Energy Spectrum Method to Quantitatively Evaluation for the Second Cementation Interface in VDL
Yujuan Wang · Well Logging Technology · 2013
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%;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.