Experimental on the Residual Life of Oil Tubing of J55 Material

Abstract

Oil tubing works as a special pipeline in oil well has the characteristic of high work efficiency and under high loading. Oil tubing failure which commonly happens during the course of oilfield development and production can bring severe economic loss because of the failure accidents caused by the eccentric friction of rods and tubing account for a great percentage. It has a great of significance to study on the fatigue fracture situation and the critical eccentric friction depth of tubing with defects. Oil tubings of J55 material with the specification of Ф73*5.51 commonly used in oilfields were chosen to be the source of semi-ellipse surface crack tensile specimens. Residual life of oil tubing with different eccentric friction percentages was studied through tensile tests. The critical eccentric friction percentage under which the residual life of oil tubing can meet pump detection period was determined, which provides reference for making a reasonable failure standard of tubing. From the tensile test results of the oil tubings of J55 material simulating the condition that the eccentric friction depth accounts for 30% ~ 50% of the wall thickness, the critical friction depth of oil tubing of J55 material is 43.0% of the wall thickness.