Types of Structural Slope-break Zone and Controls for Sand Bodies and Hydrocarbon of Huhehu Depression in Hailar Basin

Abstract

Huhehu depression is a half graben rift which down faulting in the east and overlapping in the west. The structural slope-break zone which widely developed in depression period plays a significant controlling in sand bodies and accumulation of hydrocarbon. According to the characteristics of fractures and combination patterns of plane and section, many syndepositional fracture combination styles are identified in the depression, which includes parallel faulted step, brush, fork, faults-contacting and other forms. According to the distribution of fracture slope break zone, this paper expounds the controls to sedimentary filling and system in three types, which are fault-controlling steep slope, faulted-step gentle slope and trough margin. Combined with the exploration practice, this paper discusses the relation between accumulation of hydrocarbon and the sand bodies in fracture slope-break zone. The conclusion is that the fracture slope-break zone of trough margin is the most favourable exploration area.