Testing string material selection in environment with multiple deleterious gases

摘要

While testing a deep exploratory well located in Bohai bay in China, a large amount of carbon dioxide (CO2), hydrogen sulfide (H2S) and carbon monoxide (CO) was detected unexpectedly. Being afraid of their corrosiveness and toxicity, testing work was terminated immediately. After tripped out, the string was found to have been eroded severely. In order to keep going the exploratory work, experiment was made to investigate corrosion rate of carbon steel in environment with multiple deleterious substances. A main purpose was to determine if carbon monoxide has a strong impact on anti-sulfide steel PI 10S, which is low-cost and has been widely used in sour wells. Experiment result indicates that carbon monoxide has no obvious influence on corrosion rate in circumstances that carbon dioxide and hydrogen sulfide exist. Comprehensive studies show that P110S tubing can be used as testing string to carry out down-hole work. These results eliminated worries of decision-makers.