Sensitivity Analysis and Multiobjective Optimization of CO₂ Huff-N-Puff Process after Water Flooding in Natural Fractured Tight Oil Reservoirs

Table 2

Orthogonal experimental design indices and evaluation results.

No.	Multifactors						Multiobjectives			COS
	F1	F2	F3	F4	F5	F6	O1	O2	O3
1	98.85	2	5	150	3	6	13.98	7.07	10.85	39
2	98.85	6	10	200	4	7	14.12	8.22	6.74	37
3	98.85	10	15	300	5	8	14.16	9.41	6.73	40
4	98.85	14	20	400	6	9	14.61	12.45	8.47	48
5	98.85	18	25	500	7	10	14.85	14.48	8.9	53
6	197.7	2	10	300	6	10	14.66	13.18	6.77	48
7	197.7	6	15	400	7	6	14.08	18.26	6.12	57
8	197.7	10	20	500	3	7	13.89	13.02	9.02	49
9	197.7	14	25	150	4	8	14.52	8.99	3.91	36
10	197.7	18	5	200	5	9	14.64	10.61	4.05	40
11	593.1	2	15	500	4	9	14.21	14.34	10.06	53
12	593.1	6	20	150	5	10	15.15	8.58	1.07	33
13	593.1	10	25	200	6	6	14.09	11.89	1.4	39
14	593.1	14	5	300	7	7	14.28	15.04	1.59	46
15	593.1	18	10	400	3	8	14.31	11.04	2.39	39
16	988.5	2	20	200	7	8	14.37	12.16	4.16	43
17	988.5	6	25	300	3	9	14.55	9.4	1.49	35
18	988.5	10	5	400	4	10	14.83	12.01	1.32	40
19	988.5	14	10	500	5	6	14.24	18.19	1.8	52
20	988.5	18	15	150	6	8	14.92	10.12	0.63	36
21	1383.9	2	25	400	5	7	13.8	15.24	9.53	54
22	1383.9	6	5	500	6	8	14.63	19.58	1.98	56
23	1383.9	10	10	150	7	9	15.17	10.89	0.49	37
24	1383.9	14	15	200	3	10	15.35	8.01	0.64	32
25	1383.9	18	20	300	4	6	14.19	11.96	0.9	39
A1	43.4	47.4	44.2	36.2	38.8	45.2
A2	46.0	43.6	42.6	38.2	41.0	46.5
A3	42.0	41.0	43.6	41.6	43.8	41.67
A4	41.2	42.8	42.4	47.6	45.4	42.6
A5	43.6	41.4	43.4	52.6	47.2	41.2
R	4.8	6.4	1.8	16.4	8.4	5.3

F1, F2, F3, F4, F5, and F6 are injection volume, ; injection time, day; soaking time, day; reopen production time, day; cycle number and bottom hole pressure, MPa, respectively. O1, O2, and O3 are average pressure, MPa; oil recovery, %; and gas replacing oil rate, t/t, respectively. COS is comprehensive objective scores; is the ith index average scores; is range of average scores.