Page 522 - Standard Handbook Petroleum Natural Gas Engineering VOLUME2

478 Production

(text continued fim #age 473)
Then the total pressure gradient is

= -2(1+ 75H,)(f,) (6-923)

(dp/dL)g from Equation 6-91b could be calculated.

Slug Flow Regime
In slug flow, the liquid slugs tend to contain some gas. The fraction of liquid
in the liquid slugs can be estimated by

1
E, =
(6-93)
28.4

Figure 6-56 shows the liquid holdup versus the mixture velocity v, by this
correlation.

Slug Velocity
The velocity of the liquid slugs or gas bubbles is determined by

For C, and k see Table 6-21.

Liquid Holdup

The overall liquid holdup is obtained by

(6-95)

Pressure Gradient
Two cases will be considered, slightly inclined flow and vertical flow. Pressure
for slightly inclined flow is a function of an average liquid velocity vL, a friction
factor f, and an average slug density ph.

VL = V A L (6-96a)