Abstract:

The fault nature of north-west area in Yitong Graben used to be obscure，which heavily impedes the oil prospecting works in this area. By using outcrop, core，geophysical data, it is concluded that north-west fault zone in Yitong Basin is compressive and reversed faults which are well developed. A lot of fold structures are shaped at geological outcrops in north-west area of the basin. In prospecting wells near north-west boundary core data show that strata tilted at a large angle, and some even turn perpendicular. Gravity, magnetic and geo-electrical data also show that north-west area in Yitong Graben exits compressive phenomena. Fault composite characteristics are interpreted from high resolution 3D seismic. Fault nature and its characteristics are favorable for reservoir accumulation in the area. This study greatly guides oil exploration of north-west area in Yitong Graben, and also has a guiding meaning to oil prospecting vista of the entire Tancheng-Lujiang fault zone.

Key words: north-west fault zone, Tancheng-Lujiang fault zone, Yitong Graben, reservoir accumulation