Pore Structure And Sedimentary Facies Control Of Chang 6 Reservoir In The Eastern Slope Of Northern Shaanxi

This paper chooses Chang 61 in Well B of Jianyucha Oilfield,Chang 62,63,64 in Haoyigou area of Nanniwan,and Chang 61,62 and 63 in Fuhuang area as the research objects.The sedimentary facies and petrological characteristics of the three areas are analyzed and studied.The micro-pore structure of Chang 6 reservoir in the study area is emphatically studied by means of core photographs,casting slices and high pressure mercury injection experiments.Systematic research and analysis of the i MPact have been carried out and the following understandings have been achieved:There are distributed in turn from north to south,showing obvious differences in sedimentary characteristics.Reservoir Chang 6 in Well B develops delta plain subfacies,delta front subfacies are developed in Chang 6 and 6in Haoyigou area of Nanniwan,and delta front slump turbidite fan subfacies are developed in Chang 6 in Fuhuang area.The sandstone types of Chang 6 reservoir in the study area are mainly feldspar sandstone with medium to good sorting.The sandstone grain roundness of Chang 6 reservoir in three areas from north to south is getting better and better,and the structural maturity is getting lower and lower.The main diagenesis is co MPaction,cementation and dissolution.Comprehensive analysis shows that the reservoir space of Chang 6 reservoir in the whole study area is mainly residual intergranular pore and intragranular dissolution pore,followed by intergranular dissolution pore and debris dissolution pore.The pore structure of reservoirs varies in different areas due to different sedimentary subfacies.The porosity and permeability of Chang 6 reservoir in three areas from north to South gradually decrease,and the physical properties of the reservoir as a whole gradually deteriorate.In the same area,the pore structure of reservoir varies with different sedimentary microfacies.The pore structure of distributary channel,underwater distributary channel and turbidite channel is better than that of distributary interchannel,underwater distributary interchannel and turbidite interchannel.