Paul Bossart

Federal Office of Topography swisstopo

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Christophe Nussbaum

Federal Office of Topography swisstopo

David Jaeggi

Federal Office of Topography swisstopo

Kristof Schuster

Federal Institute for Geosciences and Natural Resources

Thomas Trick

CryptoExperts (France)

Martin Mazurek

University of Bern

Peter Connolly

Chevron (United States)

Florence Nicollin

Géosciences Rennes

Dominique Gibert

Université Claude Bernard Lyon 1

Ana María Fernández

Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas

Miguel Sánchez

Universidad Nacional del Sur

Cooperative Institutions

ETH Zurich

Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas

Centre National de la Recherche Scientifique

Universidad Complutense de Madrid

École Polytechnique Fédérale de Lausanne

National Cooperative for the Disposal of Radioactive Waste (Switzerland)

Paul Scherrer Institute

Board of the Swiss Federal Institutes of Technology

University of Bern

Federal Institute for Geosciences and Natural Resources

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Creation and Evolution of Damage Zones Around a Microtunnel in a Claystone Formation of the Swiss Jura Mountains

Proceedings of International Symposium and Exhibition on Formation Damage Control (2006)

Paul Marschall Marc Distinguin Shao Hua Paul Bossart Cristian Enachescu

Creation and Evolution of Damage Zones Around a Microtunnel in a Claystone Formation of the Swiss Jura Mountains Paul Marschall; Paul Marschall Nagra Search for other works by this author on: This Site Google Scholar Marc Distinguin; Marc Distinguin ANDRA Search for other works by this author on: This Site Google Scholar Hua Shao; Hua Shao Search for other works by this author on: This Site Google Scholar Paul Bossart; Paul Bossart Search for other works by this author on: This Site Google Scholar Cristian Enachescu; Cristian Enachescu Golder Assocs. GmbH Search for other works by this author on: This Site Google Scholar Thomas Trick Thomas Trick Solexperts Search for other works by this author on: This Site Google Scholar Paper presented at the SPE International Symposium and Exhibition on Formation Damage Control, Lafayette, Louisiana, USA, February 2006. Paper Number: SPE-98537-MS https://doi.org/10.2118/98537-MS Published: February 15 2006 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Marschall, Paul, Distinguin, Marc, Shao, Hua, Bossart, Paul, Enachescu, Cristian, and Thomas Trick. "Creation and Evolution of Damage Zones Around a Microtunnel in a Claystone Formation of the Swiss Jura Mountains." Paper presented at the SPE International Symposium and Exhibition on Formation Damage Control, Lafayette, Louisiana, USA, February 2006. doi: https://doi.org/10.2118/98537-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE International Conference and Exhibition on Formation Damage Control Search Advanced Search AbstractThe investigation of damage zones around cylindrical excava¬tions such as sealing sections in tunnels or shafts is a key issue in the field of underground waste storage. Emphasis is on the geometry and extent of the excavation-induced damage zones, on their mechanical and hydraulic characteristics and, in a broader perspective, on the stability of the cavities before and after waste emplacement. Formation damage control in production and injection wells represents a similar stability problem, suggesting that a detailed understanding of coupled hydromechanical processes in the vicinity of cylindrical cavities is just as valuable for the oil and gas industry. As part of a geoscientific research programme at the Mont Terri underground rock laboratory in the Jura Mountains of Switzerland, a horizontal microtunnel was drilled in an overconsolidated claystone formation. Prior to the excavation, the rock formation was instrumented with piezometers, inclinemeters, extensometers and stress cells for monitoring the hydromechanical response of the rock formation to the drilling process. After completion of the excavation, a geoscientific characterization campaign was initiated, comprising detailed geological mapping of structural features, laser scanning of the tunnel surface and the instrumentation of the tunnel walls with surface extensometers. Complementary investigations were conducted to estimate rock stress at the site and the geomechanical rock properties, such as elastic moduli, rock strength and anisotropy. The observations to date indicate that a distinct damage zone was created by the drilling process, comprising massive breakouts and localized spalling. Break¬outs with magnitudes of up to 15 cm were observed in one of the upper quadrants of the tunnel cross section and less marked features were mapped on the opposite lower quadrant. Long-term monitoring of pore pressure and deformation around the tunnel and progressive spalling along the tunnel wall suggest that the damage zone is still developing. The complex geometry of the damage zone is explained by the interaction of a distinct stress anisotropy and rock strength anisotropy. The initiation of excavation-induced fractures can be linked to isolated tectonic features intersecting the microtunnel. The geometry and the temporal evolution of the damage zones are similar to observations in boreholes, indicating that the basic hydromechanical mechanisms are comparable.IntroductionTight claystone and shale formations are being assessed as potential host or cap rocks for the disposal of hazardous wastes such as radioactive waste, toxic chemical waste, CO2, H2S and for natural gas storage (Brosse et al[1], DOE[2], IAEA[3], Katz & Lee[4], Nilsen & Olsen[5]). Their low permeability, self-sealing capacity and the long-term stability of the geological environment are favourable aspects which enable the isolation and confinement of the wastes over very long time periods. On the other hand, special geomechanical properties (low rock strength, distinct anisotropy in geomechanical properties) and unfavourable in-situ stress conditions (distinct stress anisotropy) are often faced as serious engineering problems during the construction and operation of deep underground facilities in clay-rich formations (Aristorenas[6], Martin et al[7], Steiner[8,9]). The stability problems may range from brittle failure (over¬breaks and partial tunnel collapse, local spalling and buckling phenomena at the tunnel walls) during the construction phase to time dependent-deformation during the operational period (significant convergence of tunnels and drifts) and possible dilatancy phenomena after repository closure, caused by overpressures in the backfilled tunnels (gas production of the waste). Similar stability problems have been reported in the field of oil & gas exploration when drilling horizontal boreholes in stratified shale formations (Økland & Cook[10]), sug¬gesting that the basic failure mechanisms in deep horizontal boreholes are comparable to those in the excavation damage zone around tunnels and drifts. Keywords: Reservoir Characterization, Rock Laboratory, structural geology, pore pressure, reservoir geomechanics, displacement, experiment, laboratory, evolution, damage zone Subjects: Reservoir Characterization, Exploration, development, structural geology, Reservoir geomechanics This content is only available via PDF. 2006. Society of Petroleum Engineers You can access this article if you purchase or spend a download.

