Page 237 - Petroleum Production Engineering, A Computer-Assisted Approach

Guo, Boyun / Computer Assited Petroleum Production Engg 0750682701_chap15 Final Proof page 235 22.12.2006 6:14pm

WELL PROBLEM IDENTIFICATION 15/235

Well Bore
Gas-Oil
Contact
Intermediate
permeability

Low
permeability

High
permeability
Low
permeability

Intermediate
permeability

Figure 15.10 Gas production due to preferential flow through high-permeability zones (Clark and Schultz, 1956).
Well Bore

Gas Cap

Oil Zone

Figure 15.11 Gas production due to gas coning (Clark and Schultz, 1956).

The spreadsheet program TurnerLoading.xls has been four-phase flow model resulted in a closed-form analytical
developed for quick calculation associated with this book. equation for predicting the minimum gas flow rate.
Turner et al.’s entrained drop movement model was later
modified by a number of authors. Coleman et al. (1991)
suggested to use Eq. (15.23) with a lower constant value. 15.5.2.1 Minimum Kinetic Energy
Nosseir et al. (2000) expanded Turner et al.’s entrained drop Kinetic energy per unit volume of gas can be expressed as
model to more than one flow regime in a well. Lea and r g v 2 g
Nickens (2004) made some corrections to Turner et al.’s E k ¼ : (15:25)
2g c
simplified equations. However, the original drawbacks
(neglected transport velocity and multiphase flow pressure) Substituting Eq. (15.23) into Eq. (15.25) gives an expres-
with Turner et al.’s approach still remain unsolved. sion for the minimum kinetic energy required to keep
liquid droplets from falling:
v ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
u
15.5.2 The Guo et al. Method u sr L r g
t
Starting from Turner et al.’s entrained drop model, Guo E ksl ¼ 0:026 (15:26)
C d
et al. (2006) determined the minimum kinetic energy of gas
that is required to lift liquids. A four-phase (gas, oil, water, If the value of drag coefficient C d ¼ 0:44 (recommended by
and solid particles) mist-flow model was developed. Turner et al.) is used and the effect of gas density is
Applying the minimum kinetic energy criterion to the neglected (a conservative assumption), Eq. (15.26) becomes