Patent ID: 7257491

Claim:
A method of evaluating the hydraulic potential of the section of a porous stratum that is filled with an incoming or outgoing moving effluent and that is defined by two depths respectively z low and z high , the method being characterized in that it consists: in generating periodic modulation of the flow rate of the well; in lowering down the well and in activating for a few periods at the fixed depth z low a sonde provided: i) with a device for precisely determining depth, either relative to the geological series by a gamma ray detector or relative to elements of the well (CCL); ii) with a clock; and iii) with physical sensors suitable for measuring at least the flow of effluent in the well, the pressure, the temperature, the mean density, and the head loss gradient; in extracting from these measurements: i) the amplitude ΔQ low of the sinusoidal component of the flow rate modulation relative to one of the imposed periods T; ii) the amplitude ΔP low of the sinusoidal component of the pressure modulation relative to the same period; and iii) the phase delay of the pressure sinewave relative to the flow rate sinewave φ low ; in determining the complex response R low to the cyclical test of period T of all of the active zones delivering effluent into the well between the bottom of the well and the depth z low , by using the formula; R low = Δ ⁢ ⁢ P low Δ ⁢ ⁢ Q low ⁢ ⅇ - ⅈφ low in raising the sonde to depth z high , activating it for a few periods at said depth, performing new measurements, and from the new measurements, extracting: i) the amplitude ΔQ high of the sinusoidal component of the flow rate modulation relating to the imposed period T; ii) the amplitude ΔP high of the sinusoidal component of the pressure modulation relating to the same period T; and iii) the phase delay of the pressure sinewave relative to the flow rate sinewave φ high ; in determining the complex response R high of all of the active zones delivering effluent into the well between the bottom of the well and the depth z high , by using the formula: R high = Δ ⁢ ⁢ P high Δ ⁢ ⁢ Q high ⁢ ⅇ - o ⁢ ⁢ φ high in calculating the complex response R stratum of the stratum defined by the fact that the effluent it contains is delivered into the well between the depths z low and z high , by means of the formula: R stratum = R high · R low R low - R high in postulating a physical model for the stratum by numerically inverting the mathematical formula giving the theoretical complex response; in determining the hydraulic characteristics of the stratum defined by the measured response R stratum ; in calculating the well productivity index IP stratum relating to the stratum in question and in deducing therefrom the mean deposit pressure P D in the stratum, by applying the formula: P D = P DH + Q stratum IP given that using the sonde, and prior to activating the flow rate modulator, both the stabilized downhole pressure P DH and the net flow rate Q stratum coming from the stratum are measured.