Hydraulic Fracturing of Heterogeneous Rock Monitored by Acoustic Emission

Stanchits, Sergei; Burghardt, Jeffrey; Surdi, A.

doi:10.1007/s00603-015-0848-1

Cited by 100 publications

(66 citation statements)

References 13 publications

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“…Using acoustic plane wave reflection, it is also possible to measure fracture width [ Medlin and Masse , ; Groenenboom and Fokkema , ]; see also Kovalyshen et al [] for a comparison between ultrasonic and optical methods for the measurement of fracture width. Passive acoustic emission monitoring is also often used for monitoring hydraulic fracture growth at the laboratory scale [see Lockner and Byerlee , ; Stanchits et al , , among many others], providing an indirect measurement of the evolution of the fracture extent. Little in‐depth comparisons between theoretical predictions and experiments have been reported so far for nontransparent materials.…”

Section: Introductionmentioning

confidence: 99%

Experiments versus theory for the initiation and propagation of radial hydraulic fractures in low‐permeability materials

et al. 2017

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We compare numerical predictions of the initiation and propagation of radial fluid‐driven fractures with laboratory experiments performed in different low‐permeability materials (PMMA, cement). In particular, we choose experiments where the time evolution of several quantities (fracture width, radius, and wellbore pressure) was accurately measured and for which the material and injection parameters were known precisely. Via a dimensional analysis, we discuss in detail the different physical phenomena governing the initiation and early stage of growth of radial hydraulic fractures from a notched wellbore. The scaling analysis notably clarifies the occurrence of different regimes of propagation depending on the injection rate, system compliance, material parameters, wellbore, and initial notch sizes. In particular, the comparisons presented here provide a clear evidence of the difference between the wellbore pressure at which a fracture initiates and the maximum pressure recorded during a test (also known as the breakdown pressure). The scaling analysis identifies the dimensionless numbers governing the strong fluid‐solid effects at the early stage of growth, which are responsible for the continuous increase of the wellbore pressure after the initiation of the fracture. Our analysis provides a simple way to quantify these early time effects for any given laboratory or field configuration. The good agreement between theoretical predictions and experiments also validates the current state of the art hydraulic fracture mechanics models, at least for the simple fracture geometry investigated here.

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Section: Introductionmentioning

confidence: 99%

Experiments versus theory for the initiation and propagation of radial hydraulic fractures in low‐permeability materials

et al. 2017

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“…AE location accuracy is influenced by factors such as the focal coverage of the monitoring array, SNR, and the robustness of the velocity model. Stanchits et al () report AE location errors on the order of 6 mm for similar hydraulic fracturing experiments on shale and sandstone blocks. Vera Rodriguez et al (, ) demonstrate improvements in location accuracy with the incorporation of shear wave information using the coalescence microseismic mapping algorithm (Drew et al, ).…”

Section: Modeling Of Different Sources Of Uncertainty On the Estimatementioning

confidence: 99%

“…Uncertainties related to the velocity time-invariance assumption are the result of unaccounted variations in stress conditions, fracture development, and injection-fluid invasion during the experiment. Stanchits et al (2015) measured velocity variations for compressional waves that are also on the order of 6% during hydraulic fracturing experiments equivalent to the one considered in this work.…”

Section: Propagation Velocitiesmentioning

confidence: 99%

Spatial and Temporal Variation of Seismic Attenuation During Hydraulic Fracturing of a Sandstone Block Subjected to Triaxial Stress

Rodrı́guez

Stanchits

2017

JGR Solid Earth

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Q factors estimated with spectral ratios describe the attenuation experienced by seismic arrivals in their travel from the source(s) to the receiver(s). When Q is not the same along the travel path of each arrival, the formulation must incorporate two Q factors making the problem indeterminate. Here we show that by assuming that Q is a random variable, the parameters of its probability distribution can be recovered through a mapping workflow using the spectral ratios. An advantage of such a workflow is that uncertainties in source location and velocity model can also be incorporated by representing these elements as random variables. We apply such a methodology to an acoustic emission (AE) data set from a laboratory experiment of hydraulic fracturing in a Colton sandstone block. We assume that the probability distribution of Q is normal. Anisotropic mean (μQ) values correlate with the triaxial stress conditions imposed at the boundaries of the block, with higher stress corresponding with less attenuation. The μQ values estimated within time intervals in the direction perpendicular to the hydraulic fracture plane correlate with stress buildup at the borehole during fracture propagation and borehole pressure relaxation or drop during fracture closure. The standard deviations (σQ) reflect the attenuation heterogeneity within the sampled regions. An increase in heterogeneity is correlated with pressure buildup at the borehole, which we interpret to reflect a dynamic stress gradient formed from the hydraulic fracture toward the surroundings.

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“…В дальнейших работах будут изложены материалы исследования и подробно будет изложено развитие ма-гистральной трещины в области растягивающих напря-жений при применении метода акустико-эмиссионного прогнозирования механического разрушения и ки-нетическая модель микротрещинообразования твeрдых тел [81][82][83][84][85][86][87][88][89][90][91] с одновременной регистрацией электроста-тических полей [92][93][94][95][96][97].…”

Section: механизмы развития магистральных трещинunclassified

Термокинетическая Модель Разрушения Гетерогенных Материалов И Особенности Ее Численной Реализации При Воздействии Высокочастотными Электромагнитными Полями

Менжулин¹,

Махмудов²

2017

Журнал Технической Физики

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Hydraulic Fracturing of Heterogeneous Rock Monitored by Acoustic Emission

Cited by 100 publications

References 13 publications

Experiments versus theory for the initiation and propagation of radial hydraulic fractures in low‐permeability materials

Experiments versus theory for the initiation and propagation of radial hydraulic fractures in low‐permeability materials

Spatial and Temporal Variation of Seismic Attenuation During Hydraulic Fracturing of a Sandstone Block Subjected to Triaxial Stress

Термокинетическая Модель Разрушения Гетерогенных Материалов И Особенности Ее Численной Реализации При Воздействии Высокочастотными Электромагнитными Полями

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