Schlumberger

Performance Report: SILDRIL as a Corrosion Inhibitor

Challenge: The Operator is using aerated muds to effectively drill depleted intervals and minimize problems related to lost circulation and stuck pipe. Oxygen corrosion is a major problem in drilling these intervals and various types of corrosion inhibitors have been used without any success.

Pakistan has been successfully using SILDRIL for a similar application in foam systems and sodium silicate is also used in other industries for corrosion control.

M-I Overseas proposed a three-well test program to evaluate the use of SILDRIL as a solution to control the corrosion problem.

Solution: Three wells were used to evaluate the use of sodium silicate as a corrosion inhibitor in aerated systems. Corrosion rings were used to monitor the performance.

Result:

Well #1 – 5-6% SILDRIL L
The system contained a high concentration of bentonite. The bentonite reduced the effective concentration of silicate. Corrosion was decreased but not to an acceptable level.

Well #2 – 7% SILDRIL L
The bentonite concentration was decreased to 5ppb and the SILDRIL L increased to 7%. Results improved with the corrosion rate = 1.6 lbs/ft2/yr.

Well #3 – 8% SILDRIL L
No bentonite and an increase in SILDRIL L reduced the corrosion rate to 1.0 lbs/ft2/yr.

Observations and Conclusions

SILDRIL L proved to be a successful corrosion inhibitor for the aerated KCl polymer fluid.

Benefits

  • Reduced mud cost
  • Reduced dilution
  • Reduced corrosion rate
  • Gauge hole with low mud weights in the Nahr Umr
  • Improved shale stability
  • Favorable drilling rates

Download: SILDRIL as a Corrosion Inhibitor (0.26 MB PDF)

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