SU374566A1 - METHOD FOR DETERMINING STATIC POTENTIA | No. - ^^ '^^ -' - Google Patents

Description

one

The invention relates to geophysics and can be applied in field geophysical surveys of boreholes.

The known method of recording the static self-polarization potential (PS) in a well, which consists in measuring the potential of the PS under the condition of compensation by the screening field of PS currents at points located above and below the observation point, is characterized by low measurement accuracy, since the difference in the gradients of the natural field of the PS controlled Due to its smallness, the compensating field cannot be measured with the required degree of accuracy due to the influence of electrode potentials on the control electrodes.

The purpose of the invention is the creation of a method that can significantly improve the accuracy of determining static PS.

This is achieved by registering the potential of the PS at each point of observation and the difference in the gradients of the PS above and below this point, creating an artificial shielding electric field of alternating current, measuring the potential and the difference of potential gradients above and below the same observation point and finding t static self polarization potential

this point as a functional dependence on the measured values.

The drawing shows schematically a measurement setup that implements the proposed method.

Using the measurement setup, at each point of the well, the potential of the electrodes, denoted by V, and the difference in the gradients of the screening field occurring higher than and below the measuring point, indicated by the PS, are measured in the field of sources A, A on the electrodes N M and L2 LL. The PS gradient for each point of the well is used to calculate the difference in PS gradients above and below the measurement point - K,;. . This value is calculated by the formula:

(D.-H) - (H-H)

20

T / (2 |

PS

Where

VN, MI, l2 and Ulg2 - potentials of PS, so25

corresponding to the location of the electrodes, LH and MZ.

The potential at the point "O" for the arrangement of the electrodes given in the drawing is determined by the formula: VM, VM, the compensation current / k is determined, based on the relation: -k - | / (2) The additional potential U ° created by the screening field at the central electrodead at a current IK, is determined from the ratio F (0): / k1 / (0) - 1P. V (0) (2) Thus, the desired static potential PS will be equal; .). Subject of the Invention A method for determining the static self-polarization potential in a well, which consists in measuring the self-polarization potentials (PS), provided that the screening field of PS currents in points located higher and lower than the observation point, is characterized in that, in order to improve the measurement accuracy, the value of the potential of the PS at each point of observation and the difference of the gradients of the PS above and below this point are recorded; an artificial AC shielding electric field is created; this is measured in this field The potential and the difference of the potential gradients are higher and lower than the same observation point and determine the static potential of the own polarization at this point as a functional dependence on the measured values.

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