SU1458846A1 - Apparatus for electric testing of wells - Google Patents

Abstract

The invention relates to studies of the electrical properties of rocks in wells. The goal is to improve the accuracy and informativeness of measurements of the electrical resistivity of rocks and expand the functionality of the device. The device allows simultaneous acquisition of information from a set of probes of various types and orders. Different subgroups of electrodes are powered by different frequency currents. The signals from the components of the probes of the same order and of a different type with the same distortion of the curve of the apparent resistivity of different signs are fed to an adder. At the output, a set of unified rectangular curves of various order are recorded that carry information about the electrical properties of the rocks at different distances from the well. 4 il. (L

Description

one

The invention relates to means for investigating boreholes by geophysical methods, and more specifically to a technique for measuring boreholes with electrical properties of rocks.

The purpose of the invention is to improve the accuracy and informativeness of measurements.

Figure 1 shows the block diagram of the device; Fig. 2 is a curve obtained from a single probe; in FIG. 3, the curve obtained from the second probe in FIG. 4 is the curve after their summation, obtained at the output of the proposed device.

The device contains AC sources 1 and 2, probes 3 and 4, filters 5 and 6, adder 7 and recording device 8. Probes 3 and 4 have a common electrode system consisting of a power supply group and a measuring electrode group, each electrode being connected to Two resistances from two different sets corresponding to different probes, the value of resistance in each set is inversely proportional to the binomial coefficient (n-1) 1 / (nj) I (j-1). j, where j is the number of the electrode in the group, p is the number of electrodes in the group, equal to N, or N for the supply electrodes of the first or second probe or M, or M for the measuring electrodes of the first or second probe, while the second ends of the resistance,

00 00

four;

9)

The odd-numbered electrodes of the group are combined, and the second ends of the resistances connected to the even-numbered electrodes of the group are also combined. The connected ends of the resistances for the group of measuring electrodes are the outputs of the probes, and the connected ends of the resistances for the group

resistances, the value of which is determined by the ratio

R (i) (n-i)., (I-1) l / (Ti-1), where i is the number of the electrode,

n N (or M) f

second ends of resistances connected to odd measuring

supply electrodes — the inputs of probes, electrodes, are connected together and B- The sum of the supply and measured by the first output of the probe, the second pin of electrodes on both probes is the same, and the difference in the number of measuring electrodes of the first and second probe

the ends of the resistances connected to the even measuring electrodes are connected together and are the second 5 probe output, the second ends of the resistances connected to the odd supply electrodes are connected together and are the first input of the probe, the second ends of the resistance connected to the even feeding electrodes, are connected together and are the second input of the probe, characterized in that, in order to increase the accuracy and informativeness of

is odd.

the ends of the resistances connected to the even measuring electrodes are connected together and are the second 5 probe output, the second ends of the resistances connected to the odd supply electrodes are connected together and are the first input of the probe, the second ends of the resistance connected to the even feeding electrodes, are connected together and are the second input of the probe, characterized in that, in order to increase the accuracy and informativeness of 20

The device works as follows.

From each AC source, a current is supplied to the group of supply electrodes, through the appropriate set of distribution resistances flowing down from the supply electrodes to the medium. Since the device consists of two probes, each of the measurements, it additionally contains its own current source, the second alternating current source, the feeding current frequencies of the different probes — the first and the second filters, the second probe, are different. The current coming from the supplying power from the per-electrodes to the medium creates a common electrode with an electric probe and a state field, so that each of the N measuring and M measuring electrodes acquires electrodes connected to resistive electric potential. Through resistances that perform weight summation, the signals are filtered from 35

with the power of 4 1ltres and arrive at the summing device. The summed signal is fed to the recorder.

Claims (1)

Invention Formula A device for electrical well testing, comprising an AC source of a probe consisting of N measuring and M feeding electrodes, wherein the measuring and feeding electrodes are connected to tions, the values of which are determined by the same ratio as for the first probe, but with n N, (or M,), with N + M N, + M, and the difference N - N is odd, and the inputs of the first the probe is connected to the outputs of the first AC source, and the inputs of the second probe are connected to the outputs of the second AC source, the outputs of the first and second terminals are connected to the inputs of the first and second filters, respectively, the outputs of which are connected to the inputs of the adder device. 40 electrodes are connected together and wired by the first probe output, the second the ends of the resistances connected to the even measuring electrodes are connected together and are the second 5 probe output, the second ends of the resistances connected to the odd supply electrodes are connected together and are the first input of the probe, the second ends of the resistance connected to the even feeding electrodes, are connected together and are the second input of the probe, characterized in that, in order to increase the accuracy and information content of 0 25 measurements, it additionally contains a second AC source, the first and second filters, the second probe, similar to the first, having common electrodes with the first probe and a state of N measuring and M feeding electrodes connected to the corresponding electrodes. measurements, it additionally contains a second AC source, the first and second filters, the second probe, similar to the first, having common electrodes with the first probe and consists of N measuring and M supply electrodes connected to tions, the values of which are determined by the same ratio as for the first probe, but with n N, (or M,), with N + M N, + M, and the difference N - N is odd, and the inputs of the first the probe is connected to the outputs of the first AC source, and the inputs of the second probe are connected to the outputs of the second AC source, the outputs of the first and second terminals are connected to the inputs of the first and second filters, respectively, the outputs of which are connected to the inputs of the adder, the output of which is connected to the registering device . .i " N, U   I  V . N "Vi