Dynamic characterization of shale systems by dispersion and attenuation of P- and S-waves considering their mineral composition and rock maturity

Valdiviezo-Mijangos, Oscar C.; Nicolás-López, Rubén

doi:10.1016/j.petrol.2014.07.041

Cited by 21 publications

(3 citation statements)

References 19 publications

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“…As such, in our case, the heterogeneous isotropic composite represents the AND-2A drillcore. This SC approach has been already implemented to calculate the elastic properties of gas-oil shale systems (Valdiviezo-Mijangos & Nicolás-Lopez, 2014;Nicolás-López & Valdiviezo-Mijangos, 2016;Lizcano-Hernández et al, 2018;Nicolás-López et al, 2020;López-Lena-Estrada et al, 2021), to compute the elastic properties of shale rock samples from diverse geological origins (Nicolás-López et al, 2019) and, to estimate attenuation effects and dispersion of velocities on sandstones saturated with brine (Valdiviezo-Mijangos et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Mineral lithotype identification on the andrill AND-2A drillcore, antarctica by using ternary mineral rock physics templates built from a self-consistent approach

Meléndez-Martínez

López

Valdiviezo

2022

GeofInt

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In this work, wet bulk density ?WBD and compressional wave velocity VP core log data obtained along the AND-2A drillcore are plotted on density-velocity ternary mineral Rock Physics Templates (RPTs) built from a Self-Consistent (SC) micromechanics modelling with the purpose to deter- mine data trends that allow us to assist in identifying mineral lithotypes and lithological features throughout the 1138 m length of the drillcore. The elastic properties of the three dominant miner- als present in the drillcore (mixed clays, quartz, and calcite) and the pore-filling fluid (brine) were used as input data for the SC model. The interpreted lithology is then compared to that obtained from the analysis of the AND-2A drillcore ?WBD and VP log data using Gardner type density-velocity cross plots. Results from both the SC and Gardner methods are in good agreement with the main lithologies present in the AND-2A drillcore already reported in the scientific literature. Our findings also agree well when compared to the lithological description of six selected rock samples obtained at different depths on the AND-2A drillcore. These results suggest that the proposed SC approach could be helpful to assist to identify lithology in scientific drill holes where downhole elastic proper- ties may exist over intervals where portions of the drillcore were not recovered. Furthermore, even when elastic property data sets come from measurements on cores, the SC approach is likewise useful because, from visual analysis alone, lithology can sometimes be difficult to determine, and additional information from the analysis of the elastic properties may provide more insight.

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Section: Introductionmentioning

confidence: 99%

Mineral lithotype identification on the andrill AND-2A drillcore, antarctica by using ternary mineral rock physics templates built from a self-consistent approach

Meléndez-Martínez

López

Valdiviezo

2022

GeofInt

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“…Micromechanics attempts to estimate the physical properties of rock composites from the physical properties and the geometric characteristics of their forming microstructures [7][8][9][10] . In particular, SC micromechanics method 11,12 idealizes the rock composite as being a heterogeneous isotropic material containing a background isotropic matrix embedded with n randomly distributed isotropic spherical inclusions of different types [13][14][15][16][17] . Here, the composite represents the terrigenous rock formation where either the matrix or the mineral inclusions can be represented by any of the following forming minerals: quartz, calcite and clay.…”

Section: Micromechanics Modelling For Mineral Volume Fraction Determimentioning

confidence: 99%

Micromechanics modelling for mineral volume fraction determination: application on a terrigenous formation

