Coiled tubing wellbore clean out tool

A downhole tool(N) has both forward(FFJ) and reward(RFJ) facing jets which dislodge borehole dirt and aid in transporting the dirt to the surface respectively, the forward facing jets(FFJ) being of higher pressure than the reward facing jets(RFJ). A method is also disclosed which allows for computer modelling of the wellbore, both before and during operation, so that the required run into hole (RIH), pull out of hole (POOH) or pump rate can be discovered for each wellbore. Fluid additives such as friction reducers may be added.