ABSTRACT
It became clear immediately that the stiffness of the diaphragm would have negligible effect in constraining the hydraulic oil volume; relative to the effect of the bulk modulus of the hydraulic oil it would be ∼ (V/Voil) ⋅ (h/R) ⋅ (E /Koil) or smaller. Here: E, h, R and V are the Young modulus, initial wall
1 INTRODUCTION
Remaining oil and gas reserves can lie several km below ground or sea level. Moreover, recovery of such reserves frequently necessitates steering the drill-bit with a Rotary Steerable System (RSS); this involves either moving the drill-bit perpendicular to the previous direction of drilling (a push-thebit system) or re-orientating the bit (a point-the-bit system) (Fig. 1).
