scholarly journals In Situ Direct Displacement Information on Fault Reactivation During Fluid Injection

2020 ◽  
Vol 53 (10) ◽  
pp. 4313-4328 ◽  
Author(s):  
Maria Kakurina ◽  
Yves Guglielmi ◽  
Christophe Nussbaum ◽  
Benoît Valley

Abstract The three dimensional (3D) displacement induced by fluid injection was measured during two fault reactivation experiments conducted in carbonate rocks at the Rustrel Low Noise Underground Laboratory (LSBB URL), France, and in shale rocks at the Mont Terri Rock laboratory, Switzerland. The faults were activated by injecting high pressure fluid and using the Step-Rate Injection Method for Fracture In-Situ Properties, which allows a coupled pressure-flowrate-3D displacement monitoring in boreholes. Both experiments mainly show complex aseismic deformation of preexisting fractures that depend on (1) the fluid pressure variations related to chamber pressurization and leakage into the formation and (2) irreversible shear slip and opening of the reactivated fractures. Here we detail the processing of the 3D displacement data from both experiments to isolate slip vectors from the complex displacement signal. Firstly, we explain the test protocol and describe the in situ hydromechanical behavior of the borehole/fault system. Secondly, we define the methodology of the displacement data processing to isolate slip vectors with high displacement rates, which carry information about the key orientation of fault reactivation. Finally, we discuss which slip vectors can potentially be used to solve the stress inversion problem.

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 282 ◽  
Author(s):  
Thanh Son Nguyen ◽  
Yves Guglielmi ◽  
Bastian Graupner ◽  
Jonny Rutqvist

Faults in the host rock that might exist in the vicinity of deep geological repositories for radioactive waste, constitute potential enhanced pathways for radionuclide migration. Several processes might trigger pore pressure increases in the faults leading to fault failure and induced seismicity, and increase the faults’ permeability. In this research, we developed a mathematical model to simulate fault activation during an experiment of controlled water injection in a fault at the Mont-Terri Underground Research Laboratory in Switzerland. The effects of in-situ stress, fault shear strength parameters and heterogeneity are assessed. It was shown that the above factors are critical and need to be adequately characterized in order to predict the faults’ hydro-mechanical behaviour.


2019 ◽  
Vol 5 (3) ◽  
pp. eaau4065 ◽  
Author(s):  
Frédéric Cappa ◽  
Marco Maria Scuderi ◽  
Cristiano Collettini ◽  
Yves Guglielmi ◽  
Jean-Philippe Avouac

Faults can slip seismically or aseismically depending on their hydromechanical properties, which can be measured in the laboratory. Here, we demonstrate that fault slip induced by fluid injection in a natural fault at the decametric scale is quantitatively consistent with fault slip and frictional properties measured in the laboratory. The increase in fluid pressure first induces accelerating aseismic creep and fault opening. As the fluid pressure increases further, friction becomes mainly rate strengthening, favoring aseismic slip. Our study reveals how coupling between fault slip and fluid flow promotes stable fault creep during fluid injection. Seismicity is most probably triggered indirectly by the fluid injection due to loading of nonpressurized fault patches by aseismic creep.


2017 ◽  
Vol 114 ◽  
pp. 3167-3174 ◽  
Author(s):  
Yves Guglielmi ◽  
Jens Birkholzer ◽  
Jonny Rutqvist ◽  
Pierre Jeanne ◽  
Christophe Nussbaum

2017 ◽  
Vol 54 (8) ◽  
pp. 902-918 ◽  
Author(s):  
Jakub T. Szmigielski ◽  
M. Jim Hendry

