Evaluation of Porosity and Saturation Degree by Laboratory Joint Measurements of Velocity and Resistivity: A Model Improvement

Carrara, E.; Mazzacca, A.; Pece, R.; Roberti, N.; Vanorio, Tiziana

doi:10.1007/s000240050228

Cited by 15 publications

(11 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(1994) proposed an electro‐seismic model by assuming all phases (matrix, clay, water and air) in the rock are contiguous, i.e., in parallel for the case of electrical conductivity and in series with regard to the propagation of elastic waves, for the purpose of evaluating porosity and saturation. The validity of this model was confirmed experimentally by Carrara et al . (1999).…”

Section: Introductionsupporting

confidence: 66%

See 1 more Smart Citation

Joint elastic‐electrical effective medium models of reservoir sandstones

Han

Best

MacGregor

et al. 2011

Geophysical Prospecting

View full text Add to dashboard Cite

A B S T R A C TImprovements in the joint inversion of seismic and marine controlled source electromagnetic data sets will require better constrained models of the joint elastic-electrical properties of reservoir rocks. Various effective medium models were compared to a novel laboratory data set of elastic velocity and electrical resistivity (obtained on 67 reservoir sandstone samples saturated with 35 g/l brine at a differential pressure of 8 MPa) with mixed results. Hence, we developed a new three-phase effective medium model for sandstones with pore-filling clay minerals based on the combined selfconsistent approximation and differential effective medium model. We found that using a critical porosity of 0.5 and an aspect ratio of 1 for all three components, the proposed model gave accurate model predictions of the observed magnitudes of P-wave velocity and electrical resistivity and of the divergent trends of clean and clay-rich sandstones at higher porosities. Using only a few well-constrained input parameters, the new model offers a practical way to predict in situ porosity and clay content in brine saturated sandstones from co-located P-wave velocity and electrical resistivity data sets.

show abstract

Section: Introductionsupporting

confidence: 66%

“…2007) did not adequately describe our clay‐rich sandstone observations. Also, Carrara's electro‐seismic model (Carrara et al . 1999) did not match our clean sandstone results, although it showed the observed clay effect on the joint elastic‐electrical properties of our sandstones.…”

Section: Introductionmentioning

confidence: 99%

Joint elastic‐electrical effective medium models of reservoir sandstones

Han

Best

MacGregor

et al. 2011

Geophysical Prospecting

View full text Add to dashboard Cite

show abstract

“…Therefore, we assumed the computed porosity to be the total porosity of the samples. Measurements performed by Carrara et al (1999) on samples from the Gravina formation are also included in this study. For these measurements, the resistivity of the saturating water was 78 ohm m. The data available for these samples included weight, length, diameter, dry-rock P-wave velocity, saturation and resistivity.…”

Section: Methodsmentioning

confidence: 99%

“…They implemented differential effective-media (DEM) modeling for sandstones with a range of P-wave velocities between 4.5 and 6 km/s, and normalized resistivities -measured resistivity normalized by the resistivity of the saturating water -between 10 2 and 10 5 ohm m. In contrast, previous velocity and resistivity measurements by Carrara et al (1999) for Gravina limestone samples showed normalized resistivity values on the order of 1 to 5 ohm m, and velocities around 2 km/s. They modeled both their velocity and resistivity measurements using the harmonic average of the solid and fluid elastic moduli and density for the effective elastic properties, and the harmonic average of their resistivities for the effective resistivity; this assumes very compliant and conductive rocks.…”

Section: Differential Effective Medium Versus Self Consistent Effectimentioning

confidence: 99%

See 1 more Smart Citation

Effective medium modeling of laboratory velocity and resistivity data on carbonates from the Apulia Platform, Italy

Gomez¹,

Scotellaro²,

Vanorio³

et al. 2009

SEG Technical Program Expanded Abstracts 2009

View full text Add to dashboard Cite

This paper describes joint effective-medium modeling of elastic and resistivity laboratory data obtained on a set of outcrop carbonate samples from the Apulia Platform in Italy. The challenge is to model both the elastic-wave velocity and resistivity using a single theoretical approach. The candidate models are (a) the differential effectivemedium (DEM) theory and (b) the self-consistent approximation (SC). DEM may accurately describe the elastic properties but fails to describe resistivity, because it explicitly assumes that the pores are inclusions in the mineral matrix and thus lack adequate connectivity. On the other hand, SC treats both the pores and the matrix as inclusions, thus implicitly providing the connectivity needed to match the measured resistivity. At the same time, SC makes it possible to match both the elastic data and the measured resistivity using one set of model parameters.We show that SC, where the rock components are assumed conceptually symmetric, is a robust approach to modeling both velocity and resistivity in our carbonate rock samples, particularly when using needle-like pores, which tend to be stiff but well connected.

show abstract

Saturation Dependence of the Streaming Potential Coefficient

Jouniaux

Allègre

Toussaint

et al. 2020

Seismoelectric Exploration

View full text Add to dashboard Cite

Observations of streaming potential for unsaturated conditions do not always show the same trend depending on the hydrodynamic conditions and because of a lake of coherency between the data processing procedures. We combine the data from three studies published in the literature, acquired during non-steady state drainage experiments, and apply the same processing steps. We model the hydrodynamic behaviour of these experiments to confirm that they experienced different flow dynamics. We argue that the raw SP data should not be corrected unless a clear drift of the electrodes stability is observed. The combined hydrodynamic behaviour and the streaming potential response show that (a) the observations of one of the experiment (exp #1) are associated to a limited range of water saturation (0.85-1). The corresponding signals could therefore be fairly modelled assuming no saturation dependence of the SPC whatsoever; (b) the observations of exp #3 led to a SPC that can be larger than its value at saturation; (c) the observations of the exp #2 show a non-monotonous behaviour of the SPC as saturation decreases. The underlying physics of a non-monotonous SPC is related to water/air interfaces as shown by the results of the lattice Boltzmann numerical simulations. The main contribution to the SPC behaviour comes from the charged water/air interfaces and depends on the dynamic state of moving or entrapped bubbles. We finally describe the consequences of such a behaviour on the seismoelectric conversions for unsaturated conditions.

show abstract

Evaluation of Porosity and Saturation Degree by Laboratory Joint Measurements of Velocity and Resistivity: A Model Improvement

Cited by 15 publications

References 4 publications

Joint elastic‐electrical effective medium models of reservoir sandstones

Joint elastic‐electrical effective medium models of reservoir sandstones

Effective medium modeling of laboratory velocity and resistivity data on carbonates from the Apulia Platform, Italy

Saturation Dependence of the Streaming Potential Coefficient

Contact Info

Product

Resources

About