关键词: 柴达木, 昆北断阶带, 底砾岩, 储层特征

Abstract: Based on regional geological background, it is believed that the basal conglomerate in North-Kunlun Faults Zone is weathering eluvium. Petrographic analysis shows that the bedrock in the zone is monzogranite. Above this is semi-weathered crust, which is about 0.5m deep. Here develops rock breaking fracture. Above the semi-weathered crust is the basal conglomerate, which is 30~60m deep. This is the main hydrocarbon reservoir assemblage in North-Kunlun Faults Zone. Conventional porosity and permeability analysis shows that the average porosity value is 12.37% and the average permeability value is 69.87mD, belonging to low-porosity and mid-permeability reservoir. Reservoir pore is dominated by secondary pore including particle breaking fracture, particle dissolved pore, and intergranular dissolved pore, etc. Rock in the reservoir is unconsolidated for its weak diagenesis and big grain size, so conventional porosity and permeability analysis could not actually reflect rock property. Comparison shows that the porosity determined by conventional analysis is 25% higher than using kerosene method, and the permeability determined by conventional analysis is 80% higher than using NMR method. Therefore, using rational testing method to get reservoir property targeted at the basal conglomerate becomes more and more important to guide exploration and development in studied area.