Page 79 - Handbook Of Multiphase Flow Assurance

74 4. Hydraulic and thermal analysis

• Multiphase flow meter
• Water injection pump with limits per rock fracture gradient

Hydrodynamics of multiphase flow

Multiphase flow pressure drop—Vertical vs horizontal
Modern hydraulic analysis methods rely on software packages using mass and momen-
tum conservation equations with equations closure relationships. The closure relationships
constitute the commercial know-how of the vendors. Closure relationships are correlations
based on experiments or field data, which complete the system of equations for conservation
of mass and momentum required to calculate fluid motion. The relationships are being con-
tinuously updated based on field measurements and research data. Software is also regularly
updated to improve the accuracy of predictions.
A good summary of the basis relationships in multiphase flow is given by Hetsroni (1982).
The book presents the equations for single phase flow, two-phase flow, flow with particles,
interaction of interface with particles, liquid film condensation, drag reduction and measure-
ment techniques.
A good discussion of closure relationships is presented by Roullier et al. (2017). A more de-
tailed description of the overall multiphase flow simulator design is provided by Jansen (2009).
The summary for multiphase flow pressure drop correlations for vertical flow is provided in
the monograph by Brill and Mukherjee (1999). Many of these correlations are still in use today.
Variety of flow regimes have been identified by researchers over the past century. Few key
ones are illustrated below in Fig. 4.1 for horizontal and vertical flow. Inclined flow researchers
occasionally use terms froth or pseudo-slug which have more gas entrained in liquid slug and
are similar to churn.
Each flow regime represents a progressively increasing level of energy dissipation, as re-
flected by higher amounts of liquid droplets entrained into the gas phase. With higher pres-
sure, droplet entrainment increases.
Inclined flow tends to have a stratified flow pattern going downhill and slug flow uphill.

FIG. 4.1 Illustration of multiphase flow regimes.