Gas hold up tool for cased well boreholes.

摘要

For use in a cased well producing mixed phase fluids flowing up the well, a device (18) for measuring the gas hold up fraction comprises a low energy gamma ray source (37) to irradiate the flowing fluid, and a detector (35) to detect the gamma rays scattered by materials in the casing. The metal casing shields the formations from the gamma radiation so that the detector response is determined primarily by the mixed fluids flowing in the well. Means for counting (34) the rays, and means (12) for processing the count rate signals are also provided to give a signal indicative of gas holdup in the vicinity of the device (18). By calibration, gas/liquid ratios can be measured for specific diameter casing. <IMAGE>