Petroleum Software esmerMPFM Multiphase Flow Meter

The esmerMPFM from Petroleum Software Ltd (PSL, Kingston upon Thames, UK) measures the flow rates of every phase in an oil or wet gas production line without separating the stream first and without a radioactive source. PSL describes it as a light, compact meter that can sit permanently on one well or travel on a light truck for well testing.

What the esmerMPFM is made of

The system has two assemblies and one software package. The field unit sits in the process line. The flow computer assembly is a small Exe enclosure holding the 24 V power supply, the digital converters and a PC. The software, esmerDigital, runs on that Windows PC and performs the signal processing, display, archiving, reporting and network output.

Two field unit models exist. esmerDual uses a cone as both the flow element and the impedance probe, and the cone is retrievable for maintenance and replaceable to change the turndown ratio. esmerGSE uses a conventional venturi or cone for total flow and a quarter-inch bypass line carrying an impedance probe for water cut. Both use an industry standard multivariable transmitter for flow and PSL's own esmerMux impedance transmitter for water cut.

Technical specifications

How the measurement is calculated

esmerDigital executes fluid dynamic and equation-of-state flow models in real time and determines the physical properties and the phase flow rates second by second. The factory model for the cone or venturi discharge coefficient comes from PSL's own multiphase flow loop tests. The equation-of-state model is built from compositional PVT data supplied by the user. Both are tuned in the field with esmerConfigurator, using separator measurements or samples taken from the esmerDual bypass. PSL states that the tuning procedure and tools comply with API 2566 guidelines, and that the technology has been tested in laboratory and field trials since 1997 and used in well testing since 2002.

Fixed and mobile installation

As a fixed meter the field unit can be dropped into the line horizontally or vertically, with or without a box frame, and needs an equipment room for the flow computer. As a mobile meter the field unit is mounted on the deck of a pick-up or a small trailer, the flow computer fits in the double cabin, and operators run esmerDigital on a notebook PC. Power use is low, so mains, a portable power station charged from a solar panel, or a vehicle charger can supply it.

Selecting and ordering

Because accuracy depends on PVT data quality, GVF and flow rates, give the line size, pressure, temperature, expected rates and a compositional PVT report when you request a quotation. Related meters in the same family include the flowmeters range.

Technology background and typical uses

The name esmer stands for Expert System for Multiphase Measurement. PSL describes it as a patented technology that combines conventional fluid mechanics with flow regime identification using neural nets. Petroleum Software Limited was founded in 1992 as a spin off from Imperial College of Science and Technology, and its esmer meters have been used in on-shore and off-shore well testing since 2002.

Because the field unit is compact and light, the same instrument suits several duties: a dedicated meter on each producing well so that rates are available continuously rather than at periodic test intervals, a mobile well testing set that moves between wells on a light truck, and a meter that can be tuned against a test separator already on site. The low power draw and the single power and single data cable also keep the installation work small, which matters on remote wellheads and temporary test locations.

Information to send with an enquiry

PSL states that a specific accuracy target is provided for each application, so the quotation depends on your data. Useful inputs are the pipe size and flange class, design and operating pressure, maximum temperature, expected oil, water and gas rates, the range of GVF and water cut, whether the meter will be fixed or mobile, and a compositional PVT analysis of the produced fluid. If a test separator is available on site, say so, because separator results can be used to tune the factory calibration to the field.

Checking the meter after installation

General engineering note (not from the brochure): a multiphase meter is only as good as its tuning to the real well fluid. After installation, plan a comparison period against a test separator or a tank gauge, take liquid samples to confirm water cut, and record the PVT data used by the software. Repeating this check when the well conditions change, such as after a new water breakthrough or a change in choke, keeps the reported phase rates close to reality and gives the production engineer confidence in the numbers.

Documents and quotation

The manufacturer brochure is available as a download on this page. Seven Star LLC is an independent supplier in Muscat and prepares quotations on request; no prices are published here.