API RP 86:2005 pdf download

API RP 86:2005 pdf download.API Recommended Practice for Measurement of Multiphase Flow.
Downhole Meters. Finally, it is now possible to measure flow rates of thc multiphase constituents as thcy leave the reservoir using downhole meters. Although meter design and operation is far more difficult than at surface conditions, the how regimes encountered there may be more benign. and therefore easier to deal with from a measurement perspective.
In Section 6. a number of spcciali7ed applications of these general measurement methods are discussed.
4.4 MEASUREMENT UNCERTAINTY
Perhaps the most important single factor in the development of a strategy for well rate determination is the uncertainty in measurement that will result from various alternative schemes. However, because of the extremely complex nature of multiphasc flow, there is no single number or curve, which can describe Ehc pcrformancc of a measurement approach over the complete range of conditions which will be encountered in practice.
Because of this high level of complexity. a large portion of this Recommended Practice is devoted to the subject of measurement uncertainty. Some of the following topics are covered in Section 8 and its companion Appendix A:
• Commonly Used Uncertainty Standards and Methods
• Uncertainty Methodology
• Requirements for Presentation and Specification of Uncertainty
• Metering Performance Sensitivities
• Uncertainty Changes During Field Life
• Uncertainty from Calibration Measurements
• Efkct of Influence Quantities on Uncertainty
• Uncertainty Verification
4.5 MULTIPHASE METER ACCEPTANCE, CALIBRATION AND VERIFICATION
Once a particular solution has been chosen for an application, procedures are required to demonstrate that the system is
indeed satisfactory for the task at hand, not just initially but on a continuing basis.
Some aspects of this process arc the following:
• Test Facilities. There are a limited number of multiphase flow facilities in the World. The facility used to prove a
method’s worth is of interest.
• Acceptance Tests. The program of acceptance testing and acceptance criteria, at the factory or elsewhere, is of
great interest.
• Meter (‘alibration. The methods through which the sensors and flow calibrations take place should be documented
and acceptable to both vendor and user,
• Performance Verification. In addition to verifying the meter’s performance when accepting it, it is crucial to know
that it is operating properly when in field operation.
4.6 INSTALLATION AND OPERABILITY OF MULTIPHASE FLOW METERS
When installing measurement equipment, whether on a topside platform. inland facility, or on the sea floor, it is clearly of great importance that the proper installation and normal operation be well understood and documented in detail. For this reason, a section is devoted to recommend procedures for insuring that this is, in flict. both documented and achieved in practice.