Study On The Characteristics Of Ordovician Karst Cave Storage In Tahe District 4 And Three - Dimensional Geological Modeling Of Reservoir

Based on the researches about the karstification theory and the karst fracture-vuggy reservoir from all over the world, this paper focus on the ordovician karst carbonate reservior in Block4of Tahe Oilfield by using the methods of reservoir geology, logging geology, seismic stratigraphy, development geology. We established an identification of the carbonate reservoir (especially the karst cave type) on well drilling, logging and seismic survey. On the basis we use multi-point statistic method to set the geological3D model which shows the distribution of cave, vug and fracture, which lays the foundation of the calculation of reservoir and exploitation. The results prove that the main reservoir space includes cave, vug and fracture, with huge discrepancies, strong heterogeneity, compacted bedrock and poorly developed pores. We also divide the reservoir into the weathering karst zone(A type) and insider karst zone(B type) in vertical. Just as the3D model shows, A type develops widely, with large thickness and good connectivity. B type develops in smaller scale and worse connectivity.