Bending Deformation and Ultimate Moment Calculation of Screen Pipes in Offshore Sand Control Completion

Peer reviewed: TrueFunder: the National Ministry of Industry and Information Technology Innovation Special Project-Engineering Demonstration Application of Subsea Oil and Gas Production System-Subject 4: Research on Subsea Christmas Tree and Wellhead Offshore Testing Technology; Grant(s): MC-201901-S01-04Horizontal wells, extended-reach wells, and multi-branch wells were often used to exploit subsea oil and gas efficiently. However, during the sand control screen completion of those wells, the sand control screen pipe was easily deformed. Failure occurred when passing through the bending section due to the large bending section in the wellbore trajectory. A parametric analysis model of the screen pipe was established based on ABAQUS and Python software under pure bending load first. Then, deformation patterns and mechanisms were identified and discussed. The effects of parameters on the screen pipe bending deformation patterns and the ultimate moment were analyzed. Finally, an empirical formula for calculating the ultimate moment of the screen pipe was established. The results showed that the deformation of the screen pipe was complex, and three deformation patterns were related to the hole parameters. Due to an increase in the diameter and number of circumferential and axial holes, the ultimate moment of the screen pipe gradually decreased, and the circumferential holes had a more significant effect on the ultimate moment than the axial holes. The established empirical formula could accurately calculate the ultimate moment of the screen pipe, and the average difference between the formula and numerical simulation results was 3.25%.</jats:p

Application of dynamic models during design of a hybrid diesel-fuelled PEMFC system with fuel reformer

Design of a hybrid diesel-fuelled PEMFC system for application onboard naval ships is challenging for mul-tiple reasons. The fact that new technologies are used is only one of them. Less obvious, but also very challeng-ing is for instance choosing the ratio between installed battery capacity and fuel cell power. This ratio is a typi-cal design issue for hybrid systems. Dynamic models are necessary to find an optimal solution to this issue. In this paper the developed dynamic models are discussed, some in more detail, after which simulation results will be shown

Analysis of residual stresses resulting from the surface preparation for X-ray diffraction measurement

There is no consensus in the literature on the need to remove preprocessing layers from the material prior to the measurement of residual stresses by X-ray diffractometer. Thus, the purpose of this work was to evaluate the residual stresses induced by material preprocessing and its evolution during the preparation of the surface by electrolytic removal. Sample surfaces were pre-processed by grinding and sandblasting and the resulting residual stresses were measured by X-ray diffractometry. At each removal stage, the evolution of residual stresses, hardness and microstructure of the surface were verified. It was concluded that different preprocessing methods can induce surface residual stresses of either tension or compression, reaching different depths. Removal by electrolytic method of the modified layer has shown itself capable of reducing significantly the magnitude of the residual stresses induced by preprocessing. On the other hand, the depth of deformed grains or surface hardness proved to be incapable of predicting the depth of induced residual stresses. Finally, it was discussed whether or not the layers removed by this method reveal the subsurface stresses and if the removal should take place before or after a second processing.First Online: 29 January 2018Funders: Brazilian National Council for Scientific and Technological Development (CNPq), 302863/2016-8 and 149308/2014-0; Minas Gerais State Agency for Research and Development (FAPEMIG), TEC—APQ-01992-15.</p