Patent ID: 6089345
Filing Date: 2000-07-18
Classification: E21B,G01V,G10K

Abstract:
A well tool which is lowered into a well containing well fluid which is used for exploration of formations surrounding the well by use of elastic waves comprising at least one elastic wave emission or reception set, a self-contained gas generator provided with a pressure control and which delivers to the well fluid, on demand, calibrated gas bubbles which attenuate tube waves propagating in the well, an expansion valve which delivers gas at a predetermined overpressure in relation to pressure prevailing in the well at a selected depth, and a porous filter which calibrates dimensions of the calibrated gas bubbles and wherein the gas generator comprises a combustion chamber in which a gas-generating pyrotechnical substance is combusted, and a tank for containing the gas generated by combustion of the pyrotechnical substance.