Using an Adjustable Cone Meter to Measure Wet Gas

2021 ◽  
Author(s):  
Sakethraman Mahalingam ◽  
Gavin Munro ◽  
Muhammad Arsalan ◽  
Victor Gawski

Abstract When the gas flow rate of a well significantly changes, the flow rate can fall below that of the operating range of a traditional fixed size Venturi meter, necessitating the replacement of the original meter with one of a smaller size. However, with an adjustable cone meter, the internal reconfiguration feature allows it to automatically switch from high operating flow range to low operating flow range and there is no requirement to disassemble the meter from the flow line assembly. Adjustable cone meters were designed, developed and tested at the wet-gas flow loop at National Engineering Laboratory in East Kilbride, Scotland. After calibrating the meter with dry nitrogen gas, the meter was tested with increasing amounts of liquid being injected into the flowline, upstream of the meter. The liquid caused the differential pressure measurement on the meter to over-read. Based on the differential pressure measurements under varying flow conditions, algorithms were developed to measure the dry gas and liquid fraction. The data obtained from the tests such as differential pressure, pressure, temperature, liquid density were used to build an over-reading model of the meter and a liquid fraction estimation model based on pressure loss ratio derived from an additional differential pressure measurement. The model was used to not only to quantify the gas and liquid flow rates but also the estimated error in each measurement. The measurements show that the Adjustable Cone meter is able to provide low uncertainty in both dry and wet gas conditions and offers a turndown ratio of up to 54:1 in dry gas conditions. In addition, the automatic adjustment of the meter from high flow to low flow positions avoids the need for manual intervention that involves additional risk and cost.

2021 ◽  
Author(s):  
Sakethraman Mahalingam ◽  
Gavin Munro ◽  
Muhammad Arsalan ◽  
Victor Gawski

Abstract A traditional fixed size Venturi meter has a turndown of about 8:1 under dry gas conditions that may drop to as low as 3:1 under wet-gas flow. When the well conditions change, a replacement of the original Venturi meter with one of a different size is needed. In this paper, we present the design, development and testing of an Adjustable cone meter that has the ability to adapt itself to the flow conditions automatically and provide a turndown of as much as a 54:1 under dry gas conditions and as much as 20:1 under wet-gas conditions. The patented feature of the Adjustable cone meter is the adjustable sleeve that moves over the cone when the flow rate decreases below a preset value causing an increase in the differential pressure across the meter. In addition, traditional Venturi meters have only one differential pressure measurement and the sensor tends to overestimate the flow when there is liquid present in the flow (wet-gas). The Adjustable cone meter has two differential pressure sensors and the second measurement is used to estimate the liquid content in wet-gas. Two meters were manufactured and tested at the National Engineering Laboratory in East Kilbride, Scotland under gas flow rates of up to 18 MMscfd. Based on the differential pressure measurements under varying flow conditions, algorithms were developed to measure the dry gas and liquid fraction. An over-reading model of the meter and a liquid fraction estimation model based on the pressure loss ratio was derived from an additional differential pressure measurement. The model was used to not only to quantify the gas and liquid flow rates but also the estimated error in each measurement. The measurements show that the Adjustable Cone meter is able to provide low uncertainty in both dry and wet gas conditions and met the conditions outlined in ISO 5167-5. The Adjustable cone meter is a much needed innovation in the area of differential pressure measurement.


2011 ◽  
Vol 383-390 ◽  
pp. 4922-4927
Author(s):  
Peng Xia Xu ◽  
Yan Feng Geng

Wet gas flow is a typical two-phase flow with low liquid fractions. As differential pressure signal contains rich information of flow parameters in two-phase flow metering, a new method is proposed for wet gas flow metering based on differential pressure (DP) and blind source separation (BSS) techniques. DP signals are from a couple of slotted orifices and the BSS method is based on time-frequency analysis. A good relationship between the liquid flow rate and the characteristic quantity of the separated signal is established, and a differential pressure correlation for slotted orifice is applied to calculate the gas flow rate. The calculation results are good with 90% relative errors less than ±10%. The results also show that BSS is an effective method to extract liquid flow rate from DP signals of wet gas flow, and to analysis different interactions among the total DP readings.


