不同密度水泥石和微环尺寸情况下的套管波特征

Transmitting Feature of Sound Wave in Cased Well with Various Cement Density and Annulus Size

利用声波变密度测井评价固井质量时,掌握不同情况下套管波的特征有助于套管波的分析和剔除,提高固井质量评价的精度。利用实轴积分法模拟分析了不同密度水泥石、不同微环尺寸情况下的套管波时域和频谱特征。结果表明:对于正常密度水泥石,第一、二界面完全胶结时,无套管波;第一界面存在不同尺寸微环时,套管波出现且套管波频率相同,但幅度差别不大。对于低密度水泥石,第一、二界面完全胶结时,出现较小幅度套管波,且水泥石密度越低,套管波幅度越大;第一界面存在不同尺寸微环时,套管波出现且各套管波频率相同,但幅度差别不大。对于同一套管,不同密度水泥石、不同微环尺寸情况下套管波具有相同的频率。

When using variable density log to evaluate the cementing quality,it is necessary to investigate the transmitting feature of sound wave in casing,which can help keeping and eliminating waves,and improving cementing quality.The time and frequency feature of casing wave at cased well with different cements density and different size of annulus were analyzed using real axis integral method.The results show that for normal cement density there is no casing wave when first and second interfaces were cemented completely.When different sizes of micro-annulus exist in first interface,casing wave appears with same frequency and small difference in amplitude.For low density cement,when first and second interfaces were cemented completely,small amplitude casing wave appears and amplitude increases with the decrease of cement density.When there exist different sizes of micro-annulus in first interface,casing wave appears with same frequency and small difference in amplitude.For same casing,the frequency of casing wave is same for different cement density and different micro-annulus