Study on the azimuth sensitivity of azimuthal γ ray logging while drilling

Abstract

BackgroundThe response of azimuth gamma well logging in multiple sectors around the well cannot reflect the actual radioactive distribution of the formation.PurposeThis study aims to obtain the contribution factors of different sectors around the instrument on the detector.MethodsFirst of all, the influence of the formation around the well on the measurement results was verified through numerical simulation. Then an experimental device was designed and implemented for azimuthal sensitivity calibration, and an azimuthal sensitivity calculation method was derived by combining experimental data and numerical results.ResultsThe azimuthal gamma logging can obtain data that reflect the radioactive intensity distribution of the formation to a certain extent, but the calculated azimuth sensitivity factor can be used to accurately reflect the contribution of the 16 azimuth sectors around the well to the detector, and the intensity distribution contrast becomes better.ConclusionsThe radioactivity intensity of the formation calculated by the azimuthal sensitivity factor is closer to the real formation, hence effectively improves the measurement accuracy of azimuthal gamma logging, providing technical support for improving the measurement accuracy of azimuthal gamma logging and identifying formation boundary in the future.

Keywords

• azimuth gamma logging
• azimuth sensitivity
• geosteering
• monte carlo simulation