Quantity of Organic Matter
Organic Matter
Bitumen
Hydrocarbons
Wt.% TOC
Rock-Eval S2
Wt.% of Rock
ppm Rock
Poor
<0.50
<1.0
<0.05
<500
<300
Fair
0.5-1.0
1.0-5.0
0.05-0.10
500-1000
300-600
Good
1.0-2.0
5.0-10.0
0.10-0.20
1000-2000
600-1200
Very good
2.0-4.0
10.0-20.0
0.20-0.40
2000-4000
1200-2400
Excellent
>4.0
>20.0
>0.40
>4000
>2400
Quality of Organic Matter
Atomic H/C
Hydrogen Index (mgHC/gTOC)
Rock-Eval S2/S3
Gas
<0.80
<100
<3
Gas and Oil
0.80-1.0
100-200
3-5
Oil and Gas
1.0-1.2
200-350
5-10
Oil
>1.2
>350
>10
Maturity of Organic Matter HC Generation
Maturation
Generation
Stage
Ro(%)
TAI
Tmax (oC)
Bitumen/TOC
mg EOM/g TOC
Rock-Eval PI
Immature Beginning Peak Post
<0.60
0.60
0.90
>1.20
<2.5 2.5-2.6 2.9-3.0
>3.2
<430
430-435445-450>460
0.05-0.10 0.15-0.25
<50
50-150
150-250
<0.10
0.10-0.15
0.15-0.25
<0.20
Organic matter quantity and quality are maturation dependent. TOC = total organic carbon; TAI = thermal alteration index based on spore coloration index; Rock-Eval PI (production index) = S1/(S1*S2), HC = hydrocarbon; E0M = extractable organic matter.
