jet pump running costs , page-2

Wildo
Tht comment about running costs also puzzled me?
My experience with jet pumps is in aircraft fuel tanks.
In aircraft they just dit in the bottom of the tank and suck up water or unuseable fuel, and deposit it back at the inlet of the main pumps which feed the engines.
They have no moving parts and simply use a venturi effect where the motive flowcomes from the main tank boost pump.
So in this case O&G i am not sure if the motive flow is supplied by a pump at the surface or a pump at the jet pump itself? I would guess the latter?
Either way in my experience they are cheap to operate, but maybe in this instance they are not?
Maybe i will ask for Terry's topics to give us an answer?
GLTA@ SSN