Efficiency and Pressure Recovery in Hydraulic Jet Pumping of Two-Phase Gas/Liquid Mixtures
- Baohua Jiao (U. of Tulsa) | Roger N. Blais (U. of Tulsa) | Zellmir Schmidt (U. of Tulsa)
- Document ID
- Society of Petroleum Engineers
- SPE Production Engineering
- Publication Date
- November 1990
- Document Type
- Journal Paper
- 361 - 364
- 1990. Society of Petroleum Engineers
- 4.1.5 Processing Equipment, 3.1.3 Hydraulic and Jet Pumps, 4.1.9 Tanks and storage systems, 5.3.2 Multiphase Flow, 7.4.4 Energy Policy and Regulation, 3.1 Artificial Lift Systems, 4.3.4 Scale
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Hydraulic jet pumping of gas/liquid mixtures was studied experimentally, and a mathematical model is proposed to extend the standard single-phase model for predicting efficiency and pressure recovery to suction fluids with gas/liquid ratios up to 2,200 pressure recovery to suction fluids with gas/liquid ratios up to 2,200 scf/STB. The experimental program comprises 616 low-pressure tests in a plastic model pump designed for flow visualization and measurement of plastic model pump designed for flow visualization and measurement of pressure profile along the throat and diffuser, and 373 high-pressure tests pressure profile along the throat and diffuser, and 373 high-pressure tests on a stock pump. For the high-pressure tests, power fluid was supplied at 200 to 3,000 psi and at 200 to 860 B/D; air was supplied from 0 to 185 Mscf/D. Discharge pressures ranged from 800 to 2,000 psi.
The mathematical model extends a previous model that describes single-phase performance from mass and energy conservation. The empirical loss coefficients for the nozzle and throat/diffuser are replaced by a nondimensional expression that varies as three dimensionless parameters: nozzle-to-throat area ratio, discharge-to-power-fluid pressure ratio, and air/water ratio (which usually is in conventional units of cubic feet per stock-tank barrel but is, of course, basically dimensionless). The loss coefficient for the nozzle is constant, but for the throat/diffuser it is a constant plus a product of a constant times the three parameters, each to a power. power. Compared with the standard model, which always overpredicts pressure recovery and thus efficiency, the new model reduces the standard error of the estimate to 18% of its former value.
The accepted theory of jet-pump operation is derived from single-phase assumptions. Power fluid and suction fluid are assumed to be similar liquids. Since Rankine developed the basic theory of operation in 1870, using concepts of mass and energy conservation, most investigators have grappled with realistically assessing frictional losses, not with addressing operation when suction fluid is a multiphase mixture. Notable among these early studies are those of Gosline and O'Brien and Cunningham. Petrie et al.'s standard installation design model cautions users to apply Petrie et al.'s standard installation design model cautions users to apply it only when free gas is limited to less than 10 scf/STB. Corteville et al. recently published results of a study on two-phase performance using kerosene and N2 at power-fluid pressures up to 1,160 psi.
The two-phase model reported here is based on experiments con-ducted with water as a power fluid and with water and air as the suction fluid in a surface test loop operated at field-scale pressures and flow rates. This model extends the applicability of the standard design model by adjusting an empirical loss coefficient for the throat and diffuser. Rather than being a dimensionless constant, this coefficient becomes a function of three dimensionless parameters - one describing pump geometry; another, the operating pressures; and a third, the gas/liquid ratio. Because all tests were conducted with air and water, no empirical adjustment for physical properties of the suction or power fluid is attempted. The work reported properties of the suction or power fluid is attempted. The work reported here is drawn from Refs. 6 and 7, which provide more detailed information.
Theory and Definitions
The principal component of a jet pump (Fig. 1) is a nozzle fitted to a throat/diffuser section. Power fluid, usually clean crude from a surface pump, is injected into the nozzle under high pressure, from which it issues pump, is injected into the nozzle under high pressure, from which it issues at high speed. The resulting high-speed jet is at low pressure by Bernoulli's principle. Thus, it entrains suction fluid, and the combined mixtured is allowed to decelerate in a cylindrical throat and then passes through an expanding, conical diffuser. Pressure is recovered as the slowing fluid swaps kinetic energy for pressure.
The quantitative theory of jet-pump performance is based on mass and energy conservation. Cunningham gives a complete derivation, and Petrie et al. provide an abridged form. This steady-state model assumes uniform properties of a single-phase, incompressible discharge fluid resulting from properties of a single-phase, incompressible discharge fluid resulting from complete mixing of power and suction fluids in an axially symmetric, simplified pump geometry.
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