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10.2523/98537-ms

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Citations (2)

Research in the Mont Terri Rock laboratory: Quo vadis?

Physics and Chemistry of the Earth Parts A/B/C (2007)

Paul Bossart M. Thury

Closure (psychology)

10.1016/j.pce.2006.04.031

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Citations (50)

Twenty years of research at the Mont Terri rock laboratory: what we have learnt

Swiss Journal of Geosciences (2017)

Paul Bossart

Transferability

10.1007/s00015-017-0267-2

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Citations (8)

The Mont Terri rock laboratory, a new international research project in a Mesozoic shale formation, in Switzerland

Engineering Geology (1999)

M. Thury Paul Bossart

10.1016/s0013-7952(99)00015-0

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Citations (180)

Seismic tomography of the Excavation Damaged Zone of the Gallery 04 in the Mont Terri Rock Laboratory

Geophysical Journal International (2007)

Florence Nicollin Dominique Gibert Paul Bossart C. Nussbaum C. Guervilly

An endoscopic antenna is used to perform a seismic cross-hole tomography in the Excavation Damaged Zone (EDZ) of the new G04 gallery of the Mont Terri Underground Rock Laboratory (Switzerland) excavated in Opalinus clay. More than 800 seismic traces were recorded between two vertical boreholes by combining 22 source and 48 receiver locations. A vertical area of 1.2 × 3.4 m under the floor of the gallery is investigated with a high-resolution tomography. Data with a very good quality allow to determine the traveltimes and the amplitudes of a 40kHz source wavelet propagating between the two boreholes. The analysis of the traveltimes shows that the wave velocity is homogeneous but anisotropic with a minimum value of 2490 ± 45ms−1 in the direction normal to the bedding and a maximum of 3330 ± 90ms−1 parallel to the bedding. The amplitude of the first arrivals strongly varies depending on the source–receiver locations, and suggesting an heterogeneous distribution of the attenuation coefficient of the seismic waves. A Bayesian inversion provides likely models of attenuation that are compared with geological observations. The areas where fractures or cracks exist in the Opalinus clay appear as highly absorbing the seismic waves.

