Corrosion and EAC resistance of 14 heats of wireline materials, including a cold-rolled carbon steel, low-alloy steels, stainless steels, titanium alloys, nickel-based alloys, and copper-based alloys, were evaluated.
Historically, the testing of sour corrosion and environmental-assisted cracking (EAC) in the oil and gas industry has focused on oil country tubular goods (OCTG) with design lives of tens of thousands of hours, while wireline and wireline tools are typically exposed to sour conditions for a few hundred hours per year at most. The existing corrosion/EAC information related to wireline materials is either overly conservative or inadequate, which significantly reduces the work scope of a great number of engineering materials that could potentially be used in wireline applications. To overcome this difficulty, the H2S application limits of wireline materials need to be realistically defined.
In this work, the corrosion and EAC resistance of 14 heats of wireline materials, including a cold-rolled carbon steel, low-alloy steels, stainless steels, titanium alloys, nickel-based alloys, and copper-based alloys, were evaluated in two extreme sour environments: 180,000-mg/L chloride brine at 350°F (176.7°C) with partial pressure of H2S (PH2S) 17.2 MPa and partial pressure of CO2 (PCO2) 3.5 MPa, with and without elemental sulfur. The weight-loss corrosion rates, pitting, and cracking behavior of the wireline material were obtained, the result of which could be used as first step to guide the selection of wireline materials in sour service.
Key words: Corrosion, Material Selections, Wireline Materials, Environmental-assisted Cracking, Sulfur Stress Cracking, Stress Corrosion Cracking, Downhole equipment, Oil and Gas environment