Petrographic Characterization and Maceral Controls on Porosity in Overmature Marine Shales: Examples from Ordovician-Silurian Shales in China and the U.S.

Table 1

Lists of Wufeng-Longmaxi shale samples from Sichuan Basin and their depths, porosities, total organic carbon (TOC) contents, and mineral contents. Gas contents are also included. Gas contents include lost gas, desorbed gas, and remaining gas.

Sample ID	Depth (m)	TOC (total organic carbon content, %)	Porosity (helium, %)	Clay mineral content (%)	Quartz (%)	Pyrite (%)	Carbonate (%)	Feldspar (%)	Gas content (m^3/t)
N1	2481	1.23	5.23	43.0	38.3	3.1	12.5	3.1	1.62
N2	2487	0.96	4.35	46.3	27.4	1.1	20.3	4.9	1.38
N3	2498	0.89	4.47	35.0	47.0	2.0	10.1	5.9	1.34
N4	2503	1.07	4.22	36.6	40.7	1.1	13.5	8.1	1.42
N5	2513	1.31	4.53	34.3	36.0	1.5	16.0	12.2	1.55
N6	2534	1.51	5.30	38.2	40.3	1.5	13.1	6.9	1.98
N7	2540	2.15	5.25	35.6	43.9	2.6	12.6	5.3	2.33
N8	2554	2.98	5.30	26.0	55.1	3.6	12.0	3.3	2.41
N9	2563	3.39	5.47	25.1	46.8	3.7	20.7	3.7	2.54
N10	2567	3.52	5.67	16.2	64.8	2.7	14.3	2.0	2.61
N11	2573	3.19	5.22	15.9	54.6	2.1	24.5	2.9	2.63
N12	2576	4.18	5.88	11.8	59.3	2.7	22.3	3.9	3.08