Nicolás-López

Meléndez-Martínez

López-Lena-Estrada

et al. 2020

Sci Rep

Self Cite

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This work presents a non-linear Self-Consistent (SC) micromechanics method to model the observed physical elastic properties of a terrigenous formation with the purpose to obtain its depth mineral volume fractions profile. In this approach, it is first assumed that the observed physical elastic properties obtained from well logs, such as the density $$\rho_{o}$$ ρ o and the elastic compressional $$Vp_{o}$$ V p o and shear $$Vs_{o}$$ V s o velocities, are a non-linear relationship of the unknown mineral volume fractions $$\alpha$$ α . Then, a gradient descent algorithm is implemented to seek for those volume fractions $$\alpha$$ α for which differences between modelled and observed physical elastic properties are minimum. It is assumed that quartz, calcite and clay are the main comprising minerals of the formation. Obtained volume fractions profile follow the same general trends to those estimated by implementing the Linear Least-Squares Inversion LLSI method which is widely used in petrophysical analysis to obtain mineral concentrations from density $$\rho_{o}$$ ρ o , photoelectric effect $$Pe_{o}$$ P e o and compressional slowness $$\Delta tp_{o}$$ Δ t p o well logs. Results also show that calcite and clay volume fractions from these two methods are highly correlated while quartz volume fractions show low correlation. Further comparison between clay concentrations from SC method with clay concentrations calculated from direct measurements of gamma ray GR well logs used as a guideline also exhibits high correlation. These results suggest that the SC method is better suited to obtain clay and calcite volume fractions rather than quartz volume fractions. However, SC method can provide with insights about the general distribution of quartz along the borehole.

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“…At the same time, its brittleness index is usually lower than that of laminated shale (Liu et al, 2021;Camargo et al, 2022). In 2021, Jingru Yang and others studied the classification characteristics of shale foliation, primarily analyzed the fractal factors of shale reservoirs, described the heterogeneity of shale foliation, and studied its influence on fracture propagation (Valdiviezo-Mijangos and Nicolás-Lopez, 2014;Ruggieri et al, 2021;Xu et al, 2021;Yang et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Comparison of mechanical characteristics of different types of shales in the Ordos Basin

Dou,

Chen,

Zuo

et al. 2023

Front. Earth Sci.

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Shale gas is a very important unconventional energy. The mechanical properties of the three types of shale (laminated shale, sandwich shale and foliated shale) are different, and the difference in fracturing effectiveness is very significant. In this paper, the mineral composition, mechanical properties and conductivity of these three different types of shale were studied and compared by X-ray diffraction, triaxial mechanical experiments, and fracture conduction experiments. The study found that the foliated shale has the lowest content of rigid minerals (47.5%), lower elastic modulus and tensile strength (26.98 Gpa and 168.29 MPa, respectively), higher Poisson’s ratio (0.25), the smallest brittleness index (0.48), and larger fracture toughness (0.42). The laminated shale has a higher content of rigid minerals (68.50%), the lowest elastic modulus and tensile strength (25.77 Gpa and 122.46 MPa, respectively), the highest Poisson’s ratio (0.26), the highest brittleness index (0.56), and the lowest fracture toughness (0.18). The sandwich shale has the highest rigid mineral content (78.16%), the highest elastic modulus and tensile strength (35.31 Gpa and 197.37 MPa, respectively), the lowest Poisson’s ratio (0.24), a larger brittleness index (0.52), and larger fracture toughness (0.415). Furthermore, with the increase in the coring angle, the elastic modulus of all three shales increases. In addition, with the increase in closing pressure and the decrease in the sand laying concentration, the proppant embedding depth gradually increases and the conductivity decreases. This means that from the perspective of forming complex fracture networks, the fracturing effect of the foliated shale is unsatisfactory, while the fracturing effect of the laminated and sandwich shales is better. Moreover, it is recommended to prefer directional injection along vertical laminae or at high angles, which is conducive to the formation of complex fracture networks. For laminated shale with low strength, the sand laying concentration should be increased to ensure the conductivity of the fractured fracture. This study provides some technical guidance for the identification of different types of shale fracturing desserts and fracturing processes.

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Dynamic characterization of shale systems by dispersion and attenuation of P- and S-waves considering their mineral composition and rock maturity

Cited by 21 publications

References 19 publications

Mineral lithotype identification on the andrill AND-2A drillcore, antarctica by using ternary mineral rock physics templates built from a self-consistent approach

Mineral lithotype identification on the andrill AND-2A drillcore, antarctica by using ternary mineral rock physics templates built from a self-consistent approach

Micromechanics modelling for mineral volume fraction determination: application on a terrigenous formation

Comparison of mechanical characteristics of different types of shales in the Ordos Basin

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