Hydrochloric Compounds

(1.1)[22]
Where, MW1 and X1 are the molecular weight and mole fraction, respectively.
Compound
Chemical
Composition
Symbol (for calculations) Molecular
Weight
Critical
Pressure
(psi)
Critical
Temp.
(R)
Methane
CH4
C1
16.04
673
344
iso-Butane
C4H10
i-C4
58.12
530
733
n-Butane
C4H10
n-C5
58.12
551
766
Propane
C3H8
C3
44.09
618
666
Ethane
C2H6
C2
30.07
709
550
n-Hexane
C6H14
n-C8
86.17
434
915
n-Heptane
C7H16
n-C9
100.2
397
973
iso-Pentane
C5H12
i-C6
72.15
482
830
n-Pentane
C5H12
n-C7
72.15
485
847
Carbon Dioxide
CO2
CO2
44.01
1072
548
Nitrogen
N2
N2
28.02
492
227
n-Octane
C8H18
n-C10
114.2
361
1024
Hydrogen Sulphide
H2S
H2S
34.08
1306
673
Table 1.2: Molecular Weights and Critical Properties of Pure Components of Natural Gases
Source: …show more content…
When the case of natural gas is concerned, formation volume factor, Bg, may be associated with the implementation of real gas law for standard conditions and for reservoir conditions. Hence,

(1.3)[9]
For same given mass, nR can be cancelled out and, after substituting Tsc = 60 + 460 = 520 R, psc = 14.7 psi and Zsc ≈ 1 the above equation becomes:

(1.4)[8]
If the initial ratio of volume factor formation of natural gas, Vf i, is known, then initial gas-in-place, Gi, would be calculated as follows:

(1.5)[9]
In eq.1.5, is reservoir net thickness in ft, A is the reservoir area in acres, Sg is gas saturation and f is reservoir porosity.
1.1.4 Gas Compressibility
Gas compressibility, Cg, is usually referred to as isothermal compressibility and follows the exact thermodynamic equation:

(1.6)[8]
When an ideal gas is concerned, it is obvious that cg will be exactly equal to 1/p. For real gases, cg is neither constant nor negligible. The derivative V/p can be evaluated by using real gas law as follows:

(1.7)[8]
The volume, V, is substituted by its equivalent from real gas law and the resulting V/p from equation 1.7 results in:

(1.8)[9] or, more