Table 6: Contaminated mud treated with caustic soda and lime.
Drilling Fluid Properties (unit) |
Before Contamination |
After 20%v Contamination |
After treatment by lime and caustic to adjust the pH between 10.5-11.5 |
P.V (m.Pa.s) |
45 |
59 |
62 |
A.V (m.Pa.s) |
70 |
125 |
128 |
Y.P (Pa) |
44 |
8.5 |
22 |
Gel strength 10'(Pa) |
10 |
23 |
12 |
Gel strength 10”(Pa) |
17 |
29 |
20 |
Ca2++(mg/lit) |
200 |
4400 |
6800 |
Mg2++(mg/lit) |
10 |
1500 |
150 |
Total hardness (mg/lit) |
210 |
5900 |
6950 |
Fluid loss(ml) |
0 |
18 |
8 |
Cake thickness (mm) |
3.5 |
20 |
9 |
Pf (ml of acid) |
0.5 |
0 |
1 |
Mf (ml of acid) |
1 |
0.4 |
1.5 |
HCO3- (mg) |
0 |
488 |
42 |
CO3- (mg) |
600 |
0 |
255 |
pH |
10.5 |
6.7 |
11.5 |