METHOD AND SYSTEM FOR DRILLING AND COMPLETING UNDERBALANCED MULTILATERAL WELLS

摘要

The system of the present invention relates to underbalanced multilateraldrilling andcompleting of oil wells. In one embodiment of the present invention a systemfor drilling andcompleting multilateral wells in an underbalanced condition from a principalwellbore,comprising: a first drilling/completion subsystem, further comprising a drillstring assemblyhaving at least a drill bit and guidance system at the end of the drill stringassembly; acontainment subsystem for maintaining an underbalanced state within thewellbore, thecontainment system further comprising at least pressure controls such as ablowout prevention(BOP) stack, rotating BOP, coiled tubing or snubbing unit; and a separationsubsystem forseparating hydrocarbons that have been co-mingled with the drilling fluids asthehydrocarbon/drilling fluid mixture is returned to the surface, so that thehydrocarbons may becollected and separated from the other fluids in the system.