Drilling problems associated with wellbore stability have plagued the industry for a long time. Such problems have resulted in poor drilling performance, production impairment and eventual loss of the wells. GeoDRILL® is an engineering process designed to identify and resolve wellbore stability and hole quality problems while drilling. Based on a THMC (Thermo-hydraulic-mechanical-chemical) approach, it allows determination of the optimum drilling conditions that will result in superior hole quality and minimised risk to the operations.