Subsea chemical storage and injection systems are a new technology that moves the chemical units from topside to subsea locations, close to the wells. It has been conceived for application on field development projects with long tiebacks, whenever the objective is to replace the expensive hydraulic umbilicals for chemicals distribution. Conversely, the new subsea technology needs only a power and communication link to the existing topside facilities. So that this can occur, a dedicated industrialisation programme was launched for developing all the building blocks of the technology to achieve a sufficient readiness level for the first industrial application. The core of the industrialisation has been the extensive qualification campaign, mostly based on experimental testing carried out in laboratory and workshop environments, as well as in simulated deep-water conditions. Due to the nature of the treated fluids, specific attention has been paid to the chemical compatibility testing of materials and fluids for long term applications in harsh environments. The available technologies have been reviewed through a comprehensive market assessment, to spotlight the gaps as well as the elements of novelty of the intended application. Several industrial partners have been engaged to jointly define and carry out relevant qualification plans. The basis of design for the development and qualification of equipment has been defined considering a range of possible applications in the subsea field development and subsea processing context. The information was used to build a map of the technology requirements including the chemical fluids to be managed, flowrate and injection pressure ranges. The map, combined with a set of process data and IMR scenarios, has been further elaborated to define the storage unit size, modularization philosophy and to set relevant reliability requirements. The qualification philosophy was based on the framework set by the international guidelines for technology qualification, i.e. DNV RP A203 and API 17 Q, through a documented risk-based approach. Whenever applicable, the components have been qualified to specific relevant standards, for instance API17 F and ISO 1817 for the electronic components and the effect of liquids on polymeric materials respectively. Programme execution included the construction of several prototypes of the key equipment: the subsea pump & motor unit, electrical actuator for small-bore valves, flowmeter and the storage unit. Most of the components were subject to endurance and cycle testing to provide quantitative data to support the results of the RAM analyses. In addition, the programme leveraged the control system components that have been industrialised as part of a previous qualification initiative addressing the requirements of several subsea processing applications. The paper will introduce the elements of technological novelty of the equipment and will describe the methodology, challenges and main results of the programme. The qualification activities will be completed by the end of 2020.

Subsea pipeline repair connectors have been used in the oil & gas industry for many years and are considered a valid and safe way of repairing major damages and restoring the original pipeline condition in case of an emergency repair; they can also be used for tie-ins to allow extensions by connection of new pipeline sections to an existing one and they have an extensive track record mainly on carbon steel pipelines but are fit also for stainless steel and duplex pipelines. The increasing number of subsea pipelines with internal CRA cladding which have been deployed in recent years and are foreseen in the future poses new technological challenges since conventional sealing solutions are not suitable for or have limitations in this specific application: in this case the repair connector not only needs to be designed to be compliant with the sour product but it also needs to protect the pipeline carbon steel wall from coming into contact with the internal fluid. This paper presents a new concept of a pipeline repair connector that has been developed from the beginning specifically to target repairs on sour service lines and in particular on clad lines. This innovative repair connector is based on a metal to metal sealing technology that offers permanent repair without any reduction of the pipeline's internal diameter, provides a versatile diver/diver-less solution, can deal with multiple wall thicknesses and can also be applied to other types of pipelines, such as those for sour service with internal corrosion allowance since it can manage pipe wall thickness reduction over time. The design of the mechanical connector has been carried out in compliance with DNV pipeline codes after a comprehensive technology qualification testing campaign under DNV certification and focused on medium size pipes. A full-scale 26″ prototype connector has been designed and fabricated for completing the qualification testing program including all required pressure and loading conditions. FEM analyses of the testing configurations have been carried out for comparison with test data so to validate the FEM models and extend results to other sizes within a predefined range. The matching between the experimental data and FEM calculations has allowed setting up a Type Approval process with DNV and, after a design effort covering various pipeline sizes and types, the connector will be certified for a wide range of large bore pipelines and design conditions and be ready for release to the market.

This paper presents a solution for subsea storage of chemicals, where the conventional solid barriers between the chemical and sea water are replaced by a liquid layer, forming a liquid stacking tower inside a vertical tank. It can deal with most of the chemical formulations, providing a pressure balanced system based on barriers that are inherently damage-free. The storage units are easy to integrate and maintain as their design is simple. The benefits of the technology are discussed, also providing an overview of the ongoing qualification programme.