Although most of kicks occur when pulling the drillstring from the hole, it is also possible for kicks to occur while tripping in.
尽管大多数井涌都发生在起钻的时候,但下钻的时候也会发生井涌。
2
In this paper, the differential equation for the frictional resistance on the drillstring in branch horizontal Wells was established and the total drillstring friction during tripping was got.