Application of Fracture-Cave Quantitative Technique for Carbonate Reservoir of Yingshan Formation of Lower Ordovician in North Slope of Tazhong Area,Tarim Basin

In view of geologic models for various reservoirs,integrated with field observing system and seismic geologic conditions in studied area,the numerical simulation is conducted using Tesseral forward software,and the seismic response characteristics of favorable reservoir in highly producing wells.The predicting method for wave impedance inverse seismic attribute is selected through forward studies,analyses of the geophysical response characteristics of all kinds of reservoirs.The corrected wave impedance data body is converted into the porosity data body,followed by getting the effective reservoir spaces of the reservoirs and finally realizing the quantitative description of the effective reservoir spaces.The study shows that highly producing and effective wells are characterized by seismic features of "strong surface plus inside regular beads reflection" and "feeble surface plus inside strong beads reflection".The seismic response characteristics of the carbonate reservoir of the Lower Ordovician weathered crust are dominated by low wave impedance,low velocity,low frequency,strong frequency-division amplitude,strong coherent and intensity attenuation,etc.Through the fracture-cave quantitative sculpture,the total effective reservoir volume is 5.42×108 m3 in Block Zhonggu-8.Exploration practice indicates that the quantitative sculpture of fracture-cave in carbonate reservoir is one of the effective methods to improve the exploration success rate.