BAKER HUGHES - Drilling Fluids Reference Manual

CORROSION
are (1) to inhibit corrosion and extend the life of the tubular goods, and (2) to provide a hydrostatic
column for control of pressures in the event of a casing or tubing leak.
Packer fluids are formulated from three types of basic fluids – water-base drilling fluids, brine
water, and oil or synthetic fluids. The techniques for formulating a packer fluid are as follows.
Water-Base Drilling Fluid
1. Raise the gels to prevent the settling of solids for the extended periods over which the
fluid will be stagnant. A high temperature-high pressure Cameron test cell can be used to
provide a stable test environment.
2. Raise the pH to 11.0 with caustic soda.
3. Blend 2 - 5 gal of KD-40 corrosion inhibitor uniformly into each 100 bbl of fluid for
low to moderate corrosion rate protection. This concentration will yield 150 – 300 ppm
KD-40 in the mud filtrate. For high corrosion rates, increase the concentration of KD-
40 to 7 – 12 gal per 100 bbl of packer fluid. This concentration of KD-40 will yield
450-700 ppm KD-40 in the mud filtrate. Residual levels of KD-40 corrosion
inhibitor in the filtrate can be determined with an organophosphate analytical test kit. The
quantity of KD-40 used will depend on the type and severity of the corrosion problems
expected and on the fluid type used.
4. Corrosion rates should be monitored with drill pipe corrosion coupons.
Brine Water
1. To raise the pH for NaCl and KCI to 10.0 - 10.5, use caustic soda (NaOH) or caustic
potash (KOH). To raise the pH for high-density brines (i.e., CaCl 2 , CaBr 2 , ZnCl 2 , and
ZnBr 2 ) and combinations of these brines, do not use caustic soda to try to raise the pH.
Instead, use small amounts of lime (CaOH 2 ) and raise the pH only when absolutely
necessary.
2. Add BRINE-PAC ® to the brine water at a concentration of 55 gal per 150 - 200 bbl brine.
In severely corrosive areas it may be necessary to increase the concentration of BRINE-
PAC ® . Do not use BRINE-PAC ® with brines containing solids.
3. Do not circulate or aerate brine water containing BRINE-PAC ® as this will expend the
oxygen scavenger.
4. In areas where H 2 S is a problem, add 6 to 12 lb m /bbl of MIL-GARD ® R to control
sulfide corrosion.
5. BRINE-PAC ® 2000 is a high temperature corrosion inhibitor for high density brines such
as calcium and zinc bromide. It is stable up to 450°F and completely soluble in high
density calcium and zinc brines. BRINE-PAC ® 2000 forms a tough long lasting coating
on metal surfaces to resist penetration of dissolved organic gases, hydrogen sulfide and
carbon dioxide. The recommended treatment is 10 – 15 gallons per 100 bbl of brine.
6. BRINE-PAC ® 1500 is a filming amine type corrosion inhibitor for treatment of low to no
solids brines. It is water soluble and is effective in fresh water and sodium, potassium and
BAKER HUGHES DRILLING FLUIDS
REVISION 2006 8-13
REFERENCE MANUAL