关键词: 缝洞系统, 地震几何属性, 缝洞连通体, 储层类型, 孔隙度, 塔里木盆地

Abstract: 3D spatial carving and description are conducted on Lower-Middle Ordovician fracture-cavity carbonate system in Tarim Basin, based on integrating seismic data, underground logging and drilling data. Seismic geometric attributes are extracted by utilizing seismic data to describe such geological properties as karst watercourse, karst cave, plane round or elliptic fracture features and fracture channel related to karst reservoirs. Seismic facies analysis could be used to confirm the spatial distribution of major karst features like karst cave and fracture channel and the threshold value of seismic geometric attributes. The geocellular model is constructed to keep the same resolution with seismic data, which could be helpful to simulate geological properties of karst reservoir accurately. The spatial connectivity of major karst features is analyzed to build the spatial structural model of fracture-cavity connectors. Log facies analysis and calibration with core data and borehole imaging logs lead to the definition of reservoir rock types at wells.Modeling techniques help to characterize reservoir heterogeneity such as reservoir types and porosities derived quantitatively from log information and conditioned with seismic impedance. Fracture-cavity connectors could be incorporated with spatial structure to obtain the reservoir geological model of them. This paper introduces the application of quantitative seismic characterization approaches to the fracture-cavity carbonate reservoirs of the Ordovician. It is shown that quantitative seismic characterization of karst reservoirs provides new understandings of reservoir origins and underlying geological determination.

Key words: fracture-cavity system, seismic geometric attribute, fracture-cavity connector, reservoir type, porosity, Tarim Basin