US2017321537A1PendingUtilityA1
Calculating Static Bottomhole Pressures for Dry and Wet Gas Wells
Est. expiryMay 5, 2036(~9.7 yrs left)· nominal 20-yr term from priority
E21B 41/00E21B 47/065E21B 47/06E21B 47/07E21B 43/00
34
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Claims
Abstract
A wellbore is divided into a plurality of depth intervals. For each depth interval of the plurality of depth intervals, a specific gas gravity, pseudo-critical gas properties, a pseudo-reduced gas pressure and temperature, a gas deviation factor, and a gas gradient and a bottom node pressure are determined. The determined bottom node pressure is used as a static bottomhole pressure.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A computer-implemented method, comprising:
dividing a wellbore into a plurality of depth intervals; for each depth interval of the plurality of depth intervals:
determining a specific gas gravity;
determining pseudo-critical gas properties;
determining a pseudo-reduced gas pressure and temperature;
determining a gas deviation factor using the pseudo-reduced gas properties; and
determining a gas gradient and a bottom node pressure; and
using the determined bottom node pressure as a static bottomhole pressure.
2 . The computer-implemented method of claim 1 , wherein determining the specific gas gravity includes using an equation given by:
γ
g
=
M
a
M
air
=
M
a
28.97
,
and wherein γ g is the gas specific gravity, M a is apparent mass, and M air is the molecular weight of air.
3 . The computer-implemented method of claim 1 , wherein determining the pseudo-critical gas properties includes using equations given by:
P pch =756.8−131.0γ h −3.6γ h 2
and T pch =169.2+349.5γ h −74.0γ h 2 ,
and wherein P pch is the pseudocritical pressure of hydrocarbon components, T pch is the pseudocritical temperature of hydrocarbon components, and γ h is the specific gravity of hydrocarbon components.
4 . The computer-implemented method of claim 1 , wherein determining the pseudo-reduced gas pressure and temperature includes using equations given by:
Ppr=p/Ppc and Tpr=T/Tpc,
and wherein Ppr is pseudo-reduced pressure, Ppc is pseudocritical pressure, Tpr is pseudo-reduced temperature, Tpc is pseudocritical temperature, p is pressure, and T is temperature.
5 . The computer-implemented method of claim 1 , wherein determining the gas gradient and the bottom node pressure includes using an equation given by:
α
g
=
ρ
g
144
=
PMM
a
144
ZRT
,
and wherein ρ g is gas density, P is pressure, m is mass, α g is the gas wellbore pressure gradient, R is the Universal Gas Constant, T is temperature, and Z is compressibility factor.
6 . A non-transitory, computer-readable medium storing computer-readable instructions executable by a computer and configured to:
divide a wellbore into plurality of depth intervals; for each depth interval of the plurality of depth intervals:
determine a specific gas gravity;
determine pseudo-critical gas properties;
determine a pseudo-reduced gas pressure and temperature;
determine a gas deviation factor using the pseudo-reduced gas properties; and
determine a gas gradient and a bottom node pressure; and
use the determined bottom node pressure as a static bottomhole pressure.
7 . The non-transitory, computer-readable medium of claim 6 , wherein determining the specific gas gravity includes using an equation given by:
γ
g
=
M
a
M
air
=
M
a
28.97
,
and wherein γ g is the gas specific gravity, M a is apparent mass, and M air is the molecular weight of air.
8 . The non-transitory, computer-readable medium of claim 6 , wherein determining the pseudo-critical gas properties includes using equations given by:
P pch =756.8−131.0γ h −3.6 h 2
and T pch =169.2+349.5γ h −74.0γ h 2 ,
and wherein P pch is the pseudocritical pressure of hydrocarbon components, T pch is the pseudocritical temperature of hydrocarbon components, and γ h is the specific gravity of hydrocarbon components.
9 . The non-transitory, computer-readable medium of claim 6 , wherein determining the pseudo-reduced gas pressure and temperature includes using equations given by:
Ppr=p/Ppc and Tpr=T/Tpc,
and wherein Ppr is pseudo-reduced pressure, Ppc is pseudocritical pressure, Tpr is pseudo-reduced temperature, Tpc is pseudocritical temperature, p is pressure, and T is temperature.
10 . The non-transitory, computer-readable medium of claim 6 , wherein determining the gas gradient and the bottom node pressure includes using an equation given by:
α
g
=
ρ
g
144
=
PMM
a
144
ZRT
,
and wherein ρ g is gas density, P is pressure, m is mass, α g is the gas wellbore pressure gradient, R is the Universal Gas Constant, T is temperature, and Z is compressibility factor.
11 . A computer-implemented system, comprising:
at least one computer interoperably coupled with a memory storage and configured to:
divide a wellbore into plurality of depth intervals;
for each depth interval of the plurality of depth intervals:
determine a specific gas gravity;
determine pseudo-critical gas properties;
determine a pseudo-reduced gas pressure and temperature;
determine a gas deviation factor using the pseudo-reduced gas properties; and
determine a gas gradient and a bottom node pressure; and
use the determined bottom node pressure as a static bottomhole pressure.
12 . The computer-implemented system of claim 11 , wherein determining the specific gas gravity includes using an equation given by:
γ
g
=
M
a
M
air
=
M
a
28.97
,
and wherein γ g is the gas specific gravity, M a is apparent mass, and M air is the molecular weight of air.
13 . The computer-implemented system of claim 11 , wherein determining the pseudo-critical gas properties includes using equations given by:
P pch 756.8−131.0γ h −3.6γ h 2
and T pch =169.2+349.5γ h −74.0γ h 2 ,
and wherein P pch is the pseudocritical pressure of hydrocarbon components, T pch is the pseudocritical temperature of hydrocarbon components, and γ h is the specific gravity of hydrocarbon components.
14 . The computer-implemented system of claim 11 , wherein determining the pseudo-reduced gas pressure and temperature includes using equations given by:
Ppr=p/Ppc and Tpr=T/Tpc,
and wherein Ppr is pseudo-reduced pressure, Ppc is pseudocritical pressure, Tpr is pseudo-reduced temperature, Tpc is pseudocritical temperature, p is pressure, and T is temperature.
15 . The computer-implemented system of claim 11 , wherein determining the gas gradient and the bottom node pressure includes using an equation given by:
α
g
=
ρ
g
144
=
PMM
a
144
ZRT
,
and wherein ρ g is gas density, P is pressure, m is mass, α g is the gas wellbore pressure gradient, R is the Universal Gas Constant, T is temperature, and Z is compressibility factor.Join the waitlist — get patent alerts
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