NEHRP Clearinghouse
- Title
- Permeability of Deep Drillhole Core Samples.
- File
- PB2006113370.pdf
- Author(s)
- Morrow, C. A.
- Source
- January 2006, 10 p.
- Abstract
- The permeability of fault zone material is key to understanding fluid circulation and its role in earthquake generation. In this paper, permeability results from four different scientific drillholes are discussed in relation to recent studies on core samples from the Nojima Fault. This comparison illustrates the advantages and limitations of laboratory studies on extracted core samples. We observe that matrix permeability of core samples is extremely low, suggesting that most fluid flow at depth will occur through discrete joints and faults rather than through the bulk of the rock. The permeability of deep core samples is also more sensitive to pressure than equivalent rocks obtained from surface outcrops. In addition, stress-relief and thermal fractures due to coring and extraction may influence laboratory permeability measurements, most typically for deeper rocks and those containing abundant quartz.
- Keywords
- Fluid circulation; Drillholes; Extracted core samples; Permeability; Fault zone materials; Deep; Pressure sensitivity; Earthquakes; Crack-dominated fluid flows