BAKER HUGHES - Drilling Fluids Reference Manual

Baker Hughes Drilling Fluids
Example Calculations
Parameters
Exercise
Table 1-6
Fluid Parameters for Exercise Problem
Fluid Properties
Fluid Weight, lbm/gal 15.5
Retort Analysis
Solid, % 30
Oils, % 0
Water, % 70
MBT, lb m / bbl equivalent 15.0
Chlorides, ppm 21,000
CEC bent
CEC DS
Measurement
Calculation
63 meq/100 g
16 meq/100 g
% LGS 5.9%
Perform the steps and calculations to show that this is the correct value for % LGS. Find the %
Bentonite and % DS in the fluid and the corresponding pounds per barrel of each.
1. Make the cation exchange capacity correction.
CEC avg
=
7.69( MBT fluid )
--------------------------------------
% LGS
=
7.69( 15.0
-------------------------
)
= 19.55 meq/100 g
5.9
2. Find the % Bentonite.
% LGS( CEC avg – CEC DS )
% Be ntonite = -------------------------------------------------------------------
CEC bent – CEC DS
3. Find the pounds per barrel of Bentonite.
=
5.9(19.55 – 16)
------------------------------------ = 0.45%
63 – 16
4. Find the % drilled solids.
lb /bbl Bentonite = % Bentonite
m ( )( 9.1) = ( 0.45) ( 9.1) = 4.1 lb /bbl m
% DS = % LGS – % Bentonite = ( 5.9 – 0.45) = 5.4%
5. Find the pounds per barrel of drilled solids.
lb m
/bbl DS
=
(% DS) ( 9.1) = ( 5.45) ( 9.1) = 49.6 lb m
/bbl
Notice that the quantity of Bentonite is relatively low. This is very typical of the NEW-DRILL ®
system.
Baker Hughes Drilling Fluids
Reference Manual
Revised 2006 1-33