轴对称套管井井孔声场特征分析

Characteristics of acoustic fields in axially symmetric cased boreholes

为了给检测套管井固井水泥胶结质量提供依据,采用实轴积分方法研究了不同胶结情况下的套管井井孔声场.结果表明:第一界面发生窜槽时,会产生一个沿着钢套管传播的振铃信号;第二界面发生窜槽时,会产生沿着钢套管和水泥层复合体传播的伪瑞利波信号;2个界面同时窜槽时,能接收到一个传播速度约等于钢套管纵波速度的振铃信号,但是它的波形振动频率较低.另外,不同的胶结情况,在二维谱中会产生特点不同的耦合变形.

In order to provide a basis for the evaluation of the cementing quality of the cement in cased boreholes, the acoustic fields with various cementing cases were studied using real axis integration. The test results show that if the first interface fails, a bell signal will propagate along the casings. If the secondary interface fails, a pseudo-Rayleigh signal propagates in the structural compound of the casings and cement annuluses. When the two interfaces fail, a bell signal will emerge, and its velocity will approximately equals that of the P-wave in the steel casings. However, its vibration frequency will be much smaller. The coupling deformation in two-dimensional spectra is different with regard to different cementing cases.