DEVICE FOR ANALYSING QUALITY OF CEMENTING CASING COLUMNS OF WELLS IN ROCKS Russian patent published in 2010 - IPC G01N23/18 G01V5/12 

FIELD: physics.

SUBSTANCE: device has a gamma-radiation source inside a lead shield with an circular collimating window, a detector of gamma-radiation reflected from the walls of the casing column lying on the axis of the device, and several detectors of gamma-radiation reflected from the analysed sectors of the cased space of the well fitted in grooves on the edge of the cylindrical lead shield, as well as a detector of natural gamma-radiation of the rocks and a banking angle sensor of the device. An independent temperature correction circuit in range of operating temperature is used for each gamma-radiation detector which has a scintillation crystal and a photomultiplier. A magnetically soft steel screen is worn on each gamma-radiation detector which has a photomultiplier and a scintillation crystal. In order to obtain a criterion for evaluating the position of the defect of the cement rock from the banking angle, a well inclination angle is fitted. The natural gamma-activity channel detector lies away from the location zone of the wall thickness sensors and cement-rock density sensors and is separated from the said zone by a lead shield which covers the entire section of the device.

EFFECT: obtaining stable technical characteristics of the device for all measuring channels in the operating temperature range and any direction in space; obtaining the criterion for evaluating accuracy of detecting the position of a defect in the cement rock; elimination of the effect of gamma-radiation reradiated from density sensors of the cased space on the natural gamma-radiation detector.

1 dwg