Abstract: Daqing Oil Field has developed a number of new application technologies for geochemical well log for the purpose to solve the difficult issues concerning how to identify and assess the wellbore of the complicated oil, gas and water layers. A family of technology has been developed for identification and assessment of light oil layers, remaining oil and water layers and the oil, gas and water layers of volcanic rock. Such technology, which has played an important role in exploration of Daqing area, has been used to find a large number of wells with high-yield industrial oil and gas flow, such as well Bei-302 and Xishen-1. This article systematically briefs about the main results achieved from the study of integrated log technology for complicated oil, gas and water layers in Daqing area. The methods for data processing and appraisal are further improved and perfected in the study project.