__TOC__

=== Brief ===

[[Valco - McCain correlation]] is ...

=== Math & Physics ===

:<math> P_{bp} = e^{2.498 + 0.713 z + 0.0075 z^2}</math>

where:

:<math> z1 = -4.814074834 + 0.7480913 log(R_{sb}) + 0.1743556 log^2(R_{sb}) - 0.0206 log^3(R_{sb})</math>

:<math> z2 = 1.27 - 0.0449 Y_{oil_API}+ 0.000436 Y^2_{oil_API} - 0.00000476 Y^3_{oil_API}</math>

:<math> z3 = 4.51 - 10.84 \times SG_{g} + 8.39 \times SG^2_{g} - 2.34 \times SG^3_{g}</math>

:<math> z4 = -7.2254661 + 0.043155 \times T - 8.5548e-5 \times T^2 + 6.00696e-8 \times T^3</math>

:<math> z = z1 + z2 + z3 + z4</math>

=== Discussion ===
=== Workflow ===
=== Application range ===
=== Nomenclature ===
:<math> P </math> = pressure, MPA
:<math> P_{bp} </math> = bubble point pressure, MPA
:<math> R_s </math> = oil gas ration, m3/m3
:<math> SG_g </math> = gas specific gravity, dimensionless
:<math> T </math> = temperature, °R
:<math> Y_{oil_API} </math> = oil API gravity, dimensionless

=== References ===
<references>

<ref name=Valco - McCain>{{cite journal
|last1= Valkó |first1=P. P.
|last2= McCain |first2=W.D.
|title=Reservoir oil bubblepoint pressures revisited; solution gas–oil ratios and surface gas specific gravities.
|journal=J. Pet. Sci. Eng. 37 (3–4): 153-169
|date=2003
|url=http://dx.doi.org/10.1016/S0920-4105(02)00319-4
|url-access=registration
}}</ref>

</references>

[[Category:pengtools]]
[[Category:PVT]]

2017-04-25T09:24:47Z

Gprotsykov:

__TOC__

=== Brief ===

[[Dranchuk correlation]] is the fitting function of the classic '''Standing and Katz''' <ref name=Standing&Katz /> gas compressibility factor correlation.

=== Math & Physics ===
A1 = 0.3265<br/>
A2 = –1.0700<br/>
A3 = –0.5339<br/>
A4 = 0.01569<br/>
A5 = –0.05165<br/>
A6 = 0.5475<br/>
A7 = –0.7361<br/>
A8 = 0.1844<br/>
A9 = 0.1056<br/>
A10 = 0.6134<br/>
A11 = 0.7210<br/>
:<math> z = 1-z+
\left(A_1
+\frac{A_2}{T_{pr}}
+\frac{A_3}{T^3_{pr}}
+\frac{A_4}{T^4_{pr}}
+\frac{A_5}{T^5_{pr}}
\right)\ \rho_r+
\left(A_6
+\frac{A_7}{T_{pr}}
+\frac{A_8}{T^2_{pr}}
\right)\ \rho^2_r
-A_9\ \left(\frac{A_7}{T_{pr}}+\frac{A_8}{T^2_{pr}}\right)
+A_{10}\ \left(1+A_{11}\ \rho^2_r\right)\ \frac{\rho^2_r}{T^3_{pr}}
\ e^{-A_{11}\ \rho^2_r}
</math><ref name= Dranchuk/>
where
:<math> T_{pc} = 99.3+180\ SG_g-6.94\ SG^2_g</math>

:<math> P_{pc} = 4.6+0.1\ SG_g-0.258\ SG^2_g</math>

:<math> T_{pr} = \frac{T}{T_{pc}}</math>

:<math> P_{pr} = \frac{P}{P_{pc}}</math>

:<math> \rho_r = \frac{0.27\ P_{pr}}{({z\ T_{pr}})} </math>

=== Discussion ===
To avoid the [[Liquid loading]] the gas velocity should be above the [[Liquid loading]] velocity.

The higher the gas rate the higher the gas velocity.

The lower the wellhead flowing pressure the higher the gas rate.

The bigger the tubing ID the higher the gas rate.

In case when the gas rate is limited by the [[Reservoirs|Reservoir]] deliverability smaller tubing ID will increase the gas velocity.

=== Nomenclature ===
:<math> A_1..A_{11} </math> coefficients
:<math> \rho_r </math> = reduced density, dimensionless
:<math> P </math> = Pressure, psia
:<math> P_{pc} </math> = pseudo critical pressure, psia
:<math> P_{pr} </math> = pseudoreduced pressure, dimensionless
:<math> SG_g </math> = gas specific gravity, dimensionless
:<math> T </math> = temperature, °R
:<math> T_{pc} </math> = pseudo critical temperature, °R
:<math> T_{pr} </math> = pseudoreduced temperature, dimensionless
:<math> z </math> = gas compressibility factor, dimensionless

=== References ===
<references>

<ref name=Standing&Katz>{{cite journal
|last1= Standing |first1=M. B.
|last2= Katz |first2=D. L.
|title=Density of Natural Gases
|journal=Transactions of the AIME
|publisher=Society of Petroleum Engineers
|number=SPE-942140-G
|date=December 1942
|volume=146
|url=https://www.onepetro.org/journal-paper/SPE-942140-G
|url-access=registration
}}</ref>

<ref name= Dranchuk >{{cite journal
|last1= Dranchuk |first1=P. M.
|last2= Abou-Kassem |first2=H.
|title=Calculation of Z Factors For Natural Gases Using Equations of State
|journal=The Journal of Canadian Petroleum
|number=PETSOC-75-03-03
|date=July 1975
|volume=14
|url=https://www.onepetro.org/journal-paper/PETSOC-75-03-03
|url-access=registration
}}</ref>

</references>

[[Category:pengtools]]
[[Category:PVT]]