Optical sensing detection device and method for fluid medium interface

Abstract

An optical sensing detection device and method for fluid medium interface belong to the field of optical fiber sensing technology. The device comprises a medium interface sensor, a ground survey instrument and an armored optic / electric composite cable, and is characterized in that the medium interface sensor comprises sensing basic units which are serially connected, wherein each sensing basic unit comprises an electric heater and an optical fiber temperature measuring device which are encapsulated integrally; 1 to 2 metal wires and 1 optical fiber are included in the optic / electric composite cable; the ground survey instrument comprises an optical fiber sensing demodulation instrument, a constant-current power supply and a computer, the constant-current power supply provides heating current to the electric heater in a square wave form, meanwhile the optical fiber sensing demodulation instrument is used for reading the temperature value of the optical fiber temperature measuring device continuously, and the medium species and interface positions at the periphery of an electrical heating body are identified according to differences of characteristic parameters of temperature-time curves in different media. The optical sensing detection device has the effects and benefits of high reliability, corrosion and pollution resistance, zero maintenance and long service life, and is particularly suitable for detecting oil-water surface of in underground salt cavern made cavity.

Description

technical field [0001] The invention belongs to the technical field of instrumentation and optical fiber sensing, and relates to an optical fiber sensing device and method for fluid medium interface based on optical fiber multi-point temperature measurement, in particular to the detection of oil-water interface in underground salt cavern cavity construction and other underground oil and gas Detection of oil-water and gas-liquid interfaces in wells. Background technique [0002] The underground storage of oil and natural gas is one of the important ways to ensure the current and future national energy security. Underground salt cavern storage is a new energy storage technology developed in recent years. Underground salt caverns are usually a kind of storage space with a specific shape formed by manual control. In the process of salt cavern construction, it is necessary to control the shape of the roof of the cavern by adjusting the height of the interface between diesel oil ...

AI Technical Summary

Problems solved by technology

Since the brine in the salt chamber is very corrosive to general optical materials and metal materials, the optical method of measuring the refractive index or spectrum and the electrical method of measuring the capacitance or conductivity are used, because the detector directly contacts the measured medium. Contaminated by corrosion or salt water crystallization, it cannot meet the requirements of long-term reliable operation

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