Perpustakaan Digital ITB

Field X is situated in onshore West Java. The reservoir pressure has decline to below its bubblepoint pressure. When conventional drilling is done, couple to fracture in limestone formation, lost circulation problems occurred. With underbalanced drilling technology, lost circulation could be avoided and the amount of recoverable hydrocarbons will be improved. Re-entry wells and proposed new wells drilled in this field also will lead to maximizing recoverable hydrocarbons. No H2S exist in reservoir fluid and the amount of CO2 is insignificant. There is water production couple to oil and gas production, nevertheless, it can be neglected. Water influx can be neglected in this field.The study of this paper emphasizes drilling fluid selection, borehole stability, pressure evaluation, hole cleaning, equipments, optimum combination, gas injection methods, and the underbalanced drilling window. Nitrified mud was selected as a drilling fluid to drill the reservoir section in Field X. Drillstring injection method will be chosen for the gas injection.