Analysis of Anisotropic Strength and Wellbore Unstable Zone in Shale Formation Relating to Water Content

Table 1

Example of Iterative process for Jaeger’s plane of weakness model.

Procedure	Undetermined parameters				Calculation accuracy ()	RMSE (MPa)
	So (MPa)	fo (deg)	(MPa)	fbp (deg)
1	41	40	28	27	, , ,	30.5819
2	42	39	29.5	26.8		30.2728
3	41.6	39.2	29.45	26.85		30.2708