Performance of a Horizontally Mounted Venturi in Low-pressure Wet Gas Flow

The performance of a Venturi tube used in wet gas flow have been explored mainly under higher-pressure condition, but very often, low-pressure test exists in some oil and gas fields in Tianjin Dagang Oil and Gas Field in China. In this study, the performance of horizontally mounted Venturi meters in low-pressure wet gas flow is discussed. Three 50 mm Venturi meters were tested systematically, with fl values of 0.4048, 0.55 and 0.70, the opera- tion pressure of 0.15 MPa, 0.20 MPa, 0.25 MPa, the gas densiometric Froude number from 0.6 to 2.0, the modified Lockhart-Maretinelli parameter from 0.0022 to 0.06, and the ratio of the gas liquid mass flow rate from 0.5 to 0.99. The effects of modified Lockhart-Maretinelli parameter, pressure, gas densiometric Froude number, diameter ratio, and gas-liquid mass flow rate ratio to the Venturi tube are analyzed with new independent data. Furthermore, low-pressure performance was compared with that under high pressure.

Wet Gas Meter Development Based on Slotted Orifice Couple and Neural Network Techniques

A slotted orifice has many superiorities over a standard orifice. For single-phase flow measurement, its flow coefficient is insensitive to the upstream velocity profile. For two phase flow measurement, various characteristics of its differential pressure （DP） are stable and closely correlated with the mass flow rate of gas and liquid. The complex relationships between the signal features and the two-phase flow rate are established through the use of a back propagation （BP） neural network. Experiments were carried out in the horizontal tubes with 50ram inner diameter, ooerated with water flow rate in the range of 0.2m^3·h^-1 to 4m3·h^-1, gas flow rate in the range of 100m^3·h^-1 to 1000m^3·h^-1, and pressure at 400kPa and 850kPa respectively, where the temperature is ambient temperature. This article includes the principle of wet gas meter development, the experimental matrix, the signal processing techniques and the achieved results. On the basis of the results it is suggested that the slotted orifice couple with a trained neural network may provide a simple but efficient solution to the wet gas meter development.

2013 Production of China's Shale Gas Reaches 200 Million Cubic Meters and the First Transportation Pipeline Constructed

Results of the global shale gas resources show that minable resources of global shale gas are 187 trillion cubic meters （tern）, of which China accounts for 36 tcm （about 20% of the total amount）, which is mainly distributed in the Sichuan Basin, Yangtze Terrace, and Ordos Basin. From 2009 to 2012, China completed an accumulative number of 129 drilling wells related to shale gas, including 46 investigated vertical wells, 55 exploration wells and 28 evaluation wells, with 2012 production ranging from 25 million cubic meters （mcm） to 30 mcm.

CFD-Aided Investigation of Combined Flow Conditioners for Gas Ultrasonic Flow Meter

Stable and fully developed gas flow field is crucial for realizing accurate measurement of gas ultrasonicflow meter. To reduce the flow field distortion, a flow conditioner is usually used. However, the traditionalmonotype flow conditioner can only improve the flow field distribution partly. The measurement accuracy of thetransit time ultrasonic flow meter is still affected because of its serious flow field distortion in the complex pipelineconditions. In this paper, to further improve the flow field distribution, a combined conditioner is investigated.The combined flow conditioner is composed of fan-shaped section, turbulent mixing cavity, and honeycomb-shapedsection. The effects of fan blade angle and cavity length on the flow field of the DN50 flow meter are studied usingcomputational fluid dynamics (CFD) simulation. Simulation results indicate that compared with the monotypeconditioner, the combined conditioner has better performance on effectively reducing the swirl and turbulence andproviding more stable and repetitive velocity profiles. Experiments also validate the effectiveness of the combinedconditioner. The flow meter with the combined conditioner has better repeatability of less than 0.2%, which isbetter than those of the monotype conditioners under the same conditions. This work is very useful for accuratemeasurement of gas ultrasonic flow meter, especially for the complex pipeline conditions.