A calibrator is positioned on a logging tool at an angular orientation with respect to the logging tool. The calibrator has a radioactive source of gamma radiation distributed inside the calibrator. A first detector count rate is determined based on a detector in the logging tool detecting gamma radiation. One or more of the calibrator and logging tool is rotated by a first number of degrees. A second detector count rate is determined based on the detector in the logging tool detecting gamma radiation. One or more of the calibrator and logging tool is rotated by second number of degrees. A third detector count rate is determined based on the detector in the logging tool detecting gamma radiation. The first, second, and third detector count rates are averaged to determine a calibration gain factor based on the average detector count rate and a known indication of gamma radiation emitted by the calibrator.

The present invention considers bringing a mobile unit closer to the site of interest and conduct the quantification of the tracers by performing the detection methods in situ and in real time at the wellhead, and that can be moved to the site on numerous occasions for the preparation of results during the test where the quantification of tracers is necessary, helping to speed up and reduce times that, until now, have not been achieved with stationary laboratories and that depending on the laboratory can last up to three months providing results.

A method for adjusting a gain of a gamma detector comprises detecting gamma radiation using the detector, recording the detected radiation as count rates in channels, wherein the last channel accumulates all counts above the maximum recorded energy; comparing the last channel count rate (LCCR) to a threshold X and, if LCCR>X, decreasing the gain by a preset amount Y. If LCCRX, establishing a first estimate of a needed voltage HV1 using tool temperature and a temperature lookup table, and establishing a second estimate of a needed voltage HV2 using a backscatter peak value and a backscatter lookup table; comparing |HV1HV2| to a threshold Z; if |HV1HV2|<Z, adjusting the gain of the gamma detector by HV2 or, if |HV1HV2|Z, adjusting the gain of the gamma detector by HV1.

Aspects of the subject technology relate to a system configured to apply a voltage setting to a sensor of a downhole tool. The system is configured to identify an active gain control model for a temperature-sensitive sensor for a downhole tool, receiving temperature data for the downhole tool, and apply a high voltage setting for the first sensor based on the temperature data and the active gain control model. The system is further configured to collect sensor data from the sensor operating in a wellbore using the high voltage setting and update the active gain control model based on the sensor data.

Aspects of the subject technology relate to a system configured to apply a voltage setting to a sensor of a downhole tool. The system is configured to identify an active gain control model for a temperature-sensitive sensor for a downhole tool, receiving temperature data for the downhole tool, and apply a high voltage setting for the first sensor based on the temperature data and the active gain control model. The system is further configured to collect sensor data from the sensor operating in a wellbore using the high voltage setting and update the active gain control model based on the sensor data.

A method of creating a well image log of a cased well is provided. A passive cased well image logging tool assembly including a logging tool body, a plurality of gamma ray radiation sensor assemblies and a spatial positioning device is moved through at least a portion of the wellbore. Corrected gamma ray radiation data is vertically sampled. Based on the sampled data, a well image log is prepared. A passive cased well image logging tool assembly for use in a cased well is also provided.

A method of creating a well image log of a cased well is provided. A passive cased well image logging tool assembly including a logging tool body, a plurality of gamma ray radiation sensor assemblies and a spatial positioning device is moved through at least a portion of the wellbore. Corrected gamma ray radiation data is vertically sampled. Based on the sampled data, a well image log is prepared. A passive cased well image logging tool assembly for use in a cased well is also provided.

An integrated logging tool includes an outer housing and an insert, the insert positioned within the outer housing. The integrated logging tool further includes a gamma sensor within the insert.

An integrated logging tool includes an outer housing and an insert, the insert positioned within the outer housing. The integrated logging tool further includes a gamma sensor within the insert.

There is provided herein a system and method for automatically determining a path within a target rock unit of a directionally drilled well (a target well) using log readings, e.g., gamma log readings, taken in the target well as compared with log readings (a typelog) taken in a well that penetrates the target rock unit (an offset well). Most specifically, in some embodiments the path of the target well within the target rock unit will be obtained by solving a minimum travel distance problem which uses distances that are based on differences between well log readings in the target and offset wells. Solution of this problem will yield a collection of stratigraphic blocks lengths and dips that define a path of a well in a subsurface through the target formation or rock unit.