Page 122 - Fundamentals of Enhanced Oil and Gas Recovery

110 Pouria Behnoudfar et al.

If P b , 0:345 MPa;
MMP 5 6:056 3 10 26 3 ð1:8 3 T R 132Þ 1:06 3 ðMW C 51 Þ 1:78 (4.16)

where MMP is in MPa, MW C51 is in g/mol, Vol/Int is dimensionless, and T R has
the unit of C. If MMP is less than bubble point pressure, bubble point pressure will

be taken as MMP.

Example 4.7: Calculate the MMP for a typical CO 2 flood proposed by Alston et al. [37].
The required data are as follows:

Vol
T R 5 34:4 C; MW C51 5 212:56 g=mol; 5 1:56; MMP exp: 5 10 MPa; P b 5 6:5 MPa:

Int

Solution: Bubble point pressure is greater than 0.345 MPa. Therefore, the MMP is
calculated by means of Eq. (4.15) as follows:
0:136

MMP 5 6:056 3 10 26 3 ð1:8 3 T R 132Þ 1:06 3 ðMW C 51 Þ 1:78 3 Vol
Int
5 11:562 MPa
from Eq. (4.16)

4.3.2.6 Impurity Correction Factor by Alston et al. [37]
Alston et al. [37] also applied a correction factor (F impure ) to his previous MMP corre-
lation as a function of modified impurities critical temperature (T cm ), and their weight
fraction (w i ) by the following relationships:

ð 1:935 3 87:8Þ

87:8 ð 1:8 3 T cm 132Þ
F impure 5 (4.17)
1:8 3 T cm 132
where
X
T cm 5 w i 1 T ci (4.18)
where T ci , T cm , F impure , and w i indicate the critical temperature of each component

in C, modified impurities critical temperature in C, impurity correction factor, and

weight factor of each component in fraction, respectively. H 2 S and CO 2 critical tem-
peratures are modified to 51.678 C.

Example 4.8: In earlier example, calculate the MMP by Alston et al. [37] consider-
ing H 2 S weight fraction of 0.1 as an impure component.