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8 DRILL PIPE CORROSION
Review of mud system developments over 40 years, relative
to corrosion protection for downhole tubulars, including system
descriptions and case histories.
The following text presents an overview of drilling fluid
systems and related corrosion tendencies for muds in use from the
1940s through the mid – 1990s. It speculates on future techniques
and coatings. Important technical concepts included within the
period-oriented discussions include:
Key points of the systems;
Chemical characteristics that affect corrosion;
Proper care and handling of tubulars;
Case histories.
Further discussions include recommendations for handling
specimens for analysis, and speculation on the future concerning
drill pipe, coatings and techniques.
Figure 8.1 – Drill pipe corrosion
Early Mud Systems
In the 1940s and 1950s, some very-high-alkalinity drilling
fluids were used. Some were based on the high-pH sodium silicate
chemical mixed with a salty base fluid. It seems that drill string
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