【摘要】 目前叠后时移时差属性的研究与应用已经取得一定的成功,但有关叠前时移时差属性的研究工作还很少.本文通过模型计算对叠前时移时差属性的变化规律和特点进行了研究.结果表明,油藏注水开采前后两次测量的地震波在双层介质中的传播射线路径是不同的.在上覆地层中,地震波旅行时差总大于零,且随着炮检距增加不断增大.在储层中,随炮检距增大,地震波旅行时差由最初的正值变为零再变为负值.总时差大于零,且随炮检距增加而增大.在大炮检距范围内,总时差与储层时差存良好的线性关系,且曲线斜率基本上不随储层速度和厚度的改变而变化.利用大炮检距时移时差属性有可能确定储层动态变化,但如何来实现这一过程还有待经进一步研究.更多还原

【Abstract】 Application of poststack timelapse seismic time difference attribute have had some successful case at present, but the study on prestack timelapse seismic time difference attribute is little. Regularities and characteristics of prestack timelapse seismic time difference attribute are analyzed by model computation in the paper. Results show that ray path of seismic wave traveling in double layered medium is different for two surveys in pre and postwaterflood recovery. Seismic wave traveltime difference in overburden is always larger than zero and increases with offset enlarge. But it changes from the started positive value to zero then to negative value as offset increases in reservoir. Total time difference, which is also larger than zero and increases with offset enlarge, has a good linear relation with reservoir time difference in the range of large offsets, and the inclination angle of curve is almost same for different reservoir velocity variation and thickness. It is possible to determine reservoir performance variation using the time difference attribute of large offset, but how to carry out the idea still needs further study.更多还原