Study On Stress Corrosion Behavior Of 110ksi Casing

Recently, Oil and gas exploration has been acute with the growing global demand of oil and gas resources. As drilling depth increases, complicated geological conditions occur in the process of drilling, leading to stress corrosion cracking of casing. C110steel, as a common casing steel, was not defined as sulfur resistant steel by certain standards, or it can even be stipulated that C110can be used only with a little H2S partial pressure and has high pH value according to standard ISO15156-2and ISO11960. Meanwhile, if using C110in containing sulfide environment level casing crack problems, users themselves should take the assume corresponding responsibility. Therefore, it is vital to research the stress corrosion behavior of C110casing steel, thus providing certain preference for evaluating and optimizing casing steel. Through the above study we get the following conclusions:(1) On two kinds of tube material (made of C110steel and SMC110steel) of the conventional properties (physicochemical properties and mechanical properties were tested to obtain the corresponding), chemical composition, metallographic analysis, hardness and impact properties and inclusions and tensile properties, and provide the basis for the subsequent experimental analysis.(2) The fracture toughness of DCB double cantilever beam test of domestic C110and SMC110two kinds of casing material value of KISSC, and analysis of the fracture surface microstructure and study the mechanism of stress corrosion cracking.(3) By using TEM (transmission electron microscope) on the ultrastructure of the inner casing steel were analyzed, to study the two kinds of casing material from the microscopic mechanism of stress corrosion cracking.(4) The domestic C110and SMC110two kinds of pipe materials in the simulated condition, high temperature and high pressure constant load stress corrosion test, analyze the stress corrosion damage by two kinds of strength of the material damage, fracture analysis and surface damage.(5) Through the comprehensive analysis of the above experimental anti SSC domestic C110tube and the SMC110tube (anti hydrogen sulfide stress corrosion cracking) performance.Providing an important reference for evaluation, the research on the material of sour gas field production casing and the applicability of the high strength casing manufacturing process improvement.