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J.D. Byerlee

Publications and source records attributed to J.D. Byerlee.

At least 55 records · Page 3Linked to original sources
USGS1985

PERMEABILITY CHANGES IN CRYSTALLINE ROCKS DUE TO TEMPERATURE: EFFECTS OF MINERAL ASSEMBLAGE.

The change in permeability with time of granite, quartzite, anorthosite and gabbro was measured while these rocks were subjected to a temperature gradient. Permeability reductions of up to two orders of magnitude were observed, with the greatest reactions occurring in the quartzite. These changes are thought to be caused by dissolution of minerals at high temperatures, and redeposition of the dissolved material at lower temperatures. Quartz appears to be an important mineral in this self-sealing process. If very low permeability is desired around a nuclear waste repository in crystalline rocks, then a quartz-rich rock may be the most appropriate host.

Conference Paper↗
USGS1983

Chemical reactions accompanying fluid flow through granite held in a temperature gradient

Distilled water was passed at a low rate down a temperature gradient through cylinders of Barre and Westerly Granite. Temperatures ranged from 80–100°C at the outer edges of the cylinders to 250–300°C in central, drilled holes which housed the heating coils. The measured permeabilities of the granite cylinders decreased by as much as two orders of magnitude in experiments of 1–3 weeks' duration. The amount of permeability decrease varied directly with temperature and inversely with the rate of fluid flow. The compositions of the fluids discharged from the granites were functions of temperature and flow rate as well as mineral composition, with dissolved silica concentrations showing trends different from those of the other analyzed species. Fluids from experiments run at higher temperatures but at much lower initial rates of fluid flow had higher concentrations of most ions but substantially lower dissolved silica contents. In contrast, an increase in temperature at similar rates of fluid flow resulted in higher silica concentrations. In the experiments, the distilled water acquired enough dissolved materials at high temperatures to become supersaturated with respect to several minerals at the low-temperature edges of the cylinders. Some of this material, particularly silica, was deposited along grain boundaries and microfractures, causing the observed permeability decreases. The very low rates of fluid flow in some high-temperature experiments significantly increased the rates of SiO 2 precipitation and reduced dissolved silica concentrations relative to other species in the discharged fluids.

Geochimica et Cosmochimica Acta↗
USGS1983

A mechanism to explain the generation of earthquake lights

Explanations of how earthquake lights might arise have failed to show how large charge densities can be concentrated and sustained in a conductive Earth. A physical model is proposed, based on frictional heating of the fault, that solves this and related problems. ?? 1983 Nature Publishing Group.

Nature↗
USGS1982

Laboratory measurements of reservoir rock from the Geysers geothermal field, California

Rock samples taken from two outcrops, as well as rare cores from three well bores at the Geysers geothermal field, California, were tested at temperatures and pressures similar to those found in the geothermal field. Both intact and 30?? sawcut cylinders were deformed at confining pressures of 200-1000 bars, pore pressure of 30 bars and temperatures of 150?? and 240??C. Thin-section and X-ray analysis revealed that some borehole samples had undergone extensive alteration and recrystallization. Constant strain rate tests of 10-4 and 10-6 per sec gave a coefficient of friction of 0.68. Due to the highly fractured nature of the rocks taken from the production zone, intact samples were rarely 50% stronger than the frictional strength. This result suggests that the Geysers reservoir can support shear stresses only as large as its frictional shear strength. Velocity of p-waves (6.2 km/sec) was measured on one sample. Acoustic emission and sliding on a sawcut were related to changes in pore pressure. b-values computed from the acoustic emissions generated during fluid injection were typically about 0.55. An unusually high b-value (approximately 1.3) observed during sudden injection of water into the sample may have been related to thermal cracking. ?? 1982.

International Journal of Rock Mechanics and Mining↗
USGS1980

Hydraulic fracturing in granite under geothermal conditions

The experimental hydraulic fracturing of granite under geothermal conditions produces tensile fracture at rapid fluid injection rates and shear fracture at slow injection rates and elevated differential stress levels. A sudden burst of acoustic emission activity accompanies tensile fracture formation whereas the acoustic emission rate increases exponentially prior to shear fracture. Temperature does not significantly affect the failure mechanism, and the experimental results have not demonstrated the occurrence of thermal fracturing. A critical result of these experiments is that fluid injection at intermediate rates and elevated differential stress levels increases permeability by more than an order of magnitude without producing macroscopic fractures, and low-level acoustic emission activity occurs simultaneously near the borehole and propagates outward into the specimen with time. Permeability measurements conducted at atmospheric pressure both before and after these experiments show that increased permeability is produced by permanent structural changes in the rock. Although results of this study have not demonstrated the occurrence of thermal fracturing, they suggest that fluid injection at certain rates in situ may markedly increase local permeability. This could prove critical to increasing the efficiency of heat exchange for geothermal energy extraction from hot dry rock. ?? 1980.

