Reservoir Fluid Properties - Cased-Hole Log Analysis and Reservoir Performance Monitoring - page 34

Bottom Hole Gas Density . The bottomhole gas density is an important item of data
for correct interpretation of gradiomanometer surveys. It may be calculated directly
using the equation:

3

rg
gwf

=´ ´ 0 001223 1 . / B

g gcm

/

g

Figure 3.16 offers a nomogram that performs the same calculation. By way of
example, if the gas density to air (ʳ g ) is 0.75 a line is drawn from this point, on the
left of the chart, to the 1/ B g value of 140, on the right of the chart (as shown in the
small diagram). Where this line intersects the ˁ Fgwf . vertical axis the answer can be
read at 0.13 g/cm 3 .

Fig. 3.16 Gas density. Courtesy Schlumberger

Question #3.8 ˁ gwf
Given: 1/ B g = 100, ʳ g = 0.7 (to air)
Find ˁ gwf = ___g/cm 3