Author(s):  
Olav Mehlum ◽  
Øyvind Hundseid ◽  
Lars E. Bakken

Abstract Subsea wet gas compressors have been successfully in operation for approximately 5 years. Their use has proven to increase the recovery by approximately 10% and achieve a reliability up to 98%. Further developed and operation of subsea wet gas compression require detailed knowledge of compressor operability and how shift in operational conditions affect the compressor system. The compressors ability to handle wet gas is documented in detail for a gas volume fraction limited down to 0.90. The 4–5 last year of operation proves the wet gas concepts capability. As years pass by, well pressure and production rate declines which causes the compressor operation point to shift towards the high head and low flow (surge) area of the characteristics. In addition, compressor inlet transients increase due to pipe surge (slugs), requiring a robust control system to prevent instabilities, e.g. compressor surge. It is therefore vital to understand how the compressor inlet flow device behaves at different wet operation conditions. The article documents how a standard dry gas venturi tube behave at different wet gas operation conditions. The venturi is designed according to ISO5167-4 for dry gas conditions and is tested at the low-pressure air water compressor test rig at NTNU. The primary objective of the work has been to visualize the wet flow regime through the transparent venturi tube and to document the wet gas flow rate measurements by means of single-phase meters. The venturi tube is tested in a GMF range from 1 to 0.83 at an air volume flow rate of 1.3m3/s.


2021 ◽  
pp. 13-19
Author(s):  
Zhanat А. Dayev ◽  
Gulzhan E. Shopanova ◽  
Bakytgul А. Toksanbaeva

The article deals with one of the important tasks of modern flow measurement, which is related to the measurement of the flow rate and the amount of wet gas. This task becomes especially important when it becomes necessary to obtain information about the separate amount of the dry part of the gas that is contained in the form of a mixture in the wet gas stream. The paper presents the principle of operation and structure of the invariant system for measuring the flow rate of wet gas, which is based on the combined use of differential pressure flowmeters and Coriolis flowmeters. The operation of the invariant wet gas flow rate measurement system is based on the simultaneous application of the multichannel principle and the partial flow measurement method. Coriolis flowmeters and the differential pressure flowmeter are used as the main elements of the system. The proposed measurement system does not offer applications for gases with abundant drip humidity. The article provides information about the test results of the proposed invariant system. The estimation of the metrological characteristics of the invariant system when measuring the flow rate of wet gas is given. The obtained test results of the invariant wet gas flow rate measurement system are relevant for natural gas production, transportation, and storage facilities.


2013 ◽  
Vol 401-403 ◽  
pp. 1110-1113
Author(s):  
Quan Sheng Duan ◽  
Li Cui Wang

The lower limit of the existing vortex mass flow meter based on differential pressure is high. So the application of the existing vortex mass flow meter is limited in the measurement for low flow rate. This paper proposes a method using vortex mass flow meter of dual bluff body based on differential pressure principle. The differential pressure signal between the upstream and downstream can be amplified by the vortex overlap caused by the dual bluff body structure. The results of the simulation by Fluent show that this method can reduce the lower limit of measurement, and improve the measurement sensitivity effectively.


2012 ◽  
Vol 220-223 ◽  
pp. 875-879
Author(s):  
Ying Xu ◽  
Cun Yin ◽  
Zheng Hai Long

In order to better simulate the flowing condition of wet gas, Tianjin University has designed and built up a wet gas flow experimental facility with adjustable and intermediate pressure in the flow laboratory. The designed pressure of the facility which used standard meter method and dual closed-loop design is 4MPa. The experiment medium is air and water, and the highest operation pressure is 1.6MPa. The gas flow rate range is 3~1000m3/h, and the liquid flow rate range is 0.05~8 m3/h. This article includes the structure introduction of the facility and the calculation of pressure loss of the system, etc. By the uncertainty assessment for the discussed facility, the conclusion is stated that the facility’s gas measurement uncertainty is 1% and the facility’s liquid measurement uncertainty is 0.35%.


