Re-recognition of “unconventional” in unconventional oil and gas

JIAO Fangzheng

Table 2 Statistics on types and diameters of pores in organic-rich shale formations in the world.

Pore origin	Pore type	Connectivity	Development degree	Pore diameter/nm	Sichuan Basin	Foreign examples
Pore origin	Pore type	Connectivity	Development degree	Pore diameter/nm	Sichuan Basin	Country	Basin	Pore diameter/nm
Primary pore	Intergranular pore	Isolated or connected	Relatively developed	8-610(230)	Wufeng Formation- Longmaxi Formation, Yanchang Formation, Xujiahe Formation^[2]	Canada	Western Canada	8-17
Primary pore	Intercrystalline pore	Isolated or connected	Developed	60-100(30)		America	Appalachia	7-45
Secondary pore	Intragranular pore	Isolated	A few	10-610(270)		America	Anadarko	20-160
Secondary pore	Dissolution pore	Isolated	A few	10-4 080(1 200)		America	Fort Worth	5-100
Organic matter pore	Kerogen pore Asphalt pore	Connected	Developed	15-2 000(200)	Wufeng Formation- Longmaxi Formation	Canada	Alberta	7-45