Abstract: An apparatus and method of sensing fluid flow are provided to measure fluid flow rates in production tubing, pipelines, open wells and tunnels. The proposed invention takes advantage of a sensor with processing means to interpret the fluid flow rate, the sensor being responsive to the mechanical perturbations of the sensor itself arising from the impingement of turbulent fluid flow on the sensor. In operation, the sensor is mounted in the fluid flow such that the fluid flows through an aperture in the sensor and/or around the outside surface of the sensor. The sensor of the invention bears definite advantage over known sensors and it is particularly suited to downhole oil and gas applications. Preferably, the invention employs fiber optic sensing techniques which are amenable to multiplexing a plurality of the sensors with long down leads. Such an arrangement is robust to withstand the high temperature and pressure environment.

Abstract: An apparatus and method of sensing fluid flow are provided to measure fluid flow rates in production tubing, pipelines, open wells and tunnels. The proposed invention takes advantage of a sensor with processing means to interpret the fluid flow rate, the sensor being responsive to the mechanical perturbations of the sensor itself arising from the impingement of turbulent fluid flow on the sensor. In operation, the sensor is mounted in the fluid flow such that the fluid flows through an aperture in the sensor and/or around the outside surface of the sensor. The sensor of the invention bears definite advantage over known sensors and it is particularly suited to downhole oil and gas applications. Preferably, the invention employs fibre optic sensing techniques which are amenable to multiplexing a plurality of the sensors with long down leads. Such an arrangement is robust to withstand the high temperature and pressure environment.

Abstract: Method and apparatus for measuring oil quality based on the permittivity of the oil comprising a capacitive or radiative sensor for exposure to the oil, and an oscillator circuit including the sensor, wherein the oscillator circuit comprises a LC or crystal oscillator which provides an output signal, the amplitude of which is dependent upon the lossiness of the Tan &dgr; of the oil, and a measuring device that responds to the amplitude of the output signal as a measure of oil quality.