Experience in porosity evaluation for oil and gas reservoirs based on stray gamma radiation

An experience of evaluation of gas and oil reservoir porosity using stray gamma radiation is described. As a result of performing a number of research works using simple and complex models obtained were the experimental data which permitted to develop an effective technique for porosity evaluation, to formulate technical requirements to well apparatus design for gamma-gamma logging, to develop and produce a mockup of well gamma spectrometer with two spacings and a rigid stabilization system of energy scale permitting to measure the intensity of scattered gamma radiation within a given energy range not worse than +- 0.5 %