Chemical Effect on Wellbore Instability of Nahr Umr Shale

Table 2

The formation fluid properties of Halfaya oilfield.

	Unit	Nahr Umr
Water type		CaCl2
PH		6.3
Specific gravity (15.56°C)	sg	1.121
Resistivity (25°C)	ohm·m	0.068
Total salinity	ppm	166661
Total hardness	mg/L	16562
Na^+	mg/L	60015
Ca^2+	mg/L	8681
Mg^2+	mg/L	993
Fe^2+	mg/L	74
Ba^2+	mg/L	1
K^+	mg/L	716
Sr^2+	mg/L	356
Cl^−	mg/L	107098
SO4^2−	mg/L	874
HCO3^−	mg/L	7263
CO3^2−	mg/L	0
OH^−	mg/L	0