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Periodic well testing is universally recognized as the primary method to determine the health of the wells and hence the reservoir. Most operators find that they fall short of their well test targets and are searching for ways to increase the frequency of their well testing .…more

Test separators are a viable solution for testing wells as long as their measurement envelope still fits within the operating conditions of the field. Even then, there are also other issues like separation efficiency, liquid carry-over in gas leg, entrained gas and foaming in the liquid leg, etc., which impact the performance seriously…more

Haimo has a flow loop established in the factory for the calibration and performance testing of the manufactured meters. There is also the unique and independent Daqing Oilfield Construction & Design Research Institute (DOD) facility, available as a 3rd party test loop, where the customers have the option to test the meters under live crude conditions.

The user base is spread out across China (onshore / offshore), Kazakhstan, Oman, Kuwait and Malaysia.

Current manufacturing base is in China.
Headquarters
Lanzhou Haimo Technologies Co. Ltd.
66 Minle Road, Qilihi District,
Lanzhou, Gansu 730030, P.R. China
Tel: 86 931 2886856/7
Fax: 86 931 2886853
Email: sales@haimotech.com

Meter is supported from China as well as the regional offices in Oman, Dubai and from Malaysia. Haimo believes very strongly in customer support and after sales service and constantly works with their customers in achieving this.

As we all know, the saleable commodity is Oil and every producer wants to have an accurate estimation of oil production from the well. The net oil flow rate from a well is a “calculated” figure from “two measurements” taken by the multiphase meters namely “water cut” and “gross liquid flow rate”. With higher water cuts coupled with higher uncertainties of water cut measurement, the net oil flow rate inaccuracy worsens.

Again, in some facilities, the operator is required to monitor the absolute volumes of produced water being separated from the well fluids as the figures may have an impact on the capacity of the production facilities to handle the increasing water flow rates. The impact is also felt in the cost of treating the produced water before it is disposed. So the accurate measurement of water may be as important as oil for some producers.

By measuring the water cut within a consistent band of +2% absolute, for 0-100% water cut and 0-99% GVF, Haimo meters by and large provide the most accurate solution for the full range of water cut and GVF.

Statistically if the flow rates remain constant, the cumulative average of these instantaneous measurement errors (which fall on both +/- sides the zero error base line), tend to narrow down to lesser than 5 to 10% within a certain period of time, on a cumulative basis. The time taken is lesser when the instantaneous errors are lesser i.e. tests with lower levels of instantaneous errors work out to be of a lesser duration than those with higher instantaneous errors.

This affects the cost of measurement, as more tests can be carried out within the same period of time when working with a flow meter with lower instantaneous errors.

One of our customers presented a paper on the Haimo meter performance at a 97% water cut level testing, but which produced only a 13% net oil flow rate error against an instantaneous error that was expected to be as high as 67% .

The gas volume flow rate, relative to the multiphase volume flow rate, at the pressure
and temperature prevailing in that section, is known as Gas Volume Fraction. The GVF is normally expressed as a percentage. In a homogeneous flow regime, it is derived from the measured area of cross section occupied by the gas in the multiphase flow line under pressure and temperature conditions prevailing in the line.

Various multiphase JIP’s and related tests have established that the multiphase meter performance in terms of the liquid, gas phase flow rate measurement and water cut abs. error measurements deteriorates with increasing GVF. Haimo’s approach to this challenge is discussed elsewhere in the FAQ

Having seen the importance of the absolute error in the measurement of water cut, it is also important to note the factors that affect the water cut measurement. Water cut measurement errors are pronounced when the GVF levels are high and/or severe slugging conditions prevail in the flow. Considerable changes in the fluid properties can also impact the measurement of water cut.

For the metering specialist who is specifying his measurement requirements, the recommended practice is to plot the well data in a two phase logarithmic flow map with liquid (in m3/d) in the Y axis and Gas (in actual m3/d) in the X axis, and plotting the well data in the chart. We urge the readers to download our Automatic Well Data Plot.xls spreadsheet to play around with figures.

Such a plot will clearly show what GVF levels the wells fall under and this will assist in determining the operating envelope and also in the selection of the meter.

Various industry JIP’s and simultaneous trials carried out by Oil companies have benchmarked the performance of the various multiphase metering technologies available in the market. Some have proven to work under very favorable conditions of water cut and GVF and flow regimes, while they have faltered in their performance over more challenging GVF, water cut and flow regime conditions.

