Rock Mechanics Lab Testing and Computerized Simulation of Bit Dynamics ImprovesDrilling Performance in Horizontal Chalk Reservoirs

摘要

Maersk Oil and Gas AS are typically drilling the carbonatereservoirs in the Danish Sector of the North Sea in 8?"horizontal hole sections, with section lengths regularly over15,000 ft. The two lithological components of the formationshow a large variation in geo-mechanical properties: a soft,plastic chalk matrix and large, hard, brittle, chert nodules.Impact loading on cutting structures and penetrationdifficulties in the hard, microcrystalline chert are generally thelimiting factors on bit longevity and performance. These longhorizontal sections highlighted the opportunity for optimisingthe durability of single bit runs. In June 2001 Maersk Oilimplemented a bit development priority that was to producesignificant, beneficial results.