During the initial development phase of a new field operated by Abu Dhabi Marine Operating Company (ADMA-OPCO), due to the unavailability of processing facility, produced fluid is designed to flow into a pipeline operated by Zakum Development Company (ZADCO). The produced fluid is metered using two Custody Transfer Multi Phase Flow Meters (MPFM) with a normal operating philosophy of one-operating-one-standby and can be operated in series for verification purposes. This paper discusses the operational challenges for the custody transfer of ADMA fluid to ZADCO processing plant.
The challenges discussed in this paper are due to low production during commissioning and commingled production from multiple reservoirs.
During commissioning of the production platforms, the production was lower than the operating envelope of the meter. This would result in significant error in the meter readings. Since there was physical separation between the production facility and the metering is about fifteen kms away, the time lag between the meters and the production platform did cause further uncertainty in the measurement. To overcome this challenge a strategy was developed to meter the produced fluid with most accurate meters as available at each stage with consensus from both parties.
The commingled production from three reservoirs with significant difference in parameters posed challenge for the use of appropriate PVT properties in the custody transfer MPFMs for the conversion from line condition to standard condition. This was overcome by performing sensitivity analysis on the mixtures, developing PVT tables for commingled production ratios based on reservoirs and implementing a process on the selection of the appropriate table based on the changes in production contribution from the different reservoirs.
Other minor operational issues related to the MPFM metering are also discussed in the paper.