Environmental Engineering Reference
In-Depth Information
Ast3 is the cube of the transformed asphaltene content as calculated in Eq. ( 3.5 ),
abbreviated F,
A/Rst3 is the cube of the transformed A
/
R ratio as calculated in Eq. ( 3.6 ), abbre-
viated G ,
lnVst is the natural logarithm (ln) of the transformed viscosity as calculated in
Eq. ( 3.2 ), abbreviated H,
lnRst is the natural logarithm (ln) of the transformed resin content as calculated in
Eq. ( 3.4 ), abbreviated I,
lnA/Rst is the natural logarithm (ln) of transformed asphaltene/resin ratio as cal-
culated in ( 3.6 ), abbreviated J,
Exp(Vst)2 is the exponential of the transformed viscosity and squared—Vst as
calculated in Eq. ( 3.2 ), abbreviated K,
Exp(A/Rst)2 is the exponential of the A
/
R ratio—squared—as calculated in
Eq. ( 3.6 ), abbreviated L,
LogDst/Dst2 is the logarithm (base 10) of the exponential of the density—divided
by the square of the transformed density—the transformed density as calculated
in Eq. ( 3.1 ), abbreviated M ,
LogA/Rst/A/Rst2 is the logarithm (base 10) of the exponential of the A
/
R ratio—
divided by the square of the A
/
R ratio—the transformed A
/
R ratio as calculated
in Eq. ( 3.6 ), abbreviated N .
A simplified version of the equation is then:
=
.
+
.
.
.
.
+
.
Stability
17
8
0
013 A
1
49 B
12
6 C
0
073 D
0
0019 E
+
0
.
00016 F
4
.
23 G
0
.
59 H
+
1
.
59 I
+
4
.
028 J
+
3
.
72 X 10
(3.8)
26 K
+
1
.
207 L
+
0
.
022 M
+
0
.
11 N
where the parameters A - N are defined as above.
The stability of the resulting product is calculated using the rheological
measurements of the water-in-oil product formed. The basic uncorrected Stability or
cross product is:
Complex Modulus
Starting Oil Viscosity ×
Elastic Modulus
Starting Oil Viscosity
Xpr
=
(3.9)
The corrected stability is:
=
((
/
,
) · (
/
,
))
Stability
ln
Xpr
10
000
Xpr
10
000
(3.10)
where the Xpr is the value from Eq. ( 3.9 ).
The values of stability which are assigned to each class are given in Table 3.1 .
The viscosity of the resulting product can be taken as the average of the types at a
given time as shown in Table 3.5 .
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