Study on a Method to Evaluate Heterogeneity of Sedimentary Rocks Using a Forward Model, II (Summary)

Hoshi, Kazuyoshi*; Hou, J.-Y.*; Kawada, Koji*; Tsuji, Takashi*; Suwabe, Mizue*

Developing a method to evaluate heterogeneity of sedimentary rocks is very important for a site survey and a property test of the site. We studied siliceous shale from wells in the Horonobe area, and developed a sedimentary process modeling software in order to establish a method to evaluate heterogeneity of sedimentary rocks. Well log analysis of Koetoi and Wakkanai Formations revealed variations of porosity, shale content, and amount of erosion. We correlate marker beds, and establish a compaction curve for siliceous shale in the Horonobe area. EMI analysis revealed alternation of thin beds which can not been recognized by naked eyes. Chemical analysis shows that this heterogeneity originates from a variation in diatom and clastic material contents in the rock. We also examined seismic data using GDI method. For sedimentary modeling software, we expanded the sedimentary simulation module, and attached another module to compare the calculated results with actual data. We also attached the module to find the best input parameters. We performed a test run using the geology model we made for Horonobe area.