Quick Connection Couplings in the Permeated Gas Relief Systems of Flexible Riser End Fittings

The objective of the paper is to present a new conception for the permeated gas relief system of flexible riser end fittings. The new conception is based on a multi-function gas relief system, depending on the requirements established by the operators. The main function of the system is to relief the accumulated gas in the riser annulus. Due to the interconnection of the annulus to the external environment through the top end-fitting, other functions of this system may be required such as to allow fluid injection into the annulus or vacuum testing, for example. The presented conception of the permeated gas relief system is based on the usage of quick connection and disconnection couplings. It was firstly developed focusing the particular cases of submerged top end fittings but it can be applicable in both situations where the riser top end fitting is located either at an emerged or a submerged position. In the course of its development, the conception has led to different patterns of the system, depending on the different required functions. The gas relief system was conceived in order to allow — in an easy and quick manner, without the risk of flooding the annulus with seawater — the execution of typical operations like those required for installing a monitoring and control system, for injecting fluids into the annulus, for vacuum testing or, additionally, for removing any damaged relief valve from the end fitting in order to substitute it for a new one. The paper describes the components of the gas relief system for each required function. The idea is to have many interchangeable items of standardized sets that meet specific requirements, case by case. The performance of the permeated gas relief system is an important issue for flexible riser integrity.