Investigation and remediation of active-clay contaminated sepiolite drilling muds

Major findings of this study inferred that sepiolite drilling muds formulated in a certain mixing order of additives provided effective rheological properties and water loss. Acquired results of methylene blue test and sufficient annular velocities for all samples strongly supported availability of these muds against active-clay contamination which is the special emphasis of this study. This is also particularly important for expensive high-angle and extended-reach wells.