A misrun occurs when a wireline logging tool, drill stem test, or other downhole diagnostic equipment fails to record usable data. This failure is usually caused by tool malfunction, operator error, or adverse wellbore conditions like washouts or extreme temperatures. Because rig time is highly expensive, a misrun forces crews to pull the string, fix the issue, and rerun the test, resulting in significant delays and financial loss.
Heard on the job
We pulled the logging tool after three hours downhole only to find a misrun because the battery pack shorted out.
Insider tip
A misrun is rarely treated as just a technical glitch; it usually triggers an immediate investigation by the company man to determine who absorbs the cost of the lost rig time.