基于时域积分的热式流量检测模型与FPGA实现

Thermal flow detection model and FPGA implementation based on time domain integration

国内现有的油井大多数为低渗透油井,具有高含水、低产液特征,对其进行流量测量一直是亟待解决的技术难题。针对该问题,根据流体力学与传热学原理,并充分考虑热惯性因素影响,建立了全域热量传递理论模型。利用Simulink对理论模型进行流量仿真验证。最后,研制了一种以FPGA为主控芯片的井下热式流量计,并开展了流量相关试验。数值模拟和试验数据表明:理论推导与试验数据呈极好的一致性,仪器在低流量条件下,检测精度达到1 m^(3)/d,且测量误差在-2%~+2%范围内波动。

Most of existing oil wells in China are low permeability oil wells,which are characterized by high water cut and low liquid production.Measuring their flow has always been a technical problem to be solved urgently.Aiming at this problem,according to the principles of fluid mechanics and heat transfer,and fully considering the influence of thermal inertia factors,a full domain theoretical model of heat transfer is established.On this basis,Simulink is used for flow simulation verification of theoretical models.Finally,a downhole thermal flowmeter using FPGA as main control chip is developed,and flow correlation tests are carried out.Numerical simulation and test data show that theoretical derivation is in good agreement with the test data.Under the condition of low flow,the detection precision reaches 1 m^(3)/d,and the measurement error fluctuates within the range of-2%~+2%.