Conduit system and formation mechanism of heat fluids in diapiric belt of Yinggehai basin, China

The conduit system of heat fluids in diapiric belt of Yinggehai basin is do minantly vertical faults and fractures. Detailed research on the formation mechanism and their occurence features shows that the faults and fractures can be classified into three types: intrastratal dispersive hydrofracture, puncturing fault and upwarping-extensional fault. The development of the fa ult and fracture system not only resulted in the changes of the temperature and pressure fields in the basin, but also affected the hydrocarbon migrat ion in the overpressured system. These faults and fractures constituted the main pathways for vertical hydrocarbon migration, and opening and closing intermittently led to episodic expulsion of overpressured fluid compartment . Thus there formed the pool-forming model of multi-source mixing and ploy- stage migration and accumulation for hydrocarbons in the Yinggehai basin.