Multiphase Flow Metrology in Oil & Gas Production (MULTIFLOWMET II)

Funder

H2020 Euramet EMPIR

Value

Coventry University: 79,437.44

Total: 2,291,951.20 Euro

Collaborators

Prof Andrew Hunt, Atout

Partners

NEL TUV SUD Limited (United Kingdom ), Cesky Metrologicky Institut (Germany),  Physikalisch-Technische Bundesanstalt (Czech Republic), VTT Teknologian tutkimuskeskus VTT Oy (Finland), Christian Michelsen Research AS (Norway), Cranfield University (United Kingdom), DNV GL (Netherlands), B.V. (Netherlands), ITOMS Industrial Tomography Systems Plc (United Kingdom), Onesubsea Processing AS (Norway), Petroleum Software Limited (United Kingdom), Roxar Flow Measurement AS (Norway), Tea Sistemi S.p.A (Italy), Coventry University (United Kingdom), University of Leeds (United Kingdom), Haimo International FZE (United Arab Emirates), ROSEN Germany GmbH (Germany), Schlumberger Oilfield (S) Pte Ltd (Singapore 1), VNIIR Federal State Unitary Enterprise "All-Russian Research Institute of Flow Metering" (Russian Federation)

Team

Dr Manus Henry (PI)

Duration

1 June 2017 to 31 May 2020

Project overview

Europe, and the world, will be dependent for many decades to come on the production of oil and gas for its underpinning energy needs. Multiphase flow measurement is a fundamental enabling metrology in subsea oil and gas production. However, field measurements exhibit high measurement uncertainty, costing industry billions of euros in financial exposure and production inefficiencies. To improve this situation requires a reference measurement capability that is consistent and comparable across different test laboratories that offer this service. This project will address this need by establishing harmonisation of measurements between multiphase flow reference laboratories.

Project objectives

1. To optimise, and fully prepare for, the intercomparison testing programme by building a transfer package) whilst taking into account leading-edge methods of flow pattern visualisation and producing a comprehensive set of test matrices and protocols.
2. To carry out intercomparison testing across a network of laboratories with appropriate facilities in order to significantly extend the test envelope, in terms of flow rates (up to 120 m3/hr for liquid and 1000 m3/hr for gas), pressure (8 bar to 24 bar), and fluid properties (oil viscosity including the range of 3 cSt to 9 cSt). The intercomparison testing will include appropriate leading-edge methods of flow pattern visualisation and will be done across meters incorporating a range of technologies (e.g. Venturi, cross-correlation, gamma ray absorption, electrical impedance sensing, Coriolis and phase separation technologies).
3. To further develop modelling (e.g. computational fluid dynamics (CFD) techniques for significantly improving the metrological characterisation of multiphase flows, using small and full-scale experimental testing. Improvements will come from new data that will allow flow regime map(s) to be extended and/or new one(s) created. This will include additional research to understand geometrical influences and the influence of gas phase activity.
4. To make statistical cross-comparisons between the measurements undertaken in each intercomparison laboratory with a view to establishing comparability of measurement between test nlaboratories. The analysis will compare findings, identify anomalies, deduce their method of investigation and state the resolutions achieved.

Impact

Impact on industrial and other user communities

The results of this project will impact the oil and gas community that is becoming increasing reliant on multiphase metrology as part of subsea engineering allowing lower-cost exploitation of new fields. It will do so by creating an enlarged, comparable network of multiphase flow measurement reference facilities. This will provide oil and gas operators (the instrumentation end-users) and instrumentation developers with a renewed confidence in the testing and reference measurement infrastructure. In turn, this will lead to lower uncertainty of measurement and greater confidence in the deployment of multiphase metering technology.

Increased confidence and lower uncertainties of measurement associated with multiphase metering reduces both financial exposure and risk, as well as enabling better operational efficiency. This occurs at two levels;

• Operational decision-making – multiphase flow measurement data are key to deciding if (at the assessment stage), when and how a particular field will be exploited, balancing capital investment against revenue potential at set-up, then optimising conditions when the well is in production.
• Allocation (and fiscal) exposure – arising from uncertainty regarding how much of each operators production is being commingled into common networked flowlines. There is also significant financial exposure related to uncertainty of measurement for the application of taxation.

An end-user advisory group has been established, the members of which have been invited to the project progress meetings and been copied for comment on the project’s key draft documents. In addition to the endusers from within the consortium, there are also external members from:

• Oil & Gas Authority (UK industry regulator)
• Norwegian Petroleum Directorate (Norwegian industry regulator)
• Nexen Petroleum (international operator in UK sector)
• Apache Corporation (international operator in UK sector)
• ISO TC/28 (International Standards Organisation responsible for TR on multiphase oil & gas measurement)

Further to this, the project will produce a case study for demonstrating to end users how the outputs of the project could be used, to reduce uncertainty and increase end-user confidence in the metering technology being evaluated. The partners will work with the end user advisory group to develop a case-study that is realistic, to maximise impact. The case study will then be advertised through the end user advisory group and on the project website.

Impact on the metrology and scientific communities

A key benefit for the European flow metrology community is that it is the first step in establishing a long-term Key Comparisons programme for NMIs and other commercial and non-commercial laboratories. Key elements will be harmonised uncertainty budgets, intercomparisons, auditing and accreditation, as has existed for single phase flow metrology activity for some decades. For multiphase flow metrology, the preceding EMRP project ENG58 has already made significant progress in the former two and this project will build on these as well as producing three Good Practice guides for practitioners from end-user groups.

