多孔介质BISQ模型中的慢纵波

Slow waves propagation in BISQ poroelastic model

着重研究了多孔介质BISQ模型中慢纵波的基本特性 .给出了BISQ模型下慢纵波速度和衰减的低频近似公式 .与Biot理论对比 ,BISQ模型中慢纵波的衰减随频率降低急剧增大 ,且随喷射流长度的减小而增加 ;相速度随喷射流长度的减小而增加 ,其低频极限值不是零 ;孔隙流体位移与固相骨架位移之比的幅值随喷射流长度的增加而减小 ,其相位特点与Biot模型预测的不同 ;在流体与孔隙介质的边界上可产生更大的渗流 .为对比 ,同时也给出快纵波的行为 .依据BISQ模型可推断 :非黏滞流体饱和孔隙介质中不存在喷射流机理 ;BISQ模型中不会发生“动力协调”

The slow compressional wave (P2 wave) in porous media based on BISQ model is investigated. The low frequency approximate expression for velocity and attenuation of P2 wave is presented. Compared with Biot model, BISQ model predicts that the attenuation of P2 waves is very large at low frequency and decreases with increasing characteristic squirt flow length ( R ), the velocity low frequency limit is not zero and decreases with increasing R , variation of the ratio of pore fluid displacement to bulk displacement is similar to that of attenuation and its phase is different from that of Biot model. The seepage flow induced by P2 wave at the fluid porous media interface is larger than that of Biot model. For the sake of contrast, the properties of the fast compressional wave are also presented. Two conclusions are induced from the BISQ model: there is no squirt mechanism in inviscid fluid saturated porous media and there is no “dynamic compatibility” phenomenon in viscid fluid saturated porous media.