US 5,710,717 AGranted

Method for predicting and adjusting the distribution of two-phase fluids flowing through a piping network

AssigneeChevron U.S.A. Inc.

InventorsKi Choong Hong, Suzanne Griston

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Abstract

A new, improved method is disclosed for reliably and accurately predicting and adjusting vapor-liquid split ratios to branches of a piping network incorporating a plurality of impacting tee junctions for a wide range of two-phase steam or gas-liquid conditions representative of field distribution systems. The vapor velocity and liquid volume fraction of the two-phase entering an impacting tee junction are computed from measured pressure, quality and rate of a two-phase fluid entering the impacting tee junction. The velocities of the vapor split to each branch tee junction are computed from measured or computed vapor mass flow rates. The liquid volume fraction of the two-phase fluid exiting a branch or arm of the tee junction is then computed as a function of inlet vapor velocity and liquid volume fraction and from the vapor velocity exiting the branch or arm using an empirical correlation equation. Finally, the vapor mass fraction (or quality) of the two-phase fluid exiting the tee branch is computed from the liquid volume fraction exiting the branch.

Claims13

Dependent claims

A method for managing the mount of heat injected into a reservoir in a steam flood project comprising the steps of:

a. measuring the pressure, quality and rate of a two-phase fluid entering an impacting tee junction;
b. determining the flow cross-sectional area of a pipe inlet to the tee junction;
c. determining the vapor-phase and liquid-phase specific volumes at measured inlet pressure, or obtaining said specific volumes from steam tables when the two-phase fluid is wet steam;
d. determining the vapor velocity entering the tee junction;
e. determining the liquid volume entering the tee junction;
f. determining the vapor velocity in a first tee branch or arm;
g. computing coefficients, a and b, wherein
a=a1+a2*ln(LVF.sub.in *V.sub.in)+a3*(LVF.sub.in *V.sub.in).sup.0.5
and
b=b1+b2*(LVF.sub.in *V.sub.in)+b3*ln(LVF.sub.in *V.sub.in)+b4*(LVF.sub.in *V.sub.in).sup.0.5
and
a1=0.2088;
a2=-0.2541;
a3=0.3928;
b1=-3.0662;
b2=-0.4052;
b3=-1.0381;
b4=2.7228;
h. calculating the liquid volume fraction of fluid exiting the first tee branch wherein
LVF.sub.arm =a*LVF.sub.in *(V.sub.arm /V.sub.in).sup.b
i. computing vapor mass fraction of fluid exiting the first tee branch, wherein
x.sub.arm ={1+(LVF.sub.arm *.nu..sub.g)/(1-LVF.sub.arm)*.sub.-- .nu..sub.L !}.sup.-1
j. determining the vapor velocity in a second tee branch or arm;
k. calculating the liquid volume fraction of fluid exiting the second tee branch;
l. computing vapor mass fraction of fluid exiting the second tee branch;
and
m. controlling the amount of heat injected into the reservoir based on the vapor mass fraction of the fluid exiting the first tee branch and the second tee branch.

24 more elements

A method for managing the amount of liquid and vapor distributed in an impacting tee junction comprising the steps of:

a. measuring the pressure, temperature, quality and rate of a two-phase fluid entering the impacting tee junction;
b. determining the flow cross-sectional area of a pipe inlet to the tee junction;
c. determining the vapor-phase and liquid-phase specific volumes at measured inlet pressure and temperature;
d. determining the vapor velocity entering the the junction;
e. determining the liquid volume entering the tee junction;
f. determining the vapor velocity in a first tee branch or arm;
g. computing coefficients, a and b, wherein
a=a1+a2*ln(LVF.sub.in *V.sub.in)+a3*(LVF.sub.in *V.sub.in).sup.0.5
and
b=b1+b2*(LVF.sub.in *V.sub.in)+b3*ln(LVF.sub.in *V.sub.in)+b4*(LVF.sub.in *V.sub.in).sup.0.5
h. calculating the liquid volume fraction of fluid exiting the first tee branch wherein
LVF.sub.arm =a*LVF.sub.in *(V.sub.arm /V.sub.in).sup.b
i. computing vapor mass fraction of fluid exiting the first tee branch, wherein
x.sub.arm ={1+(LVF.sub.arm *.nu..sub.g)/(1-LVF.sub.arm)*.sub.-- .nu..sub.L !}.sup.-1
j. determining the vapor velocity in a second tee branch or arm;
k. calculating the liquid volume fraction of fluid exiting the second tee branch;
l. computing vapor mass fraction of fluid exiting the second tee branch;
and
m. controlling the amount of liquid and vapor exiting the first tee branch and the second tee branch.

16 more elements

Dependencies are inferred from the claim text.