Close in:
1.To shut in a well temporarily that is capable of producing oil or gas.
2.
To close the blowout preventers on a well to control a kick.
The blowout preventers close off the annulus so that pressure from below cannot flow to the surface.
3.
To close a valve to stop or isolate fluid flow.
The term is most commonly applied to “closing-in the well,” meaning isolation of the wellbore by closing the master valve.
