Electric and elastic properties of rock samples: a unified measurement approach

Abstract

A series of tests were carried out employing a modified triaxial cell able to measure both elastic and electric properties simultaneously at reservoir conditions. Measured quantities such as porosity, permeability, resistivity and P-and S-wave velocities were cross plotted, and possible correlations were investigated. Identified experimental trends were then tested against a variety of rock physics models. A good correlation was obtained in most cases. Such results together with petrophysical logging data can be used to constrain possible joint inversion of controlled source electromagnetic data and seismic data. The simultaneous use of resistivity and acoustic measurements to monitor a water-substituting-oil process at reservoir conditions was also investigated. This study indicated that the electrical properties are much more sensitive to changes in saturation in the case of water flooding for enhanced oil recovery than the elastic properties.

Experimental investigation of deformation mechanisms during shear‐enhanced compaction in poorly lithified sandstone and sand

“…Compressional velocities (Vp) were computed from measured transit time and sample dimensions. Uncertainties in the velocity measurements can be estimated using the analysis described by Wang and Gelius [] and Mondol et al . [], where the errors in picks and sample height are considered.…”

Joint elastic-electrical properties of reservoir sandstones and their relationships with petrophysical parameters

“…The first and only available simultaneous joint resistivity‐velocity measurements found in the literature were made by Wang and Gelius (2010) on six relatively clean (clay content <5.3%) reservoir sandstones using the apparatus adapted by Wang, Gelius and Kong (2009). The small number of clean samples used in the study of Wang and Gelius (2010) precluded any statistical analysis of comprehensive joint relationships among elastic, electrical and reservoir petrophysical properties.…”

Experimental investigation of CO 2 breakthrough and flow mechanisms in shale

“…Arrows on Figure 8 (c and d) show the obtained arrival time through auto-correlation operation. The uncertainties in the P-and S-wave velocity measurement can be estimated employing the analysis by Wang & Gelius (2010) that are described in Appendix A. Figures 9 and 10 show the calculated P-and S-wave velocities of the sample at different stages of the test.…”

“…The uncertainties in the P and S wave velocity measurement can be estimated employing the analysis described by Wang & Gelius (2010). Velocities are calculated from measured travel times of transmitted ultrasonic pulses using the expression where L is sample length, t M is the measured travel time through the sample , and t T is a reference travel time from the head-head measurement.…”