7 Field Application Comparison Conditioning Type Orifice Plates (4-holed) and Generic Cone Meters Mark W. Davis, Senior Staff Engineer Shell Exploration & Production Co. Inc. Houston, Texas USA Philip A. Lawrence, Director of Business Development Cameron Measurement Systems, Inc. Houston, Texas USA
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• Allocation measurement of produced hydrocarbon gas inthe upstream area require different measurementtechniques and strategies than those used for standardpipeline quality gas measurement
• Wet Gas, Hydrate Formation, Liquid Slugging, well clean-up debris and short meter runs all add to the difficult task ofcollecting meaningful data from High Pressure Full Well
Stream (HPFWS) allocation metering points.
• Various meter types have been employed for these flowregimes in order to meet the necessary accuracy
requirements and the arduous duty
• This paper details the real world experience of such aallocation metering system operating in Wyoming, USA.
Field Location• The location of the subject field is in West Central
Wyoming consisting of remote well pad locations where
access can pose problems during the winter months dueto various environmental factors such as weather andanimal migrations.
• From a sustainability standpoint, the remotemeasurement systems must operate effectively withminimum maintenance during these months with limitedaccess
• The measurement systems installed at the locationsshown use full well-stream metering and are adjusted byusing a well test separator to calculate the volumecorrection factor for the wet gas metering.
The environmental issue is one of keeping the productionfacilities to the smallest footprint possible, due to the impacton the local wildlife particularly the mule deer which use the
• Continuous readings are taken during the well testingprocess.
• The test separator gas volumes are compared to the(HPFWS) Differential Pressure Meters (e.g. Cone Meter,Conditioning Orifice Plate, or similar devices) readings.
• From this data gas volume correction factors calculated.
• Once the gas volume correction factor (GVCF) is obtained,the gas only volumes from the HPFWS Meter is used tocalculate liquid volumes
• The well test is used to calculate a daily well theoreticalcontribution percentage for oil, water, and gas. Thispercentage is calculated using algorithms involving thedaily readings from the HPFWS Meter and the well testfactors.
• The daily sales are then allocated to each well based oneach wells calculated contribution percentage. The fiscalallocation occurs when the daily sales readings are
replaced with final sales readings and the same dailytheoretical contribution percentage is applied.
• The use of Differential Pressure Technology (D.P.) tomeasure the full well stream wet gas was favoredbecause these types of devices appeared to be less
susceptible to the effects caused by the multiphaseaspects of the fluid and correction can be done from thewell test data.
• Since a correction factor / allocation factor is calculatedfor each well location the most important requirementsare that the full well stream meter is robust, has a
predictable and repeatable operating envelope, and isrepresentative between well tests. (Usually 24 hrs 1 xper month to develop the GVCF)
• A well test manifold is installed in the flow linedownstream of the HPFWS meters. There are chokessituated upstream of the HPFWS meters on most of the
locations.
• Samples are taken at least semi-annually from each gas
and condensate stream.
• Shrinkage factors are applied to the gross volume
obtained by the well test separator condensate/oilturbine meters to determine the net stock tankcondensate volumes.
• Beta RatioThe effective area ratio for all differential
pressure devices is a function of the restrictionversus the pipe area, the manufacturer’spublished data sheet table for the four holedplate meter shows the beta ratio calculation for
Differential Pressure Cone Meter• All Cone Meters (non-wall tap design) consist of a conically shaped
differential pressure producer fixed concentrically in the center of a
pressure retaining pipe using a cantilever member, by which adifferential pressure can be obtained across the interface of twocone frustums via an internal portway system.
• It is known from research that the use of a cone shapeconcentrically mounted in a closed conduit (pipe) can
facilitate a flow conditioning effect by “velocity profile re-distribution”.
•This effect seems to occur over quite a wide ReynoldsNumber (ReD) range and appears to be enhanced fartheraway from the transition region and also as a function of betaratio.
• Various generic cone meters supplied by CameronMeasurement Systems were tested at the ColoradoEngineering Experimental Engineering Station (CEESI)facility in Nunn recently for the API chapter 22.2 test
protocol requirements.
• Test results for a 2 inch 0.45 beta meter which involved afull suite of disturbance testing is shown next.
•The test is extreemly aggressive incorporating ½ moonplate testing , O.P. elbow test , swirl generator test.