Authors: Young Jin Choi, Young Shin Lee, Jae Hoon Kim, Won Shik Park, Hyun Soo Kim
Abstract: The hot gas casing of the gas turbine has operated in high temperatures and thermal
gradients. The structure safety of hot gas casing will be highly depend on the thermal stress. In this paper, flow and thermal stress analysis of the hot gas casing is carried out using ANSYS program. The obtained temperature data by flow analysis of hot gas casing is applied to the load condition of the thermal analysis. The thermal stress analysis is carried out the elastic-plasticity analysis. The pressure, temperature and velocity of the flow and thermal stress of the hot gas casing are presented
169
Authors: Zhi Qian Xu, Xiang Zhen Yan, Xiu Juan Yang
Abstract: Considering the differences of pressure and temperature along well depth, the distribution law of casing inner wall corrosion rate was calculated with the Norsok model. According to the measured pressure values, the law of well pressure changing with the time can be obtained with the empirical method or the derivative curve method. Then the changing laws of the corrosion rate and the thickness reduction of casing inner wall are derived during the casing service life. Finally, the time-varying characteristic of casing internal pressure strength influenced by corrosion is researched.
555
Authors: Xian Yong Zhang, Jin Feng
Abstract: Reliability of eccentric wear casing was studied by Monte-Carlo and finite element method. In different internal pressures, calculated reliability of P110 steel grade 9 5/8 inches casing with wear depth less than 0.5 times wall thickness. The influence of different cement ring circumferential missing amount and stratum pressures on wear casing reliability were presented. The results provide basis for casing safety evaluation and reasonable replacement.
1362
Authors: Yan Bin Qin, Yi Hua Dou, Xiao Zeng Wang, Jing Wen Yang
Abstract: In deep wells and ultra-deep wells the complex geological conditions often result in serious casing wear. In order to be able to accurately measure the wear efficiency and friction coefficient required in the process of the prediction of casing wear, a ring-block drill pipe and casing wear tester is specifically designed and produced, the scheme of tester is proposed, and the design of structure, driving device, and the detecting system of the friction and contact forces of tester is completed. Adopting the ring block drill pipe casing wear tester and simulating down hole conditions P110 casing wear experiments are finished. The results show that the ring block drill pipe casing wear tester meets the requirement of down hole casing wear experiment. P110 casing wear efficiency decreased with the increasing of wear time. The friction coefficient between the P110 casing and the drill pipe sample is about 0.25.
3582
Authors: Yi Hua Dou, Hai Ling Zhou, Xiao Zeng Wang, Jing Wen Yang
Abstract: Worn casing often appears in deep and ultra deep well which effected by many factors in drilling process, such as casing grades, drilling fluid density and contact forces, and so on. Using polysulfide water-based drilling fluid, simulating the actual bit pressure, rotary speed and other influencing factors, the wear experiments of TP140,VM140,P110 and N80 casing which often are adopted in the oilfield are completed, and the wear efficiency and friction coefficient which are adopted to predict down hole casing wear are obtained. The experimental results show that the higher casing steel grade, the greater the hardness, the better wear performance. The experiments can help deepen the understanding of the mechanism of casing wear. Adopting the results which are obtained in research the prediction accuracy of down hole casing wear can be improved.
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