| 摘要 |
In a method of avoiding a drill string becoming stuck during drilling of a well over depth intervals where such equipment has become stuck in similar wells in a geological province, a multiplicity of well drilling variable quantities are measured substantially simultaneously at a known depth in each of a multiplicity of wells. Such multiplicity of wells includes those in which drilling equipment has stuck due to mechanical problems or differential pressure between the drill string and an earth formation penetrated by the well bore, or both, and a multiplicity of similar wells where the drill string did not stick. By multivariate statistical analysis of all variables in all wells of each class, together with maximum separation of said classes from each other, a plotting plane for a currently drilling well relative to said classes is established. The location of the relative position of all variables in such a drilling well with respect to the well classes is determined by summing the products of the coefficient of each variable for the complete group of wells times the current value of the variables in the drilling well. The variables are then modified within allowable values to change the plotted location of the drilling well toward the mean of the wells that did not cause the drill string to stick. |