Bedding

Vertical seismic profile

Seismic Tomography

10.1111/j.1365-246x.2007.03615.x

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Citations (31)

Rock magnetic properties and structural development in the core of the Hazara‐Kashmir Syntaxis, NE Pakistan

Tectonics (1990)

Paul Bossart Robert Ottiger Friedrich Heller

Paleomagnetic and structural analyses have been conducted on three well‐exposed sections through a 6–8 km thick pile of molassic red beds (Murree formation) in the lowermost tectonic unit of the Hazara‐Kashmir Syntaxis. Micropaleontological age determinations of the lowermost Murree sediments indicate Late Paleocene deposition (55 m.y.). From south to north, the sections are situated in the Jhelum, Neelum (both in Azad Kashmir), and Kaghan (northeastern Pakistan) valleys. Thermal demagnetization experiments suggest that haematite with high unblocking temperatures carries stable characteristic remanence directions. The relationship between finite strain and magnetic fabric was established by mapping deformed reduction spot strain markers and by measuring the anisotropy of magnetic susceptibility (AMS). For the Jhelum valley the weakly tectonized Murree beds are characterized by flattened AMS ellipsoids resulting from diagenetic compaction. Inclination values suggest that the Murree foreland basin started to develop at about 8°N during the early suturing of India and the development of island arcs to the north. India has moved northward by at least 2600 km since collision with Eurasia in the Paleocene. Declination values suggest 45° of clockwise rotation of the block supporting the Murree formation relative to the Indian craton. For the Neelum and Kaghan valleys, quantitative strain mapping shows a progressive increase of deformation northward. NRM directions rotate passively toward the cleavage plane which parallels the foliation of the AMS ellipsoids. NRM directions and AMS ellipsoids are deformed because of superposition of tectonic strain on a primary compactional strain. The AMS pattern is interpreted in light of this superposition, and a regional deformation path from south to north is suggested. A tectonic rotation model is proposed which is consistent with the transport directions around the Hazara‐Kashmir Syntaxis and the rotation of thrust sheets indicated by the NRM data. This model relates the convergent transport directions with the mean indentation direction of India into Asia.

Main Central Thrust

Clockwise

Lineation

Paleogene

10.1029/tc009i001p00103

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Citations (20)

Instrumentation for a Gas Path through Host Rock and Along Sealing Experiment

Thomas Trick Paul Marschall Ursula Rösli Yanik Lettry Paul Bossart

A key issue in the field of underground waste storage is the investigation of the barrier function of the host rock and the sealing of the disposal tunnel. For the demonstration of gas escape, a large scale "gas path through host rock and along sealing experiment" is currently being conducted at the Mont Terri Rock Laboratory in Switzerland. The experiment is focused on the gas paths along an excavation damaged zone (EDZ) developed around a sealed microtunnel section and the gas paths through the excavation undisturbed host rock. The instrumentation of the test site comprises suitable sensors to assess the hydraulic and geo-mechanic characteristics and the coupled hydromechanical processes around the tunnel. The first test data show a good response of the sensors to the induced pressures and stresses.

Instrumentation

10.1061/40940(307)72

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Citations (4)

Mont Terri Project - Heater experiment : rock and bentonite thermo-hydro-mechanical (THM) processes in the near field of a thermal source for development of deep underground high level radioactive waste repositories

I. Goebel H.-J. Alheid Kaufhold Michael Naumann Th. Pletsch

Bentonite

High-level waste

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The Rock Mechanical Behavior of Opalinus Clay – 20 Years of Experience in the Mont Terri Rock Laboratory

Springer series in geomechanics and geoengineering (2017)