Having an effective Condition Monitoring CdM Program on large assets has been proven to be valuable on Reciprocating Compression fleets. Recently, one of our long standing clients had reported low flow rates to their sales meter from a pair of compressors at a large gas gathering facility. This was concerning to the plant operations and production staff as the potential flow loss would equate to a loss of $2000 per day even at the lower gas costs of today’s markets.
Utilizing our Windrock analyzer and years of experience, within minutes of evaluating each machine, our analysts identified that the compression health was acceptable. There were no performance robbing issues such as gas recirculation due to ring or valve leakage and performance was excellent. As an additional service, we completed an ultrasonic survey of any potential re-circulation or leak points such as packings, process drain valves, flare valves, bypass valves or vents from vessels between the meter and the compressor to ensure there were no potential leakage or re-circulation sources. From that data it was determined that the combined flow from the compressors was well above the reported flow at the plant sales meter location.
The compressor health was verified, the potential leakage points were evaluated, and the overall flow rate for the compressors were deemed to be within the acceptable range for the units known load. With that information in hand the next logical step was to verify the plant flow meter for these units. There were multiple in-process live checks and online drains made to the meters while the units were in service with no change in results. It was not until the meter was serviced during a plant outage that the discrepancy was found with the meter calibration and was corrected. The calibration of the meter was being affected by foreign matter in the system and was not able to be cleaned while in service.
Days after the repair, the metered flows matched the compressors calculated flows from the analysis data. Plant performance was always being optimized by our analysts on our quarterly inspection interval and monitored. Now looking back at the flow discrepancy of the plant meter and compressor output, the real value of this error came under investigation.
The estimated loss of revenue due to the meter error was near $400,000 for the time between the first reporting of the flow loss and the service of the meter system. Up to the service, the compressor flow was not deemed correct and there must be some issue with one of the compressor’s performance. The analyzer data collected and verified by our analysts put the investigation back on track to determine the actual cause of the lost flow.
In the modern age, there is a lot of trust placed on electronic metering and reporting systems without first ensuring that the systems are correct. The ability to have the access to mass data has given all of us a false sense of security to deem that data as credible. We are entering an era where the DRIP (Data Rich Information Poor) syndrome is ever present and we are left to sift through mass amounts data to find the actual key points that matter.