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Title: Fracture Evolution in Multimineral Systems: The Role of Mineral Composition, Flow Rate, and Fracture Aperture Heterogeneity

Authors:
ORCiD logo [1];  [1];  [1];  [2]
  1. Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
  2. Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States, Earth and Planetary Science, University of California, Berkeley, Berkeley, California 94720, United States
Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1418895
Grant/Contract Number:
AC02-05CH11231
Resource Type:
Journal Article: Published Article
Journal Name:
ACS Earth and Space Chemistry
Additional Journal Information:
Journal Volume: 2; Journal Issue: 2; Related Information: CHORUS Timestamp: 2018-02-15 04:05:09; Journal ID: ISSN 2472-3452
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English

Citation Formats

Deng, Hang, Steefel, Carl, Molins, Sergi, and DePaolo, Donald. Fracture Evolution in Multimineral Systems: The Role of Mineral Composition, Flow Rate, and Fracture Aperture Heterogeneity. United States: N. p., 2018. Web. doi:10.1021/acsearthspacechem.7b00130.
Deng, Hang, Steefel, Carl, Molins, Sergi, & DePaolo, Donald. Fracture Evolution in Multimineral Systems: The Role of Mineral Composition, Flow Rate, and Fracture Aperture Heterogeneity. United States. doi:10.1021/acsearthspacechem.7b00130.
Deng, Hang, Steefel, Carl, Molins, Sergi, and DePaolo, Donald. 2018. "Fracture Evolution in Multimineral Systems: The Role of Mineral Composition, Flow Rate, and Fracture Aperture Heterogeneity". United States. doi:10.1021/acsearthspacechem.7b00130.
@article{osti_1418895,
title = {Fracture Evolution in Multimineral Systems: The Role of Mineral Composition, Flow Rate, and Fracture Aperture Heterogeneity},
author = {Deng, Hang and Steefel, Carl and Molins, Sergi and DePaolo, Donald},
abstractNote = {},
doi = {10.1021/acsearthspacechem.7b00130},
journal = {ACS Earth and Space Chemistry},
number = 2,
volume = 2,
place = {United States},
year = 2018,
month = 1
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1021/acsearthspacechem.7b00130

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  • Understanding of single and multi-phase flow and transport in fractures can be greatly enhanced through experimentation in transparent systems (analogs or replicas) where light transmission techniques yield quantitative measurements of aperture, solute concentration, and phase saturation fields. Here we quanti@ aperture field measurement error and demonstrate the influence of this error on the results of flow and transport simulations (hypothesized experimental results) through saturated and partially saturated fractures. find that precision and accuracy can be balanced to greatly improve the technique and We present a measurement protocol to obtain a minimum error field. Simulation results show an increased sensitivity tomore » error as we move from flow to transport and from saturated to partially saturated conditions. Significant sensitivity under partially saturated conditions results in differences in channeling and multiple-peaked breakthrough curves. These results emphasize the critical importance of defining and minimizing error for studies of flow and transpoti in single fractures.« less
  • Investigations on texture evolution and through-thickness texture heterogeneity during equal channel angular pressing (ECAP) of pure magnesium at 200 °C, 150 °C and room temperature (RT) was carried out by neutron, high energy synchrotron X-ray and electron back-scatter diffraction. Irrespective of the ECAP temperature, a distinctive basal (B) and pyramidal (C{sub 2}) II type of fibers forms. The texture differs in the bottom 1 mm portion, where the B-fiber is shifted ~ 55° due to negative shear attributed to friction. - Highlights: • ECAP of magnesium was carried out at 200 °C, 150 °C and room temperature. • Microstructure andmore » micro-texture evolution was examined using EBSD in FEG–SEM. • Bulk-texture was studied using neutron diffraction and compared with micro-texture. • Through thickness texture heterogeneity was observed by synchrotron radiation. • Changes in these parameters with respect to deformation temperature are discussed.« less
  • Fracture transmissivity and detailed aperture fields are measured in analog fractures specially designed to evaluate the utility of the Reynolds equation. The authors employ a light transmission technique with well-defined accuracy ({approximately}1% error) to measure aperture fields at high spatial resolution ({approximately}0.015 cm). A Hele-Shaw cell is used to confirm the approach by demonstrating agreement between experimental transmissivity, simulated transmissivity on the measured aperture field, and the parallel plate law. In the two rough-walled analog fractures considered, the discrepancy between the experimental and numerical estimates of fracture transmissivity was sufficiently large ({approximately} 22--47%) to exclude numerical and experimental errors (<more » 2%)as a source. They conclude that the three-dimensional character of the flow field is important for fully describing fluid flow in the two rough-walled fractures considered, and that the approach of depth averaging inherent in the formulation of the Reynolds equation is inadequate. They also explore the effects of spatial resolution, aperture measurement technique, and alternative definitions for link transmissivities in the finite-difference formulation, including some that contain corrections for tortuosity perpendicular to the mean fracture plane and Stokes flow. Various formulations for link transmissivity are shown to converge at high resolution ({approximately} 1/5 the spatial correlation length) in the smoothly varying fracture. At coarser resolutions, the solution becomes increasingly sensitive to definition of link transmissivity and measurement technique. Aperture measurements that integrate over individual grid blocks were less sensitive to measurement scale and definition of link transmissivity than point sampling techniques.« less
  • Model fractures with variable apertures are generated by a statistical method, and water flow and tracer transport in these fractures are calculated. Tracer injection and collection are simulated for parallel and convergent flow fields. The impact of the use of different injection flow rates and the different locations of injection and collection points are studied. The results show that the transport time, dispersion, and the so-called mass balance fracture aperture are very sensitive to the location of the injection point and the injection flow rate. These anomalous effects appear to be consistent with observations in several recent field experiments. Themore » implications of the calculated results on the analysis of tracer tests are discussed. It is concluded that because of the stochastic nature of variable fracture apertures (and their permeabilities) a point tracer test in a fracture is not sufficient to characterize the properties of the fracture. Dispersivities and apertures calculated from different tracer tests in the same fracture may vary by orders of magnitude depending on the flow rate and the location of the injection. However, a line injection of tracer, averaged over a series of adjacent points, may avoid some of these problems.« less