API RP 85-2003 pdf free download

API RP 85-2003 pdf free download.Use of Subsea Wet-gas Flowmeters in Allocation Measurement Systems.
4 Subsea Meter Calibration and Testing 4.1 GENERAL This section addresses testing and calibration of meters that is performed for the purpose of qualiÞcation, prior to installation for actual Þeld operation. The status of multiphase measurement for wet gas service is immature. Accepted calibration practice uses test and pro- duction separation techniques, which rely on separation and metering of each individual phase to known standards by tra- ditional methods and metering equipment. Further complicating the situation is the subsea location of these meters when in service. This means that not only are they unavailable for removal and veriÞcation of their perfor- mance, but that even routine test and inspection of sensors and other components is extremely difÞcult. The following describes what reference loop testing is required prior to a meterÕs being declared qualiÞed for subsea wet-gas service, what these reference facilities must possess in order to be certiÞed as Þt for the task, and what a success- ful calibration test should entail. 4.2 TESTING REQUIREMENTS The nature of multiphase ßows is complex. It is much more difÞcult to assure the reproducibility of ßuid ßow behavior at ßow measurement sectionsÑat different installation locations and through service lifeÑthan is the case for single phase ßow. This results in a signiÞcantly higher degree of uncer- tainty in meter calibration for multiphase applications.
4.2.1.1 Installation Pipework. Depending on the tech- nique of multiphase ßow measurement and the type of sensor technology used, the meterÕs response may be inßuenced by geometrical details of the surrounding pipework. To the max- imum degree possible, the meter installation at the ßow facil- ity should be made to mimic that which will be implemented in the application. 4.2.1.2 Meter Size. Bulk ßow rates requiring a previously unqualiÞed meter size (both nominal diameter and meter opening) may necessitate testing of the speciÞc proposed meter type of that size. Depending on the technique of mul- tiphase ßow measurement and the type of sensor technology used, meter response may be inßuenced by geometrical, dimensional and material speciÞcations. The extent of the testing will be dependent on the meterÕs performance during testing as compared with previously qualiÞed similar meters of a different size. 4.2.1.3 Fluid Properties. Meter response also depends on how sensors respond to changes in ßuid properties such as salinity (conductivity), viscosity, density, etc. Consideration must be given to how closely the test facility can replicate the ßuid properties expected. Furthermore, this and the pipework discussed above are the determining factors of ßow regime. It must be demonstrated that the ßow regimes tested are repre- sentative of those which are expected to be encountered in practice. 4.2.1.4 Operating Range. The proposed test facility should, to the maximum extent possible, operate over a simi- lar range of phase ßow rates, pressures, and temperatures to that expected in the application. It is recommended that test- ing be performed extending the operating range into antici- pated transient start-up temperatures and pressures.
4.2.3 Factory Acceptance Testing (FAT) It is recommended that at the factory of the supplier, or at another location agreed to by the parties, each meter, meter component, and the complete meter system be operationally tested. Testing of individual meters or components should be con- ducted under as realistic conditions as possible over a reason- able range of input conditions, noting any deviations from speciÞcation. In testing the complete metering system, it should be con- nected as it will be when installed subsea. This may or may not require an actual ßow test, but should demonstrate the complete suite of functionality which will be employed when the metering system is in actual operation. In this activity all aspects of the meters, meter components, and metering system operation should be simulated, and the response of the system observed. Any errors or anomalies should be noted, and either corrected or explained prior to the systemÕs deployment. 4.3 FLOW TEST FACILITIES Flow testing shall be carried out at a ßow laboratory which is capable of matching the requirements of the application as detailed in 4.2.1. These ßow test facilities may be specially built reference facilities, or may be part of a hydrocarbon pro- duction or transportation facility. The ßow test facilities shall provide for witness testing, for traceability and calibration documentation, and for all pertinent facility and test data records. Test program management protocols shall assure the interests of all investing parties, and shall impose and enforce an agreed demarcation on what test data constitute calibra- tion, validation and repeat test points respectively