Multiphase flow models for the oil and gas industry are required to investigate and understand the co-current or counter-current flow of different fluid phases under a wide range of pressure and temperature conditions and in several different flow configurations.
To compliment this theoretical effort, experimental measurements are required to verify multiphase flow models under controlled conditions and assess their range of applicability. This is why there exists a large number of multiphase flow loops around the world.
However, there are numerous varieties of multiphase flow occurrences due to differences in pressure and temperature, fluid types, flow regimes, pipe geometry, inclination and diameter, and whether the flow is steady-state or transient.
Consider the example of hydrocarbon producing fields in the North Sea. Typical parameters for an oil well in the northern basins are as follows: production rate of 800–1600 cubic meters per day, tubing diameter of 0.102–0.130 meters, reservoir depth of 3000–3500 meters, oil density of 825–930 kilograms per cubic meters, gas-oil-ratio of 100 standard cubic meters per standard cubic meters and water cut up to 90%. For a gas well in the southern gas basin, the typical parameters become: initial production rate of 0.7 to over 2.8 million standard cubic meters per day, tubing diameter of 0.114–0.140 meters, reservoir depth of 2500–3500 meters and initial liquid-gas-ratio of less than 1 to over 30 standard cubic meters per million standard cubic meters. The operational pressure at the wellhead may reach up to 10 MPa and reservoir pressures can be as high as 30 MPa. Furthermore, not only do well performance values vary considerably across the world and, they also vary with time for the same field.
Building a flow loop that reproduces real hydrocarbon wells, including the reservoir inertia and the complex heat transfer process taking place between the wellbore and the reservoir, is not feasible. Thus, downscaling of typical field parameters is necessary for the study of multiphase flows at laboratory conditions.
This paper presents a critical review of multiphase flow loops around the world, highlighting the pros and cons of each facility with regard to reproducing and monitoring different multiphase flow situations.
The authors suggest a way forward for new developments in this area.