A typical data presentation format, among many others, is to have the liquid flow rate on X axis with gas flow rate on the Y axis at standard conditions for diff operating pressures - this is ideal for the operator to understand the meter. A sample of such a Operator assistance graph (Link to the website) is available for download from our Downloads page

It is an established fact that different multiphase meters can perform within their stated accuracies only up to certain values of GVF. Beyond these GVF limits, the performance tends to deteriorate. The Haimo meter is practically the only meter in the market that performs consistently within claimed accuracies over the full range of 0-100% water cut and 0-99% GVF range.

In moderate GVF cases for the Haimo meter, i.e. up to 95% GVF, the flow conditioner plays a major role in regulating the GVF before measurement of the water cut in the Dual gamma meter, while in extreme GVF cases, over 95% GVF, Haimo uses a partial separation device upstream of the multiphase meter.

With references to GVF, you can work out your calculation from the following
Haimo - GVF calculation work sheets.

1. GVF from GLR
To Download Click here

2. Gas in sm3d from GVF
To Download Click here

3. GVF from scfd Gas
To Download Click here

Heavy oil presents various challenges to multiphase flow meters:

High viscosities impact the very design of the meter and also create higher pressure drops across the spool piece of the meters. Haimo has innovative concepts to circumvent these effects by meeting client’s pressure drop requirements. More details are available on request.

Another factor relating to the heavy oil is the close proximity between the oil and the water densities. Sometimes, the oil may be even heavier than water. Haimo meter DOES NOT use density based measurements to calculate the water in the multiphase flow, typically associated with meters that use high energy gamma sources using Compton effect.

Haimo meters utilize the photo electron effect that is associated with the low energy gamma sources, in this case, Americium 241. Rather than depending on the densities (as in the Compton effect), the phase discrimination occurs by measuring the relative presence of the Carbon to Oxygen (raised to the 4th power) atoms in the Oil and water respectively. This gives the Haimo meter the unique advantage of measuring oil and water fractions, even if separated by a narrow margin of density.

The Single and Dual energy gamma meters deployed for the measurement of the phase fractions in the Haimo meter look at the oil and water as Carbon and Oxygen at the atomic levels, rather than any permittivity factors associated with the oil and water. Hence the abs. error in the watercut remain lesser than 2%, irrespective of whether flow regime is emulsion, water continuous or oil continuous.

Yes – typically meter turndown is 15: 1. However, the Haimo meter can achieve much larger turndowns, if required, as they are custom built. Typically 20 m3/d of liquid is the low flow limit; but this can change based on the process data.

Haimo carries out the measurement of the water cut independent of the 2 phase (liquid/gas) flow rate measurements in the downstream of a patented flow conditioner. The flow conditioner removes slugs, knocks out gas, homogenizes the gaseous liquid and provides a conditioned sample to the dual gamma water cut meter. Under the conditions created by using this unique arrangement / system, the dual gamma meter measures within +/- 2% abs. error for the water cut for the entire 0-100% range and 0-99.8% GVF range.

The Haimo multiphase meter is built out of modules for measurement of phase flow rates and phase fractions, independent of each other.
Phase flow rates and Gas Volume fractions are calculated using X relation and venturi sensors with real time input of densities from the Single gamma meter.

Gas flow rate is calculated as: Total multiphase flow rate * GVF
Liquid flow rate is calculated as: Total multiphase flow rate * (1-GVF)

Software flow models are used moderately to handle slip issues. The use of multiple complementing and co-existing modules of X relation and venturi help the meter to depend more on fundamental laws of physics rather than flow models to bring down the uncertainties in the measurement.

Oil / water phase fractions are measured in the Dual gamma meter, by compensating for the presence of gas in regulated quantities after the flow conditioner, under a conditioned flow regime.

Oil flow rate is calculated as: Liquid flow rate * (1-watercut)
Water flow rate is calculated as: Liquid flow rate * water cut

The 4-20 mA hard wired outputs are volumetric flow rates for oil / water / gas, total gross liquid flow, water cut, process temperature, process pressure and Gas Volume Fraction.
As a standard 8 hard wired outputs are available – more can be provided if requested. This is apart from the RS-485 MODBUS serial output, which comes as standard.

As compared to the traditional test separators with their residence times, multiphase meters are flow-through meters and the data is actually available in real time. End users, who were used to their test separators testing for 24 hours or more, generally start using the multiphase meter also with similar test durations. However, once they get a feel of the multiphase meter performance, they even use test times of 4 to 8 hrs.

Test durations should ideally accommodate for sudden changes in well behavior, which may not be so apparent from the minute data. Haimo works with their customers in optimizing the test times in the field e.g. when we come back to test a well which was last tested with our meter, we have the previous well test results in hand, and the test could be stopped within the first couple of hours itself, if the signature of the well has not changed considerably.