Experience in the Petroleum Industries [and Discussion]

The petroleum industry engages in the design, construction and operation of huge steel constructions of almost every type. The design temperature of vertical cylindrical storage tanks ranges from -- 196 to + 80 degrees C: they are often sufficiently large to hold far more than 100 000 t of product in a single container. Pipelines, often larger than 48 in (122 cm) in diameter are used to transport crude oil and gas at high pressure over distances of hundreds of miles often in arctic climates. Offshore platforms are designed for service in the deep sea: in the North Sea the depth of water may exceed 200 m and waves of 30 m are encountered. Fracture mechanics, notably crack opening displacement (c.o.d.), are used extensively in selecting materials and welding procedures for such constructions, but J-integral and linear elastic methods (l.e.f.m.) are used also when these alternatives seem appropriate. The selection of steel grades is greatly facilitated by the use of fracture mechanics techniques but weld metal deposits provide special problems for which solutions are still sought.