Natural gamma-ray instrument can determine the formation position. It can also determine whether the instrument leaves the reservoir or not, but it can not distinguish the azimuth.
Azimuthal gamma-ray instrument can detect the natural gamma data in different directions. By reading gamma data variation from different directions, it is judged in which direction the instrument leaves or will leave the reservoir. The directional engineer would deal with it and make the instrument return to the reservoir.
In real-time drilling, azimuthal gamma-ray instrument records gamma data of eight different sectors in the formation. These data would generate trajectory imaging map after well completion. Through imaging data, formation fault information, especially the fault dip angle information could be read out, which is a significant reference for comprehensive understanding of formation.
Product photo
1.Azimuthal gamma-ray


2.Drill-collared azimuthal gamma-ray (imaging gamma-ray)


GS-AziGR:Azimuthal gamma-ray
GS-ImgGR: Drill-collared azimuthal gamma-ray (imaging gamma-ray)
GS-AziGR is widely used in directional wells and horizontal wells in Yanchang county of northern Shaanxi province. During in-window phase, lower part of the instrument enters the window firstly, following the upper part of the instrument. During the drilling process, GS-AziGR is located in deep reservoir, capable of displaying the average gamma data of each sector. When deviated from the reservoir, it can determine the deviating direction from the variance between the upper and lower gamma data, so as to help engineers re-adjust trajectory and make it return to the reservoir.
With the advantage of optimizing the algorithm continuously, GS-AziGR is more and more used in horizontal wells and directional wells.
In the future, the usage of azimuthal gamma-ray instrument is believed to increase.