The effects of plastic deformation and H2 S on fracture toughness of high strength casing steel（C110 steel） were investigated. The studied casing specimens are as follows： original casing, plastic deformation（PD）...The effects of plastic deformation and H2 S on fracture toughness of high strength casing steel（C110 steel） were investigated. The studied casing specimens are as follows： original casing, plastic deformation（PD） casing and PD casing after being immersed in NACE A solution saturated with H2S（PD＋H2S）. Instrumented impact method was employed to evaluate the impact behaviors of the specimens, meanwhile, dynamic fracture toughness（JId） was calculated by using Rice model and Schindler model. The experimental results show that dynamic fracture toughness of the casing decreases after plastic deformation. Compared with that of the original casing and PD casing, the dynamic fracture toughness decreases further when the PD casing immersed in H2 S, moreover, there are ridge-shaped feature and many secondary cracks present on the fracture surface of the specimens. Impact fracture mechanism of the casing is proposed as follows： the plastic deformation results in the increase of defect density of materials where the atomic hydrogen can accumulate in reversible or irreversible traps and even recombine to form molecular hydrogen, subsequently, the casing material toughness decreases greatly.展开更多
In high sour gas reservoir drilling process, it happens occasionally that high-strength drill pipe suffers brittle fracture failure due to stress corrosion cracking, and poses serious hazard to drilling safety. To sol...In high sour gas reservoir drilling process, it happens occasionally that high-strength drill pipe suffers brittle fracture failure due to stress corrosion cracking, and poses serious hazard to drilling safety. To solve this problem, this paper studied the stress corrosion cracking mechanism and infl uencing factors of highstrength drill pipe in sour environment with hydrogen permeation experiments and tensile tests. We simulated practical conditions in laboratory and evaluated the stress corrosion cracking performance of the high-strength drill pipe under conditions of high stress level. For the problems occurring in use of high-strength drill pipe on site, the paper proposed a technical measure for slower stress corrosion cracking.展开更多
基金Funded by the Construction of Key Disciplines for Young Teacher Science Foundation of the Southwest Petroleum University(No.P209)the Research Fund for the Doctoral Program of Higher Education(No.20105121120002)the National Natural Science Foundation of China(Nos.51004084 and 51374177)
文摘The effects of plastic deformation and H2 S on fracture toughness of high strength casing steel（C110 steel） were investigated. The studied casing specimens are as follows： original casing, plastic deformation（PD） casing and PD casing after being immersed in NACE A solution saturated with H2S（PD＋H2S）. Instrumented impact method was employed to evaluate the impact behaviors of the specimens, meanwhile, dynamic fracture toughness（JId） was calculated by using Rice model and Schindler model. The experimental results show that dynamic fracture toughness of the casing decreases after plastic deformation. Compared with that of the original casing and PD casing, the dynamic fracture toughness decreases further when the PD casing immersed in H2 S, moreover, there are ridge-shaped feature and many secondary cracks present on the fracture surface of the specimens. Impact fracture mechanism of the casing is proposed as follows： the plastic deformation results in the increase of defect density of materials where the atomic hydrogen can accumulate in reversible or irreversible traps and even recombine to form molecular hydrogen, subsequently, the casing material toughness decreases greatly.
基金Funded by the Program for National Science Fund for Distinguished Young Scholars of China(No.51125019)the National Natural Science Foundation of China(Nos.50904050,51244007)+2 种基金the Basic Projects of Sichuan Province(2011JY0106)the Department of Education Science and Technology Innovation Team Program of Sichuan Province(13TD0026)the Sichuan Distinguished Youth Fund(2013JQ0037)
文摘In high sour gas reservoir drilling process, it happens occasionally that high-strength drill pipe suffers brittle fracture failure due to stress corrosion cracking, and poses serious hazard to drilling safety. To solve this problem, this paper studied the stress corrosion cracking mechanism and infl uencing factors of highstrength drill pipe in sour environment with hydrogen permeation experiments and tensile tests. We simulated practical conditions in laboratory and evaluated the stress corrosion cracking performance of the high-strength drill pipe under conditions of high stress level. For the problems occurring in use of high-strength drill pipe on site, the paper proposed a technical measure for slower stress corrosion cracking.
