Underground fluid identification device based on distributed optical fiber sensing technology and measurement method

Abstract

The invention provides an underground fluid identification device based on a distributed optical fiber sensing technology and a measurement method. The underground fluid identification device comprises a ground high-power electromagnetic excitation source and an armored optical cable, and the armored optical cable is arranged outside or inside a metal sleeve or fixed outside or inside an oil pipe;three-component optical fiber electric field sensors and three-component optical fiber magnetic field sensors are uniformly distributed in the armored optical cable; and the armored optical cable isconnected with a composite modulation-demodulation instrument on the ground. The ground high-power electromagnetic excitation source continuously excites forward and reverse square wave source signalswith the duty ratio of 1 to the underground, and the proportion of water, oil and gas in multi-phase fluid at each measuring point position is determined according to the actually measured true resistivity value of the fluid inside and outside the metal sleeve or inside and outside the oil pipe; and online real-time measurement, identification and long-term dynamic monitoring of change rules of underground fluid in the development and production process of an oil and gas production well or a liquid injection displacement well are achieved.

Description

technical field [0001] The invention belongs to the technical field of distributed optical fiber sensing, and in particular relates to a downhole fluid identification device and measurement method based on distributed optical fiber sensing technology. Background technique [0002] Optical fiber sensing technology began in 1977 and developed rapidly with the development of optical fiber communication technology. Optical fiber sensing technology is an important symbol to measure the degree of informatization of a country. Optical fiber sensing technology has been widely used in military, national defense, aerospace, industrial and mining enterprises, energy and environmental protection, industrial control, medicine and health, metrology and testing, construction, household appliances and other fields, and has a broad market. There are hundreds of optical fiber sensing technologies in the world, and physical quantities such as temperature, pressure, flow, displacement, vibratio...

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Problems solved by technology

Most of the above-mentioned downhole fluid identification methods, devices or systems have complex structures of downhole sensors or probes, difficult and cumbersome installation process, low reliability and accuracy, and it is difficult to realize full well detection without affecting the normal production of oil and gas wells. On-line real-time measurement or monitoring of downhole fluid

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