| 摘要 |
The invention relates to a drilling system and method for drilling a well bore into an earth formation, comprising:-drilling means for drilling a well bore;- pumping means for pumping drilling fluid into the well bore during drilling; and - a drilling fluid outlet system for retrieving drilling fluid from the well bore, said drilling fluid outlet system comprising choke means for choking the return flow of retrieved drilling fluid, and alternating means for alternating the flow direction through the choking means. |
