Study on application of wet gas metering technology in shale gas measurement

doi:10.1016/j.flowmeasinst.2020.101777

Flow Measurement and Instrumentation

Volume 74, August 2020, 101777

https://doi.org/10.1016/j.flowmeasinst.2020.101777 Get rights and content

Highlights

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Flow conditions of shale gas.
•
Metering principles of current wet gas flow meter.
•
Wet gas flow test of wet gas flow meter.
•
Performance features of wet gas flow meter.
•
Feasibility of wet flow meter in shale gas application.

Abstract

The application of wet gas flow meter at shale gas wellhead is of great significance to reduce the investment and operation cost of shale gas extraction. In this paper, the flow conditions at the wellhead of shale gas and the principles of the current wet gas flow meters are briefly analyzed. A wet gas flow meter was tested on the wet gas flow test facility, and its performance of flow rates evaluation is studied, which is helpful to optimize the wet gas metering process design of shale gas wellhead and to improve the wet gas metering technology. This study shows that the measurement principles of the current wet gas flow meters are feasible, however, the calibration by using the wet natural gas at working conditions can help to enhance the meter's measure performance.

Introduction

In natural gas industry, the production of natural gas from a well is always accompanied by water and hydrocarbons. This unprocessed output from gas well is called wet gas, and it is a particular subset of gas-liquid two phase flow. Now, there is no unanimous definition of wet gas in industry, various methods have been used to define and even to classify the wet gas, and it is most commonly defined as the Lockhart-Martinelli parameter is less than or equal to 0.3 [1,2]. Because of the presence of liquid in the gas flow, single phase gas flow meters fail to work or even damaged when expose to wet gas flows. Nowadays, separation technology is commonly applied in the wet gas flow measurement in China.

Section snippets

Flow conditions of shale gas wellhead and the demand of wet gas flow metering

Compared with the conventional extraction of natural gas, there is no water or light hydrocarbon output produced from the shale gas reservoir. However, in the process of shale gas exploitation, unconventional hydraulic fracturing technology is used to stimulate the reservoir, quantities of fracturing fluid are injected into the reservoir. As a result, a large amount of fracturing fluid generated in the shale gas in the process of shale gas extraction. The exploitation of shale gas can generally

Basic principles and technical features of current wet gas flow meters

The wet gas flow meter technology is a new metering technology developed based on single phase flow meters with correlation in recent few decades. The core principle of the wet gas flow meter is using the wet gas correlation created based on large amount of experiment data to correct the meter bias caused by liquid phase in the gas flow [3,4]. Most of the available wet gas meters are based on some sort of differential pressure device with wet gas correlations and incorporate some other

Wet gas flow test facility and the test method

In order to study the performance of wet gas flow meter at the conditions of wet natural gas flow, a wet gas flow meter was tested at the wet gas test facility of Chengdu Verification Branch of National oil and gas large flow rate measurement station of China.

This facility is designed for gas-liquid two phase flow studies consisting of water and natural gas. The schematic diagram of the wet gas test facility of CVB is shown Fig. 1, Fig. 2. This facility is mainly composed of gas and liquid

Conclusions and suggestions

It can be seen from the performance test and re-test after calibration that the metering principles and methods of the current wet gas flow meters are feasible, however, the wet gas correlations of the wet gas flow meter must be re-calibrated with wet natural gas according to the working conditions. Uncertain deviation will occur when the wet gas flow meters that calibrated using air and water at low pressure are directly used at wet natural gas flow, which cannot meet the needs of field

CRediT authorship contribution statement

Qiang Zhang: Writing - original draft, Formal analysis, Writing - review & editing. Dingfa Liu: Data curation, Investigation.

Declaration of competing interest

We wish to draw the attention of the Editor to the following facts which may be considered as potential conflicts of interest and to significant financial contributions to this work.

We confirm that the manuscript has been read and approved by all named authors and that there are no other persons who satisfied the criteria for authorship but are not listed. We further confirm that the order of authors listed in the manuscript has been approved by all of us.

We confirm that we have given due

Acknowledgments

The authors gratefully acknowledge Petrochina for funding the research and CVB staffs who were involved in the wet gas flow facility construction and wet gas flow test.

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