... and penetration rate, whether controlled by rotary speed or by weight on bit. Factors affecting either of the two parameters of this relationship are shown to be differential pressure on bottom, mud characteristics, circulation rate, jet velocity and rock-bit design. Examples are cited from...

... drilling fluids and materials pore pressure Reservoir Characterization Upstream Oil & Gas pressure differential differential crater reservoir geomechanics strength resistance hold-down force drilling fluid management & disposal drilling rate drilling economics low strength...

... of the kick or very large influx volwnes. Drilling with mlnlffiwn differential, or with a differential imposed on the system with choke pressure, should then pose no problems due to surface pressures. INTRODUCTION The trend towards using a mlnlffiwn differential in drilling appears to offer a considerable...