Multistage interwell chemical tracing for step-by-step profile control of water channeling and flooding of fractured ultra-low permeability reservoirs

To monitor the dynamic variations of sweep area and formation parameters during the process of multiple slugs step-by-step profile control, the multistage interwell chemical tracing technique was proposed and tested in field, in line with the features of the step-by-step profile control in fractured ultra-low permeability reservoirs and the basic principle of chemical tracing test. According to the design scheme of step-by-step profile control and the characteristics of water channeling and flooding in fractured ultra-low permeability reservoirs, this study worked out times-design method for interwell tracing, optimized the selection principle of chemical tracer and calculation formula of tracer dosage, and set up the parameter optimization forecasting method of step-by-step profile control based on multistage interwell tracing. The application results of the method show multistage interwell chemical tracing can reflect dynamic variation of fractured parameters effectively, and the monitoring results match with the dynamic production testing results, demonstrating good adaptability of the method.