BAKER HUGHES - Drilling Fluids Reference Manual

CORROSION
• KD - 700 – Scale inhibitor
5. Treating Methods – Where the intrusion of CO 2 is not severe, neutralization with
caustic soda and lime, or gypsum by maintaining a pH of 10.0 or higher may be the
easiest and most cost-effective method. If lime or gypsum is used, SCALE-BAN TM
should also be used to inhibit the deposition of calcium carbonate scale on the drillpipe.
This type of scale can aggravate oxygen corrosion cells. Therefore, NOXYGEN
treatments may have a favorable effect at reducing corrosion.
When a CO 2 influx has become severe, or where neutralization requires large treatments, several
steps may be necessary to minimize the corrosive effect on the drillstring.
• When possible, raise the fluid weight to stop the influx.
• MIL-TEMP ® or ALL-TEMP ® treatments can be extremely effective at controlling
rheological properties which will minimize the entrapment of CO 2 and O 2 . The MIL-
TEMP ® or ALL-TEMP ® will also minimize the flocculating effects of lime additions
which are essential to precipitate carbonates and balance alkalinities.
Use AMI-TEC, KD–700 or SCALE BAN TM to form a protective film on the drillstring.
AMI-TEC should be used with solids-laden fluids. Treatment is accomplished by pumping a 25
to 35 gal “batch” down the drillpipe on a regular basis. A “batch” is prepared by mixing AMI-
TEC, diesel oil and/or ISO-TEQ ® in a 1:5 to 1:20 ratio depending on the level of protection
required. The batch size (number of gallons) depends on the length of the pipe to be coated and the
annular diameter. KD-700 may be used in all water-based drilling fluids. KD-700 contains an
organophosphate filming agent.
In order to effectively maintain an inhibitive film with amines, tourly treatments are recommended.
Note:
Entrainment of excessive amounts of amines into drilling fluids may
result in flocculation of the system, therefore avoid over-treatment.
• Continue to treat with caustic soda and lime to neutralize the acid gas. In addition,
treat the system with SCALE-BAN to prevent scale deposition. Treatment with
SCALE-BAN is 3 to 5 gal per 1000 bbl initially, and 1 to 2 gal each day thereafter.
• Testing Procedures – Monitor alkalinities and pH periodically to ensure that carbonates are
precipitated and solubility of carbon dioxide is minimized. The Garrett Gas Train for
carbonates is necessary to properly monitor the fluid system quantitatively.
Hydrogen Sulfide (H 2 S)
WARNING!
Hydrogen Sulfide Gas is highly poisonous and
extremely corrosive. Small concentrations in air may be
fatal in just a few minutes (See Table 8-1). When H 2 S is
expected, thoroughly familiarize yourself with protective
measures in advance.
BAKER HUGHES DRILLING FLUIDS
REVISION 2006 8-4
REFERENCE MANUAL