METHOD AND APPARATUS TO DETERMINE BEGINNING OF STRATUM FLUID APPEARANCE AND ABSORPTION OF DRILLING MUD Russian patent published in 1995 - IPC

FIELD: oil and gas extracting industry. SUBSTANCE: sensors are measuring consumption and concentration of drilling mud рat borehole input and its output. Signals from concentration sensors 1 and 2 and from consumption sensors 3 and 4 are coming to comparison blocks 5 and 6. Values of differential consumption and differential concentration of drilling mud at borehole output and value of pipeline inner diameter in place of measurements drilling mud consumption at borehole input are determined. Amplified by amplifiers 10 and 11 signals after passing through multiplying blocks 12 and 15 are fed to summer 16 and after that are registered by computation block 17, that determines mean value and value of dispersion of dynamic pressure absolute increment distribution, obtained from numeral measurements. Signal from block 17 through key members 19 and 20 comes to memory blocks 22 and 23, to which signal from clock 18 is also fed. Computation block 17 signals, corresponding previous and following distributions of pressure absolute increments values, are compared in comparison block 7. Block 7 output signal is analyzed by threshold block 24. In case input signal exceeds threshold value, then signal from block 24 output goes to registering block 26. EFFECT: method and apparatus increased accuracy to determine beginning of stratum fluid appearance and beginning of absorption of cleansing solution by permeable stratum. 2 cl, 1 dwg