Collapse of Thick Wall Pipe in Ultra Deep Water

Abstract

Literature pertaining to the subject matter is evaluated and discussed. The subject matter is categorized by type of loading: (1) Pure external pressure; (2) pressure plus tension; and (3) pressure plus bending. The subject matter is concerned with the buckling or yield type of failure rather than fracture; and with well casing as well as conventional high strength line pipe. The failure theories are discussed and summarized; and the data and theories are compared. It is found that elastic stability should be based on mean diameter. Although not sensitive to imperfections elastically, plasticity effects especially prevalent in thick wall pipe are recognized as a cause of substantial imperfection sensitivity with respect to initial ovality. The abundance of data for oil well casing is found to contrast sharply with the lack of data for line pipe. Tension plus pressure appears to be amenable to a tangent modulus approach. Bending plus pressure is found to be the least well documented both in terms of theory and testing.