地层切片穿时现象对地震属性的影响

THE IMPACT OF TIME-CROSSING OF STRATA SLICE ON SEISMIC ATTRIBUTES

结合实际地震资料,采用以同相轴(波峰相位)为中心上下一个视周期内(穿时半个视周期)跳跃解释层位、以同相轴为中心上下3/2个视周期内(穿时3/4视周期)跳跃解释层位和严格按照同相轴(波峰相位)解释层位,并以解释出的层位为顶约束,以另一自动追踪同相轴解释的层位为底约束,内插建立层段地层切片;通过对不同方式制作的地层切片进行对比,研究了穿时对属性地层切片的影响。研究发现:轻微穿时对属性地层切片有一定的影响,但对地层切片上岩相分布的整体态势影响不大;瞬时相位和振幅瞬时值相关性不明显;当穿时超过3/4视周期时,振幅瞬时值属性地层切片上岩相分布的整体态势将受到很大影响,穿时程度越大,属性切片受到的影响也越大;穿时对属性地层切片的影响与时窗大小和属性本身的特性有关,时窗越小,影响越明显;与瞬时属性相比,切片属性为时窗内统计类属性时,穿时对属性地层切片的影响较小。

With real seismic data,this paper makes the model restrained by top and bottom.The tops are positions which are interpreted along lineups skipping phases in an apparent cycle and following lineups strictly.The bottom is a position which is interpreted along lineups automatically.Through comparing the slices in different models,the authors studied the effect of time-crossing on strata slice.The findings show that slight time-crossing has a certain effect on strata slice,but will not affect the whole state of lithofacies distribution.Instantaneous amplitude is not related to instantaneous phase.When time-crossing is higher than 3/4 of a apparent cycle,the whole state of lithofacies distribution in strata slice with instantaneous amplitude will be affected.If the extent of time-crossing is greater,the effect will be more obvious.The effect of time-crossing on strata slice is connected with the size of the time window and the characteristics of seismic attributes.The smaller the time window is,the more obvious the effect is.A comparison with instantaneous attributes shows that,when the seismic attribute in strata slice is a statistic one,time-crossing will have a slight effect on strata slice.