Casing deformation affects the implementation of stimulation and development measures of oilfields directly;however, the reshaping forceand torque usually are determined by experience when the deformed casing is repai...Casing deformation affects the implementation of stimulation and development measures of oilfields directly;however, the reshaping forceand torque usually are determined by experience when the deformed casing is repaired with the spinning reshaping technology;if the repairingforce or torque is too large, it will result in the damage of casing and cement sheath as well as sticking accident. So, the collapse experimentswere performed on the YAW-200 pressure testing machine by using one production casing which is often used in the oilfield and then thereshaping test of deformed casing (C110) was performed in turn by using two spinning casing swages of which the diameter is 126 mm and129 mm respectively. The continuous rotator and thrust bearing were used to provide the torque and reshaping force respectively in the repairingprocess. The reshaping force and torque required to reshape the deformed casing, the deformation law and the springback value of deformedcasing were obtained. Test results show that the diameter differential between the two spinning casing swages is reasonable. Furthermore, inorder to ensure the safety and reliability of the implementation of post-production technologies, the mechanical properties of deformed casingbefore and after reshaping were tested. It was found that all the mechanical parameters of the deformed casing after reshaping reduced, whichresulted in the decrease of the strength of the reshaped casing. These research achievements would provide important experimental data inoptimizing the structure and construction parameters of spinning casing swages.展开更多
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
文摘Casing deformation affects the implementation of stimulation and development measures of oilfields directly;however, the reshaping forceand torque usually are determined by experience when the deformed casing is repaired with the spinning reshaping technology;if the repairingforce or torque is too large, it will result in the damage of casing and cement sheath as well as sticking accident. So, the collapse experimentswere performed on the YAW-200 pressure testing machine by using one production casing which is often used in the oilfield and then thereshaping test of deformed casing (C110) was performed in turn by using two spinning casing swages of which the diameter is 126 mm and129 mm respectively. The continuous rotator and thrust bearing were used to provide the torque and reshaping force respectively in the repairingprocess. The reshaping force and torque required to reshape the deformed casing, the deformation law and the springback value of deformedcasing were obtained. Test results show that the diameter differential between the two spinning casing swages is reasonable. Furthermore, inorder to ensure the safety and reliability of the implementation of post-production technologies, the mechanical properties of deformed casingbefore and after reshaping were tested. It was found that all the mechanical parameters of the deformed casing after reshaping reduced, whichresulted in the decrease of the strength of the reshaped casing. These research achievements would provide important experimental data inoptimizing the structure and construction parameters of spinning casing swages.
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.
