top hole in the Oil and Gas IndustryPowered by COBUILD (tɒp hoʊl)
Word forms: (regular plural) top holes
(Extractive engineering: Field development, Drilling) A top hole is the first, shallow part of the borehole. ⇒ The top hole is the topmost section of hole in drilling a well. ⇒ For the top hole or very first section of the borehole, a base from which to commence drilling is required. ⇒ A top hole is the first, shallow part of the borehole.
Related wordsCompare top hole with intermediate section, which is the section of the borehole after the top hole, which has more consolidated rock.