111/1365-2478.12955
/content/journals/10.1111/1365-2478.12955
/content/journals/10.1111/1365-2478.12955
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  • Article Type: Research Article
Keyword(s): Elastic properties; Pore aspect ratio; Simulated annealing; Velocity; Wave

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