Digital carbonate rock physics

Saenger, Erik H.; Madonna, Claudio; Osorno, Maria; Uribe, David; Steeb, Holger

doi:10.1190/segam2014-0479.1

Cited by 4 publications

(7 citation statements)

References 4 publications

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“…This porosity-velocity trend is exactly the same as has been observed for a carbonate data set from a different location used in Saenger et al (2014). In their paper this trend has been observed for three different resolutions (65 nm, 1 and 4 µm).…”

Section: Elasticitysupporting

confidence: 68%

“…This data-driven upper bound is much stricter than the bound given by Hashin-Shtrikman (see Fig. 8) and is now confirmed for several carbonates using several resolutions (this study and Saenger et al, 2014). Only for the low-resolution images we observe a slightly different trend for P waves (Eq.…”

Section: Discussion Of Elasticity: Experiments Vs Digital Rock Physicsmentioning

confidence: 43%

“…4 and 5), which is supported by two observations. First, this trend was already observed by Saenger et al (2014) on different scales on a different carbonate data set. Second, there is an observed self-similarity for carbonates (Jouini et al, 2015).…”

Section: Elasticitymentioning

confidence: 79%

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Digital carbonate rock physics

et al. 2016

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Abstract. Modern estimation of rock properties combines imaging with advanced numerical simulations, an approach known as digital rock physics (DRP). In this paper we suggest a specific segmentation procedure of X-ray microcomputed tomography data with two different resolutions in the µm range for two sets of carbonate rock samples. These carbonates were already characterized in detail in a previous laboratory study which we complement with nanoindentation experiments (for local elastic properties). In a first step a non-local mean filter is applied to the raw image data. We then apply different thresholds to identify pores and solid phases. Because of a non-neglectable amount of unresolved microporosity (micritic phase) we also define intermediate threshold values for distinct phases. Based on this segmentation we determine porosity-dependent values for effective P -and S-wave velocities as well as for the intrinsic permeability. For effective velocities we confirm an observed twophase trend reported in another study using a different carbonate data set. As an upscaling approach we use this twophase trend as an effective medium approach to estimate the porosity-dependent elastic properties of the micritic phase for the low-resolution images. The porosity measured in the laboratory is then used to predict the effective rock properties from the observed trends for a comparison with experimental data. The two-phase trend can be regarded as an upper bound for elastic properties; the use of the two-phase trend for low-resolution images led to a good estimate for a lower bound of effective elastic properties. Anisotropy is observed for some of the considered subvolumes, but seems to be insignificant for the analysed rocks at the DRP scale. Because of the complexity of carbonates we suggest using DRP as a complementary tool for rock characterization in addition to classical experimental methods.

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Section: Elasticitysupporting

confidence: 68%

Section: Discussion Of Elasticity: Experiments Vs Digital Rock Physicsmentioning

confidence: 43%

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Digital carbonate rock physics

et al. 2016

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“…), and intermediate thresholding (Saenger et al . ). Automatic thresholding consists of several methods such as Visual Science Group, Stanford University, and Kongju University segmentation methods.…”

Section: Standard and Alternative Methods In Digital Rock Physicsmentioning

confidence: 97%

“…Segmentation effect is important in carbonate samples where Saenger et al . () proposed a specific segmentation procedure based on some intermediate thresholds.…”

Section: Introductionmentioning

confidence: 99%

Application of alternative digital rock physics methods in a real case study: a challenge between clean and cemented samples

Karimpouli

Khoshlesan

Saenger

et al. 2018

Geophysical Prospecting

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High‐resolution three‐dimensional images are used in digital rock physics to numerically compute rock physical properties such as permeability and elastic moduli. These images are not widely available, and their preparation is both expensive and time consuming. All of these issues highlight the importance of alternative digital rock physics methods that are based on two‐dimensional images and use different approaches to compute effective properties of three‐dimensional samples. In addition, the scale of study in both standard and alternative digital rock physics is very small, which applications of its results are questionable at wells or reservoir scale. The aim of this study is to use two‐dimensional images and alternative digital rock physics techniques for computing seismic wave velocity and permeability, which are compared with well and laboratory data. For this purpose, data from one well in a reservoir located in the southwestern part of Iran are used. First, two clean (carbonate) and two cemented (limy sandstone) samples were collected from well cores at different depths. Then, two‐dimensional images by scanning electron microscope and conventional microscope were captured. In the next step, two alternative digital rock physics methods, namely, empirical relations and conditional reconstruction, have been employed to compute P‐wave velocity and permeability of a three‐dimensional medium. Results showed that, in clean (mono‐mineral) samples, velocity values were reasonably close to well data. However, permeability values are underestimated compared with laboratory data because laboratory data were obtained at ambient pressure, whereas alternative digital rock physics results are more representative of reservoir pressure conditions. Nevertheless, permeability–porosity trends are valid for both samples. In the case of cemented samples, a two‐scale procedure, along with a method for two‐scale computation and grain‐cement segmentation, is presented and developed. Results showed that P‐wave velocity is overestimated probably due to random sampling in this method. However, velocity–porosity trends are in agreement with well data. Moreover, permeability results obtained for cemented samples were also similar to those obtained for the clean samples.

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Coda Wave Interferometry for Accurate Simultaneous Monitoring of Velocity and Acoustic Source Locations in Experimental Rock Physics

et al. 2019

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In many geoscientific, material science, and engineering applications it is of importance to estimate a representative bulk seismic velocity of materials or to locate the source of recorded seismic or acoustic waves. Such estimates are necessary in order to interpret industrial seismic and earthquake seismological data, for example, in nondestructive evaluation and monitoring of structural materials, and as an input to rock physics models that predict other parameters of interest. Bulk velocity is commonly estimated in laboratories from the time of flight of the first‐arriving wave between a source and a receiver, assuming a linear raypath. In heterogeneous media, that method provides biased estimates of the bulk velocity, and of derived parameters such as temporal velocity changes or the locations of acoustic emissions. We show that coda wave interferometry (CWI) characterizes changes in the bulk properties of scattering media far more effectively on the scale of laboratory rock samples. Compared to conventional methods, CWI provides significant improvements in both accuracy and precision of estimates of velocity changes, and distances between pairs of acoustic sources, remaining accurate in the presence of background noise, and when source location and velocity perturbations occur simultaneously. CWI also allows 3‐D relative locations of clusters of acoustic emissions to be estimated using only a single sensor. We present a method to use CWI to infer changes in both P and S wave velocities individually. These innovations represent significant improvements in our ability to characterize the evolution of properties of media for a variety of applications.

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Digital carbonate rock physics

Cited by 4 publications

References 4 publications

Digital carbonate rock physics

Digital carbonate rock physics

Application of alternative digital rock physics methods in a real case study: a challenge between clean and cemented samples

Coda Wave Interferometry for Accurate Simultaneous Monitoring of Velocity and Acoustic Source Locations in Experimental Rock Physics

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