Microstructural effects on the unconfined mechanical behavior of a tectonically deformed calcareous shale, a study case in the Santiago Formation, México

Camargo, Jubier Alonso Jiménez; Cerca, Mariano; Carreón‐Freyre, Dora

doi:10.1016/j.petrol.2022.110856

Cited by 3 publications

(2 citation statements)

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“…The primary objective of extended reach wells is to access remote or hard-to-reach hydrocarbon reserves while minimizing the number of surface locations and drilling costs. , One of the significant challenges associated with extended reach wells is the risk of shale swelling when exposed to different water-based drilling fluids (WBDFs) . Shale swelling occurs when the shale formations encounter WBDFs, leading to the expansion and deformation of the shale rocks. − Shale is composed of clay minerals, which can absorb water and expand. − The interaction between shale and drilling fluids can have far-reaching consequences, including wellbore instability, formation damage, lost circulation, and decreased drilling efficiency. − …”

Section: Introductionmentioning

confidence: 99%

An Experimental Study and Machine Learning Modeling of Shale Swelling in Extended Reach Wells When Exposed to Diverse Water-Based Drilling Fluids

Tariq,

Murtaza,

Alrasheed

et al. 2024

Energy Fuels

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Shale swelling poses considerable challenges for companies involved in extended-reach well drilling, particularly when it comes to maintaining wellbore stability. Despite the incorporation of swelling inhibitors in water-based drilling fluids (WBDFs), shale swelling can persist as an issue. Currently, the assessment of WBDFs' ability to prevent swelling usually involves costly, timeconsuming, and labor-intensive laboratory experiments. Therefore, this study leverages machine learning techniques (ML) to forecast the dynamic linear swelling behavior of sodium bentonite-based shale wafers. These shale wafers were subjected to different WBDFs containing diverse inorganic salts such as sodium chloride (NaCl), potassium chloride (KCl), magnesium chloride (MgCl 2 ), and calcium chloride (CaCl 2 ). To gather sufficient data to train the ML models, an extensive experimental study was conducted using various WBDF formulations. The experiments were conducted on wafers, wherein each wafer treated with an inorganic salt underwent a linear swell test for 120 h until the swelling reached a plateau. Moreover, the conductivities and zeta potential of WBDFs, which were prepared using varying concentrations of salts, were recorded. Several ML techniques, namely gradient boosting, decision trees, adaptive gradient boosting (AdaBoost), K-nearest neighbors, random forest, extreme gradient boosting, and stacked generalized regression (SGR) were used to forecast shale swelling. The ML models were trained using input features such as salt types, salt concentrations, salt conductivities, salt zeta potential, and elapsed time. The results revealed that the SGR model outperformed other techniques by effectively predicting linear swelling in terms of coefficient of determination (R 2 ) above 0.95. The developed ML model offers an efficient approach to assess the maximum swelling potential of various WBDFs that can help in effectively mitigating the wellbore instability concerns by continuously evaluating the interaction between shale and the drilling fluid for drilling for extended reach or maximum contact wells.

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Section: Introductionmentioning

confidence: 99%

An Experimental Study and Machine Learning Modeling of Shale Swelling in Extended Reach Wells When Exposed to Diverse Water-Based Drilling Fluids

Tariq,

Murtaza,

Alrasheed

et al. 2024

Energy Fuels

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“…In 2021, Liu Bo, Camargo JAJ, and others conducted relevant research on foliated shale, which proved that foliated shale usually contains higher organic matter abundance and a high pressure coefficient, which is more conducive to oil and gas accumulation. 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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A Regional Shallow Décollement at the Front of the Mexican Fold and Thrust Belt: Microstructure of the Santiago Shale

Valdez-Barrera,

Cerca,

Jimenez-Camargo

et al. 2024

Lithosphere

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This contribution analyses the role played by the mechanical properties of a decollément shale layer in the evolution of the Mexican Fold and Thrust Belt (MFTB). The mobility of overpressured shales can accommodate large strains by grain-scale plastic mechanisms, and affect the folding and thrusting styles of the overburden. Research on shale deformation mechanisms is necessary to improve the knowledge of these processes and their influence on the structural style of fold and thrust belts. The ductile behavior of rocks involving grain-scale plasticity was documented in the Jurassic Santiago shale sequence using geological mapping, microstructural observations on thin-oriented sections, and scanning electron microscopy (SEM) imaging. Structural styles such as detachment folding, fault-bend folding, and shale-cored fold-thrusts were observed at the regional scale. At the outcrop scale, the shale developed strong foliation and pencil cleavage, with immersed packstone boudins. Observed structures include thrusting, soft and open folds, and buckle folding. In thin section, the ductile textures include a strong penetrative foliation with lenticular and wavy-parallel laminae composed of carbonates, ribbons of reoriented clays and organic matter (clay+OM), s-c structures, porphyroblasts microtextures, development of oblique cleavage concerning folded foliation (crenulation cleavage), and carbonates dissolution. The Santiago shale shows also evidence of brittle deformation including calcite-filled fractures and cataclastic gouges. X-ray diffraction (XRD) analysis of the clay size fraction suggests that the authigenic calcareous shale was deformed in conditions of the deep diagenetic zone (between 100 and 200°C) and fluid overpressure (>70 MPa). The results help to improve the understanding of ductile microstructure and its role in shale deformation cretaceous cover, promoting the formation of localized fault propagation folds in the overburden. This study aims to open new perspectives in the kinematics and rheology interpretations for this sector of the MFTB, highlighting the role of the décollement layers during the progression of the orogen.

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Microstructural effects on the unconfined mechanical behavior of a tectonically deformed calcareous shale, a study case in the Santiago Formation, México

Cited by 3 publications

References 59 publications

An Experimental Study and Machine Learning Modeling of Shale Swelling in Extended Reach Wells When Exposed to Diverse Water-Based Drilling Fluids

An Experimental Study and Machine Learning Modeling of Shale Swelling in Extended Reach Wells When Exposed to Diverse Water-Based Drilling Fluids

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

A Regional Shallow Décollement at the Front of the Mexican Fold and Thrust Belt: Microstructure of the Santiago Shale

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