裸眼时差与变密度测井地层波能量相结合改进固井Ⅱ界面评价

固井Ⅱ界面胶结情况直接影响生产井中油、水层的窜通，是固井质量检测的重要环节。利用裸眼井声波时差资料计算出变密度波列中的地层波波至，结合现场变密度资料在频域内对地层波能量进行了准确求取，并对固井Ⅱ界面进行了评价。结果表明，固井Ⅰ、Ⅱ界面水泥完全胶结时，地层波能量和声波时差存在一定的指数关系。在此基础上考虑地层声速参数对地层波能量的影响，特别是快、慢地层对Ⅱ界面评价的影响，给出了一种新的主要反映水泥胶结质量的Ⅱ界面胶结指数的定义。评价结果表明，新的胶结指数曲线在固井Ⅱ界面胶结良好井段相对较平滑且数值接近于1，基本能够消除地层声速对Ⅱ界面胶结质量的影响，进而改进了固井Ⅱ界面的评价质量。

Improved second interface cementing evaluation using open hole slowness and formation wave energy of variable density log

As an important link for cementing quality measurement,the bond of second interface has direct effect on the connection between oil and water bearing zones in the producing well.The arrival time of the formation wave of variable density log(VDL) waveform was derived from the open hole acoustic data and the formation wave energy was calculated accurately in frequency domain.By the method,field VDL data were processed.The results show that,when the cement of first and second interface bonds well,there exists exponential relationship between the formation wave energy and slowness.Considering the effects of formation slowness on formation wave energy,especially the effect of fast or slow formation on the evaluation of second interface,a new bond index of second interface that mainly reflects the cement bond quality was provided.The processed results show that the new bond index curve is relatively smooth and the value is close to one in the well-bonded second interface,which can basically eliminate the influence of the formation velocity on the bond quality of second interface and can improve the evaluation quality of second interface.