The offshore oil and gas industry is continuing to push into deeper water and more onerous environments, using increasingly bigger vessels and equipment. This, combined with more erratic and unpredictable global weather patterns has increased uncertainty in offshore production operations.Monitoring mooring lines can help reduce this uncertainty by providing tools to calculate fatigue accumulation, based on tension measurement, during major storm events. This greater understanding helps to optimise inspection and maintenance schedules and assess the likelihood of future mooring line failures. Added to this, most FPSOs are only designed to cope with the failure of a single line. If this is not detected then increasing loads on the remaining lines may result in additional failures. This is regarded as a system failure and could lead to the FPSO breaking away from its moorings and drifting off station. This can have consequences for both well control and riser integrity, resulting in huge costs for operators. Unless the operator inspects on a regular basis or monitors in real time it is impossible to know for certain whether all mooring lines are in place.A popular technique for monitoring mooring systems is to measure mooring line angle (using accelerometer based inclinometers), and use this measurement to infer theoretical mooring line tension. Whilst these systems are effective at alerting operators to a line failure, the fact that tension must be inferred requires a certain amount of uncertainty in the calculation. This uncertainty is difficult to quantify and thus has been little understood. Also, the use of shackle load cells can give varying results depending on where the chain is sitting on the load shackle. These often fail in service due to the dynamic nature of the mooring line and the typical shackle location within it. This paper documents the sea trial of a new mooring line technology capable of measuring both mooring line angle and direct line tension. The improved accuracy associated with direct monitoring of line tension can help reduce levels of uncertainty in offshore operations and thus reduce future levels of conservatism in design and analysis models. This can help save costs and increase efficiency for future operations, whilst also helping support safety strategies.

Flexible riser systems are widely adopted by the industry as solutions to interconnect subsea equipment and pipelines to floating production units. Their unique ability to withstand motion and their ease of installation make flexible riser systems a favorable solution when compared to conventional rigid riser systems. Historically, the integrity of flexible risers has been an issue and it is therefore critical that risers are designed and qualified according to the current continually challenging operating conditions. Flexible riser integrity management and complex riser qualification processes have consequently become the main focus for major operators in guaranteeing the safety of offshore operations to reduce the risk of human, environmental and material losses. The industry has requested several qualification tests to verify the manufacture of the new flexible risers, e.g. a dynamic fatigue test, which is required to qualify the flexible pipe for deepwater installation. A means of monitoring the flexible riser response is also required in order to record the integrity of the riser and assist operators in identifying and implementing suitable remedial action, ranging from inspection plans through to riser replacement, as necessary. Based on these requirements, Pulse Structural Monitoring developed an armour wire failure monitoring system and, after extensive testing including offshore tests, validated the system through a full-scale dynamic test cycled to damage 1.0 (safety factor 10), performed by Wellstream. This test continued for more than one year and validated the monitoring system that was able to detect 100% of the wire breaks. This paper presents the results and conclusions from the blind test conducted to qualify the monitoring system. The results demonstrate that the monitoring system was able to detect the wire breaks caused during the full-scale dynamic test and would be a suitable solution to employ on flexible risers to detect failures in the field. Introduction Flexible risers are responsible for oil and gas transportation of approximately 80% of Brazilian offshore production and are mainly used in highly dynamic loaded environments, where outstanding fatigue performance is essential. Flexibles are commonly used in today's harsh ultra deepwater developments and play an outstanding role in deepwater offshore operations worldwide. Given that the depths are increasing where flexibles operate, environmental conditions are becoming ever more challenging, and the engineering challenges in designing and manufacturing risers are also increasing. There are more than 1,200 flexible risers currently in use offshore Brazil whilst over 1,000 flexible risers are operational in the North Sea. A complex engineering process takes place for the design and fabrication of flexible risers, based on presumptions about environmental loading conditions and the specific requirements of the application over its lifetime. As production expands into increasingly deeper water depths, more advanced riser designs and qualifications are required from offshore operators.

The development of deepwater oil fields based on a production platform with dry trees, connected to a Floating Production Storage and Offloading (FPSO) vessel, has proved to be technically and economically attractive. However, a key issue for the practical implementation of this production concept is the availability of a cost-effective oil and gas transfer riser solution. The use of conventional catenary or self-standing riser technologies is sometimes avoided by operators due to high costs and flow assurance issues. To counter these problems operators are seeking a cost-effective solution for fluid transportation between two vessels at a water depth close to the surface. This type of riser system has been used successfully in benign environments like West Africa and is now being considered for harsher environments such as offshore Brazil. 2H Offshore conducted a preliminary feasibility study encompassing installation and in-service dynamic response, to prove the technical feasibility of a system composed of a group of large diameter free-hanging flexible pipes, required to connect two platforms offshore Brazil. The paper demonstrates that this configuration is practical and simple because it can be designed with regular flexible pipe and standard components. Additionally, it can be deployed using conventional flexible pipe laying vessels. Introduction The design of a riser solution to connect a spread moored Floating Production Storage and Offloading vessel with a dry completion platform (Tensioned Leg Wellhead Platform - TLWP) is a complex engineering process which is being sought by operators as a novel and cost effective solution for fluid transportation. The objective is to transfer the produced oil from the TLWP to the FPSO for processing, storage and later off-loading to a shuttle vessel. Additionally water is injected from the FPSO back to the TLWP and into the wells. This type of system has been proposed by several companies and is referred to as a " Mid-Water Transfer System??, hereinafter referred to as MWTS. Due to the increasing demand for riser solutions in deep water developments, the use of conventional catenary risers (Flexible/SCRs) or Free Standing Hybrid Riser (FSHR) technologies, are sometimes avoided due to their cost. This paper evaluates a novel and cost effective solution for fluid transportation between the two rigs, considering flexible risers which are suspended close to the water surface. This allows the use of cheaper flexible risers with low collapse pressure limits which, reduces the cost of the riser system. 2H Offshore has conducted a preliminary feasibility study to prove the technical feasibility of a system composed of a group of large diameter free-hanging flexible pipes required to connect two platforms in offshore Brazil. The study covers the installation, in-service dynamic response and slugging behaviour of the system.

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