Experience from implementing a metering solution for subsea and topside multiphase flow metering

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Rodney Ellis
7 years ago
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1 Experience from implementing a metering solution for subsea and topside multiphase flow metering by David E. Olaussen, FMC Technologies Co-Author: Kåre Kleppe, Statoil ASA

2 Content Introduction Best Practice Statutory Requirements Typical Topology Software Functionality Topside & Subsea Multiphase Meters Uncertainties in PVT calculations Testing and verification Methods and uncertainty levels

Topside & Subsea Multiphase Meters Uncertainties in PVT

3 Introduction Statoil has more than 20 years of experience operating multiphase meters and have approximately 230 meters installed Multiphase meters is used on single wells, templates and on flow lines for both well allocation and ownership allocation metering Photo: Tor Alvseike Statoil ASA

meters is used on single wells, templates and on flow lines for both

4 Introduction FMCTI has together with Statoil for many years, collaborated on developing of common solutions for multiphase metering The solutions have developed into standards used on both new and existing fields Existing installations are often extended with subsea tie-in of new fields Independent of meter brand Photo: Anne Lise Tveit Statoil ASA

used on both new and existing fields Existing installations are often extended with

5 Statutory Requirements Reference is made to the NPD regulations, chapter IV, section 13 NPD Regulations: 7. Verification 8. Allowed uncertainty 18. Application for approval Operational requirements 29. Operational documentation

6 Best Practice Integrate the multiphase meters into a Metering Supervisory Computer On-line verification of multiphase meters Use PVT calculations Use HC mass for both allocation and verification Optimal test separator instrumentation and design

multiphase meters Use PVT calculations Use HC mass for both

7 Typical Topology

8 Typical Configuration Choke Test separator Metering Metering Metering Gas Oil Water Choke Gas Topside Multiphase meters Inlet separator Oil Topside Water Subsea Gas lift Field A W1 W2 Subsea Multiphase meters Gas lift Field B

Multiphase meters Inlet separator Oil Topside Water

9 Typical Process Model

10 Data Flow and PVTpack κ w _ 0 20 [ ms / m] P,T ρ [ kg w / 3 m ] ρ w [ kg / Sm 3 ] Q Q ρ ρ o ρ g [ kg / m [ kg / 3 3 m ] ] ' Z ( MPFM) P,T Q g Q o Q v P,T [ t / h] [ t / h] [ t / h] Z Q o Q ρ o Q w ρ w [ kg / 3 Sm ] Q w ρ w

11 Topside MPFM For the topside multiphase meters, changes in the PVT input data (composition) will change due to the relative production from the different wells or reservoirs With known fluid compositions of wells and reservoirs, model-based PVT-input to the topside multiphase meters should be implemented Samples of produced gas and liquids should always be planned for Photo: Statoil ASA

compositions of wells and reservoirs, model-based PVT-input to the topside multiphase meters

12 Subsea MPFM Used for well optimisation and monitoring Can act as a back-up for the topside multiphase meters Subsea multiphase meters flow rates should be continuously compared to the topside multiphase meters The use of gas lift on the well head must be taken into consideration for the PVT input data Photo: FMC Kongsberg Statoil ASA

continuously compared to the topside multiphase meters The use of gas lift on the

13 Software Functionality PVT Calculation of all measurements and converting to standard conditions (mass and volumes) Verification of topside multiphase meters Calculation of PVT data input for the topside multiphase meter and test separator including gas lift On-line supervision of the deviation between subsea and topside metering Generating reports for all verifications and parameters change (including the composition)

multiphase meter and test separator including gas lift On-line supervision of the deviation between

14 Software Functionality Optional use of gas lift must be included in the well composition by an on-line composition mixing The metering system will collect all relevant data and measurements in a unified system in which all measurements will be compared without further conversion and correction

will collect all relevant data and measurements in a unified system in

15 Requirements: Uncertainty in PVT Calculations A high quality updated analyze of the fluid composition A known GOR at test separator P&T Possibility to automatically adjust the composition (densities) to match the measured GOR The composition mix is not close to its critical pressure and temperature

Possibility to automatically adjust the composition (densities) to match

16 Uncertainty in PVT Calculations The uncertainty in PVT calculations is estimated by Calsep to be: Fractions 5% Oil and gas density 3%

17 Testing and Verification Continuously monitor the HC mass an water flow between subsea and topside meters Calculate an average weekly deviation between topside and subsea meters Initiate actions if the average deviation is > 10% Perform well testing in order to identify source of the deviation More extensive test programs should be performed only when observing considerable deviations between topside and subsea flow measurement The test separator should be used periodically for verification and calibration of the topside multiphase meters

identify source of the deviation More extensive test programs should be performed only when observing considerable deviations between

18 Methods and uncertainty Uncertainty Level levels Production measurement method To be verified against 1 Topside Test Separator Measurements Normal maintenance procedures. 2 Topside Multiphase Meter Topside Test Separator Measurements 3 Sub-sea Multiphase Meter Topside Multiphase Meter 4 Topside Choke Setting Sub-sea Multiphase Meter 5 Sub-sea Choke Setting No available reference

2 Topside Multiphase Meter Topside Test Separator Measurements 3 Sub-sea Multiphase Meter

19 Thank You! Any questions?

Roxar Multiphase meter 2600 Class - Turning information into value

Roxar Multiphase meter 2600 Class - Turning information into value This presentation is provided for information purposes only. It should not be used or considered as an offer to sell or a solicitation