Study on Geological Genesis and Sedimentary Model of Complex Low Resistivity Reservoir in Offshore Oilfield — A Case of NgIII Formation of X Oilfield in Bohai Sea

In order to study the micro genetic mechanism and main geological controlling factors of low resistivity reservoir in NgIII formation X oilfield Bohai sea China, clay mineral composition, irreducible water saturation, salinity conductive minerals were studied by using data core, cast thin section analysis, compared with normal reservoir. At same time, control effect sedimentary environment on was discussed. The results show that additional conductivity high bound content montmorillonite together leads significant reduction resistivity, which is microscopic cause resistance, mainly controlled background such as paleoclimate cycle. During deposition period formation, dry cold, it at end advance medium-term hydrodynamic force river channel weak, carrying capacity riverbed swayed frequently, resulting fine lithologic particle size, shale complex pore structure reservoir, resistance. research conclusion would have strong guiding significance for development reservoirs this area.