Optimization calculation method of ultra-deep production logging velocity profile correction coefficient

In recent years, with the continuous development of China's industry, the country's demand for petroleum energy has also increased. Therefore, maintaining stable production in oil fields is crucial for ensuring the stable development of the Chinese economy. Dynamic monitoring of production logging is an important means of stabilizing and increasing oil and gas production. Generally, the flow rate values of fluids in each production layer in the production wellbore are measured using a turbine flowmeter. When measuring flow in the production wellbore using a turbine flowmeter, it is placed at the center of the wellbore fluid due to supporting equipment. The flow value measured by the turbine flowmeter is the flow value at the center of the wellbore. During the measurement process, when the turbine flowmeter is centered, it reflects the velocity Va of the fluid in the middle of the casing wellbore. In order to accurately obtain the cross-sectional flow rate value of the wellbore, it is necessary to measure the velocity value Vm of the fluid in the cross-section of the casing wellbore. At this point, dividing Vm by Va is denoted as Cv. The traditional method takes Cv as a constant value of 0.83. By studying the fluid velocity value in ultra deep production logging, it was found that the value Cv is not a constant value of 0.83. This value is closely related to the wellbore inner diameter, the ratio of turbine blade diameter to wellbore inner diameter, fluid density value, fluid viscosity value, and average fluid velocity value. This article designs an iterative optimization calculation method to calculate the Cv value. Comparing and analyzing the results of iterative optimization calculation with experimental values, it was found that the calculation accuracy of this method reached 97%. It can fully meet the requirements of calculating the fluid velocity value in the wellbore for production logging.