Rat Hole 4 (well) : The hole below the pay zone. Commonly drilled to drop off perforating guns or as a gathering or sump area for liquids to separate from gas prior to being pumped out of the well
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}