The Quartz Pressure/Magnetic Positioning Logging Tool (QPC03) is primarily used to measure the column gradient pressure of the wellbore fluid, providing information for fluid property analysis. Through computer processing of the gradient pressure, the tool generates differential pressure curves. It is used to analyze the properties of the wellbore fluid and the environmental pressure at the instrument's location, making it an important parameter for production fluid property studies. The magnetic positioning is mainly used to measure the casing or tubing collar, aiding in the depth correction of the formation.