BAKER HUGHES - Drilling Fluids Reference Manual

Water Based Drilling Fluids
Element/Compound
or ion
Table 3-8
Atomic/Molecular
Weight
Equivalent Weights
Valency
Equivalent
Weight
Na, Na + 23 1 23
K, K + 39.1 1 39.1
Mg, Mg 2+ 24.3 2 12.15
Ca, Ca 2+ 40.1 2 20.05
Fe(iii), Fe 3+ 55.8 3 18.6
Cl – 35.5 1 35.5
SO 4
2–
96 2 48
H 2 SO 4 98 2 49
HCl 36.5 1 36.5
NaOH 40 1 40
Ca(OH) 2 74.1 2 37.05
CaSO 4 136.1 2 68.05
Na 2 CO 3 106 2 53
CaCO 3 100.1 2 50.05
MgCO 3 84.3 2 42.15
NaHCO 3 84 1 84
AgNO 3 169.9 1 169.9
NaCl 58.5 1 58.5
Conversion of Units
Conversion from w/v to w/w and vice versa, depends on the density of the solution,
mg / L
ppm =
Density of Solution
Or, converting the other way
1% = 10 g/L x Density of the solution
This relationship is ignored by many people in the oil industry who take ppm and mg/l as
equivalent units. In a dilute solution, where the density is very close to 1.00 this is true. In heavy
brines or weighted drilling fluids the units (ppm vs. mg/L) are very different.
It is recommended that all analysis of drilling fluids be calculated on a w/v basis as g/l or mg/l.
Conversions of molarity to w/v depends on the molecular weight. Thus 1M HCl contains 36.5 g
HCl dissolved in one liter of solution, as the molecular weight is 36.5. Thus, 1M HCl = 36.5 g/l.
Equivalent Weights
The equivalent weight of an element or ion is:
AtomicWeight
equiv . wt.
=
Valency
Reference Manual
Baker Hughes Drilling Fluids
3-24 Revised 2006