Abstract
The production from an entire oil field, or a substantial field area can be achieved by using multiphase pumps (MPP), either on their own or in conjunction with some well activation techniques (electro submersible pumps, gas lift, etc). MPP are applied for oil fields with a GOR generally in the range of 100 to 1000 scf/bbl, extending sometimes to higher values.
It can be seen from this paper that MPPs can realistically be considered to represent a viable and proven solution for oil field developments up to about 250,000 bopd. This is due to the development of higher capacity helico-axial pumps which are now capable of handling total volumetric (actual flow at pump inlet: oil, gas and water) capacities in excess of 500,000 bpd (3,300 m3/h).
The use of MPP is especially advantageous for remote fields in inhospitable environments where unmanned facilities are preferred.
The pump is of the barrel casing design with an axially split inner casing, incorporating conventional mechanical seals and bearings. A pressurised seal system (similar to a standard Plan 53 system) prevents gas leakage or solid particles contaminating the bearing area and ensures that a liquid film is always present at the seal faces even when the pump is operating under dry running conditions. An overpressure of approximately 5-10 bar is maintained between the seal fluid circuit and the product side of the mechanical seal.
The inner casing and hydraulic components is generally supplied as a cartridge or pull-out block for A case is described where four high capacity and high power (up to 8,000 HP or 6,000 kW) helico-axial multiphase pumps have been selected to overcome a pipeline capacity restraint at the Priobskoye oilfield in Siberia. This field is operated by JSC Nefteyugansk, part of Yukos.
