Stabilizer subs for use with expandable reamer apparatus, expandable reamer apparatus including stabilizer subs and related methods

A stabilizer sub for connection to an expandable reamer apparatus used for enlarging a borehole in a subterranean formation, the stabilizer sub comprising:

• a tubular body having a longitudinal axis, an upper end, a lower end, an inner bore, and an outer surface, one of the upper end and the lower end of the tubular body for direct connection to an expandable reamer apparatus without the use of drill pipe or subs located therebetween;
• a drilling fluid flow path extending through the inner bore;
• and
• at least one stabilizer rib located on a portion of the outer surface of the tubular body, the at least one stabilizer rib extending in an at least partial spiral configuration around 45° or more of a circumference of the portion of the outer surface of the tubular body, the at least one stabilizer rib having a diameter thereon substantially under gage of a nominal diameter of a borehole by an amount from 0.00 inche less than the nominal borehole diameter to substantially 0.50 inche less than the nominal borehole diameter, the at least one stabilizer rib located on the stabilizer sub to be within a range of about four (4) feet to ten (10) feet of a blade of an expandable reamer apparatus connected directly thereto, the at least one stabilizer rib further comprising:
• a profile including a first transition surface substantially aligned with a rotational leading edge of the at least one stabilizer rib, the first transition surface for transition from a rotational leading face of the at least one stabilizer rib to a bearing surface of the at least one stabilizer rib;
• a second transition surface for transition from the rotational leading face of the at least one stabilizer rib to the first transition surface;
• and
• a layer of hardfacing alloy disposed on each of the bearing surface, the first transition surface, and the second transition surface.