Chemical Effect on Wellbore Instability of Nahr Umr Shale

Table 4

Clay mineral composition and content of the Nahr Umr Shale.

Depth	Clay mineral content (%)						Interbed ratio (% S)
	S	I/S	It	Kao	C	C/S	I/S	C/S
3645.10		34	7	48	11		14
3649.83		33	3	40	24		11
3666.00		44	7	49			21