New Stress-dependent Elastic Wave Velocity Models for Reservoir Rocks with Applications

TL;DR

This paper introduces new stress-dependent elastic wave velocity models for reservoir rocks, validated with core samples, and demonstrates their practical application in well analysis for hydrocarbon exploration and safety.

Contribution

The paper develops and validates novel elastic velocity-effective stress laws incorporating critical porosity, improving prediction accuracy for reservoir rock wave velocities.

Findings

High correlation between models and core sample data (R^2 > 0.998)

Maximum velocity prediction uncertainties are below 7.5%

Models successfully applied to predict velocity logs in field case studies

Abstract

This study presents new elastic velocity-effective stress laws for reservoir rocks. These models are grounded in previously established correlations between elastic modulus and porosity, which incorporate critical porosity. The accuracy of the models is validated against wave velocities from 38 core samples, yielding coefficients of determination ($\mathrm{R}^2$) of 0.9994 for compressional wave and 0.9985 for shear wave. A sensitivity analysis reveals that the maximum uncertainties for compressional and shear waves are less than $\pm$5.5% and $\pm$7.5%, respectively. To demonstrate the applicability of the proposed models, a case study was conducted on three wells in the Northern Carnarvon Basin, where the new elastic wave velocity-effective stress laws produced reliable predictions for velocity logs in the studied formations. The relationships reported herein may prove beneficial for hydrocarbon exploration, production, and ensuring drilling safety in both unconventional and conventional fields.