CHOKE PERFORMANCE

Baxendell

• Baxendell’s correlation linking the rate of multiphase flow through a choke and the upstream pressure – and fundamentally an update of the Gilbert correlation is:

Gilbert

• Gilbert developed a generalized correlation based on data from flowing oil wells. The rate of multiphase flow through a choke and the upstream pressure can be correlated by the following relationship

Ros

• The rate of multiphase flow through a choke and the upstream pressure are, according to Ros on the basis of Gilbert’s and other prior work, correlated by the following relationship:

• Achong• Achong updated Gilbert’s relationship on the

basis of data from oil wells. The rate of multiphase flow through a choke and the upstream pressure are:

Multiphase Flow• Ashford-Pierce: Developed a correlation

specifically describing multiphase flow through safety valves and tested it against field data. Their correlation has the form:

This relationship applies both at and above the critical pressure ratio, .Ashford and Pierce further define the critical pressure ratio, , as

Assuming critical flow in the choke throat, the downstream pressure and fluid velocity can be calculated, and with the latter plus the produced fluid ratios, the mass flowrate of each phase is obtainable.

• References• Achong, I., "Revised Bean Performance Formula for Lake Maracaibo

Wells", internal co. report, Shell Oil Co., Houston, TX, Oct 1961 • Ashford, F.E. and Pierce, P.E., "Determining Multiphase Pressure Drops

and Flow Capacities in Down-Hole Safety Valves", SPE Paper No. 5161, J. Pet. Tech., Sep 1975, 1145

• Baxendell, P.B., "Bean Performance – Lake Maracaibo Wells", internal co. report, Shell Oil Co., Houston, TX, Oct 1967

• Gilbert, W.E., "Flowing and Gas-Lift Well Performance", Drill. & Prod. Practice, 1954, 126

• Omana, R., Houssiere, C. Jr., Brown, K.E., Brill, J.P., and Thompson, R.E., "Multiphase Flow Through Chokes", SPE Paper No. 2682, paper presented at Annual Fall Meeting of the SPE of AIME, Denver, CO, Sep 28 – Oct 1, 1969

• Ros, N.C.J., "An Analysis of Critical Simultaneous Gas-Liquid Flow Through a Restriction and Its Application to Flowmetering", Appl. Sci. Res. (9), 1960, 374

Choke Sizing

Liquid Mass Flow

Rawlins-Schellhardt

Szilas

Omana et al.

• Omana et al. carried out field experiments with natural gas and water flowing through restrictions. Carrying out a dimensional analysis, Omana derived the following correlation