Natural gas is currently seen as the energy source that will help transition from a world that relies heavily on fossil fuels to one that is dominated by renewable energy. As a result, Oil&Gas companies are working hard to develop gas fields, even those located in difficult subsea areas such as reservoirs that are far from shore and/or located in deep or ultra-deep waters.
One way to exploit these fields is by using long subsea tiebacks to shore. However, during such long transport, chemical and physical phenomena can occur that could cause production to end prematurely. This is mainly due to the lack of pressure in the depleted reservoir and/or liquid accumulation in the export lines causing flowrate reduction and/or flow instabilities due to accumulation at low points.
To overcome these Flow Assurance issues, when the field architecture is not sufficiently flexible (i.e., the number and diameters of the export lines are not sufficient), subsea process solutions such as Gas/Liquid separation or subsea compression are generally considered. However, even if these two solutions could bring significant benefits, they do not fully solve the issue linked to liquid accumulation in export lines.
For these reasons, SUBGAS, a subsea process station performing gas dewpointing in subsea conditions, has been developed. This station can be deployed in a wide range of application cases for removing liquid and condensable components from the production gas coming from wells. The treated gas is sent from the station in the export line(s) while the liquids and condensable components are pumped to shore via a dedicated line. Thanks to this configuration, the pressure drops in the export gas line(s) are reduced, hydrate or wax formation risk is avoided or significantly reduced, and the operability of the line is improved as there is no or a very low amount of liquid.
From a technological standpoint, this station can be considered an innovative solution that can help overcome some of the challenges associated with subsea tiebacks.
