When dealing with areas of formation instability it is necessary to:
– trip cautiously through swelling formations
– pick up and ream midway through each stand (if hole conditions are severe, more frequent reaming may be required)
– trip through tight sections using slow rotation and circulation (after pulling into a tight spot, run back into gauge hole and circulate before back reaming out)
– ensure that sections of the hole found to be tight on the way out are always reamed on the trip back in.
– increase MW to maximum allowable for sloughing shales
– increase YP to avoid settling cuttings around the BHA
Note: If drag is indicated after a connection, the joint should be reamed twice.