扇区水泥胶结测井(SBT)响应的数值模拟

用有限元素法数值模拟SBT测井贴井壁的点声源激励下套管井中接收到的声压波形.计算模型中包括了几种可能影响套管波波形特征的情况,使用的声源频率为实际的测井频率.分析结果表明:套管波波形特征除了与固井第Ⅰ、Ⅱ界面的胶结情况有关外,还与套管厚度、水泥环厚度、第Ⅰ界面裂缝宽度等测井参数有关;在套管厚度或者水泥环厚度较小的井段,套管波的幅度大小受到后续波的影响.

Numerical Simulation of the Logging Response of Segmented Bond Tool (SBT)

Finite Element Method (FEM) is used in simulating the acoustic pressure waveforms of the acoustic field stimulated by a point source adhering to the casing according to analyzing the measuring theory of Segmented Bond Tool (SBT). Several cases that may influence the characteristic of the casing arrivals are considered in the calculating models, the center frequency of the acoustic source used in calculation is the same as the logging tool used in field. The characteristic of casing arrivals is related to the thickness of the casing, thickness of the cement layer and the width of the crack when the casing and the cement are not bonded except for the bonding conditions. The amplitude of the casing arrivals is influenced by the forthcoming wave when the thickness of the casing or the thickness of the cement layer is very little.