Dump sub theory
24 December 2009
Good people of the community,
I am looking at the theory behind Dump Sub operations - the spring loaded piston type that used to be run above Positive Displacement Motors.
Does anyone have any details on the theory behind operation?
I want to work out flow rates / mud weights etc and the spring force required.
It was called a dump valve & was utilized by Dyna Drill to allow the drill string to fill on the way in the hole & then to drain on way out of the hole. It worked off of flow velocity, after a certain flow rate was reached the valve closed. Therewere alot of problems with it and it was blanked off alot of times. You used plugs or pennies to put behind the screens.
In 1991 Baker did away with the dump valve and incorporated a float sub in place of the dump valve, which is a better idea.