Page 119 - Fundamentals of Enhanced Oil and Gas Recovery

Miscible Gas Injection Processes 107

Table 4.1 The Governing Equations Derived for IFT Determination at Various Thermodynamic
Condition [29]
Temperature (K) Pressure (MPa) IFT (mN/m)

313.15 0.69 # P # 6.20 IFT 52 2:3512P 1 24:01
313.15 6.89 # P # 8.96 IFT 52 1:3624P 1 15:84
333.15 0.69 # P # 8.96 IFT 52 1:7652P 1 23:02
333.15 8.96 # P # 11.72 IFT 52 0:8343P 1 14:59
353.15 0.69 # P # 8.96 IFT 52 1:5603P 1 21:89
353.15 8.96 # P # 15.85 IFT 52 0:6899P 1 13:94
373.15 0.69 # P # 8.96 IFT 52 0:9375P 1 16:06
373.15 8.96 # P # 18.27 IFT 52 0:4382P 1 11:86
IFT, interfacial tension.

Solution:
1. IFT 52 1:7652P 1 23:02 5 12:40 mN=m
2. IFT 52 1:5603P 1 21:89 5 10:18 mN=m
3. IFT 52 0:4382P 1 11:86 5 7:47 mN=m

4.3.2 Minimum Miscibility Pressure Correlations
4.3.2.1 Cronquist [33]
In 1978, Cronquist [33] proposed a correlation in a mathematical form as function of
reservoir temperature (T R ), molecular weight of C 51 (MW C51 ), and volatile compo-
nents (Vol) for the first time in the history of petroleum industry. This correlation is as
follows:
Y
MMP 5 0:11027 3 1:8 3 T R 132ð Þ (4.9)
where
Y 5 0:744206 1 0:0011038 3 MW C51 1 0:0015279 3 Vol (4.10)

where MMP is in MPa, MW C51 is in g/mol, Vol is dimensionless, and T R has the

unit of C. This correlation is valid for oil gravities from 23.7 to 44 API, reservoir

temperature from 21.67 to 120 C, and MMP values from 7.4 to 34.5 MPa.

Example 4.3: Calculate the MMP for a typical CO 2 flood by using proposed correla-
tion by Cronquist [33]. The required data are as follows:

T R 5 80 C; MW C51 5 240:7 g=mol; Vol 5 53:36%; MMP exp: 5 27:52 MPa:

Solution: At first, exponent Y has to be calculated as follows:
Y 5 0:744206 1 0:0011038 3 MW C51 1 0:0015279 3 Vol 5 1:092, from Eq. (4.10)