BAKER HUGHES - Drilling Fluids Reference Manual

Chapter 8
Table of Contents
CORROSION...........................................................................................................................................8-1
INTRODUCTION.......................................................................................................................................8-1
FACTORS AFFECTING CORROSION RATE ...............................................................................................8-1
Temperature .......................................................................................................................................8-1
Pressure..............................................................................................................................................8-2
pH.......................................................................................................................................................8-2
Dissolved Salts...................................................................................................................................8-2
CORROSIVE AGENTS AND TREATMENTS................................................................................................8-2
Oxygen (O 2 ) .......................................................................................................................................8-2
Carbon Dioxide (CO 2 ) .......................................................................................................................8-3
Hydrogen Sulfide (H 2 S).....................................................................................................................8-4
CORROSIVITY OF VARIOUS FLUIDS........................................................................................................8-7
USE OF CORROSION COUPONS ...............................................................................................................8-8
Ring Coupons.....................................................................................................................................8-8
Ring Placement and Scheduling ........................................................................................................8-9
Handling of Corrosion Rings .............................................................................................................8-9
Calculation of Corrosion Rate..........................................................................................................8-10
CORROSION TREATMENT TIPS .............................................................................................................8-10
Oxygen Scavengers..........................................................................................................................8-10
NOXYGEN..................................................................................................................................8-10
Film-Forming Amines .....................................................................................................................8-11
AMI-TEC.....................................................................................................................................8-11
KD-700 ........................................................................................................................................8-11
KD-40 ..........................................................................................................................................8-12
Scale Inhibitor..................................................................................................................................8-12
SCALE-BAN ...............................................................................................................................8-12
PACKER FLUID TREATMENT ................................................................................................................8-12
Water-Base Drilling Fluid................................................................................................................8-13
Brine Water......................................................................................................................................8-13
Invert Emulsion Fluids.....................................................................................................................8-14
List of Figures
FIGURE 8- 1 CONDUCTIVITY OF BRINES...................................................................................... 8-15
FIGURE 8- 2 OXYGEN SOLUBILITY VERSUS SALINITY.................................................................. 8-16
FIGURE 8- 3 OXYGEN SOLUBILITY IN FRESH WATER VERSUS TEMPERATURE (AT ONE
ATMOSPHERE) .......................................................................................................................... 8-17
FIGURE 8- 4 SALT (KCL & NACL) CONCENTRATION VS. CORROSION RATE............................ 8-17
FIGURE 8- 5 EFFECT OF PH ON CORROSION OF IRON ............................................................... 8-18
FIGURE 8- 6 APPROXIMATE DISTRIBUTION OF H 2 S, HS – , AND S = AS A FUNCTION OF PH....... 8-18
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 8-i