Casing While Drillng "CWD" The concept of drilling and casing the hole in the same time is, of course, valuable by combining two time consuming processes. So how is it possible? What are the limitations? What are the challenges? And what are the benefits? The main purpose of Casing Drilling, or Casing while Drilling (CwD), is to eliminate classic casing runs and isolate formations while drilling. By using Standard casing string instead of conventional drill string, the drilling and casing are ex