This overview of different applications of CBR in petroleum engineering is based on a survey and comparative evaluation of different successful applications of CBR. The number of papers and research groups is indicative of importance, need, and growth of CBR in different industries. Application-oriented research in the area of case based reasoning has moved mature research results into practical applications. In this paper we present the evolving story of CBR applied in petroleum engineering especially in drilling engineering. Drilling engineering contains several potential domains of interest, in which CBR can be employed successfully.