地震层砂泥含量的地质意义及其应用中需要注意的问题

砂泥含量是油气地质研究中一项重要的岩性参数。地震层定量解释的砂泥含量与地质研究中岩石的砂泥含量意义不同。地震层划分与岩性层一致时,地震层砂泥含量与岩层砂泥含量意义相同,数值大小能够反映岩层的形成条件:地震层划分与岩性层不一致时,地震层砂泥含量只能反映地震层内砂泥地层累积厚度百分数,不能用于直接解释地震层的形成环境。地震层砂泥分量既与形成时的地质条件有关,也与地层的压实作用有关。由于泥岩层的压实率远大于砂岩层,所以沉积初期表现为低砂含量的地震层,在埋深较大的情况下表现为高砂含量。这个问题在砂泥分量的应用中需要特引引起注意。

Geological meaning of sand or shale content of seismic horizon,and points for attention in its application.

Sand or shale content is an important lithologic parameter in oil geology re- search.The meaning of sand or shale content of seismic horizon is generally different from that of geologic horizon.When seismic horizons coincide with geologic ones, the meaning of sand or shale content of seismic horizon is the same as that of geo logic horizon,and the content magnitudes indicate horizon generation environment. When they don't coincide each other,the sand or shale content of seismic horizon means sand or shale accumulated percentage thickness in the seismic horizon,hut can not be used to interpret horizon generation environment directly.The sand or shale content of seismic horizon relates to both horizon generation environment and sedimentary compaction.Since shale layer is much easier compacted than sand layer, the seismic horizon which had low sand content in the early time becomes a high sand content horizon in the case of big depth.This problem should be particularly noticed in applying sand and shale contents.