International Journal of Rock Mechanics and Mining↗
USGS1978

Velocity anomalies: An alternative explanation based on data from laboratory experiments

Locations and velocities were calculated for microseisms occurring in samples of rock subjected to triaxial loading and injection of pore fluid. This was accomplished by analyzing arrival times of acoustic emission using an automatic first arrival picker. Apparent velocity anomalies were observed prior to both failure of intact samples and violent slip in samples containing saw cuts. Further analysis revealed that these fluctuations in calculated velocity were not due to changes in the true seismie velocity. Instead, variations in calculated velocity are shown to be related to sampling errors in picking first arrivals. The systematic picking of late first arrivals for small magnitude events was found to be a persistent bias resulting in low calculated velocities. This has encouraged the reexamination of earthquake records to determine how important sampling biases are in contributing to reported velocity anomalies. ?? 1978 Birkha??user Verlag.

Pure and Applied Geophysics PAGEOPH↗
USGS1976

A magnetic method for determining the geometry of hydraulic fractures

We propose a method that may be used to determine the spatial orientation of the fracture plane developed during hydraulic fracture. In the method, magnetic particles are injected into the crack with the fracturing fluid so as to generate a sheet of magnetized material. Since the magnetization of a body with extreme dimension ratios, such as a crack, exceeds that of an equidimensional body and since this magnetization is sensitive both to orientation and geometry, this could be used to obtain information about the crack. By measuring the vertical and horizontal components of the magnetic field and field gradients at the earth's surface surrounding the injection well with superconducting magnetometers having 10-4 gamma sensitivity and also by measuring field direction within the well itself, it should be possible to calculate the orientation and perhaps infer the approximate geometry of the fracture surface. Experiments on electric field potential operated in conjunction with this experiment could further constrain estimates of shape and orientation. ?? 1976 Birkha??user Verlag.

Pure and Applied Geophysics PAGEOPH↗
USGS1975

Stable sliding preceding stick-slip on fault surfaces in granite at high pressure

The distance of stable sliding before sudden slip on fault surfaces in granite decreases rapidly as the confining pressure is increased. At a pressure of 6 kb the amount of stable creep is very small or absent. Two orders of magnitude change in strain rate has no effect on the distance of stable sliding. Our results suggest that in the earth, fault creep should predominate in the shallow crust but in the deep crustal layer most of the stresses are probably relieved by sudden earthquake type of motion. Below the crust high temperature would promote stable-slip so in this region creep would once more predominate.

Pure and Applied Geophysics↗
USGS1975

The fracture strength and frictional strength of Weber Sandstone

The fracture strength and frictional strength of Weber Sandstone have been measured as a function of confining pressure and pore pressure. Both the fracture strength and the frictional strength obey the law of effective stress, that is, the strength is determined not by the confining pressure alone but by the difference between the confining pressure and the pore pressure. The fracture strength of the rock varies by as much as 20 per cent depending on the cement between the grains, but the frictional strength is independent of lithology. Over the range 0 &lt; &#x3C3; n &lt; 2 kb "> 0 < σn< 2kb , the frictional strength follows the relationship &#x3C4;=0&#xB7;85 &#x3C3; n where &#x3C4; "> τ=0·85 σnwhereτ is the shear stress and &#x3C3; n "> σn is the normal stress, and for &#x3C3; n &gt;2 kb , &#x3C4;=0&#xB7;5 + 0&#xB7;6&#x3C3; n "> σn>2kb, τ=0·5 + 0·6σn . This relationship also holds for other rocks such as gabbro, dunite, serpentinite, granite and limestone.

International Journal of Rock Mechanics and Mining↗
USGS1970

The mechanics of stick-slip

Physical mechanisms that have been proposed to explain the occurrence of stick-slip motion during frictional sliding have been examined in the light of results obtained from experiments with rocks and brittle minerals. An instability caused by sudden brittle fracture of locked regions on surfaces in contact is the most likely explanation for stick-slip during dry frictional sliding of brittle rocks at room temperature. Areas requiring further study and the uncertainties in applying the results of laboratory experiments to earthquake studies are emphasized.

Tectonophysics↗
USGS1970

Static and kinetic friction of granite at high normal stress

Frictional sliding on ground surfaces of granite, angle of sliding planes 30° and 45°, was investigated as a function of confining pressure. Over the normal stress range of 2–12 kb, the static frictional shear stress τ s follows the relationship τ s = 0·5 + 0· σ n and the kinetic frictional shear stress τ k was calculated to be τ k = 0·25 + 0·47 σ n .

International Journal of Rock Mechanics and Mining↗