An improved method for determining oil saturation by chlorine hydrogen ratio based on neutron self-shielding correction
A method is proposed to use iron's captured gamma rays to mark the neutron self-shielding correction factor and combine it with the chlorine to hydrogen ratio to determine the oil saturation. The Monte Carlo method is used to establish a wellbore-formation model to simulate different porosity and formation water salinity. Captured gamma energy spectrum under conditions, studied the neutron self-shielding factor and oil saturation logging response, and verified the method through simulation examples. The results show that: the chlorine-to-hydrogen ratio after iron-labeled neutron self-shielding correction increases with porosity It increases with the increase in porosity. When the porosity is the same, it has a linear relationship with the water saturation. The relative sensitivity can be increased to more than 1 times, which can solve the problem of reduced sensitivity of conventional chlorine to hydrogen ratio in determining oil saturation. The error in calculating oil saturation is reduced, as Pulse neutron capture logging provides a new method for quantitative evaluation of oil saturation in high-salinity water formations.