Page 200 - Well Control for Completions and Interventions

Completion, Workover, and Intervention Fluids 193

Table 5.4 Brine compressibility coefficients (Bridges)
Brine type Density (ppg) Density decrease Fluid compression
in ppg/100 F lb/gall/1000 psi

NaCl 9.0 0.314 0.0189
NaCl 9.5 0.386 0.0188
NaBr 12.0 0.336 0.0190
9.5 0.285 0.0188
CaCl 2
10.0 0.289 0.0187
CaCl 2
10.5 0.273 0.0186
CaCl 2
11.0 0.264 0.0187
CaCl 2
12.0 0.325 0.0190
CaCl 2 /CaBr 2
12.5 0.330 0.0193
CaCl 2 /CaBr 2
13.5 0.343 0.0201
CaCl 2 /CaBr 2
CaCl 2 /CaBr 2 14.5 0.362 0.0212
15.5 0.387 0.0226
CaCl 2 /Zn-CaBr 2
16.5 0.416 0.0224
CaCl 2 /Zn-CaBr 2
17.5 0.453 0.0264
CaCl 2 /Zn-CaBr 2
18.0 0.475 0.0276
CaCl 2 /Zn-CaBr 2
18.5 0.501 0.0288
CaCl 2 /Zn-CaBr 2
19.0 0.528 0.0301
CaCl 2 /Zn-CaBr 2
5
In “Well Completion Design,” the following equations are used to
calculate brine weight adjusted for temperature and pressure.
Temperature correction:
! !
1
ρ 5 ρ 70 2 2 (5.2)
T
1 2 T 2 70 α
where:
ρ T is the adjusted brine density (at average wellbore temperature),

ρ 70 is the brine density at the API reference temperature of 70 F,
T is the average wellbore temperature, and

α is the expansion coefficient in vol/vol/ F(Table 5.2).
Pressure correction:
!
1
ρ 5 ρ 2 2 (5.3)
p T 1 1 P β

where:
ρ p is the pressure corrected density,
P is the average pressure of the fluid in the wellbore, and
β is the compressibility coefficient in vol/vol/psi (Table 5.3).