Using underbalanced drilling to reduce invasive formation damage and improve well productivity - An update

Underbalanced drilling (UBD) is becoming increasingly used as a technique to reduce significant invasive formation damage In vertical and horizontal wells to improve production rates of oil and gas, and enhance injectivity in gas and water injection situations. UBD may be a technically demanding procedure to execute in certain reservoirs and much of the benefit with respect to mitigation of formation damage may be compromised if the underbalanced drilling operation is not screened, designed and conducted in an appropriate fashion. This paper reviews common formation damage mechanisms which may occur in reservoirs and how, in certain situations, these types of damage may be reduced or eliminated through the appropriate use of underbalanced drilling technology. Various situations in which underbalanced drilling technology may result in potential significant formation damage are also discussed.