Effects of lithology and depth on the permeability of core samples from the Kola and KTB drill holes

Morrow, C. A.; Lockner, D. A.; Hickman, Stephen H.; Rusanov, M. S.; Röckel, Thomas

doi:10.1029/93jb03458

Cited by 78 publications

(62 citation statements)

References 21 publications

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“…DR1). This can be easily explained by the fact that stressrelief microfractures are more abundant in feldspar, quartz, and garnet than amphibole and other retrograde minerals (Morrow et al, 1994;Ji et al, 1997Ji et al, , 2003. Thus, the rocks with high feldspar, quartz, and garnet contents may have more stress-relief and thermal-cracking damage.…”

Section: Discussionmentioning

confidence: 99%

“…3C and 3D), however, have sinuous and discontinuous edges with higher α values, as they may have been partially dissolved or sealed with hydrated secondary minerals such as kaolinite, illite, chlorite, sericite, serpentine, calcite, gibbsite, and goethite. The partially dissolved or fi lled cracks are hard to close completely under hydrostatic pressures due to crack surface mismatch (Morrow et al, 1994), which accounts for the characteristic reduction in the pressure sensitivity of P-wave velocities in the nonlinear regime.…”

Section: Discussionmentioning

confidence: 99%

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P-wave velocity differences between surface-derived and core samples from the Sulu ultrahigh-pressure terrane: Implications for in situ velocities at great depths

Sun

Wang

et al. 2012

Geology

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We compared the averages of P-wave velocities (V p ) for four lithologies (felsic gneiss, eclogite, retrograde eclogite, and amphibolite) collected from core material sampled by the Chinese Continental Scientifi c Drilling Project (CCSD) at depths to 5158 m, and from surface outcrops in the Dabie-Sulu (China) ultrahigh-pressure metamorphic terrane. The velocities were measured at pressures to 800 MPa for 69 CCSD samples and 145 surface samples. The V p -pressure relationship is described by a four-parameter exponential equation, allowing the determination of the crack-closing pressure (P c ), the intrinsic pressure derivative of velocity (D), the intrinsic velocity of the crack-free compacted rock at zero pressure (V 0 ), and the maximum velocity increase due to crack closure (B 0 ). The shape of the nonlinear segment of the velocity-pressure curve is controlled by a decay parameter (k). The CCSD core samples are characterized by signifi cantly higher V 0 , B 0 , and k values and lower D and P c compared to their surface analogues. This suggests that extrapolation of the surface rock data to depth may result in substantial underestimates in seismic velocities, and that the intrinsic pressure derivatives obtained from the V p -pressure relations for the core samples are more suitable for the determination of in situ velocities at great depth than those derived from measurements on rocks exposed at the surface.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

P-wave velocity differences between surface-derived and core samples from the Sulu ultrahigh-pressure terrane: Implications for in situ velocities at great depths

Sun

Wang

et al. 2012

Geology

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“…Similar approaches to the problem of experimental determination of the previous highest effective pressure have been taken by Locknet et al [1991] and Morrow et al [1994] with respect to crystalline material collected from the Kola sue•.rdeep and KTB (German continental deep borehole) wells. ':_ this work, determination of the previous highest effective pressure also proved problematic.…”

Section: Previous Highest Pressurementioning

confidence: 99%

Comparisons of water and argon permeability in natural clay‐bearing fault gouge under high pressure at 20°C

