Logging method for formation water salinity determination by PGNAA technology

A prompt gamma neutron activation analysis logging method for formation water salinity determination is proposed. The response of formation water salinity for capture gamma ray spectrum and thermal neutron counts ratio are studied by Monte Carlo simulation method. Formation porosity and borehole fluid salinity influence on formation water salinity is corrected. A synthetical logging case is simulated to indicate the effectiveness of this logging method. The new logging method is also applied in oil field, and the formation water salinity of different depth is calculated.