Geofluids

Research Article

Light Hydrocarbon Geochemistry: Insight into Mississippian Crude Oil Sources from the Anadarko Basin, Oklahoma, USA

Table 2

Key light hydrocarbon ratios of crude oil samples sensitive to source, transformation, and maturity.


Sample ID	Oil—correlation parameters					Oil—transformation ratio								Maturity
Sample ID	2,3-DMP	2,2-DMP	EtP	3,3-DMP	2,4-DMP	TR-1	TR-2	TR-3	TR-4	TR-5	TR-6	TR-7	TR-8	C₇ ratio	isoC₇ ratio

Group 1
Alf-1	1.12	0.33	1.13	0.31	0.44	0.01	0.89	0.79	0.61	0.71	1.64	1.20	0.96	34.0	0.9
Alf-2	1.06	0.47	1.10	0.49	0.56	0.15	0.98	0.88	0.76	0.83	1.42	1.15	0.87	50.3	1.5
Woo-1	1.12	0.32	1.00	0.36	0.42	0.01	0.69	0.66	0.57	0.62	1.60	1.03	0.58	57.2	1.7
Woo-2-	1.06	0.36	1.10	0.52	0.61	0.08	0.84	0.79	0.63	0.61	1.36	1.02	0.63	45.3	1.3
Kay-1	1.09	0.31	1.31	0.40	0.52	0.15	0.60	0.71	0.68	0.66	1.21	0.92	0.65	22.7	0.9

Group 2
Lin-1	1.03	0.23	1.57	0.30	0.57	0.01	0.64	0.78	0.51	0.55	1.47	1.42	1.06	16.9	0.8
Lin-2	1.12	0.37	1.20	0.51	0.44	0.16	0.96	0.75	0.53	0.65	1.67	1.23	0.90	15.1	0.5
Log-1	1.19	0.27	1.80	0.31	0.48	0.15	0.72	0.61	0.43	0.53	1.37	1.09	0.87	23.9	0.7
Log-2	1.13	0.30	1.26	0.48	0.44	0.09	0.78	0.68	0.46	0.58	1.20	1.02	0.86	18.5	0.5
Pay-1	1.08	0.24	1.43	0.55	0.46	0.05	0.86	0.77	0.52	0.66	1.50	1.25	0.83	27.1	0.8
Pay-2	1.21	0.26	1.13	0.35	0.41	0.02	0.84	0.70	0.50	0.61	1.55	1.21	0.95	25.6	0.8

Group 3
Can-1	0.85	0.87	0.79	1.03	0.85	0.21	0.86	0.75	0.55	0.66	1.22	1.49	0.67	28.9	0.4
Can-2	0.83	0.65	0.79	1.06	0.83	0.18	0.75	0.76	0.77	0.75	1.23	1.30	0.59	31.0	0.7
Kin-1	0.94	0.70	0.78	1.08	0.94	0.25	0.81	0.68	0.76	0.86	1.24	1.22	0.70	52.0	1.8
Kin-2	0.91	0.73	0.79	1.06	0.91	0.27	0.71	0.66	0.62	0.68	1.33	1.44	0.76	29.6	1.2
Bla-1	0.85	0.87	0.79	1.03	0.85	0.21	0.86	0.75	0.55	0.66	1.22	1.49	0.67	28.9	0.4

P1: 2,2-dimethylpentane + 2,3-dimethylpentane + 2,4-dimethylpentane + 3,3-dimethylpentane + 3-ethylpentane; 2,2-DMP: 2,2-dimethylpentane/P1; 2,3-DMP: 2,3-dimethylpentane/P1; 2,4-DMP: 2,4-dimethylpentane/P1; 3,3-DMP: 3,3-dimethylpentane/P1; EtP: 3-ethylpentane/P1; X: 1,1-dimethylcyclopentane; P2: 2-methylhexane + 3-methylhexane; TR1: toluene/X; TR2: nC7/X; TR3: 3-methylhexane/X; TR4: 2-methylhexane/X; TR5: P2/X; TR6: 1-cis-2-dimethylcyclopentane/X; TR7: 1-trans-3-dimethylcyclopentane/X; TR8: P1/P2; C₇ ratio: 100n-heptane/cyclohexane + 2-methylhexane + 1,1-dimethylcyclopentane (DMCP) + 3-methylhexane + 1-cis-3-DMCP + 1-trans-3DMCP + 1-trans-2-DMCP + n-heptane + methylcyclohexane; isoC₇ ratio: 2-methylhexane + 3-methylhexane/1-cis-3-DMCP + 1-trans-3DMCP + 1-trans-2-DMCP.