Permeability of granite under high pressure

Brace, W. F.; Walsh, J. B.; Frangos, William

doi:10.1029/jb073i006p02225

Cited by 1,485 publications

(703 citation statements)

References 9 publications

Supporting

Mentioning

680

Contrasting

Unclassified

Order By: Relevance

“…Then, just before the failure, the permeability increased to ∼ 10 −18 m 2 in the both experiments. There are a lot of studies dealing with permeability-porosity relationship and permeability-stress relationship (e.g., [43][44][45]). In our experiment, permeability reduction is approximately an exponential function of effective mean stress [45] and mainly attributed to elastic crack closure [43].…”

Section: Resultsmentioning

confidence: 99%

Changes in Electrokinetic Coupling Coefficients of Granite under Triaxial Deformation

Kuwano

Yoshida²

2012

International Journal of Geophysics

View full text Add to dashboard Cite

Electrokinetic phenomena are believed to be the most likely origin of electromagnetic signals preceding or accompanying earthquakes. The intensity of the source current due to the electrokinetic phenomena is determined by the fluid flux and the electrokinetic coupling coefficient called streaming current coefficient; therefore, how the coefficient changes before rupture is essential. Here, we show how the electrokinetic coefficients change during the rock deformation experiment up to failure. The streaming current coefficient did not increase before failure, but continued to decrease up to failure, which is explained in terms of the elastic closure of capillary. On the other hand, the streaming potential coefficient, which is the product of the streaming current coefficient and bulk resistivity of the rock, increased at the onset of dilatancy. It may be due to change in bulk resistivity. Our result indicates that the zeta potential of the newly created surface does not change so much from that of the preexisting fluid rock interface.

show abstract

Section: Resultsmentioning

confidence: 99%

Changes in Electrokinetic Coupling Coefficients of Granite under Triaxial Deformation

Kuwano

Yoshida²

2012

International Journal of Geophysics

View full text Add to dashboard Cite

show abstract

“…In fact, the hypothesis of intant pressure equilibrium stated by Brace et al (1968) is not true and affects permeability measurement in very low permeability porous media. Nevertheless, Chenevert and Sharma (1993) did find consistant data between pulse decay experiment interpreted by Equation (15) and steady state measurement, their findings can be affected by uncertainties that were not reported in their work.…”

Section: Sample B -Experiments On a 08 Nd Samplementioning

confidence: 99%

“…Pressure wave propagation is known to be fast in porous media and is proportional to k w L 2 /S s (in Brace et al (1968), it is supposed to be instantaneous). Based on simulations, pore pressure equilibriums within the sample are presented in Figures 21 and 22 for steady state and pulse decay tests carried out on sample B.…”

Section: Duration Of the Experimentsmentioning

confidence: 99%

“…Its principle, illustrated in Figure 1, was first proposed by Brace et al (1968). It consists in a sample bounded by two reservoirs that are initially at equal pressures.…”

Section: Introductionmentioning

confidence: 99%

“…The pulse decay technique was first proposed by Brace et al (1968). The interpretation is based on the exponential decrease of the pressure difference (P usptream -P downstream ) with time.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Contribution of the Steady State Method to Water Permeability Measurement in Very Low Permeability Porous Media

Boulin

Bretonnier

Gland

et al. 2012

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

View full text Add to dashboard Cite

Résumé -Contribution de la méthode stationnaire dans les mesures des très faibles perméa-bilités à l'eau -Les milieux très peu perméables (k < 10 nD (10 −20 m 2 )) comme les argiles sont étudiés dans le cadre de problématiques très diverses telles que le stockage du CO 2 , les surpressions en forage profond ou le stockage des déchets radioactifs. La caractérisation pétrophysique de ces roches, et notamment la mesure de leur faible perméabilité, est difficile. La technique en laboratoire la plus répandue est celle du pulse decay. Cette technique consiste à imposer un pulse de pression en amont de l'échantillon puis de suivre l'évolution des pressions amont et aval. La durée de l'essai est supérieure à la journée pour des échantillons d'un nanoDarcy. Le signal est fortement tributaire des fuites dans le système ou des variations de température. La méthode stationnaire consiste à mesurer directement le débit d'eau à travers l'échantillon pour un gradient de pression donné. Cette technique est rarement utilisée pour les milieux très peu perméables car réputée très longue (Hsieh et al., 1981, Int. J. Rock Mech. Min. Sci. Geomech. Abstr. 18, 245-252). Des essais en laboratoire ont été réalisés sur trois échantillons. La méthode stationnaire ainsi que des méthodes transitoires (dont le pulse decay) furent employées. La limitation principale des méthodes transitoires est la difficulté d'interpréter correctement les profils de relaxation. La méthode stationnaire s'est montrée aussi rapide (trois jours pour un échantillon de 0.8 nD (8 × 10 −22 m 2 )), voire plus rapide (moins d'une journée pour un échantillon de 2.6 nD (2.6 × 10 −21 m 2 )), que la méthode du pulse decay. La perméabilité a été plus simple à déterminer et cette méthode peut être rapide avec un équipement adapté. En réalité, la faible compressibilité de la roche permet une propagation rapide des ondes de pression. De ce fait, il ne peut pas être soutenu que les conditions de régime permanent ne soient pas atteintes en un temps raisonnable. La méthode pulse decay reste une alternative intéressante à la méthode stationnaire lorsque la perméabilité est supérieure à 50 nD (5 × 10 −20 m 2 ). Abstract

show abstract

Physical properties and brittle strength of thermally cracked granite under confinement

et al. 2013

View full text Add to dashboard Cite

[1] Effects of thermal crack damage on the rupture processes of a fine-grained granite were investigated under triaxial stress, under water (wet) and argon gas (dry) saturated conditions, and at room temperature. Thermal cracking was introduced by slowly heating and cooling two samples of La Peyratte granite up to 700 ı C, which were compared to two intact specimens. For each rock sample, a hydrostatic test was first carried up to 90 MPa effective pressure (5 MPa constant pore pressure). The samples were then deformed to failure at a constant strain rate of 2.10 -6 s -1 , at 30 MPa effective pressure. Our results show that (1) permeability of heat-treated specimens was 4-5 orders of magnitude larger than that of intact specimens at low effective mean pressure; (2) nevertheless, at our experimental conditions (2.10 -6 s -1 ), thermal cracking had no significant influence on the brittle strength; (3) similarly, no obvious water weakening effect was observed; (4) however, with increasing stress, elastic anisotropy appeared at lower differential stress in heat-treated specimens than in intact ones, but close to failure, the magnitude of P wave anisotropy was approximately the same for both types of specimens; (5) acoustic emission hypocenter locations and P wave velocity anisotropy in the basal plane demonstrate that strain localization started right at the onset of dilatancy for heat-treated specimens, later in the intact specimens; and (6) inverting wave velocities for crack density, we show that failure was reached for vertical crack densities of 0.35 for dry specimens and possibly 0.5 for water-saturated specimens.

show abstract

Permeability of granite under high pressure

Cited by 1,485 publications

References 9 publications

Changes in Electrokinetic Coupling Coefficients of Granite under Triaxial Deformation

Changes in Electrokinetic Coupling Coefficients of Granite under Triaxial Deformation

Contribution of the Steady State Method to Water Permeability Measurement in Very Low Permeability Porous Media

Physical properties and brittle strength of thermally cracked granite under confinement

Contact Info

Product

Resources

About