Method of fabrication of corrosion resistant oil field tubulars
A corrosion resistant waste-water disposal or chemical injection screen is fabricated from extruded, double cold pilgered N06625 or N07716 nickel alloy in a standard oilfield tubular length. After providing each end with a premium thread for a box and a pin end, and slotting the body of the well screen with slits no wider than 0.015 inches and no longer than 2.5 inches, the well screen is ready for deployment in a well. Other types of oilfield tubulars in standard OCTG lengths could be fabricated in the manner described herein.
1. A method of fabrication of corrosion resistant tubular having a minimum tensile strength of 65-ksi comprising:
selecting a low-cobalt, non-ferromagnetic nickel alloy blank selected from a group of nickel alloys consisting of: N06625, N07716, and N06985, having a mass and a longitudinal extent sufficient to create a tubular in a standard oilfield length;
forming a hole in the longitudinal axis of said blank to create a tubular;
increasing the grain size of the low-cobalt, non-ferromagnetic nickel alloy of the tubular by heating the tubular and by water quenching;
cold working the tubular;
heat treating by a non-oxidizing annealing and water quenching the tubular to increase a grain size of the tubular member toward ASTM Grain Size No. of 0 to permit machining; and,
machining the tubular to form a final product.
2. The method of claim 1 wherein the low-cobalt, non-ferromagnetic nickel alloy blank is a billet to be extruded.
3. The method of claim 2 wherein the forming comprises the additional steps of trepanning and radiusing the nose of the billet, then heating the billet to achieve a saturated billet and extruding to form a tubular.
4. The method of claim 1 wherein the low-cobalt, non-ferromagnetic nickel alloy blank is a bar to be drilled.
5. The method of claim 4 wherein the forming process comprises the additional steps of drilling the bar to form a tubular, then annealing the tubular to permit further cold working of said tubular.
6. The method of claim 1 wherein the low-cobalt, non-ferromagnetic nickel alloy blank is a spin-pierced billet.
7. The method of claim 1 wherein the cold working is cold pilgering.
8. The method of claim 1 wherein the cold working is shear forming.
9. The method of claim 1 wherein the cold working is drawing.
10. The method of claim 1 wherein the step of cold working is accomplished by two passes having an annealing step at about 2050° F. for one hour, followed by a water quench, said annealing and water quench completed between the first cold working step and the second cold working step.
11. The method of claim 10 comprising the further step of solution annealing and aging the tubular member after machining to obtain desired strength levels of at least 110 ksi.