Positron tomography device and method for multiphase flow

Abstract

The invention relates to a multiphase flow positron emission tomography device used in an oil pipeline. According to the device, a pair of gamma rays with 511keV energy, which can be coincident, are generated by utilizing positron and negatron annihilation and used as a positron emission tomography means and provides an on-line positron emission tomography function for multiphase flow measurement in the oil pipeline of an oil field. The device comprises a plurality of groups of parallel high-precision gamma ray detector arrays which are arranged according to a specific space structure, a positron radioactive source and a shield and can be used for acquiring the phase fraction of a multiphase mixture comprising oil, gas, water and the like only under the condition of the single radioactive source by combining an image processing function. Due to the adoption of the design of the plurality of groups of high-precision detector arrays, the accuracy of the multiphase flow measurement and the applicability of the multiphase flow positron emission tomography device in different flow patterns and flow states of multiphase flow are also greatly improved. Image information of fluid generated by the multiphase flow positron emission tomography device can greatly enrich measurement information of petroleum and natural gas in the petroleum and natural gas industries and provide basic data for more effective reservoir management and production optimization.

Description

technical field [0001] The invention relates to a positron tomography device for multiphase flow in oil pipelines, that is, using gamma rays produced by the annihilation of positrons and electrons as tomography means to provide multiphase flow measurement on oil and gas field pipelines The utility model relates to a multi-phase flow positron tomography device with on-line tomography function, and also relates to a method for performing positron tomography on multi-phase flow in oil pipelines. Background technique [0002] Multiphase flowmeters have gradually replaced traditional test separators due to their advantages of low investment, low operating costs, and no need to separate oil well products. Multiphase flowmeters can provide online real-time flow and phase fraction data of oil, gas, and water, providing a basis for oil companies to understand the actual production situation and capacity of each single well, and implement effective reservoir management and production ...

AI Technical Summary

Problems solved by technology

Therefore, the overall measurement accuracy is relatively reduced.

(2) The spatial symmetry is not good

(3) The required measurement time is longer

This relies on the statistical average of the ergodics to solve the problem of measuring space asymmetry, but its effect on reducing the impact of overall non-uniformity is not ideal

(4) Under extreme flow conditions, the measurement accuracy of a single-phase flow will be greatly reduced

The current multiphase flow metering technology is based on the measurement of the total flow and phase fraction, and then the flow rate of each single phase is obtained through calculation; poor precision

(5) The flow characteristics of the fluid flow state cannot be obtained

[0006] At present, the imaging research of multiphase flow adopts the technology of measuring the characteristics of medium electrics / ERT, optics / Optical, ultrasound / Ultrasound, magnetic resonance / MR, etc., but they all have their own shortcomings, and have not been successfully applied in the field of multiphase flow measurement.

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