Abstract
This paper aims to present the results of long-distance tieback sizing connecting a manifold located 45km away from an FPSO through a multiphase flow steady-state simulation to present recommendations for sizing flow lines in terms of diameter, thermal insulation, flow, pressure, and service temperature, as well as the requirements for multiphase pumping (power, operating points, rotation, flow regime, fraction of gas in the suction, pressure differential, etc.).
With the results of the simulations, it was possible to observe the behavior of the fluid flow along the flowline and riser. In addition, we found an arrangement of multiphase pumps, based on an available catalog, that would allow the transport of the fluid to the FPSO. We faced the challenge of finding the adequate flow velocity, ensuring that the residence time as well as the adequate head loss of the fluid along the entire pipeline was sufficient to avoid temperatures lower than the paraffin formation temperature.
Based on stationary simulations, it was found that the flow temperature remains above 40 °C for higher production capacities. However, it is important to highlight that by reducing the production of the wells, the flow temperature may reach the paraffin point.
Another aspect observed in the stationary simulations was that the flow of the fluid tends to present a "slug" type behavior in the ascending section of the riser, especially close to the point of arrival at the FPSO.
