The Study Of Gaotaizi Oil Layer’s Microscopic Reservoir Characteristics In Qijia Area

Qijia area is located in Qijia-Gulong depression in the west of Daqing Placanticle. Gaotaizi oil layer’s reservoir is a combination of argillaceous siltstone. It has four oil-bearing formations. The third and forth oil-bearing formation are the source bed of Qingshankou formation. Gaotaizi oil layer buried deep. It has been through strong diagenetic transformation. We need the study of microscopic reservoir characteristics,because the reservoir pore and throat are irregular.Using the cores, identification under microscope, SEM and mercury injection, I did some research on pore, throat, cracks. Reservoir petrology characteristics, structural characteristics, petrographic features, etc. I identified the type of pore, throat and cracks through the study of microscopic reservoir characteristics and configuration relationship. The reservoir in the study area was divided into three general-types, four fine-types through clustering analysis by using mercury injection experiment parameters. I established reservoir microscopic classification methods and analyzed different types of reservoir pore throat structure.Based on the study of reservoir microstructure characteristics, I determined the main control factors of pore structure is sedimentation, diagenesis and waterflood development by using the core, microscopic image, logging data, etc. I explored different sedimentary microfacies control action on pore structure, through different types of sedimentary microfacies characteristics. I explored diagenetic control action on pore structure, through the characteristics of diagenetic evolution. I also explored waterflood control action on pore structure, through different pore characteristics under different waterflood degree.Using the effection of sedimentation, diagenesis and waterflood development, combine with the control of sedimentation on primary pore and diagenesis on post reservoir reformation, I combined two kind of facies maps and classified different areas after composite analyzing. The combination of feldspar dissolution diagenesis facies and distributary river microfacies is the best for type Ⅰ reservoir. The combination of forced compaction diagenesis facies and distributary interchannel microfacies is the worst for type Ⅲ reservoir. The combination of cementation diagenesis facies and mouth bar microfacies, sheed sand microfacies is for type Ⅱ reservoir. While type Ⅰ reservoir have been through washing and high degree of development, type Ⅱ reservoir can be precinct as the focus of the petroleum exploration target in the future.