Table 2. Statistical Table of Stratigraphic Parameters in Ordos Basin.

formation parameters	upper boundary	lower boundary	average
vertical depth (m)	3000	4200	3600
horizontal minimum principal stress gradient (MPa/100 m)	1.23	1.48	1.38
horizontal maximum principal stress gradient (MPa/100 m)	2.21	2.14	2.13
vertical principal stress gradient (MPa/100 m)	1.9	2.33	2.11
pore pressure gradient (MPa/100 m)	0.85	0.9	0.88
abandonment pressure (MPa)	4	6	5