Small bore connection

The aim of the study is to aid in formalizing the purpose, procedures, expectations and outputs from the SBB research projects. The projects aim at addressing the industry wide acknowledgement that small bore branches are predisposed to vibration induced fatigue when designs do not consider the probable risks. This is a relatively new method for MOQ tasked with providing a comprehensive, straight forward means of ensuring all SBC’s 2” and are continually evaluated in auditable manner.

The study provides guidance from the Energy Institute’s Guidelines for avoidance of vibration induced fatigue failure in practice pipework second edition of 2008 and, furthermore, the workflow presentation given by Bureau Veritas. However, there are inbuilt conservatism within the processes that have to be analyzed during the duration of these projects to ensure alignment with Fac. Eng. expectations. The projects’ main goal is achieved by analyzing 9 different locations which are split into 25 assets including wellhead, utility, production and flare. Further analysis is made on FDP-2005 installations and all free ended SBC which are 2” and below. In order to determine the SBC’s risk factors, COF shall be systematically applied. Close offshore monitoring of SBC’s with LOF valves is paramount; this is done in order to determine the pipe work’s ability to withstand vibrations (Energy Institute, p. 9).

Instrumental departments in the process include the recording department which is split into two teams, which operate simultaneously in all locations to make all necessary offshore survey; moreover, there is the monitoring department whose main task is monitoring the SBC and development of all offshore surveys. It is appropriate to have two separate recording and monitoring teams. A design team may be formed whenever necessary while the installation team is tasked with MOQ offshore constructions under fabrication contractors. In order to improve knowledge retention by the various teams, it is vital that the teams are ‘ring fenced’ from one another. The project process includes onshore planning, installation and familiarization of the different teams, offshore recording of all free ended SBC’s that are 2” and below, analysis of recordings, reporting and population of the spreadsheets. Moreover, the process entails onshore preparation of bracing scopes of works and design of the same, close monitoring of the SBCs, handover of design packages for MOQ contractors and installation of prefabricated bracing by MOQ. Essentially the procedure makes use of equipment such as digital cameras, visibility scale bars, laptops with backup facilities, remote hard drives for data storage and vibration data loggers and calibration shakers (Energy Institute, p. 16).

Once sufficient information is collected and recorded, LOF calculations are made according to the E.I.G MathCAD which are eventually saved using unique identification numbers or separate spreadsheets where necessary. Calculations should be carried out by the recording staff to ensure the plant’s historical knowledge is not lost. In case of alternative solutions by the designer, checker and DDE, engineering judgment should be applied to ensure accuracy. This occurrence should be indicated in the master spreadsheets. After the reporting phase, a series of branches requiring bracing is prepared and a new project initiated within the DDE. All SBCs are monitored to determine factors that precipitate natural frequency and damping of the material. Each free end of the SBC is struck using the same force and any lines seen to vibrating are reported to the MOQ PE and necessary vibration measures put in place (Energy Institute, p. 23).

Work cited

Energy Institute.  Guidelines for avoidance of vibration induced fatigue failure in process

pipework (2nd ed.) London: EI. 2008. Print.


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