轮南地区碳酸盐岩油气藏的地震响应特征

SEISMIC RESPONSE PROPERTIES OF CARBONATE ROCK OIL POOLS IN LUNNAN REGION

塔里木盆地轮南地区奥陶系碳酸盐岩油气藏的地震响应特征十分明显，主要表现在（１） 碳酸盐岩中裂隙发育处的阻抗差变小、反射能量减弱，致使反射波振幅明显变低；（２）裂隙发育之处高频信号衰减较快，因而反射波的频率降低；（３） 孔隙中若充注有液体会使地层对地震波的吸收系数明显增大；（４） 孔隙中所含流体的波阻抗远小于碳酸盐岩，孔隙中若有流体，其波阻抗值会明显降低。经对钻井统计分析，其前３ 项特征的符合率均较高，达８７～９０；最后一项因储集空间的极度不均一，影响了横向的分辨率。

Seismic response properties of Ordovician carbonate rock oil pools in Lunnan Region,Tarim Basin are evidence:1.the impedance differentiae of the carbonate rocks with well developed fractures change smaller,the reflection energy decreases thus resulting in decrease of reflection amplitude;2.high frequency of the fracture developed area damp out quickly,so the reflection frequency decreases;3.if the fractures are filled with liquid,the ratio of formation absorbing seismic wave will considerably increase;4.the wave impedance of fracture fluid is much lower than that of fractures with no fluid.According to drilling statistical analysis,the coincidence rates of the first three terms are as high as 870/0～900/0,but the last one is only 650/0 since reservoir spaces are extremely heterogeneous and this effects lateral resolution.