Shale gas characterisation for hydrocarbon accumulation and brittleness by integrating a rock-physics-based framework with effective reservoir parameters

Guo, Zhiqi; Lv, Xiaoyu; Liu, Cai; Liu, Xiwu; Liu, Yuwei

doi:10.1016/j.jngse.2022.104498

Cited by 9 publications

(4 citation statements)

References 37 publications

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“…As shown by the formation micro-scanner image (FMI) logs (Figs. 14 and 15), the target shales in Well A developed more bedding fractures than those in Well B. Additionally, we conducted a rock physical analysis to evaluate the development degree of bedding fractures for the shale in Well A and Well B using the modeling method of Guo et al (2022). The computed Hashin-Shtrikman bounds were illustrated on the bulk modulus versus porosity cross-plot (Fig.…”

Section: Seismic Dispersion Attributes and Their Implications Of Shal...mentioning

confidence: 99%

Hydrocarbon Identification and Bedding Fracture Detection in Shale Gas Reservoirs Based on a Novel Seismic Dispersion Attribute Inversion Method

et al. 2022

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Prediction of hydrocarbon enrichment and natural fractures is significant for sweet spot characterization in shale gas reservoirs. However, it is difficult to estimate reservoir properties using conventional seismic techniques based on elastic and isotropic assumptions. Considering that the viscoelastic anisotropic model better represents organic shale, we propose a new seismic inversion method to improve shale gas characterization by incorporating the anisotropic reflectivity theory in the frequency-dependent inversion scheme. The computed P-wave velocity dispersion attribute DP evaluates the hydrocarbon enrichment by estimating the inelastic properties of shale associated with organic materials. The inverted anisotropic dispersion attribute Dε detects the development intensity of bedding fractures using frequency-dependent anisotropy owing to wave-induced fluid flow in parallel fractures. Synthetic tests indicate that DP can robustly estimate shale attenuation and Dε is sensitive to the frequency-dependent anisotropy of shale. The results are validated by reservoir properties measured in gas-producing boreholes and rock physical modeling analysis, supporting the applicability of the dispersion attributes for hydrocarbon identification and bedding fracture detection. The predicted hydrocarbon enrichment and the development of bedding fractures correlate with the structural characteristics of the shale formation. The depth-related shale properties can be described by improving the geological understanding of the study area. Finally, favorable areas with high hydrocarbon enrichment and extensive development of bedding fractures are identified by simultaneously considering high DP and Dε anomalies, providing essential information for predicting potential shale gas reservoirs. Article Highlights A novel seismic inversion method for anisotropy dispersion attributes is proposed P-wave velocity dispersion attribute is used to identify hydrocarbon enrichment in shale Anisotropic dispersion attribute is used to detect bedding fractures in shale

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Section: Seismic Dispersion Attributes and Their Implications Of Shal...mentioning

confidence: 99%

Hydrocarbon Identification and Bedding Fracture Detection in Shale Gas Reservoirs Based on a Novel Seismic Dispersion Attribute Inversion Method

et al. 2022

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“…In practice, various templates constructed based on appropriate rock physics models provide effective tools for estimating reservoir parameters utilizing elastic properties in various hydrocarbon resources [16][17][18][19]. For instance, the rock physics templates (RPTs) were employed for fluid identification [20] and brittleness evaluation [21] in tight sandstone reservoirs.…”

Section: Introductionmentioning

confidence: 99%

Pore and Microfracture Characterization in Tight Gas Sandstone Reservoirs with a New Rock-Physics-Based Seismic Attribute

Guo¹,

Qin²,

Liu³

2023

Remote Sensing

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Pores and microfractures provide storage spaces and migration pathways for gas accumulation in tight sandstones with low porosity and permeability, acting as one of the controlling factors of gas production. The development of a rational rock physics model is essential for better understanding the elastic responses of tight sandstone with complex pore structures. Accordingly, seismic characterization of pores and microfractures based on the rock physics model provides valuable information in predicting high-quality tight gas sandstone reservoirs. This paper proposes a rock-physics-based approach to compute the pore–microfracture indicator (PMI) from elastic properties for pore structure evaluation in tight sandstones. The PMI is achieved based on the axis rotation of the elastic parameter space using well-log data. The rotation angle is determined by finding the maximum correlation between the linearized combination of the elastic parameters and the introduced factor associated with total porosity and microfracture porosity. The microfracture porosity is then estimated with an inversion scheme based on the double-porosity model. Finally, the optimized rotation angle is employed to compute the PMI with seismic data. The obtained results are of great benefit in predicting the permeable zones, providing valuable information for sweet spot characterization in tight gas sandstone reservoirs.

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“…By using logging data and seismic-inverted elastic properties, the TOC in the shale has been evaluated by its elastic properties. A low density or an elastic impedance usually corresponds to a high TOC [5][6][7][8][9]. Also, the brittleness of the shale rock has been estimated by its mechanical properties, such as Young's modulus and Poisson's ratio [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the shale anisotropy that is related to clay lamination and microstructural fabrics has been investigated by using modeling methods [43,46,47]. The shale brittleness has also been incorporated in the rock physical modeling for the prediction of engineering sweet spots in shale reservoirs [9,48]. However, shale models that quantify the effect of horizontal fractures on the shale elastic properties are rare.…”

Section: Introductionmentioning

confidence: 99%

Geophysical Interpretation of Horizontal Fractures in Shale Oil Reservoirs Using Rock Physical and Seismic Methods

Guo,

Gao,

Liu

2023

Energies

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Horizontal fractures are one of the factors that significantly affect the ultimate productivity of shale oil reservoirs. However, the prediction of horizontal fractures by using seismic methods remains a challenge, which is due to the complex elastic and seismic responses that are associated with horizontal fractures. A framework that predicts horizontal fractures by seismic rock physical methods has been developed in the present study. A shale model is then proposed to quantify the shale elastic responses that are associated with the properties of the horizontal fractures. The modeling results that are based on the logging data validated the applicability of the proposed model, and the predicted fracture properties could be used to evaluate the development of horizontal fractures. According to the framework of the Poisson impedance, a horizontal fracture indicator is suggested to represent the logging-derived fracture density in terms of a combination of elastic properties. By using seismic-inverted elastic properties, the obtained indicator enabled an estimation of zones with the potential development of horizontal fractures. The established indicator showed a good correlation with the fracture density and could be used as an effective indicator in the prediction of horizontal fractures in shale oil reservoirs. Furthermore, seismic data applications show a consistency between the development of horizontal fractures and the production status of the boreholes. This result highlights the importance of horizontal fractures for the ultimate productivity and emphasizes the applicability of the proposed methods.

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Shale gas characterisation for hydrocarbon accumulation and brittleness by integrating a rock-physics-based framework with effective reservoir parameters

Cited by 9 publications

References 37 publications

Hydrocarbon Identification and Bedding Fracture Detection in Shale Gas Reservoirs Based on a Novel Seismic Dispersion Attribute Inversion Method

Hydrocarbon Identification and Bedding Fracture Detection in Shale Gas Reservoirs Based on a Novel Seismic Dispersion Attribute Inversion Method

Pore and Microfracture Characterization in Tight Gas Sandstone Reservoirs with a New Rock-Physics-Based Seismic Attribute

Geophysical Interpretation of Horizontal Fractures in Shale Oil Reservoirs Using Rock Physical and Seismic Methods

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