基于常规测井数据的纵波本征衰减估计

Estimation of P-wave intrinsic attenuation from well data

地震波本征衰减反映了地层及其所含流体的一些特性,对油气勘探开发有重要意义.已有的理论研究与实验发现,地震频带内的衰减主要与中观尺度(波长与颗粒尺度之间)的斑状部分饱和、完全饱和岩石弹性非均匀性情况下波诱导的局部流体流有关.这种衰减与岩石骨架、孔隙度及充填流体的性质密切相关.本文着重讨论均匀流体分布、斑状或非均匀流体分布两种情况下部分饱和岩石的纵波模量差异.以经典岩石物理理论和衰减机制认识为基础,通过分析低频松弛状态、高频非松弛状态岩石的弹性模量,讨论储层参数(如孔隙度、泥质含量以及含水饱和度等)与纵波衰减之间的确定性关系.上述方法与模型在陆相砂泥岩地层与海相碳酸盐岩地层中的适用性通过常规测井资料得到了初步验证.

As a response of property of layer and fluid,seismic intrinsic attenuation is very important for oil and gas exploration.An original theory of attenuation mechanism and experiment imply that attenuation in seismic range has some relation with middle scale＇s（between wave and grain） partial patches water saturation and heterogeneity in pore reservoir or in full water saturation rocks.It is caused by portion liquid flow which was generated during wave propagation.This kind of attenuation has an intimate relation with porosity,fluid and solid matrix.This paper is focus on the difference of P-wave modulus in both homogeneous rocks and patchy saturation or called heterogeneity rocks.Based on rock physics theory and attenuation analysis method raised recently,we tried to find the relationship between P-wave attenuation and reservoir parameter（such as porosity,clay content and saturation et al.） by analyzing elastic modulus in low frequency and high frequency,which also called relaxed and unrelaxed condition in water saturation rocks.The expediency of above method and model has been originally proved by standard well log data.