RU2011146663A - METHOD FOR LITTING WELLS UTILIZED WITH METAL COLUMN - Google Patents

Abstract

Method for electric cased hole logging with a multi-element probe consisting of N measuring equidistant neighboring electrodes L apart from each other along the well axis, two current electrodes are placed outside and on different sides of them, in which bipolar pulses of electric current are supplied alternately with respect to electrode B , and at each of the current supply, the electric field potential of one of the measuring electrodes is measured, the supplied currents and potential differences between each measuring electron ododes and measuring electrodes spaced from it on L and 2L; on the basis of these measurements of electrical signals, the electrical resistivity (resistivity) of the rocks surrounding the well is determined, characterized in that it further introduces a cycle for monitoring the measurement conditions, in which bipolar electric current pulses are supplied between the first and second current electrodes; in this cycle, the supplied currents and potential differences between each measuring electrode and measuring electrodes spaced from it by L and 2L are also measured; based on the obtained data, resistivity is determined at N-2 points at depths corresponding to the location of the measuring electrodes with numbers 2 ÷ N-1 in this case, to find each of the aforementioned resistivities, data are used related to three adjacent measuring electrodes, hereinafter referred to as “middle, upper, lower, extreme” and forming a measuring triple, the middle of which corresponds to depth at which the resistivity is measured, to determine the resistivity at a particular point performs the following steps: from the data obtained by applying a current between the current e

Claims (1)

Method for electric cased hole logging with a multi-element probe consisting of N measuring equidistant neighboring electrodes L apart from each other along the well axis, two current electrodes are placed outside and on different sides of them, in which bipolar pulses of electric current are supplied alternately with respect to electrode B , and at each of the current supply, the electric field potential of one of the measuring electrodes is measured, the supplied currents and potential differences between each measuring electron ododes and measuring electrodes spaced from it on L and 2L; on the basis of these measurements of electrical signals determine the electrical resistivity (resistivity) surrounding the borehole rocks, characterized in that it further introduces a cycle for monitoring the measurement conditions, in which bipolar pulses of electric current are supplied between the first and second current electrodes; in this cycle, the supplied currents and potential differences between each measuring electrode and the measuring electrodes spaced from it by L and 2L are also measured; on the basis of the data obtained, resistivity is determined at N-2 points at depths corresponding to the location of the measuring electrodes with numbers 2 ÷ N-1, while to find each of the mentioned resistivity, use data related to three adjacent measuring electrodes, hereinafter referred to as “middle, upper , lower, extreme ”and forming a measuring triple, the middle of which corresponds to the depth at which the resistivity is measured; to determine the resistivity at a specific point, perform the following steps: from the data obtained when the current between the current electrodes is applied, take the current I (1,2) passing through them, the potential difference between the extreme measuring electrodes ΔU (1,2) and the potential difference or between the middle and upper measuring electrode ΔU (1,2 ) _up , or between the middle and lower measuring electrode ΔU (1,2) _down , which determine the second potential difference Δ ² U (1,2) by the formula Δ ² U (1,2) = ΔU (1,2) -2ΔU (1,2) _up or Δ ² U (1,2) = 2ΔU (1,2) _down -ΔU (1,2), respectively; from the data obtained by applying a current I (1,0) between the ground and the upper current electrode, take the potential of one of the measuring electrodes U (1,0), the potential difference between the extreme measuring electrodes ΔU (1,0) and the potential difference or between the middle and upper measuring electrodes ΔU (1,0) _up , or between the lower and middle measuring electrodes ΔU (1,0) _down , which determine the second potential difference Δ ² U (1,0) by the formula Δ ² U (1, 0) = ΔU (1,0) -2ΔU (1,0) _up or Δ ² U (1,0) = 2ΔU (1,0) _down -ΔU (1,0), respectively; from the data obtained when a current I (2.0) is applied between the ground and the lower current electrode, the potential of one of the measuring electrodes U (2,0), the potential difference between the extreme measuring electrodes ΔU (2,0) and the potential difference or between the middle and upper measuring electrodes ΔU (2,0) _up , or between the lower and middle measuring electrodes ΔU (2,0) _down , which determine the second potential difference Δ ² U (2,0) by the formula Δ ² U (2, 0) = ΔU (2,0) -2ΔU (2,0) _up or Δ ² U (2,0) = 2ΔU (2,0) _down -ΔU (2,0) respectively; calculate the resistivity of rocks by the formula

. Where

; K ₀ (0.004 · R) is the MacDonald function of zero order, the argument of which includes the radius of the casing R.