Multiphase Flow Helico-Axial Turbine: Applications and Performance

Abstract

Following the installation in production fields of several tens of Two Phase Helico Axial Pumps, IFP and DBGP have recently launched a R&D program for the development of Two Phase Helico-Axial Turbines. These turbines may be used in many process applications in replacement of let down valves for energy recovery but also to increase the cooling duty or the liquid production. They may also be used in systems including a two phase separator with single phase expanders / turbines in view of reducing the number of equipment, space and weight. These turbines, suitable for all gas fractions, may find applications in the production of hydrocarbons (HP/HT wells, fractured reservoirs, oil stabilisation, electricity production in remote areas) but also in hydrocarbon treatment or in gas liquefaction. These applications cover a broad range in flow rate, pressure, temperature, gas fraction and fluid composition. A two phase helico-axial turbine prototype has been tested during the present year confirming the expected hydraulic performance. The hydraulic efficiency was found satisfactory to provide significant energy and liquid recoveries in many applications. Introduction Multiphase pumping is a long-established activity at IFP. First works were initiated in the seventies to extend the application of downhole electrical pumps. In the mid-eighties, multiphase pumping raised a renewed interest to transport the production of subsea satellite fields. At that time, subsea satellite developments were frequently substituted to stand-alone platforms in the North Sea to reduce offshore development costs. As tied-back distances to existing facilities were limited between 15 and 20 km due to the available natural reservoir pressure, multiphase pumps were a possible means of increasing these distances by adding energy to the liquid-gas mixture (Falcimaigne, 1992). After an extensive test programme on an IFP multiphase loop to investigate the hydraulic and mechanical behaviour in steady-state and slug flows, the P300 pump prototype was tested in 1991. This prototype is still in service in the IFP experimental loop, twelve years later, to boost multiphase mixtures. In 1994, first field applications of the Poseidon technology were characterised by relatively low flow rates and powers. Typical examples are the pump installed in the TotalFinaElf Pecorade field, in south of France, with a capacity of 360 m3/hr and drive power of 600 kW (Figure 1.1 - Falcimaigne et al., 1994, Leporcher and Taiani, 1995), or the pump installed in the Statoil Gullfaks A Platform in the North Sea with a total capacity 200 m3/hr and drive power of 750 kW (Vangen et al. 1995). A subsea helico-axial turbo-pump was also installed in 1994 at the Draugen field in the North Sea by Norske Shell. The progressive accumulation of field experience secured the oil operators to apply the technology on a larger scale. The power of recent Poseidon pumps reaches 4.5 MW for the TotalFinaElf Dunbar field in the North Sea and 6 MW for the Youkos Priobskoye oilfield in Siberia (total flowrate capacity : 3300 m3/hr). At present, helico-axial pumps are the largest multiphase pumps in the world both in capacity and power, and also the deepest in the world for subsea applications (750 m water depth in Ceiba field, Gulf of Guinea).

Performance Evaluation and Dimensional Analysis of Multistage Helicoaxial Pump for Two-Phase Flow

“…However, successful field trials and its ability to handle high GVF have made helicoaxial pumps a well-established alternative to conventional mixed-flow pump technology. Few studies have been focused on understanding the two-phase flow behavior and performance of the pump [10][11][12][13][14][15][16][17][18][19], however, not much has been done on modeling and predicting the performance of helicoaxial pumps operating with two-phase flow. The objective of this study is to evaluate the two-phase flow performance of a 4-stage helicoaxial, including two different liquid viscosities for a wide range of GVFs, and to develop dimensionless numbers to extend the affinity laws using homogeneous flow properties.…”

Shape Optimization of Helico-axial Multiphase Pump Impeller Based on Genetic Algorithm

“…[1] Helico-axial multiphase pump, which hold the advantages of larger flowrate, abiding grit and so on, is one of two reliable multiphase pumps. [2] The shape of helicoaxial multiphase pump, which usually can be optimized adopting design and experiment by turns, is one of the most important determinants. However, with the development of statistical optimization techniques and computational flow dynamics (CFD), we can optimize turbo machinery blade and reduce the experimental expenses combine optimization algorithm, such as Genetic algorithm (GA), with CFD.…”