Investigation on the anisotropy of meso-mechanical properties of shale rock using micro-indentation

Ma, Tianshou; Liu, Keyan; Su, Xue; Chen, Ping; Ranjith, P. G.; Martyushev, Dmitriy A.

doi:10.1007/s10064-023-03510-y

Cited by 12 publications

(2 citation statements)

References 68 publications

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“…Considering the Biot's effective stress theory, the equation for the wellbore stress in the well column coordinate system is derived as Eq. 2 (Ma et al, 2016;Liu et al, 2020;Aslannezhad et al, 2020;Qiu et al, 2023;Yang et al, 2023a;Ma et al, 2024a),…”

Section: Stress Around Wellborementioning

confidence: 99%

Study of wellbore instability in shale formation considering the effect of hydration on strength weakening

Li,

Zhou,

Lan

2024

Front. Earth Sci.

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Shale formations often contain a high proportion of clay minerals, which, upon contact with drilling fluid, undergo hydration expansion. This leads to wellbore instability, a problem that poses significant challenges globally. This study aims to investigate the variation of mechanical properties of shale with respect to hydration time. We employ an empirical model that relates shale strength parameters to the time of drilling through geological formations. Additionally, we consider both shear failure along the wellbore boundary and shear sliding along bedding planes in the analysis. We establish a predictive model for wellbore instability in shale formations. The model quantitatively analyzes the variation of wellbore collapse pressure with drilling time. The research findings indicate that, when the influence of bedding is considered, both the wellbore collapse pressure and the optimal well trajectory undergo significant changes, in addition, for some wellbore trajectories, the collapse pressure can increase by more than 30%. Therefore, it is essential to account for the influence of bedding in wellbore stability analysis in shale formations. As the bedding dip angle changes, both the numerical values and distribution range of wellbore collapse pressure and the optimal well trajectory change noticeably. Changes in bedding dip direction, however, do not affect the numerical values of collapse pressure but do influence the distribution region of the optimal well trajectory. Thus, in wellbore trajectory design within shale formations, it is crucial to determine the orientation of bedding and adjust the well trajectory accordingly to enhance wellbore stability. Furthermore, shale hydration does not impact the optimal well trajectory for a block, but with prolonged hydration, the minimum drilling fluid density required to maintain wellbore stability gradually increases. This suggests that hydration intensifies the weakening effect on bedding plane strength. The research results are helpful to understand the effect of hydration on shale wellbore stability and ensure shale wellbore stability during drilling cycle.

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Section: Stress Around Wellborementioning

confidence: 99%

Study of wellbore instability in shale formation considering the effect of hydration on strength weakening

Li,

Zhou,

Lan

2024

Front. Earth Sci.

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“…Conventional well-logs provide an extensive overview of the physical properties of the rock [24,25]; hence, many attempts have been made to optimise the functions of conventional well-logs by applying different kinds of methods by incorporating machine learning and statistical methods to understand the fracture behaviour of the reservoir and to provide an automated prediction tool. For instance, ref.…”

Section: Introductionmentioning

confidence: 99%

Fracture Density Prediction of Basement Metamorphic Rocks Using Gene Expression Programming

Hasan,

Tóth

2024

Minerals

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Many methods have been developed to detect and predict the fracture properties of fractured rocks. The standard data sources for fracture evaluations are image logs and core samples. However, many wells do not have these data, especially for old wells. Furthermore, operating both methods can be costly, and, sometimes, the data gathered are of bad quality. Therefore, previous research attempted to evaluate fractures indirectly using the widely available conventional well-logs. Sedimentary rocks are widespread and have been studied in the literature. However, fractured reservoirs, like igneous and metamorphic rock bodies, may also be vital since they provide fluid migration pathways and can store some hydrocarbons. Hence, two fractured metamorphic rock bodies are studied in this study to evaluate any difference in fracture responses on well-log properties. Also, a quick and reliable prediction method is studied to predict fracture density (FD) in the case of the unavailability of image logs and core samples. Gene expression programming (GEP) was chosen for this study to predict FD, and ten conventional well-log data were used as input variables. The model produced by GEP was good, with R2 values at least above 0.84 for all studied wells, and the model was then applied to wells without image logs. Both selected metamorphic rocks showed similar results in which the significant parameters to predict FD were the spectral gamma ray, resistivity, and porosity logs. This study also proposed a validation method to ensure that the FD value predictions were consistent using discriminant function analysis. In conclusion, the GEP method is reliable and could be used for FD predictions for basement metamorphic rocks.

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The Investigation into Sand Production Under Supercritical Carbon Dioxide (SC-CO2) Flooding in Sandstone Reservoirs Using the Resolved CFD-DEM Method

Wang,

Zhang,

et al. 2024

Rock Mech Rock Eng

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Investigation on the anisotropy of meso-mechanical properties of shale rock using micro-indentation

Cited by 12 publications

References 68 publications

Study of wellbore instability in shale formation considering the effect of hydration on strength weakening

Study of wellbore instability in shale formation considering the effect of hydration on strength weakening

Fracture Density Prediction of Basement Metamorphic Rocks Using Gene Expression Programming

The Investigation into Sand Production Under Supercritical Carbon Dioxide (SC-CO2) Flooding in Sandstone Reservoirs Using the Resolved CFD-DEM Method

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