crooked-hole country

crooked-hole country

[′kru̇k·əd ¦hōl ‚kən·trē]
(petroleum engineering)
An area where it is difficult to drill completely vertical holes because the formations possess alternating hard and soft strata steeply inclined from the horizontal.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.