In this paper I construct a macroscopic geological structural map of northern Honshu, Japan, including Niigata Prefecture, in order to comprehend its structural features. I also propose two tectonic models for late Cenozoic tectonics of northern Honshu and Japan Sea opening in particular: strike-slip fault system and rift system. The latter system consists of first- and second-order (smaller scale) rift systems. Both rift systems have three arms of a triple junction. During Japan Sea opening, two of the three arms failed or stopped spreading in a shorter time than the third arm.
Japan for the most part does not possess energy resources, whereas Russia is abundantly endowed with oil and natural gas, etc.. Japanese firms hold oil and natural gas rights in their neighboring country, and in addition to participating in exploration have shown interest in new LNG projects also. The policy of promoting the east which the Putin Administration has been developing and the 3/11 catastrophe in Japan have turned into an opportunity to promote yet further the energy cooperation between the two countries. Niigata has been known as an oil and gas production area since remote times, and today is also fulfilling the role of a gateway for energy, sending natural gas to the area embracing the Tohoku, Kanto, and Chubu regions. Amid the progress of Japan-Russia cooperation it is expected that Niigata's functions will strengthen still further.
It is very difficult to find the way to solve conflict of interest between oil producing countries and industrial countries. Fortunately JOGMEC has a training section, which counts for much in making nice human relationships to cope with such matter. Oil producing countries need training for their young engineers. On the other hand, Japan needs a person who could support favorably Japanese companies in order to get information about upstream business. I call such kind of relationships both are satisfied with as “win-win relationships”. JOGMEC should maintain and develop this relationships featuring Japanese history & culture and also training new technology distinctively from other rival countries.
A long-term monitoring of carbon dioxide (CO2) in a reservoir at depth is required for the geological storage of CO2. For this requirement, an inversion technique utilizing tilt data of the ground surface associated with migration of CO2 may be one of promising techniques. Poroelastic parameters of reservoir rocks (e.g., sandstone) should be well understood to increase reliability of the monitoring technique, because the inversion technique is based on the poroelastic theory. Better understanding of poroelastic parameters also contributes to geomechanical reservoir characterizations. For this purpose, focusing on a water-saturated part within a sandstone reservoir, a set of five kinds of laboratory tests has been conducted on Kimachi sandstone and Berea sandstone, saturated with water, to determine poroelastic parameters at various combinations of confining pressure (7-40 MPa) and pore pressure (5-25 MPa), namely various Terzaghi's effective stresses (2-35 MPa). Skempton's coefficient B and undrained bulk modulus have been determined by the B-test, in which volumetric strain and pore pressure changes with confining pressure. Drained bulk modulus and parameter H (inverse number of poroelastic expansion coefficient) have been determined by the P-test and the H-test, in which volumetric strain changes with confining pressure and pore pressure, respectively. Young's modulus and Poisson's ratio have been determined by both drained and undrained triaxial compression tests. Confining pressure and pore pressure dependencies for the poroelastic parameters have been examined separately, revealing that both dependencies may be integrated by Terzaghi's effective stress dependency. That is, every poroealstic parameter (y) having Terzaghi's effective stress dependency may be described by a function of Terzaghi's effective stress (σeff), y=a+b(1-e-σX(X=eff/10)), where a and b are constants. Additionally, it has been revealed that Biot-Willis (effective stress) coefficient of sandstone with swelling clays can exceed unity at relatively high Terzaghi's effective stresses.