Research On The Measurement Method Of The Thermal Gas Mass Flow For Small Flow

Oil as an important strategic energy for the country, the development of the whole country cannot be ignored the important significance. With the growing demand for the exploitation of petroleum resources, reasonable and effective method is particularly important, and the situ combustion technology is one of the key methods to improve oil recovery. In order to grasp the gas injection status of oil wells and the effective absorption characteristics of gas reservoirs in real time, the mass flow rate of mixed gas must be monitored accurately. The thermal gas mass flow measurement method has the advantage that the measurement of small flow gas cannot be compared with other methods, and it can be widely used in the measurement of mixed gas mass flow.In order to study the burning air wells in Liaohe oilfield(combustion) injection condition, for the purpose of monitoring micro gas flow, a new method for measuring the flow rate of gas mass flow with automatic temperature compensation and mixed gas component compensation is presented. First of all, the theoretical analysis of the thermal gas mass flow measurement method is carried out, and the mathematical model of mass flow measurement is established. Then put forward the constant temperature difference measurement method and the fixed power measurement method, through the comparative analysis of the characteristics of the two methods, the choice of constant temperature difference measurement method as the measurement model of this paper, determine the design. Finally the temperature compensation algorithm and component compensation algorithm, and proposed improved temperature compensation algorithm and hardware implementation scheme based on the principle of temperature compensation.On the basis of theoretical analysis, the FLUENT is used to simulate the fluid, and the velocity and temperature images are analyzed. Determine the sensor structure by simulation, and put forward a join distributor in the pipeline optimization model. The mathematical model of mass flow measurement is verified by the simulation of the optimization model with different Reynolds number, and the optimal structure of the sensor is finally determined, which improves the reliability of the design scheme.In this paper, the gas quality flow measurement system controlled by STM32F103ZET6 single chip microcomputer. The improved automatic temperature compensation circuit is used to obtain the corresponding voltage values of the instantaneous flow and the gas temperature. Through the calculation and real time voltage curve, different velocity corresponding to the instantaneous flow and cumulative flow value displayed on the LCD screen. The design software mainly includes ADC conversion module, flow data processing module and traffic display module.The experimental results can be obtained from the experimental results of the small flow thermal gas mass flowmeter: the design of the prototype in the measurement of flow rate of 0m/s~3m/s of small flow gas with high sensitivity and good repeatability, measurement accuracy of up to ±1.5%. At the same time, it also verifies the feasibility of the improved automatic temperature compensation algorithm and the hybrid gas component compensation algorithm. Therefore, the measurement method proposed in this paper can be applied to the measurement of small flow gas mass flow. In order to provide a reliable basis for further understanding of the gas content in each layer, fully burning oil layer and enhancing oil recovery.