浸透率の現場計測機器とその適用限界の検討

抄録

TEMCO's MP-401 (mini-permeameter) is a gas permeameter that is capable of making direct and immediate measurements of rock permeability at the outcrop. The equipment was used to measure deformation bands arising along small displacement faults within an aeolian sandstone. The bands appear as cataclastic fragments that have a reduced porosity. The results demonstrated that the permeability of the deformation bands was an order of magnitude less than in host sandstone.
The mini-permeameter provides a ready and direct measure of the permeabilities of any rocks or sediments, although it has been found desirable to check field values by alternative means to ascertain the limitations. Therefore, the values measured at the outcrop were compared with the permeabilities determined for the same samples in the laboratory using other techniques. Although Darcy's equations provide an excellent model of the permeability of intact porous sedimentary rocks, they are limited in their application to cases such as fault rocks, fractured rocks, and highly impermeable rocks. Not only are the fluid pathways in such materials narrow but they may also be convoluted. The results confirmed the outcrop measurements and established the limitations of the gas permeameter.