Table 5. Comparison of Pore Characteristics of Shale Reservoirs in Southern Sichuan.

	periphery of the Sichuan basin82−85	Luzhou area	Changning area77−79	Weiyuan area80,81	Yuxi area80,81
formation	Niutitang	Longmaxi
buried depth		3890–4050 nm	3000–3500 m	About 3700 m	3300–4400 m
depositional environment	shallow-sea continental shelf	deep water shelf—shallow water shelf
pore type	mainly intergranular pores and microfractures	OM pores, intergranular pores, intragranular pores, and microfractures	organic pore and inorganic mineral pore	organic pores, inorganic pores, and microfractures
major pore size	2–10 nm	0.5–0.7, 2–4, and 10–30 nm	0.3–0.9, 40–50, and 100–200 nm	0–2 and 2–4 nm	0.45–0.65 nm and 2–5 nm
pore morphology	mainly open pores shaped like tubular and slit with parallel walls	the parallel plate pores in upper part are gradually transformed into ink bottle- and slit-like pores in Lower Formation	slit-, cylinder-, and inkbottle-like holes	inkbottle-like and parallel slit-like pores	inkbottle- and parallel plate pores
pore size distribution	total PV is mainly contributed by mesopores, followed by marcopores	total PV is mainly contributed by mesopores; SSA is mainly contributed by micropores and mesopore	total PV is mainly contributed by mesopores and marcopores; SSA is mainly contributed by micropores and mesopore	total PV and SSA are mainly contributed by micropores and mesopores	SSA is mainly contributed by micropores