Effective elastic properties of solid clays

Geophysics ◽  
2001 ◽  
Vol 66 (2) ◽  
pp. 428-440 ◽  
Author(s):  
Zhijing (Zee) Wang ◽  
Hui Wang ◽  
Michael E. Cates
Keyword(s):  
Clay Minerals ◽  
Elastic Properties ◽  
Reservoir Characterization ◽  
Seismic Exploration ◽  
Data Set ◽  
Effective Elastic Properties ◽  
Seismic Properties ◽  
Sonic Log ◽  
Log Interpretation ◽  
Composite Samples

Clay minerals are perhaps the most abundant materials in the earth’s upper crust. As such, their elastic properties are extremely important in seismic exploration, seismic reservoir characterization, and sonic‐log interpretation. Because little exists in the literature on elastic properties of clays, we have designed a method of measuring effective elastic properties of solid clays (clays without pores). In this method, clay minerals are mixed with a material with known elastic properties to make composite samples. Elastic properties of these clay minerals are then inverted from the measured elastic properties of the composite samples using the weighted Hashin‐Shtrikman average. Using this method, we have measured 66 samples of 16 types of clays. In this paper, we present a comprehensive data set of elastic properties of solid clays that commonly occur in, or are related to, petroleum reservoirs. Although uncertainties (up to 10%) exist, the data set reported here is by far the most comprehensive set of elastic properties in the literature. These data can be used potentially in modeling the seismic properties of clay‐bearing rocks.

AVO inversion using pseudoisotropic elastic properties

2021 ◽  
Vol 40 (1) ◽  
pp. 52-59
Author(s):  
Michinori Asaka
Keyword(s):  
Elastic Properties ◽  
Oil And Gas ◽  
Reservoir Characterization ◽  
Elastic Anisotropy ◽  
Data Set ◽  
Amplitude Variation With Offset ◽  
Avo Inversion ◽  
Characterization Study ◽  
Anisotropy Parameters ◽  
Using Data

Amplitude variation with offset (AVO) inversion of an anisotropic data set is a challenging task. Nonnegligible differences in the anisotropy parameters between the various lithologies make the seismic data AVO response completely different from the isotropic synthetic seismogram. In this case, it is difficult to invert for VP/VS and density consistent with well-log data. AVO inversion using pseudoisotropic elastic properties is a practical solution to this problem. Verification of this method was performed using data from an offshore Western Australia field. It was found that wavelet extraction and density inversion are improved significantly by replacing the isotropic elastic properties with the pseudoisotropic properties. Inverted density shows reasonable quality and therefore can be included in the reservoir characterization study. Postinversion analyses can be performed effectively on the pseudoisotropic elastic properties because crossplot analysis shows the increased separation of different lithofacies due to contrasts in anisotropy parameters. This result could have significant implications for other fields, as shale constitutes most of the overburden in conventional oil and gas fields and often shows strong elastic anisotropy.

Application of nanoindentation for uncertainty assessment of elastic properties in mudrocks from micro- to well-log scales

Geophysics ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. D327-D339 ◽  
Author(s):  
Clotilde Chen Valdes ◽  
Zoya Heidari
Keyword(s):  
Young’S Modulus ◽  
Clay Minerals ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Soft Rock ◽  
Elastic Stiffness ◽  
Mechanical Tests ◽  
Well Log ◽  
Eagle Ford ◽  
Effective Elastic Properties

Uncertainty in estimates of elastic properties of soft mudrock components, such as clay minerals and kerogen, can influence well-log-based evaluation of effective elastic properties in organic-rich mudrocks. Existing methods, such as effective medium models for well-log-based assessment of elastic properties, assume a constant stiffness and an idealized shape for rock components. However, these characteristics might vary depending on the distribution and size of that particular component, as well as its adjacent components. Furthermore, there is a significant uncertainty in elastic properties of kerogen in the case of organic-rich mudrocks. The uncertainty associated with the aforementioned parameters on effective elastic properties of rocks has not been investigated in existing publications. In this paper, we quantified the variability in elastic properties of individual mudrock components caused by their spatial distribution, size, and rock fabric at the microscale and their impacts on well-log-based evaluation of effective elastic properties. We performed nanoindentation mechanical tests on samples from the Haynesville and the lower Eagle Ford Formations, to measure Young’s modulus and hardness at targeted locations. Then, we quantified the variability of Young’s modulus in the microscale and its impact on effective elastic properties at the micro- and well-log scales. Results reveal significant uncertainties in measurements of elastic properties of soft rock components, associated with their location and size. Young’s moduli of individual clay components are higher when located adjacent to stiff rock components, such as large quartz and calcite grains. Results reveal that 25% and 12% uncertainties in measured elastic properties of clay minerals affect well-log-based estimates of effective elastic stiffness coefficients up to 29% and 11% in the Haynesville and the lower Eagle Ford Formations, respectively. These uncertainties can be more significant in cases with a higher concentration of clay minerals and kerogen.

On the Mechanical Behavior of the Orthotropic Cord-Rubber Composite

1976 ◽  
Vol 4 (4) ◽  
pp. 219-232 ◽  
Author(s):  
Ö. Pósfalvi
Keyword(s):  
Mechanical Behavior ◽  
Uniaxial Tension ◽  
Elastic Properties ◽  
Large Deformations ◽  
Virtual Work ◽  
Poisson's Ratio ◽  
Principle Of Virtual Work ◽  
Effective Elastic Properties ◽  
Rubber Composite ◽  
Mooney Equation

Abstract The effective elastic properties of the cord-rubber composite are deduced from the principle of virtual work. Such a composite must be compliant in the noncord directions and therefore undergo large deformations. The Rivlin-Mooney equation is used to derive the effective Poisson's ratio and Young's modulus of the composite and as a basis for their measurement in uniaxial tension.

scholarly journals Effective elastic properties of transversely isotropic materials with concave pores

2021 ◽  
Vol 153 ◽  
pp. 103665
Author(s):  
K. Du ◽  
L. Cheng ◽  
J.F. Barthélémy ◽  
I. Sevostianov ◽  
A. Giraud ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Transversely Isotropic ◽  
Effective Elastic Properties ◽  
Isotropic Materials ◽  
Transversely Isotropic Materials

Geometry Dependent Effective Elastic Properties of Open-Cell Foams Based on Kelvin Cell Models**

2013 ◽  
Vol 15 (12) ◽  
pp. 1292-1298 ◽  
Author(s):  
Johannes Storm ◽  
Martin Abendroth ◽  
Dongshuang Zhang ◽  
Meinhard Kuna
Keyword(s):  
Elastic Properties ◽  
Cell Models ◽  
Open Cell ◽  
Effective Elastic Properties ◽  
Open Cell Foams
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