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Production Well Testing Using Non-radioactive Multiphase Flow Meters
Figure 2: Rule of Thumb for Multiphase Flow Meter Classification
Cost–Benefit Analysis – Non-radioactive versus
Radioactive Multiphase Flow Meters
Field conditions Non-radioactive MPFMs, without sacrificing accuracy, are much
In-line meter Separation Wet gas
cheaper in terms of construction, as they do not use any additional
meter meter
gamma sensors, as utilised by radioactive MPFMs. On top of
the extra construction costs for the latter, the cost related to the
export/import of radioactive equipment is higher due to the nature
0% 85% 95% 100%
of the goods, which require specialised packing and clearance.
0% GVF Oil 100% GVF
Additionally, the intangible cost of handling export/import
100% water cut Oil 0% water cut
procedures for radioactive equipment can be very tiring in almost all
(Wide range of non-radioactive MPFM applications)
countries, as it takes at least three to 12 months to complete the
process of delivery after innumerable clearances from different
GVF = gas volume fraction; MPFM = multiphase flow meter.
statuary bodies. In addition, the operational expenditure when
Figure 3: ESMER Non-radioactive System Installed at
operating a radioactive system can be enormous due to various
Offshore Platform for Well Testing health, safety and environment (HSE) requirements. Hence, MPFMs
are cheaper and more beneficial for operations.
Advantages of Non-radioactive Multiphase Flow Meters
Non-radioactive MPFMs are an example of the saying ‘all good things
come in small packages’. Irrespective of the type of non-radioactive
MPFM system, these units have small footprints, weigh much less than
conventional systems and have high mobility for fast implementation.
Other advantages of non-radioactive MPFMs are outlined below.
Realtime Data
Digitised data acquisition allows realtime on-line readings of oil, gas
and water flow rates, GVF, water cut, line temperature, line
pressure, density and velocity. Once these data are logged into the
The categorisation of is based on the MPFM’s ability to handle GVF MPFM software, it is possible to: view graphical trends of ‘flow rate
contents and water cuts, always keeping accuracy in mind. versus time’ per well, ‘GVF versus time’ per well and ‘water cut
versus time’ per well; view historical data and trends (data archiving);
Effect of Gas Volume Fraction generate daily/weekly/monthly/yearly reports; and log files – nearly
As the GVF of the flow stream increases, the level of accuracy of the all of the well test information needed by a production and facility
liquid (oil and water) rate determination by a non-radioactive and/or engineer for making quick and responsive decisions.
even radioactive multiphase metering system is adversely affected.
Multitier Data Integration
Effect of Water Cut The data are stored in a database, and it is possible to transfer the
As the water cut in the flow stream increases, it becomes more data into a multitier system in a corporate database management
difficult for a multiphase metering system to achieve high levels of system for easy information management. Also, MPFMs can be
accuracy for the oil phase, which is frequently the major focus of the connected to an existing/future SCADA system through third-party
measurements. Hence, based on field conditions, the rule of thumb interface protocols, allowing complete open connectivity and data
for MPFM types shown in Figure 2 can be utilised. exchange via any of the available communication backbones.
The Challenge Capital Expenditure Savings –
In-line meters with no need for separation are predominantly referred Light Weight and Small Footprint
to as true MPFMs in today’s world. Since their commercialisation in MPFMs weigh less than 10% of their conventional counterparts with
1990, major research and development (R&D) efforts have been made equivalent capacities and also have a very small footprint. This is a very
to extend their capabilities for the full range of 0–100% GVF and important advantage of MPFMs, as it allows large capital expenditure
0–100% water cut measurements with minimum or no need for (CAPEX) savings when installing these systems on offshore platforms,
auxiliary systems such as separators, tracer techniques, etc. as the platforms can be designed for smaller loads and can have extra
space for other things. These savings can sometimes run into several
Among the many highly accurate commercial non-radioactive MPFMs, millions of dollars, so even before you install an MPFM the
probably only one (see Figure 3) – or very few – uses the advanced justifications are there to impress your management.
technique of intelligent metering coupled with other electromechanical
sensors and has proved its performance in the full range of 0–100% Low Cost – Most Suitable for Marginal Fields
GVF and 0–100% water cut. For performance data for this system, Non-radioactive MPFMs tend to be much cheaper than radioactive
please refer to the ‘Conclusion’ section of this article. systems and conventional test separators. The running costs for
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EXPLORATION & PRODUCTION – VOLUME 7 ISSUE 1
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