Study On The Connectivity Of Fracture-cavity Bodies And Remaining Oil Distribution In Yingshan Formation Of Zhonggu 8 Well Block

Fracture-cavity reservoir is an important part of carbonate reservoirs in the world.However,their strong heterogeneity and complex fracture-cavity connectivity seriously restrict the development of oil fields.The fracture-controlled karst carbonate reservoirs are mainly developed in Zhonggu8 well block.The multi-stage tectonic movements and the superposition of karstification lead to diverse connectivity modes of fracture-cavity reservoirs in the study area,and the distribution of remaining oil is complex.It is of great significance to analyze the connectivity of fracture-cavity reservoirs and the distribution of remaining oil in the study area for the adjustment of subsequent oilfield development plan.This study is based on the results of fracture-cavity reservoirs identification by drilling and logging data in the study area.The ant-tracking technology and principal component analysis method were used to identify the fractures and caves by making full use of seismic data,and the geological model was established.According to the Combination characteristics of fractures and cavities in space,this research summarizes the connectivity types of fracture-cavity reservoir in the study area.Combined with production data,typical well groups were selected to analyze the connectivity of different types,and the connectivity models of fracture-cavity reservoirs in study area were established.According to the water cut and daily production curve of production well,combined with the combination characteristics of fracture-cavity reservoirs under different connectivity modes,the distribution law of remaining oil in different connectivity modes was analyzed.According to the research results of fracture-cavity reservoir connectivity,under the comprehensive influence of fault and fracture system,unconformity,diagenesis,fracture-cavity combination characteristics in different types,the fracture-cavity reservoirs in the study area mainly develops four connectivity types: unconformity connectivity type,fault connectivity type,cavity to cavity fracture connectivity type and isolated cave type.Different types of connection correspond to different connection modes.In the unconformity connection mode,the remaining oil is mainly concentrated in the upper uncontrolled area of the production well section.In the fault connectivity mode,the remaining oil is mainly concentrated in the fault and fracture dissolved pore area.In the cavity to cavity fracture connectivity mode,the remaining oil is mainly concentrated in the low permeability area near the high conductive flow path and the connection position between the fractures and caves.In the isolated cave mode,the remaining oil is mainly affected by the energy intensity,and is relatively enriched at the top of reservoir.