USGS Science⌕ Search
Home/Archive/USGS

USGS · 70010858

A magnetic method for determining the geometry of hydraulic fractures

J.D. Byerlee·M.J.S. Johnston
View original source ↗Export metadata ↓

Abstract

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.

Explore related subjects

Pure and Applied Geophysics PAGEOPHArticle

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

J.D. Byerlee, M.J.S. Johnston. 1976. A magnetic method for determining the geometry of hydraulic fractures. https://doi.org/10.1007/bf00876942

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2016

Introduction to “Global tsunami science: Past and future, Volume I”

Twenty-five papers on the study of tsunamis are included in Volume I of the PAGEOPH topical issue “Global Tsunami Science: Past and Future”. Six papers examine various aspects of tsunami probability and uncertainty analysis related to hazard assessment. Three papers relate to deterministic hazard and risk assessment. Five more papers present new methods for tsunami warning and detection. Six papers describe new methods for modeling tsunami hydrodynamics. Two papers investigate tsunamis generated by non-seismic sources: landslides and meteorological disturbances. The final three papers describe important case studies of recent and historical events. Collectively, this volume highlights contemporary trends in global tsunami research, both fundamental and applied toward hazard assessment and mitigation.

Pure and Applied Geophysics PAGEOPH↗
USGS1995

Implications of Coulomb plasticity for the velocity dependence of experimental faults

Simulated fault gouges often deform more stably than initially bare surfaces of the same composition. It is important to understand why the sliding stability is enhanced because the presence of gouge on natural faults may have the same effect as seen in experiments, and thus explain the absence of earthquakes at shallow depths. Gouge stabilization in experiments has been attributed to positive contributions to velocity dependence within gouge layers from either dilation (Maroneet al., 1990) or grain fracture (Biegelet al., 1989). In this study we test the hypothesis that some aspects of gouge and initially bare surface velocity dependence are identical by measuring the time-dependent constitutive parameter b. An important result follows however from stress analysis: if both sample configurations are frictional in the Mohr-Coulomb sense, each configuration is required to deform on planes of distinctly different orientation. The measured strength and velocity dependence will reflect this geometric difference. Our observed values of b for simulated granite and quartz gouge are two to two and a half times smaller than b for initially bare surfaces. This difference is completely accounted for if gouge is represented as a cohesionless-Coulomb plastic material. The analysis demonstrates the following points: 1) gouge deformation is fully consistent with Coulomb plasticity, 2) observed gouge velocity dependence is a function of observed strength and 3) the constitutive parameter b is the same for both bare surfaces and gouge. Furthermore, the results suggest that there is no time-dependent strengthening associated with stabilizing effects in gouge. These observations provide a framework for understanding how slip on initially bare surfaces and gouge deformation are related. ?? 1995 Birkha??user Verlag.

Pure and Applied Geophysics PAGEOPH↗
USGS1995

The effect of fault-bend folding on seismic velocity in the marginal ridge of accretionary prisms

Fluid venting in accretionary prisms, which feeds chemosynthetic biological communities, occurs mostly on the marginal thrust ridge. New seismic data for the marginal ridge of the Cascadia prism show significantly lower velocity than that in the adjacent oceanic basin and place important constraints on the interpretations of why fluid venting occurs mostly on the marginal ridge. We employed a finite-element method to analyze a typical fault-bend folding model to explain the phenomenon. The fault in the model is simulated by contact elements. The elements are characterized not only by finite sliding along a slide line, but also by elastoplastic deformation. We present the results of a stress analysis which show that the marginal ridge is under subhorizontal extension and the frontal thrust is under compression. This state of stress favors the growth of tensile cracks in the marginal ridge, facilitates fluid flow and reduces seismic velocities therein; on the other hand, it may close fluid pathways along the frontal thrust and divert fluid flow to the marginal ridge. ?? 1995 Birkha??user Verlag.

Pure and Applied Geophysics PAGEOPH↗