Study on a method to evaluate heterogeneity of sedimentary rocks using a forward model, 3 (Contract research)

Hara, Akio*; Hoshi, Kazuyoshi*; Kato, Arata*; Maekawa, Keisuke  

It is very important for performance assessment of high-level radioactive waste disposal to develop a method to estimate heterogeneity of sedimentary rocks. We studied siliceous shale from boreholes in the Horonobe area, and developed a sedimentary process modeling software in order to establish a method to estimate heterogeneity of sedimentary rocks. In this study, we aimed for addition of functions in sedimentary process modeling software and improvement of operability. For the former aim, we added functions which were enable to consider the second sedimentation style and influences by subsidence and upheaval of basement of sedimentary basin at the time of a shoreline movement calculation. And, on the occasion of the output of calculation results, we changed the file format in order to enable to adapt to the current visualization software. For the latter aim, we developed the Graphic User Interface (GUI) to support a work for data input. Using this sedimentary process modeling software with the above-mentioned improvement, we carried out simulations for Horonobe area. For making of input data, we utilized the existing data from geological surveys which were carried out by not only Japan Atomic Energy Agency but the others. Therefore we showed two realizations of geological model of Horonobe area. Moreover, we suggested a possibility of sand deposition in a remote area from accutual boreholes. From these results, we showed an applicability of this modeling methodology.