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Title: Estimation of fracture flow parameters through numerical analysis of hydromechanical pressure pulses

Abstract

The flow parameters of a natural fracture were estimated by modeling in situ pressure pulses. The pulses were generated in two horizontal boreholes spaced 1 m apart vertically and intersecting a near-vertical highly permeable fracture located within a shallow fractured carbonate reservoir. Fracture hydromechanical response was monitored using specialized fiber-optic borehole equipment that could simultaneously measure fluid pressure and fracture displacements. Measurements indicated a significant time lag between the pressure peak at the injection point and the one at the second measuring point, located 1 m away. The pressure pulse dilated and contracted the fracture. Field data were analyzed through hydraulic and coupled hydromechanical simulations using different governing flow laws. In matching the time lag between the pressure peaks at the two measuring points, our hydraulic models indicated that (1) flow was channeled in the fracture, (2) the hydraulic conductivity tensor was highly anisotropic, and (3) the radius of pulse influence was asymmetric, in that the pulse travelled faster vertically than horizontally. Moreover, our parametric study demonstrated that the fluid pressure diffusion through the fracture was quite sensitive to the spacing and orientation of channels, hydraulic aperture, storativity and hydraulic conductivity. Comparison between hydraulic and hydromechanical models showed that themore » deformation significantly affected fracture permeability and storativity, and consequently, the fluid pressure propagation, suggesting that the simultaneous measurements of pressure and mechanical displacement signals could substantially improve the interpretation of pulse tests during reservoir characterization.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Earth Sciences Division
OSTI Identifier:
950850
Report Number(s):
LBNL-1664E
Journal ID: ISSN 0043-1397; WRERAQ; TRN: US200911%%94
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Water Resources Research
Additional Journal Information:
Journal Name: Water Resources Research; Journal ID: ISSN 0043-1397
Country of Publication:
United States
Language:
English
Subject:
54; 58; BOREHOLES; CARBONATES; DEFORMATION; DIFFUSION; FRACTURES; HYDRAULIC CONDUCTIVITY; HYDRAULICS; NUMERICAL ANALYSIS; ORIENTATION; PERMEABILITY; SIMULATION

Citation Formats

Cappa, F, Guglielmi, Y, Rutqvist, J, Tsang, C -F, and Thoraval, A. Estimation of fracture flow parameters through numerical analysis of hydromechanical pressure pulses. United States: N. p., 2008. Web. doi:10.1029/2008WR007015.
Cappa, F, Guglielmi, Y, Rutqvist, J, Tsang, C -F, & Thoraval, A. Estimation of fracture flow parameters through numerical analysis of hydromechanical pressure pulses. United States. https://doi.org/10.1029/2008WR007015
Cappa, F, Guglielmi, Y, Rutqvist, J, Tsang, C -F, and Thoraval, A. 2008. "Estimation of fracture flow parameters through numerical analysis of hydromechanical pressure pulses". United States. https://doi.org/10.1029/2008WR007015. https://www.osti.gov/servlets/purl/950850.
@article{osti_950850,
title = {Estimation of fracture flow parameters through numerical analysis of hydromechanical pressure pulses},
author = {Cappa, F and Guglielmi, Y and Rutqvist, J and Tsang, C -F and Thoraval, A},
abstractNote = {The flow parameters of a natural fracture were estimated by modeling in situ pressure pulses. The pulses were generated in two horizontal boreholes spaced 1 m apart vertically and intersecting a near-vertical highly permeable fracture located within a shallow fractured carbonate reservoir. Fracture hydromechanical response was monitored using specialized fiber-optic borehole equipment that could simultaneously measure fluid pressure and fracture displacements. Measurements indicated a significant time lag between the pressure peak at the injection point and the one at the second measuring point, located 1 m away. The pressure pulse dilated and contracted the fracture. Field data were analyzed through hydraulic and coupled hydromechanical simulations using different governing flow laws. In matching the time lag between the pressure peaks at the two measuring points, our hydraulic models indicated that (1) flow was channeled in the fracture, (2) the hydraulic conductivity tensor was highly anisotropic, and (3) the radius of pulse influence was asymmetric, in that the pulse travelled faster vertically than horizontally. Moreover, our parametric study demonstrated that the fluid pressure diffusion through the fracture was quite sensitive to the spacing and orientation of channels, hydraulic aperture, storativity and hydraulic conductivity. Comparison between hydraulic and hydromechanical models showed that the deformation significantly affected fracture permeability and storativity, and consequently, the fluid pressure propagation, suggesting that the simultaneous measurements of pressure and mechanical displacement signals could substantially improve the interpretation of pulse tests during reservoir characterization.},
doi = {10.1029/2008WR007015},
url = {https://www.osti.gov/biblio/950850}, journal = {Water Resources Research},
issn = {0043-1397},
number = ,
volume = ,
place = {United States},
year = {Sun Mar 16 00:00:00 EDT 2008},
month = {Sun Mar 16 00:00:00 EDT 2008}
}