SPE Journal ◽  
2006 ◽  
Vol 11 (02) ◽  
pp. 199-205 ◽  
Author(s):  
David I. Atkinson ◽  
Oyvind Reksten ◽  
Gerald Smith ◽  
Helge Moe

Summary Dedicated wet-gas flowmeters are now commercially available for the measurement of gas and liquid flow rates and offer a more compact measurement solution than does the traditional separator approach. The interpretation models of traditional multiphase flowmeters emphasize the liquid rate measurements and have been used to well test and meter mostly liquid-rich flow streams. These models were not developed for the measurement of gas flow rates, particularly those of wet gas. A new interpretation is described that allows a traditional multiphase flowmeter to operate in a dual mode either as a multiphase meter or as a wet-gas meter in 90 to 100% gas. The new interpretation model was developed for a commercially available multiphase flowmeter consisting of a venturi and a dual-energy composition meter. This combination results in excellent predictions of the gas flow rate; the liquid rate prediction is made with acceptable accuracy and no additional measurements. The wet gas and low-liquid-volume-fraction interpretation model is described together with the multiphase flowmeter. Examples of applying this model to data collected on flow loops are presented, with comparison to reference flow rates. The data from the Sintef and NEL flow loops show an error (including the reference meter error) in the gas flow rate, better than ± 2% reading (95% confidence interval), at line conditions; the absolute error (including the reference meter error) in the measured total liquid flow rate at line conditions was better than ± 2 m3/h (< ± 300 B/D: 95% confidence interval). This new interpretation model offers a significant advance in the metering of wet-gas multiphase flows and yields the possibility of high accuracies to meet the needs of gas-well testing and production allocation applications without the use of separators. Introduction There has been considerable focus in recent years on the development of new flow-measurement techniques for application to surface well testing and flow-measurement allocation in multiphase conditions without separating the phases. This has resulted in new technology from the industry for both gas and oil production. Today, there are wet-gas flowmeters, dedicated to the metering of wet-gas flows, and multiphase meters, for the metering of multiphase liquid flows. The common approach to wet-gas measurement relates gas and liquid flows to a "pseudo-gas flow rate" calculated from the standard single-phase equations. This addresses the need for gas measurement in the presence of liquids and can be applied to a limit of liquid flow [or gas volume fraction, (GVF)], though the accuracy of this approach decreases with decreasing GVF. The accurate determination of liquid rates by wet-gas meters is restricted in range. The application and performance of multiphase meters has been well documented through technical papers and industry forums, and after several years of development is maturing (Scheers 2004). Some multiphase measurement techniques can perform better, and the meters provide a more compact solution, than the traditional separation approach. It is not surprising that the use of multiphase flowmeters has grown significantly, the worldwide number doubling in little over a 2-year period (Mehdizadeh et al. 2002). Multiphase-flowmeter interpretation emphasizes the liquid rate measurement, and the application of multiphase flowmeters has been predominantly for liquid-rich flow stream allocation and well testing.


Author(s):  
Enrico Munari ◽  
Michele Pinelli

Nowadays, wet gas flow rate measurement is still a challenge for experimental investigators and it is becoming an even more important issue to overcome in the turbomachinery sector as well, due to the increasing trend of wet compression applications in industry. The requirement to determine gas turbine performance when processing a wet gas leads to the need to understand certain phenomena, such as type of liquid flow re-distribution, and errors introduced when the mass flow rate measurement of a two-phase gas is attempted. Unfortunately, this measurement is often affected by the presence of liquid. Literature does not offer a unique definition of the term wet gas, although it is recognized that a wet gas can generally be defined as a two-phase gas in which the liquid percentage is lower than the gas one. This paper aims to collect and describe the main works present in literature in order to clarify i) the most used parameters that describe the types of wet gas, and ii) the types of errors and flow patterns which occur in different types of applications, in terms of pressure, percentage of liquid, Reynolds number, etc. Therefore, this literature review offers a comprehensive description of the possible effects of liquid presence in a wet gas and, and an in-depth analysis of the limitations and beneficial effects of current single-phase flow rate sensors in order to identify the best solutions, and empirical corrections available in literature to overcome this challenge.


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