UNDERBALANCED DRILLING TECHNOLOGY

Historically, most underbalanced drilling (UBD) projects Were undertaken to eliminate drilling problems and cost. However, recently, the reduction of formation damage has become a main focus for underbalanced operations. This has the greatest potential in directly increasing the profit to the operating company. Potential benefits include increasing of production rate, the ultimate recovery, and enabling accelerated production. Underbalanced technology, while still on a sharp growth curve, is finally becoming accepted as a normal method for handling the drilling and completion of wells This paper details the benefits and limiting factors of UBD technology, underbalanced fluid system selection, and UBD techniques, as well as candidate screening and selection.