Onset of Hydraulic Fracture Initiation Monitored by Acoustic Emission and Volumetric Deformation Measurements

Stanchits, Sergei; Surdi, A.; Gathogo, Patrick; Edelman, Eric; Suárez‐Rivera, Roberto

doi:10.1007/s00603-014-0584-y

Cited by 97 publications

(47 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Acoustic emission (AE) events, which radiate elastic waves in a manner similar to seismic events observed in earthquakes, are closely associated with the microcracking process of the material under compression Mlakar et al, 1993;Mongi, 1962;Ohnaka & Mogi, 1982;Scholz, 1968a;Stanchits et al, 2014). Observation on microcracks in this study thus provides an insight into the development of AE events in the faulting (shear fracturing) process.…”

Section: Implications To Seismic Activitymentioning

confidence: 59%

Microscopic Characterization of Tensile and Shear Fracturing in Progressive Failure in Marble

Cheng

Wong

2018

JGR Solid Earth

View full text Add to dashboard Cite

Compression‐induced tensile and shear fractures were reported to be the two fundamental fracture types in rock fracturing tests. This study investigates such tensile and shear fracturing process in marble specimens containing two different flaw configurations. Observations first reveal that the development of a tensile fracture is distinct from shear fracture with respect to their nucleation, propagation, and eventual formation in macroscale. Second, transgranular cracks and grain‐scale spallings become increasingly abundant in shear fractures as loading increases, which is almost not observed in tensile fractures. Third, one or some dominant extensional microcracks are commonly observed in the center of tensile fractures, while such development of microcracks is almost absent in shear fractures. Microcracks are generally of a length comparable to grain size and distribute uniformly within the damage zone of the shear fracture. Fourth, the width of densely damaged zone in the shear fracture is nearly 10 times of that in the tensile fracture. Quantitative measurement on microcrack density suggests that (1) microcrack density in tensile and shear fractures display distinct characteristics with increasing loading, (2) transgranular crack density in the shear fracture decreases logarithmically with the distance away from the shear fracture center, and (3) whatever the fracture type, the anisotropy can only be observed for transgranular cracks with a large density, which partially explains why microcrack anisotropy usually tends to be unobvious until approaching peak stress in specimens undergoing brittle failure. Microcracking characteristics observed in this work likely shed light to some phenomena and conclusions generalized in seismological studies.

show abstract

Section: Implications To Seismic Activitymentioning

confidence: 59%

Microscopic Characterization of Tensile and Shear Fracturing in Progressive Failure in Marble

Cheng

Wong

2018

JGR Solid Earth

View full text Add to dashboard Cite

show abstract

“…This difference stems from the strong viscous effects at play during wellbore pressurization, fracture initiation, and early propagation (i.e., fluid entrance in the newly created fracture). It has been observed on a number of experiments [ Weijers , ; Zhao et al , ; Stanchits et al , ] and discussed theoretically for plane strain conditions [ Detournay and Carbonell , ; Lakirouhani et al , ]. We will clarify which dimensionless parameters control the difference between the fracture initiation pressure and the maximum pressure.…”

Section: Introductionmentioning

confidence: 70%

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

et al. 2017

View full text Add to dashboard Cite

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.

show abstract

“…Ishida et al [] injected water and viscous oil into blocks of Kurokami‐jima granite with monitoring pressure change of the flat jacks applying the confining pressure. Stanchits et al [] injected two kinds of silicon oil having thousandfold different viscosity into low permeability blocks of Colton sandstone with monitoring volume of the injected fluid. Their results both indicated that the higher viscosity tends to induce the larger aperture cracks, which is inconsistent with our results shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

Features of CO₂ fracturing deduced from acoustic emission and microscopy in laboratory experiments

et al. 2016

View full text Add to dashboard Cite

We conducted hydraulic fracturing (HF) experiments on 170 mm cubic granite specimens with a 20 mm diameter central hole to investigate how fluid viscosity affects HF process and crack properties. In experiments using supercritical carbon dioxide (SC‐CO2), liquid carbon dioxide (L‐CO2), water, and viscous oil with viscosity of 0.051–336.6 mPa · s, we compared the results for breakdown pressure, the distribution and fracturing mechanism of acoustic emission, and the microstructure of induced cracks revealed by using an acrylic resin containing a fluorescent compound. Fracturing with low‐viscosity fluid induced three‐dimensionally sinuous cracks with many secondary branches, which seem to be desirable pathways for enhanced geothermal system, shale gas recovery, and other processes.

show abstract

Onset of Hydraulic Fracture Initiation Monitored by Acoustic Emission and Volumetric Deformation Measurements

Cited by 97 publications

References 12 publications

Microscopic Characterization of Tensile and Shear Fracturing in Progressive Failure in Marble

Microscopic Characterization of Tensile and Shear Fracturing in Progressive Failure in Marble

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

Features of CO₂ fracturing deduced from acoustic emission and microscopy in laboratory experiments

Contact Info

Product

Resources

About

Onset of Hydraulic Fracture Initiation Monitored by Acoustic Emission and Volumetric Deformation Measurements

Cited by 97 publications

References 12 publications

Microscopic Characterization of Tensile and Shear Fracturing in Progressive Failure in Marble

Microscopic Characterization of Tensile and Shear Fracturing in Progressive Failure in Marble

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

Features of CO2 fracturing deduced from acoustic emission and microscopy in laboratory experiments

Contact Info

Product

Resources

About

Features of CO₂ fracturing deduced from acoustic emission and microscopy in laboratory experiments