The geometry and spatial distribution of a polygonal fault system (PFS) and collapse features within Cretaceous strata (predominantly mudstones and claystones) were investigated using three high-resolution three-dimensional seismic datasets of the Williston Basin, Saskatchewan, Canada. Mapping of the planform geometry and fault throw distributions (throw–depth (T–z) profiling) shows that the PFS present in the Colorado Group and Pierre Fm has a vertical extent of 200–330 m. Variation in the lateral planform geometry is attributed to the relative rates of stress accumulation during early development of the planar faults and is constrained using sequence stratigraphic principles. The mean fault dip is 60° ± 12° (number of measurements, n = 225). The T–z profiles appear as partial C-type profiles, demonstrating that at least half of the total height of the PFS was removed during post-Cretaceous erosion. The presence of polygonal faults in equivalent strata of the Western Interior Sedimentary Basin (WISB) suggests the PFS described in the current study (1510 km2) may be present across the WISB. Collapse features, formed in response to dissolution cavities within underlying strata, crosscut the entire Cretaceous sequence and are subcircular in plan view with typical diameters of 350–450 m. These features are present in each of the datasets at a rate of 0.02–0.11 collapses/km2. The prevalence of collapses in areas where faults display modified throw distributions may suggest post-Cretaceous fault reactivation associated with Pleistocene glacial periods. Although these secondary rock structures likely affect groundwater and solute transport at the basin scale, the impact remains to be determined.


2015 ◽  
Vol 52 (10) ◽  
pp. 1457-1465 ◽  
Author(s):  
Jeoung Seok Yoon ◽  
Günter Zimmermann ◽  
Arno Zang ◽  
Ove Stephansson

Enhanced geothermal systems, shale gas, and geological carbon sequestration all require underground fluid injection in high-pressure conditions. Fluid injection creates fractures, induces seismicity, and has the potential to reactivate nearby faults that can generate a large magnitude earthquake. Mechanisms of fluid injection–induced seismicity and fault reactivation should be better understood to be able to mitigate larger events triggered by fluid injection. This study investigates fluid injection, induced seismicity, and triggering of fault rupture using hydromechanical-coupled discrete element models. Results show that a small amount of fluid pressure perturbation can trigger fault ruptures that are critically oriented and stressed. Induced seismicity by rock failure shows in general higher b-values (slope of magnitude–frequency relation) compared to seismicity triggered by the fault fracture slip. Numerical results closely resemble observations from geothermal and shale-gas fields and demonstrate that discrete element modeling has the potential to be applied in the field as a tool for predicting induced seismicity prior to in situ injection.


Author(s):  
J. P. Revel

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.


Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.


Author(s):  
S. Naka ◽  
R. Penelle ◽  
R. Valle

The in situ experimentation technique in HVEM seems to be particularly suitable to clarify the processes involved in recrystallization. The material under investigation was unidirectionally cold-rolled titanium of commercial purity. The problem was approached in two different ways. The three-dimensional analysis of textures was used to describe the texture evolution during the primary recrystallization. Observations of bulk-annealed specimens or thin foils annealed in the microscope were also made in order to provide information concerning the mechanisms involved in the formation of new grains. In contrast to the already published work on titanium, this investigation takes into consideration different values of the cold-work ratio, the temperature and the annealing time.Two different models are commonly used to explain the recrystallization textures i.e. the selective grain growth model (Beck) or the oriented nucleation model (Burgers). The three-dimensional analysis of both the rolling and recrystallization textures was performed to identify the mechanismsl involved in the recrystallization of titanium.


Author(s):  
W.F. Marshall ◽  
A.F. Dernburg ◽  
B. Harmon ◽  
J.W. Sedat

Interactions between chromatin and nuclear envelope (NE) have been implicated in chromatin condensation, gene regulation, nuclear reassembly, and organization of chromosomes within the nucleus. To further investigate the physiological role played by such interactions, it will be necessary to determine which loci specifically interact with the nuclear envelope. This will not only facilitate identification of the molecular determinants of this interaction, but will also allow manipulation of the pattern of chromatin-NE interactions to probe possible functions. We have developed a microscopic approach to detect and map chromatin-NE interactions inside intact cells.Fluorescence in situ hybridization (FISH) is used to localize specific chromosomal regions within the nucleus of Drosophila embryos and anti-lamin immunofluorescence is used to detect the nuclear envelope. Widefield deconvolution microscopy is then used to obtain a three-dimensional image of the sample (Fig. 1). The nuclear surface is represented by a surface-harmonic expansion (Fig 2). A statistical test for association of the FISH spot with the surface is then performed.


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