DOWNHOLE HYDROMETER CALIBRATION METHOD AND DEVICE Russian patent published in 2006 - IPC G01F25/00 E21B47/00 

FIELD: testing or calibrating of apparatus for measuring volume, volume flow, or liquid level, or for metering by volume.

SUBSTANCE: method involves supplying water-oil emulsion having predetermined moisture content into test chamber containing downhole hydrometer to be calibrated; recording volumetric moisture content in oil by water content increase in the emulsion; stopping calibration operation as water percentage in emulsion reaches maximal value. The test chamber additionally has standard hydrometer. Water-oil emulsion is prepared directly in test chamber. Volumetric moisture content in oil is measured directly during emulsification operation with the use of the standard hydrometer. Downhole hydrometer is calibrated in control points with the use of standard hydrometer. After calibration operation termination the obtained emulsion is settled to separate the emulsion into components, which are further used in new calibration cycle. All hydrometer emulsification and calibration cycle is automatically performed. In another embodiment oil equivalent is used for emulsion preparation. Hydrometer calibration device comprises water tank, test chamber, proportioning means for metered water supply into test chamber and emulsifier for emulsion preparation. The test chamber is located over water tank and is communicated with water tank by means of controllable valve installed in bottom and by means of outer pipeline. The outer pipeline has the first end connected with upper level of test chamber and free end communicated with lower level of water tank. Water tank is also used as settling chamber. The device additionally has standard hydrometer installed in test chamber, expansion tank arranged over test chamber, computer and computer/standard hydrometer interface unit, downhole hydrometer to be calibrated, emulsifier and proportioning means. Expansion chamber volume exceeds downhole hydrometer volume. Settling chamber volume is equal to double test chamber volume.

EFFECT: increased calibration accuracy and improved structural reliability.

4 cl, 2 dwg