The Good Practice guides will be on 1) Good Practice guide on general preparation and approach to multiphase intercomparison testing, 2) Good Practice guide on the acquisition of experimental data for the determination of multiphase flow patterns and 3) Good Practice guide for minimising uncertainty of laboratory flow reference measurement.

The Good Practice guides will be published on the project webpage and will also be disseminated to the metrology community and end users through the end- user advisory group and project partners.

Impact on relevant standards

There exists a timely and unique opportunity for this project to influence standardisation in a major way, as ISO TC/28 (Petroleum products) has begun work on a new ISO standard on Multiphase Flow Measurement.

The project team will meet on a regular basis with the drafting committee to both influence, and be influenced by the new standard as it develops. Other standards committees through whom the project outputs may also be exploited include ISO TC/30 (Flow measurement in Close Conduits), ISO TC/193 (Natural gas), the Energy Institute’s Hydrocarbon Management Committee, EURAMET TC Flow and the American Petroleum Institute Manual of Petroleum Measurement Standards (API MPMS) Chapter 20.3 - Measurement of Multiphase Flow.

Outputs

Objective 1 – Preparation for the intercomparison testing programme

Specification and provision of the measurement transfer package.

This consists of common instrumentation and other physical elements that are deployed alongside the MPFMs at each laboratory. Designs for the different sub-system components have been proposed. These include the mechanical design by NEL of two transfer packages – based respectively around a 2-inch MPFM supplied by PSL and around a 3-inch MPFM supplied by Roxar, both of which include a high-pressure qualified optical section for observation of flow patterns. Two tomography systems have also been agreed for use with the 3-inch transfer package, these being supplied by ITOMS and UCov.

Test matrix and protocols

A test matrix defining the test points, in terms of laboratory flow conditions, for optimally selected permutations of test laboratories and MPFMs is being developed. Agreement on test matrices is well advanced. Operating envelope capability from all participating flow loops and MPFM vendors have been analysed and compared in the process of defining the test matrices in terms of flow rates, water cut and GVF ranges. An agreed set of intercomparison testing protocols (methods) will also be agreed.

Logistics plan

This will include testing schedules, shipping details, detailing of customs requirements by country and definition of special licensing and/or certification requirements and the means of obtaining them.

Objective 2 – Execution of the intercomparison testing programme across the laboratories

Test laboratory data

Component flow rates will be measured for each test matrix point from each test laboratory in turn. Reference meter outputs, pressure and temperature will also be measured.

Multiphase Flow Measurement (MPFM) data

Component flow rates and appropriate raw data outputs e.g. differential pressure will be measured for each of the MPFMs.

Two sets of data (laboratory reference meters + MPFMs) from the NEL facility will be taken under identical conditions, at the start and end of the test programme, to rule-out (or detect) drift in any of the instrumentation.

Flow pattern experimental evidence - tomography and viewing section video footage.

These data will require subsequent analysis before yielding numerical or other results e.g. flow pattern categorisation.

Objective 3 - Further development of modelling techniques

Inter-laboratory analysis

An analysis of the inter-laboratory differences has been carried out, including the geometrical variances, as a focus for the modelling work. It has led to the identification of key configuration features that may be associated with recorded measurement variances between laboratories. The iterative process of gathering information from the participating laboratories has allowed the definition of fully-instrumented experiments at CU to ensure greater granularity in data collection for the CFD modelling exercise.

Small-scale modelling

Results from small-scale experimental modelling will be conducted to better quantify the key inter-laboratory influences, such as those above.

CFD simulations

A number of CFD simulations will be produced that can be validated against small-scale and full-scale experimental data and, thereby, support data rationalisation in the intercomparison test programme.

Full scale experimental research

Using the NEL and DNV GL facilities further experimental research will be carried out at full scale, to assist with intercomparison data rationalisation directly as well as provide additional verification data for the modelling processes.

Objective 4 - Cross-comparisons between measurements undertaken in each laboratory
Intercomparison analysis.

A full analysis of intercomparison data will be undertaken, to compare findings, identify anomalies, deduce their method of investigation and the resolutions achieved.

Intercomparison conclusions

A set of conclusions will be produced, summarising where good measurement agreement has been obtained between laboratories across a range of MPFM technologies.
Intercomparison comparison.

A case-by-case summary will be written covering any areas where good measurement agreement is not obtained, detailing the analysis carried out to rationalise any measurement variances together with the results.

Additional information

The world will be dependent for many decades to come on the production of oil and gas for its underpinning energy needs. Over half of the world’s energy demand is satisfied from oil and gas. When oil is extracted from a well it typically exists as a multiphase flow, comprising time-varying ratios of oil, water and gas. Measuring the flow rate of each component is an underpinning metrology requirement of sub-sea production, a direction in which the industry has been moving for a number of years.

Typical multiphase flow measurement systems can have an uncertainty on component flow rate of 20% or greater under field conditions. The financial exposure alone from this uncertainty is difficult to quantify but thought to be in the region of many $ billions. There is also the cost of production inefficiencies and sub-optimal decision-making that can result from the stated measurement uncertainty. Despite this, the industry has struggled to improve upon these levels of uncertainty.

Beside the intrinsic complexity of the fluids and the relative infancy of the technology, lack of standardised facilities (and procedures) for testing MPFMs for either development or evaluation purposes, is seen as a major barrier to the ongoing development and improvement in multiphase metering technology.

The project has addressed this problem by creating the world’s first multiphase measurement harmonisation. The preceding EMRP project ENG58 MultiFlowMet developed and piloted an approach for such harmonisation and this follow-on project is applying the harmonised approach to an enlarged network of laboratories, covering a wider range of flow conditions with applicability across a wider range of multiphase meter types.
This joint research project is funded by EURAMET and involves eleven partners from across Europe.