变密度测井能量谱法定量评价固井第Ⅱ界面

Energy Spectrum Method to Quantitatively Evaluation for the Second Cementation Interface in VDL

分析变密度测井机理,将5ft全波列能量划分为直达波能量、地层波能量和套管波能量3部分,依据各波段频率范围相对固定以及套管波与地层波能量高低相关联的特性构建能量谱图。采用地层波能量与地层波及套管波能量和之比衡量地层波能量的强弱。当第Ⅱ界面水泥胶结差时,地层波能量所占总能量比例接近于0%;当胶结好时,比例接近100%;而胶结介于好与差之间时,套管波、地层波能量都具有一定的数值量,比例介于0%～100%之间。建立第Ⅰ、第Ⅱ界面的胶结评价指数,给出具体的算法步骤和计算公式。

By the analysis of variable density logging mechanism, we divide the spectrum energy of 5 ft wave into three parts, such as, direct wave energy, ground wave energy and the casing wave energy. The band frequency range is relatively fixed and the casing wave and ground wave energy level have a certain relative relationship. Based on this, we build an energy spectrum method which measures the strength of the ground wave energy by the rate of the ground wave energy to the ground wave energy and casing wave energy. When cementation second interface is poor, the rate is close to 0~//00~ when cementation is good, the rate is close to 100~. When the cementation is between good and poor, the ground wave energy and casing wave energy have a certain amount of value, the rate is between 0% and 100~[ We establish the cementation evaluation index of the first and second interface, and propose specific algorithm step and calculation formula. The actual data processing results show that the method is visual, easy operation, simple implementation and has good application prospect.