An umbilical cable plays a vital role in Offshore Industries for exploration and exploitation of oil, gas and other mineral resources. It is widely used in many areas like telecommunication, power, remotely operated vehicles (ROV), seabed mapping, drilling and deep sea mining. Umbilical cable is the common terminology used for a sub-sea cable which is bundled with of power conductors for power transmission, fibre optic cables for signal & communication and strength members Generally this type of cables are designed for continuous operations at Offshore. The objective of this paper is to assess the changes in umbilical cable parameters like change in resistance, electrical insulation, fibre optic losses, cable elongation etc. which influence the reliability and safety of operation in off shore applications. Specific tensile load tests on the sample length of umbilical cables were conducted at in-house developed test setup/fixture. One specific sub-sea cable type was tested. The measured values of the aforementioned parameters will be useful in selection and sizing of correct cable to suit the particular sub-sea operations, considering safety, reliability and longtime operations. All the measurements were taken online during the testing process. The methodology of testing and the instrumentations for measuring various parameters is elucidated in the subsequent sections below. Testing of cable was carried out based on the DNV-RP-F401 (2012) guidelines. The test parameters measured will be used to access the different properties of the cable such as the conductor yielding point, cable elongation and the safe working limit of the cable etc. which are very important factors in determining the type of strength member, de-rating and conductor arrangement.
Umbilical are special type of sub-sea cables used in off shore industries for certain specific applications. Selection and sizing of such cables depend on certain important parameters specifically when it needs to handle a considerable amount of weight in vertically free suspended mode. In such case the cable has to undergo lot of dynamic loads which eventually gets exaggerated at higher sea states of operations. Certain parameters like tension at conductor yield, torisional stiffness, elongation, strength member material are important in sizing and selection of the cable. The tension test on umbilical cable was carried out by Vaz AM (1998) and load versus axial deformation was calculated. This paper brings out method of testing and characterizing the sub-sea cable for such offshore applications and load versus axial deformation was plotted for different loading conditions.
