Two autoclave exposure tests were conducted simulating wellhead shut-in and bottom hole Thamama gas conditions. Based on these tests, all materials evaluated up to 42 percent nickel (13Cr, 22Cr, 28Cr, Alloy 825 and Alloy 925), exhibited excessive general corrosion pitting, crevice corrosion and/or stress corrosion cracking. It is recommended that materials with nominally 50 percent nickel such as Hastelloy Alloy G, 2550 and NIC 52 be considered for downhole Thamama gas service.
|