Watson Millican experts were requested to provide the buyer an independent analysis of the ethylene measurement performance, practices and measurement data to determine if a custody transfer measurement issue existed. Watson Millican experts visited the seller’s and buyer’s facilities to witness the ethylene meters on both sides of the custody transfer point, were provided the ethylene meter measurement data from both the seller’s and buyer’s meters, and the records of the seller’s and buyer’s meters’ checks and calibrations. The buyer also provided their internal ethylene mass balance analysis for review.

Watson Millican experts performed a statistical analysis comparing the seller’s and buyer’s respective measurement data across time to assess whether either set of data exhibited the introduction of bias or other unexplained variances (error) over the defined period. The conclusion was that the variance witnessed between the seller’s and the buyer’s measurement was within the allowable variance for the type and specifications of meters being used and that that the performance of the seller’s metering system and practices were equal to, if not exceeding, the performance of the buyer’s metering system.

Additionally, the buyer’s ethylene internal mass was analysed and found to not be persuasive as a reliable indicator for the ethylene custody transfer measurement. Watson Millican experts recommended that the buyer consider upgrades to their ethylene metering system and to work more closely with the ethylene seller. Areas for cooperation included improving review of the other’s ethylene measurement practices and performance to identify custody transfer concerns sooner and to work to resolve them cooperatively to minimize the financial risk to both parties should the ethylene custody measurement system on either side begin to be in error.