Fault characteristics of Chang-8 oil formation and their impact on reservoir in northwest of Jiyuan,Ordos Basin,China

Based on the preceding research results,the authors make a systematic analysis of Chang-8 oil formation's fault characteristics,formation mechanism and their control on the reservoir in the northwest of the Jiyuan district,Ordos Basin,and discuss how the faults influence on the reservoir. The result shows that the formation of the faults are affected by Yanshan and Himalayan tectonic movements.The SE-NW thrust faults have developed in the Majiatan-Gufengzhuang uplift belt on the east,and in middle part,the Hongjingzi depression belt,the NW-SE and NNW-SEE thrust faults and vertical faults have well developed,but on the west side,the Hongliugou clinoform zone is distributed by the S-N normal faults which are featured by Graben combination.According to the formation mechanism and development characteristics,the faults can be classified as the vertical fault,the former thrust fault,the later normal fault and the transverse fault.Combined with the characteristics of the three reservoir types(the fault-small anticline type reservoir,the fault anticline type reservoir and the lithologic reservoir)in the survey region,the authors think that the control of the faults on the oil and gas reservoir is mainly to control the migration of the reservoir from lateral and vertical directions,to seal the lateral direction and adjust the later state.Finally,this paper presents two kinds of accumulation model pulled by low pressure and channeled through capillary.