Evaluating Conceptual Plays
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40% to 60%. This would refl ect a mature source rock and be defi ned as
follows:
P [40% ≤ mature ≤ 60%] = 0.70
Figure 5.2B displays the probability distribution for total organic
carbon. From this distribution, there is a 70% chance that the play has a
100
A
B
80
60
60
40
40
Immature
75%
Marginally mature
20
20
CUMULATIVE FREQUENCY
GREATER THAN, %
CUMULATIVE FREQUENCY
GREATER THAN, %
0
0
0 . 5 1
2
3
4
TOTAL ORGANIC CARBON, %
5
6
7
8
0
10
100
80
20
30
40
HYDROCARBON IN EXTRACT, %
Total organic carbon
P (
≥ 0.5) = 0.7
TOC
50
60
70
80
90
100
Mature
5%
Over mature
P (Mature) = 0.70
Figure 5.2. (A, B) Example probability distributions for a random variable of
source rock maturation (A) and amount of total organic matter (B). TOC, total
organic carbon.