Research On Two Kind Of Good Performance Expandable Turbular Materials

The expandable tubular has been a revolution in oil drilling projects，and becomethe core technology of petroleum engineering. The engineering superiority of theexpandable tubular and its requirement performances were summarized to study twokind of expandable tubular steel.A new principle for designing an expandable tubular of dual region steel wasproposed and medium carbon steel have been made, which has excellentcharacteristics, strength-plasticity is20000MPa. The elongation curve of thematerials has a low yield stage followed by a strong hardening trend. Practically, itproved that the new developed expandable tubular materials can be widely used inEngineering.One kind anticorrosion material was developed at the same time. The designedalloy exhibited enhanced passivity properties in3.5%NaCl electrolyte when comparedto the304ss.. EIS result shows that the corrosion performance is improved. Accordingto measurement results by the Mott-Schottky plot, the donor and acceptor densities ofpassive film formed on sample Zp10surface is larger than304. This illustrate that thepassive film formed on sample Zp10surface is less stable than304and was destroyedeasily with anion. The measurement results by the Mott-Schottky plot correspondwith polarization curves. According to the Mott-Schottky plots, the passive film onthe304and Zp10specimens represented the same semiconductor property type. Thevalues of donor and acceptor densities are the same order. This illustrate that there isno essential difference among the films which formed on304and Zp10specimens atsame conditions in potential range,1.0～1.0VSCE. So the rare earth element Ce didnot change the semiconductor property of passive film on the304SS specimen.