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Structural styles of deep zones in southern central Hokkaido, northern Japan

2004; Japanese Association for Petroleum Engineers; Volume: 69; Issue: 2 Linguagem: Inglês

10.3720/japt.69.131

1881-4131

Minoru Kuniyasu, Yasuhiro Yamada,

Geological Modeling and Analysis

Southern central Hokkaido is an important hydrocarbon province and over 100 wells were drilled by METI and private companies in the past 50 years. The rea can be divided into three zones(Zone I, II and III) from the structural styles and stratigraphy, both of which are revealed by the extensive exploration activity. Zone I is characterized by basement horst structures and located in the west of the area. Zone II also has basement horst structures but its shallow sediments are thrust faulted. The thrust faults were originated from the east. East of the area is Zone III and characterized by a thrust-and-fold belt. The structural styles of these zones are in accordance with the tectonic history proposed in studies of surrounding regions. However, the results of palaeostress analysis using core fractures in Zone I and in-situ stress analysis using well logging data in Zone II revealed that the stresses couldn't be fully explained by the tectonic history. This suggests that the nature of structural development processes is far complicated from our ectonic image and we have to continue our effort to construct comprehensive geologic model for exploration of this area.