Tracer-Placement Techniques for Improved Radioactive-Tracer Logging Academic Article uri icon


  • The accuracy of a radioactive-tracer log depends on the tracer rapidly mixing with the wellbore fluid and traveling with the same velocity as the wellbore fluid. In addition, log quality depends on the ability to measure the tracer transit time from the gamma ray detector responses accurately; the tracer must maintain a sharp peak, or sharp leading edge, for reliable transit-time measurement. The author conducted experiments in a model wellbore to determine the factors affecting tracer slug distribution and the response at tracer detectors resulting from these factors. Tracer-placement parameters studied included tracer shot velocity, shot duration, wellbore flow rate, and tracer viscosity. When wellbore flow was laminar, the tracer dispersion could be predicted with a theoretical model and the experimental results compared well with the theory. As would be expected, optimal results were obtained when the bulk of the tracer was placed in the high-velocity, central region of the wellbore. In turbulent flow, a fairly low ejection rate and large shot size most consistently yielded sharp slugs that were maintained at both detectors.

author list (cited authors)

  • Hill, A. D., Boehm, K. E., & Akers, T. J.

citation count

  • 2

publication date

  • November 1988