Moisture content measuring device based on plug-in capacitive sensor

Abstract

The invention relates to a moisture content measuring device based on a plug-in capacitive sensor. The moisture content measuring device comprises a capacitance sensor, a signal processing unit, an effective value measuring unit and a calculating unit. The capacitive sensor includes an excitation and measuring electrode as an excitation electrode and a measuring electrode, and two protection electrodes fixed above and below the excitation and measuring electrode. The signal processing unit comprises a front amplifier, a coaxial cable, an AC signal generator and a differential amplifier. A negative input end of the front amplifier is connected to the excitation and measuring electrode in the capacitive sensor through a coaxial cable signal line. A positive input end of the front amplifier is connected to the AC signal generator and is connected to the two protection electrodes in the capacitive sensor, a shielding layer of the coaxial cable and a negative input end of the differential amplifier. A standard resistor and a capacitor are connected in parallel and are connected to the negative input end and an output end of the front amplifier. The output end of the front amplifier is connected to a positive input end of the differential amplifier.

Description

Technical field [0001] The invention relates to the field of oilfield exploitation, and in particular to a water cut measurement device based on an inserted capacitance sensor. Background technique [0002] The development of today's society has an ever-increasing demand for energy. As the "first energy source", petroleum has a very important position in the national economy and national strategy. However, oil is a non-renewable energy source, so it is of great significance to minimize mining losses and make full use of resources during the mining process. In petroleum engineering, in order to improve the efficiency of crude oil extraction, high-pressure water injection and polymer injection technologies are often used in the secondary extraction of oil wells. However, this process makes the extracted crude oil contain water, resulting in a two-phase flow of oil and water in the process of oil well extraction and transportation after extraction. Crude oil extraction, dehydratio...

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Problems solved by technology

Although the excitation field distribution of this kind of electrode is uniform, there are problems such as the edge effect of the electric force line, the electrode facing area, and the electrode spacing are difficult to determine. It is suitable for square pipes; most of the coaxial cylindrical capacitive sensors are truncated installations, which are complicated to install and difficult to maintain. ; Cross-sectional multi-electrode (such as ECT imaging technology) can accurately measure the distribution of two-phase flow in the pipeline, but its structure is complicated, installation is inconvenient and the cost is high

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