BAKER HUGHES - Drilling Fluids Reference Manual

Baker Hughes Drilling Fluids
Then,
=
100 mL of methylene blue
---------------------------------------- × ----------------------------------------------------------
(% LGS) ( ρ LGS ) mL of fluid
mL of methylene blue
lb /bbl equivalent 5
m
= × -----------------------------------------------------------
mL of fluid
or,
mL of methylene blue
-----------------------------------------------------------
mL of fluid
lb /bbl equivalent
m
= --------------------------------------------------
5
Again, substituting one equation into another, you derive,
100
lb m
/bbl equivalent
CEC fluid = ---------------------------------------- × --------------------------------------------------
(% LGS) ( ρ LGS )
5
20( lb /bbl equivalent
m )
= -------------------------------------------------------------
(% LGS) ( ρLGS)
The density of the low-gravity solids (ρ LGS ) is typically assumed to be 2.6 g/cm 3 . However,
measurement of the density of the drilled solids at a particular location will provide a more accurate
value. Therefore, replacing ρ LGS with 2.6 in the equation gives,
7.69( lb /bbl equivalent
m )
CEC fl uid
= ------------------------------------------------------------------
% LGS
The following notation is common:
where,
CEC avg
7.69( MBT fluid )
= --------------------------------------
% LGS
CEC avg = cation exchange capacity correction
MBT fluid = methylene blue capacity, lb m / bbl equivalent
% LGS = volume % of low-gravity solids (e.g., 6.1%)
Baker Hughes Drilling Fluids
Reference Manual
Revised 2006 1-27