Sensor probe for measuring downhole rock electrical parameters

Abstract

The invention provides a sensor probe for measuring downhole rock electrical parameters. The sensor probe comprises an emitting electrode, a collecting electrode and an emitting electrode voltage source. The emitting electrode voltage source is connected with the collecting electrode and the emitting electrode through wires. The sensor probe is characterized by further comprising a bucking electrode and a bucking electrode voltage source, the bucking electrode is of an annular structure, the emitting electrode is arranged in the ring of the bucking electrode, the bucking electrode voltage source is connected with the collecting electrode and the bucking electrode through wires, the emitting electrode and the collecting electrode are arranged on the same side of sampled downhole rock, the bucking electrode voltage source is loaded on the bucking electrode, and therefore current flowing out of the emitting electrode can penetrate through conductive slurry and enter the rock to reach the collecting electrode. Downhole real-time measurement can be conducted on a rock core sample, and stratum rock core information is accurately and efficiently obtained in real time.

Description

Background technique [0001] Core electrical parameters are very important for correcting logging curves. The traditional method of measuring core electrical parameters needs to collect core samples and send them back to the ground laboratory for measurement. The sensor probe used in the measurement includes the emitter electrode and the collector electrode. The emitter electrode and the collector electrode are connected through a voltage source. The current flowing from the emitter electrode passes through the rock to the collector electrode. When the current passes through the rock, it will be affected by the rock resistivity and dielectric constant. Therefore, the circuit impedance will change. By establishing the relationship between the circuit impedance and the rock resistivity and permittivity, the resistivity and permittivity of the rock core to be tested can be deduced according to the measured impedance value. Since it needs to be taken out of the well and sent back t...

AI Technical Summary

Problems solved by technology

Since it needs to be taken out of the well and sent back to the laboratory, this process results in a long measurement period and high cost, and the resistivity and dielectric constant of the core sample cannot be obtained in real time

[0002] Real-time measurement of core samples in the downhole can obtain formation core information in real time, but the downhole environment is different from the laboratory measurement environment, and the measurement will be affected by many factors. First, the downhole is filled with conductive mud solution. The outgoing conduction current will directly pass through the conductive mud to reach the collecting electrode, and very little current can penetrate the mud and enter the rock. At this time, because the resistivity of the rock is much higher than the mud resistivity, the current cannot enter the rock, which will inevitably lead to Unable to measure electrical parameters of the rock

[0003] Since the conductive mud will block the current flowing from the electrode into the high-resistance rock, it will not be sensitive to the change of the electrical parameters of the rock.

Images