An older well design process of using a single joint of the heaviest wall casing in the well just below the wellhead. (Note: this restricts access of fullbore tools to all points below the joint)
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}