Underbalanced Drilling Technology, the Key for Solving Drilling Problems

RS 12 well is the twelfth well in the 2 year underbalanced drilling project involving NIDC and Weatherford. NIDC supplied the UBD equipment and Weatherford supplied the UBD expertise to assist NIDC personnel on UBD techniques. National Iranian South Oil Company was the operating company whose oil wells were drilled under the contract between NIDC and Weatherford. RS 12 is a deviated well with the 9 5/8" casing shoe at 2,138 m and 7" liner shoe at 2,328 m and 5" liner shoe at 2824 m. The UBD interval will be from 2,905 m to TD of 3,250 m. Underbalanced conditions will be established by injecting nitrogen gas down the drill string along with native crude four objectives.