Osmotic generation of ‘anomalous’ fluid pressures in geological environments

C. E. Neuzil ()
Additional contact information
C. E. Neuzil: US Geological Survey, 431 National Center

Nature, 2000, vol. 403, issue 6766, 182-184

Abstract: Abstract Osmotic pressures are generated by differences in chemical potential of a solution across a membrane. But whether osmosis can have a significant effect on the pressure of fluids in geological environments has been controversial, because the membrane properties of geological media are poorly understood1. ‘Anomalous’ pressures—large departures from hydrostatic pressure that are not explicable in terms of topographic or fluid-density effects—are widely found in geological settings, and are commonly considered to result from processes that alter the pore or fluid volume2, which in turn implies crustal changes happening at a rate too slow to observe directly. Yet if osmosis can explain some anomalies, there is no need to invoke such dynamic geological processes in those cases. Here I report results of a nine-year in situ measurement of fluid pressures and solute concentrations in shale that are consistent with the generation of large (up to 20?MPa) osmotic-pressure anomalies which could persist for tens of millions of years. Osmotic pressures of this magnitude and duration can explain many of the pressure anomalies observed in geological settings. They require, however, small shale porosity and large contrasts in the amount of dissolved solids in the pore waters—criteria that may help to distinguish between osmotic and crustal-dynamic origins of anomalous pressures.

Date: 2000
References: Add references at CitEc
Citations:

Downloads: (external link)
https://www.nature.com/articles/35003174 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:403:y:2000:i:6766:d:10.1038_35003174

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/35003174

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().