Pilot Hole 1 : A small (sometimes) diameter hole drilled through a pay zone to determine the pay top and bottom or various contacts, before the main well position is selected. May also use a pilot hole to better control influx rate
George E. King Engineering, 5000 Oilfield Terms: A Glossary of Petroleum Engineering Terms, Abbreviations and Acronyms, US 2010. http://gekengineering.com/Downloads/Free_Downloads /Glossary_of_Petroleum_Engineering_Terms_25_August _2010.pdf, (Oil - Amer) {593}