Abstract
The expanding demand for primary energy has pushed exploration and production activities towards more challenging environments, such as the north slope of Alaska, Siberia and deeper oceans. In many cases associated gas could be a limiting factor in the field developments. While stabilised oil could be transported by pipelines and/or tankers, the options for gas and associated gas is rather limited and/or not economical.
There are strict limitations on flaring due to environmental/economical concerns, and most of the available options for gas utilisation (e.g. gas to liquid, gas to wire, compressed natural gas…) require considerable CAPEX. Recently, we have proposed HYDRAFLOW, which is a Cold Flow solution for avoiding gas hydrate problems. This could provide a solution for gas transportation.
The concept of HYDRAFLOW is based on allowing/encouraging gas hydrate formation, but preventing their agglomeration and pipeline blockage by using chemicals and/or mechanical means. The aim is to eliminate/minimise the gas phase by converting it into hydrates and dispersing hydrates in oil and/or aqueous phase. Water could be added to maximise gas conversion into hydrates and/or adjusting the slurry viscosity. Furthermore, a loop concept has been developed where part of the liquid phase could be recycled, minimising chemical discharge to the environment.
As HYDRAFLOW basically converts gas into hydrates and transport it as slurry in a liquid phase, it could provide a solution for gas utilisation for fields where the ambient temperature and pipeline pressure are inside the hydrate stability zone. In this communication, after introducing the HYDRAFLOW concept, the latest results of laboratory tests at subzero conditions are presented as well as an economical evaluation and a pipeline transportation simulation on one of the West Siberian oil fields. These simulations demonstrate that the concept is viable, and suggest that HYDRAFLOW technology could offer significant benefits over existing flow assurance strategies, providing a novel low CAPEX/OPEX solution for gas utilisation.
