抄録
For the effective design of the disposal of the water-waste from oil and gas fields in the subsurface, the estimation of clay mineral content, its mineralogical studies, and the flood test, which is the continuous measurements of water-permeability of cores during the circulation of brine with varied salinity water, have been conducted in the pyroclastics of Takinoue Formation “T1 member”in Yufutsu Oil and Gas Field, Hokkaido, Japan.
The mineralogical study showed that the clay mineral in T1 pyroclastic member can be identified with a smectite. The smectite expanded more after dropping brines with thinner salinity on the smectite. According to the chemical composition and concentration, the expandability of smectite, which can be detected in the measurements of space (d001) by X-ray diffractmeter, varied. More water-permeability of T1 cores decreased more with increasing smectite content, when the brine with relatively thinner salinity was injected through the core. These results suggest that smectite expanded and stuffed more pore space with decreasing salinity of brine, and then the permeability decreased. Meanwhile, the standard mineral of montmorillonite supplied by The Clay Science Society of Japan showed the same trend in the variation of d011 of the T1 smectite qualitatively, but differed from the T1 smectite quantitatively. It means that quantitative feature of the expandability of smectite should be required for the detail design for the water-waste. And these data could be also useful to evaluate the effects of the formation water on the permeability of the production zone.
