套管中泄漏弯曲型Lamb波的传播特征  

The propagation characteristics of leaky flexural-Lamb waves in casing

作　　者：陈雪莲[1] 李建赛 唐晓明 李盛清 苏远大[1] 

机构地区：[1]中国石油大学(华东)地球科学与技术学院

出　　处：《声学学报》2016年第3期296-304,共9页Acta Acustica

基　　金：国家自然科学基金(40804020);山东省自然科学基金(ZR2011DQ020);中央高校基本科研业务费专项资金(14CX05010A)资助

摘　　要：低阻抗水泥固井质量检测是油气田生产亟需解决的问题。套管中传播的最低阶泄漏弯曲型Lamb波(以下简称为A0弯曲型Lamb波)对套管后介质尤其是低阻抗水泥的声学参数和胶结状况具有很高的敏感性。通过建立多层介质模型,从理论上计算了其频散和衰减与套管后介质属性及水泥环第Ⅰ界面胶结状况的关系,并数值模拟了有限尺寸定向辐射探头激发和接收的全波波形。结果表明,在套管后耦合慢速水泥时,A0弯曲型Lamb波的频散曲线存在断点,曲线分为两个分支;A0弯曲型Lamb波的衰减在套管后耦合慢速水泥时最大并且对水泥环第Ⅰ界面胶结差时流体环厚度有很高的灵敏度,利用其衰减可以实现对套管后介质类型、水泥环第Ⅰ界面胶结状况及窜槽厚度的有效判别。Low-impedance cementing quality evaluation is an urgent subject to be solved in oil and gas production. The lowest order antisymmetric mode of leaky Lamb waves （hereinafter referred to as Lamb flexural mode） have been used for cement evaluation because it is sensitive to the acoustic parameters of layered media （especially the low- impedance cement） and cementation condition. An investigation into the relationships among flexural mode dispersion and attenuation, cement acoustic properties, and bonding conditions between casing and cement is conducted using multi-layered media model. The full waveforms launched and received by finite and directional emitting and receiving transducers are simulated then. The result shows that the flexural mode dispersion curve is broken into two branches when slow cement exists behind casing; the flexural mode attenuation maximizes when slow cement exists behind casing and it is sensitive to channel fluid thickness between casing and cement. We can distinguish the type of layered media behind casing, bonding conditions between casing and cement and also channel fluid thickness in the presence of free pipe condition effectively by observing the flexural mode attenuation.

关 键 词：套管波 LAMB波 弯曲型 水泥环 频散曲线 传播特征 固井质量 相速度 多层介质 油气田生产 

分 类 号：O347.4[理学—固体力学]