Wellbore logging performance verification method and apparatus

An instrument for imaging subsurface materials, the instrument comprising:

• a sensor comprising at least one transmitter and at least one receiver configured for transmitting an electric signal through the subsurface materials and collecting material data;
• at least one test circuit configured for generating an electric test signal comprising an amplitude and a phase that mimic a downhole measurement environment to generate correction information for at least one of adjusting the material data and adjusting controls or settings used to produce the material data;
• and
• a device for switching disposed between the sensor and the at least one test circuit, the device comprising a coupling to an electronics unit for providing one of the material data and the electric test signal for analysis.

A method for estimating an electrical property of a subsurface material using an instrument, the method comprising:

• applying an electric signal to the subsurface material using at least one transmitter and at least one receiver;
• receiving a data signal from the subsurface material that comprises a current;
• measuring the current in the data signal;
• estimating a phase difference between the electric signal and the current of the data signal;
• periodically evaluating a transfer function of the instrument using a test circuit that generates an electric test signal comprising an amplitude and a phase that mimic a downhole measurement environment;
• and
• estimating the electrical property of the subsurface material by adjusting the data signal according to the transfer function.