Page 247 - Well Logging and Formation Evaluation

Solutions to Exercises 237

The DEMV (in $M) is given by:

DEMV =-0 02 0 7 0 5. + . * . * [20* (180 000, - 60 000, ) - ] 1
+ 0 3 0 5* [20 ( * -60 000 ) - ] =1 $ 0 14 M
,
.
.
.*
The DEMV expressed as a function of the reliability, R, is given by:
(
.
*
*
.
DEMV R) =-002 + R 0 5.* (1 4. ) + (1 - R) 05.* ( -22 )
The EMV becomes zero at a value of R of 0.62. So unless the tool will
give the right answer at least 62% of the time, it is not worthwhile to run it.

0.8
0.6
0.4
0.2
0.0
DEMV –0.2
–0.4
–0.6
–0.8
–1.0
–1.2
–1.4
0.000 0.200 0.400 0.600 0.800 1.000
Reliability

If there is an estimated 70% chance that the zone is not flushed, the
DEMV becomes:

.
.
*
*
DEMV R) =-002 + R 0 7* (1 4. ) + (1 - R) 03* ( -22 )
.
(
.
For R = 0.7, the DEMV becomes $0.468M; the R required for 0 EMV
becomes 0.42
If there is an estimated 30% chance that the zone is not flushed:
.
.
DEMV R) =-002 + R 0 3* (1 4. ) + (1 - R) 07* ( -22 )
.
(
*
.
*