Faulkner¹,

Rutter²

2000

J. Geophys. Res.

178

152

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Abstract. Quantification of fluid transport through fault zones is critical for the understanding of fault mechanics and prediction of subsurface fluid flow. The permeability of clay-bearing fault gouge has been determined using first argon then water as pore fluids under total confining pressures ranging up to 200 MPa and pore pressures of 40 MPa at room temperature. Use of the two pore fluids allows interactions between the gouge and pore fluids to be examined. Natural clay-bearing fault gouge recovered from surface exposures of the Carboneras fault zone in southeastern Spain was used and was collected in such a way that the in situ microstructure was preserved. Cores were collected in directions relative to the well-developed planar fabrics seen in these types of fault rock. The mineralogy of the gouges included muscovite/illite, chlorite, and quartz, with minor amounts of gypsum, albite, and graphite. Glycolation of the gouge showed no discernible amounts of swelling phases. Grain size analyses revealed a bimodal grain size distribution, with the <2 •xm fraction dominant (>50 wt %). This fraction contained predominantly 17 2 22clay phases. Permeabilities in the range of 10-m to 10-m 2 were measured. Experimental results show that the previous highest in situ effective pressure to which the fault gouge had been subjected (overconsolidation pressure) could not be determined from changes in permeability. Differences between water and argon permeabilities determined on the same sample amounted to -•1 order of magnitude, even if the sample had been pressure cycled (reduction to zero and reapplication of both confining and pore pressure) using argon as pore fluid until asymptotic values for permeability had been attained. Volumetric strain measurements showed no enhanced compaction due to the introduction of water as the pore fluid, leading to the conclusion that the reduction in permeability must be due to physicochemical interactions of the water with the fault gouge. The low permeabilities measured support models invoking high fluid pressure weakening of large faults with minimal fluid loss. The stability of structured water films with varying temperature, water pressure and water chemistrv may produce a heterogeneous permeability profile with depth in fault zones.

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“…Naturally, the most common approach was empirical curve fitting. Two functional forms have generally been used, the exponential, k = k r exp[Àγ (p eff À p r )] [e.g., Wyble, 1958;David et al, 1994;Morrow et al, 1994;Seront et al, 1998] (note also that linear combinations of exponentials were used by Farquhar et al [1993]), and the power law, k = k r (p eff /p r ) Àα [e.g., Kilmer et al, 1987;Ghabezloo et al, 2009;Dong et al, 2010]. In these two expressions, p r represents an arbitrarily selected reference effective pressure (20 MPa in the present study) and k r the corresponding permeability (an unknown fitting parameter akin to γ and α).…”

Section: Appendix A: Response-surface Methodsmentioning

confidence: 99%

Nonlinear effective pressure law for permeability

Xiao

Bernabé

et al. 2014

JGR Solid Earth

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The permeability k of porous rocks is known to vary with confining pressure pc and pore fluid pressure pf. But it is, in principle, possible to replace the two‐variable function k(pf, pc) by a function k(peff) of a single variable, peff(pf, pc), called the effective pressure. Our goal in this paper is to establish an experimental method for determining a possibly nonlinear, effective pressure law (EPL) for permeability, i.e., find the function κs(pf, pc) such that the effective pressure is given by peff = pc − κs(pf, pc) pf. We applied this method to a set of 26 sandstone cores from various hydrocarbon reservoirs in China. We found that κs greatly varied, from sample to sample, in magnitude and range, sometimes even reaching theoretically prohibited values (i.e., greater than 1 or lower than porosity). One interesting feature of κs(pf, pc) is that it could be approximately described in all rocks but one as a decreasing function κs(pc − pf) of Terzaghi's differential pressure. We also investigated the dependence of permeability on peff for each of our samples. Three models from the literature, i.e., exponential (E), power law (P), and the Walsh model (W), were tested. The (W) model was more likely to fit the experimental data of cores with a high pressure dependence of permeability whereas (E) occurred more frequently in low‐pressure‐sensitive rocks. Finally, we made various types of two‐ and three‐dimensional microstructural observations that generally supported the trend mentioned above.

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Effects of lithology and depth on the permeability of core samples from the Kola and KTB drill holes

Cited by 78 publications

References 21 publications

P-wave velocity differences between surface-derived and core samples from the Sulu ultrahigh-pressure terrane: Implications for in situ velocities at great depths

P-wave velocity differences between surface-derived and core samples from the Sulu ultrahigh-pressure terrane: Implications for in situ velocities at great depths

Comparisons of water and argon permeability in natural clay‐bearing fault gouge under high pressure at 20°C

Nonlinear effective pressure law for permeability

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