Compound probe, device and method for monitoring corrosion of down-hole string on line and in real time

Abstract

The invention discloses a compound probe for monitoring corrosion of a down-hole string on line. The compound probe comprises a probe body, an electrical resistance probe, and an alternating current impedance probe, wherein the probe body is sleeved by a cylindrical shell; the electrical resistance probe comprises a sealing reference element and a sensitive element, which are in series connection, and materials of the sealing reference element and the sensitive element are the same as that of the down-hole string; the alternating current impedance probe comprises a reference electrode, a working electrode and an auxiliary electrode and forms an electrochemical three-electrode system. Corrosion allowance of the down-hole string is calculated by collecting terminal voltages of the reference element and the sensitive element of the electrical resistance probe; sine wave signals of different frequency points are loaded on the working electrode, and the polarization current of the auxiliary electrode and the polarization potential of the reference electrode are synchronously collected, so as to obtain the polarization resistance of the working resistance, and then the corrosion velocity can be measured. The invention further discloses a monitoring device with the probe and a monitoring method. According to the compound probe for monitoring the corrosion of the down-hole string on line, the monitoring device and the monitoring method, the quick on-line monitoring of the corrosion velocity of a down-hole oil gas sleeve or string can be realized; and the probe, the monitoring device and the monitoring method are suitable for an environment with any mixed medium of oil, water and gas in a down-hole high-temperature high-pressure environment.

Description

technical field [0001] The invention belongs to the technical field of oil and gas field corrosion monitoring, in particular to a probe, device and method for online real-time monitoring of downhole oil casing corrosion, which is suitable for high-precision online corrosion of any mixed medium of oil, water and gas in a deep well high temperature and high pressure environment Monitoring and evaluation of anti-corrosion measures. Background technique [0002] With the oil and gas field CO 2 Large-scale promotion of tertiary oil recovery technologies such as flooding, led by CO 2 The corrosion problem of deep well tubing and casing caused by oil flooding is becoming more and more serious. Therefore, downhole online corrosion monitoring, as an important task for the safe production of oil and gas fields, has attracted the attention of many oil and gas production enterprises. [0003] At present, conventional downhole oil casing corrosion monitoring adopts the method of corros...

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Problems solved by technology

[0005] However, since the realization principle of the resistance probe is based on Ohm's law, its corrosion resolution is low. This solution is more suitable for long-term corrosion monitoring, but not suitable for rapid corrosion monitoring. reduce

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