METHOD AND DEVICE TO DETERMINE LIQUID OUTPUT FROM OIL WELL Russian patent published in 2006 - IPC E21B47/10 

FIELD: oil production, particularly to determine oil well output.

SUBSTANCE: method involves periodically supplying gas-and-liquid mixture in measuring bullet tank; separating gas-and-liquid mixture to obtain gas; keeping time at which gas-and-liquid mixture reaches measuring levels of above bullet tank; measuring hydrostatic pressure of gas-and-liquid mixture at above bullet tank levels and determining fluid output in mass rate units. The separation is performed up to distinct liquid-foam interface forming then gas-and-liquid mixture is supplied to measuring bullet tank section without above liquid-foam interface breakage. Rate of gas-foam and liquid-foam interface movement is determined as above interfaces reach at least two measuring levels of bullet tank. Fluid output in mass rate units is determined with taking into consideration mass of liquid in foam, which is calculated from interface movement rates and from data obtained by hydrostatic pressure sensors. Time at which interfaces reach the measuring levels is determined from hydraulic pressure increase change, characterized by change in derivative of hydrostatic pressure function with respect to time and/or by graphic pressure line jog as a function of time. Time at which interfaces reach the measurement levels is determined with the use of polynomial extrapolation of sections of time-dependence hydraulic pressure. Liquid pressure is additionally measured in at least one point of measuring bullet tank and above liquid pressure is compared with pressure at measuring levels. The obtained pressure difference is used to accommodate liquid density non-uniformity along measuring bullet tank height and to determine mean value thereof. Device for above method realization comprises measuring bullet tank with inlet and outlet nipples, as well gas discharge nipple. The measuring bullet tank is shaped as vertical cylinder and is provided with hydrostatic pressure transducers located at different measuring levels along bullet tank height. Gas-and-liquid medium separation tray is arranged in bullet tank interior and has gutter-like cross-section communicated with inlet nipple and adjoining bullet tank wall by one side surfaces thereof along helical descending line. Angle of above tray inclination is enough to form and retain liquid-foam interface during gas-liquid medium presence on it. Hydrostatic pressure transducers of corresponding measuring level are installed in upper part of tray wall adjoining bullet tank wall. Separation tray may have rectangular cross-section and width more or equal to side tray wall heights.

EFFECT: increased accuracy and reduced time of oil well yield measurement.

6 cl, 5 dwg