基于声波变密度测井的固井质量综合评价方法

声波变密度测井作为评价固井质量的主要方法,可以提供第一和第二界面的水泥胶结质量状况.通过从变密度波形中提取套管波和地层波幅度(或能量)值,计算第一和第二界面的水泥胶结指数,用于评价第一和第二界面固井质量.由于地层波在传播过程中受影响因素较多,在使用地层波评价第二界面时需要进行衰减校正、干扰校正等常规处理.在此基础上,提出对地层波幅度进行声阻抗差校正,使最终获得的地层波幅度变化主要反映第二界面水泥胶结状况.同时,分析了微间隙在声幅曲线上的特征.实际资料分析取得了良好的效果.

A comprehensive evaluation method for cementing quality based on acoustic variable density logging

The acoustic variable density logging,a main method for evaluation of cementing quality,was employed for calculation of the bonding indexes of the first and the secondary interfaces by extracting the amplitude information(or energy value) of casing waves and formation waves from variable density logging,and further for evaluation of the cementing quality.Owing to the fact that the propagation of formation waves is influenced by many factors, some conventional processing methods,such as attenuation correction and disturbance correction should be taken when the formation wave was used for evaluation of cementing quality of the secondary interface.Furthermore,the acoustic impedance gradient correction of the amplitude of the formation wave was suggested so that the variation of the amplitude of the formation wave finally obtained mainly reflected the status of cement bonding of the secondary interface.Moreover, the micro-annulus feature in cement bonding logging(CBL) curve was analyzed.The results of cementing quality obtained by field data interpretation were satisfactory.