Page 238 - Well Logging and Formation Evaluation

228 Well Logging and Formation Evaluation

Exercise 4.2: Log-derived J function

A value of S wirr of 0.05 has been assumed. Fitting S wr to J:

1.0

Swr

Log (Swr) = 0.354 – 0.458*log (J)
0.1

0.01

0.1 1.0 J 10

This yields a = 0.354, b = –0.458. The full function is:

.
.
+
.
(
S w = 0 05 0 354* JŸ -0 458 )
-
.
.
J = (1 02 0 85 ) 0 433 3 281* . * . ( * h)* k ( f ) 26
h = (646 depth )
-
Where h is in m, k in md, f as fraction.
There is virtually no difference between the core and log derived
functions, so it does not really matter which is used. I would nevertheless
recommend to use the core-derived function, since this can be more
easily updated if further core data becomes available.