It is important to have good lubricity due to the lack of pipe rotation. The ability to transfer weight to the bit can be reduced due to buckling (sinusoidal as well as helical) of the flexible coil if adequate lubricity is not present. The ability to transfer weight in conventional drilling is enhancedwith pipe rotation. Minimizing solids and soft-settled cuttings, as well as the use of lubricants, reduces mechanical friction coefficients.