Finite difference method and transfer matrix method were used to get spectrum response curve of unit impulse function signal to research the spectrum characteristics of acoustic traveling though the drill string. Similarities and differences of the two methods were discussed through analysis of spectrum curve get from the two approaches. The results show that: The distribution of band-pass and band-stop get by the two calculating methods is basically the same, some transmission coefficient of finite difference method is less than 1, is not completely transmission phenomenon. Analysis of the reason for this is that the transfer matrix method is an analytic method, finite difference method is a numerical algorithm. From the calculation precision of speaking, analytic algorithm is higher than that of numerical algorithm. But to verify the reliability of two methods needs based on laboratory experiment or field test.

Vertical Well-bore Section Anti-collision is one of the main problems to be resolved for clustering directional well during the construction process. In order to effectively reduce the Vertical Well Section collision risk of this wells, the relationship between Wellbore cross-collision probability and the Wellbore separation was studied, the relationship between Wellbore cross-collision probability and the parallel Section length of the two Wellbore was also studied, Based on the above study found the method to calculate the Vertical Wellbore Section cross-collision probability of the clustering directional well. The Vertical Well-bore Section arrangement with smallest cross-collision probability was found by analyzing the cross-collision probability in line style wellhead of cluster wells consisting of 4 wells through this method. The results show that when the Well-bore separation is less than 1.5m. Wellbore collision probability rapidly decrease with the increase of Well-bore separation, the wellbore collision probability trends to smooth when wellbore separation is more than this distance, and the tendency will increase with the increase of parallel section length of the two Wellbore. By optimizing the arrangement and design methods can effectively reduce the collision risk. This study provides a new idea to reduce the overall risk of Cluster Well development.