Abstract:

:Log technique have been employed in the recognition of many meaningful geological events. However, the subtle changes of logs are seldom recognized and used, thus limiting the accuracy and reliability of interpretation. The issue could be tackled be establishing genetic relationships between the variety of important geological events and logs, and that between geological evolution and the vertical and horizontal changes of the logs based on a comprehensive study on geological responses and the combined features of associated logs. The method is used to identify geological events of clastic and carbonate rocks as well as their formation mechanism. Based on an analysis of the variety of geological events, an approach for identifying geological events of clastic rocks is proposed. Through identification and tracing of isogenesis geologic boundaries, an approach for identifying contemporaneous carbonate rocks of different facies. Approaches for identifying geological events of these two kinds of rocks are different as they vary in lithology and genesis. Their major differences include tracing basis and log responses of geologic boundary, and corresponding relationships between log data and geologic boundaries. Application of the abovementioned methods in Dagang Oilfield, Puguang Gasfield and many other fields in Australia has successfully solved the problem of identifying geologic boundaries.