Results of nuclear geophysical methods application in evaluation of oil strata in the fields of Stavropol region

The paper describes a method for estimating flowing oil saturation based on the use of a set of pulsed and steady-state neutron logging methods and reference formations of known saturation. The saturation is determined by graphical comparison of lambda, the decrement of damping of thermal neutron density measured by impulse neutron logging, with Ksub(p), the value for porosity estimated by thermic neutron-neutron logging. In the estimation of Ksub(p) account is taken of the salinization of the cement. The parameter lambda is normalized on the basis of gamma logging data, by reduction to a formation with zero clay content. The estimated absolute error in the determination of the residual oil saturation is +-8%. (author)