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Collaborating Authors
Sato, Tsutomu
Abstract It is important to understand the long-term migration of radionuclides considering carious rock engineering projects such as the geological disposal of radioactive wastes. The network of fractures and pores in a rock mass can play important roles as the pathway of the fluid flow of rock. The geometry of the network can change due to sealing of a material in the long term. The result of laboratory measurements shows that the permeability of a fractured igneous rock decreased by the sealing of the fracture by the fine-grained materials. The above results have been obtained by the permeability test using distilled water. Usually groundwater contains fine-grained minerals such as clays. It is probable that the accumulation of the fine-grained minerals occurs in a fracture if the groundwater flows in a fracture in a rock. In addition, the aperture of the fracture can decrease if the fine-grained materials accumulate, which decreases the permeability. Therefore, it is essential to conduct the permeability measurement using water including fine-grained materials to understand the characteristics of the permeability of a rock. However, none has conducted the permeability measurement using water containing fine-grained materials. In this study, we have conducted the permeability measurement using water including clays. Specifically, we used a macro-fractured granite as a rock sample, and investigated the change of the permeability under the flow of the water including clays. It was shown that the hydraulic conductivity decreased with elapsed time. The accumulation of the clays was observed in the fracture of the granite sample. It is concluded that the accumulation of fine-grained minerals in the fracture decreases the permeability of fractured rock. In addition, it is concluded that the sealing and the healing of the fractures in rock are possible under the flow of the groundwater including clays. 1. Introduction It is important to understand the long-term migration of radionuclides considering carious rock engineering projects, such as the extraction of petroleum, carbon capture and storage, and the geological disposal of radioactive wastes. The network of fractures and pores in a rock mass can play important roles as the pathway of the fluid flow of rock (Nara et al., 2011a). The geometry of the network can change due to sealing of a material in the long term. The result of laboratory measurements shows that the permeability of a fractured igneous rock decreased by the sealing of the fracture by the fine-grained materials (Wang et al., 2016; Perez-Flores et al., 2017).
- Geology > Rock Type > Igneous Rock (1.00)
- Geology > Mineral > Silicate > Phyllosilicate (1.00)
The Relationship Between Smectite/ Illite Ratios and Diagenetic History of Sandstone Reservoir, Batu Ayau Formation, Upper Kutai Basin, East Kalimantan, Indonesia
Puji Astuti, Tri Rani (U. Gadjah Mada) | Surjono, Sugeng Sapto (U. Gadjah Mada) | Warmada, I Wayan (U. Gadjah Mada) | Kusuma, Didit Putra (U. Gadjah Mada) | Tsukada, Yasumoto (Hokkaido U.) | Otake, Tsubasa (Hokkaido U.) | Sato, Tsutomu (Hokkaido U.)
Abstract The Middle – Late Eocene sandstones of Batu Ayau Formation have been examined for the potential as a reservoir based on subsurface data and outcrop samples taken along Ritan and Belayan's River. Petrographic study, XRD, SEM/EDS, porosity measurement, and quantitative determination of reservoir properties were carried out in this study. The sandstones are fine- to coarse-grained, moderately well to well sorted litharenite with subordinate lithic arkose, subarkose, sublitharenite and feldsphatic litharenite. The framework compositions of all sandstones are entirely quartz and plagioclase with trace amounts of K-feldspar and muscovite. The diagenetic processes include compaction, cementation, overgrowth of autigenic minerals (smectite), and dissolution due to alteration of feldspars. The SEM photomicrographs exhibit four types of cement such as mordenite, kaolinite, smectite and overgrowth quartz which are present over the entire samples. Quartz and kaolinite occur as pore-lining and pore-filling cements which locally developed as vermiform and accelerated the minor porosity loss due to pore-occlusion. Result of XRD analysis for the whole work are consistent with the qualitative result of petrographic analysis. Result of XRD analysis with ethylene glycol solvation for clay fraction (<2 µm) indicate a progressive alteration of smectite to illite. Based on the Watanabe's Diagram, the presence of smectite layers in interstratified illite/smectite continously decrease from 100% to 65% with increasing the burial depth. The result indicate that the paleotemperature for sandstone diagenesis around 60–90°C. This is interpreted to be the result of temperature controlled chemical compaction, i.e. transformation from smectite to illite, feldspar dissolution and quartz precipitation. The laboratory analysis as well as field data demonstrate the sandstones of Batu Ayau Formation were subjected to mesodiagenesis and result in good to tight ranges of porosity.
- Asia > Indonesia > Kalimantan (0.65)
- Asia > Indonesia > East Kalimantan > Makassar Strait (0.51)
- Phanerozoic > Cenozoic > Paleogene > Eocene > Bartonian (0.48)
- Phanerozoic > Cenozoic > Paleogene > Eocene > Priabonian (0.34)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (1.00)
- Geology > Mineral > Silicate > Phyllosilicate (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.57)
- Europe > United Kingdom > North Sea > North Sea Basin (0.99)
- Europe > Norway > North Sea > North Sea Basin (0.99)
- Europe > Netherlands > North Sea > North Sea Basin (0.99)
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