用斯通利波评价套管井水泥胶结质量

Evaluation of the Cement Quality in Cased Well from the Stoneley Wave of Full Sonic Well - logging

根据套管井声波全波测井理论，导出了斯通利波久期方程，数值计算并绘制了斯通利波在无水泥和水泥胶结不好时的相速度、衰减以及波形曲线，详细分析了各种曲线的特点，指出套管井中具有两类斯通利波：第一类产生于井中流体与套管之间，称套管斯通利波，它的相速度和衰减与套管外有无水泥没有关系；第二类产生于套管与地层之间，称水泥层斯通利波，当水泥胶结不好或无水泥时，必有此波存在，它的相速度和衰减与水泥厚度、流体层的位置有密切关系。当水泥胶结好时，此波消失．因而从理论上证实了斯通利波在套管井中的传播特性能够反映水泥胶结质量。

The Stoneley period equation is derived from full sonic well - logging.The Stoneley phase velocities, attenuation as well as its waveform are numerically calculated and their curves are plotted respectively for no and little cement in a well. The characteristics of various curves are analysed and it is found that there are two types of Stoneley waveform in cased wells: the frist generates between the fluid and the case in the well; the second occurs between the case and formation. When there is no or little cement in the well, the second Stoneley wave must exist, its velocity and attenuation depends on the thickness of the cement and the location of the fluid layer. When there is more cement in the well, this wave disappears. Therefore, the propagating feature of Stoneley wave can reflect the cement quality.