Technical practice of enhanced oil recovery in medium and high permeability fault block reservoirs: A case study of Chun-47 block in Dongying Sag of Jiyang Depression

Most mature oilfields in eastern China, particularly medium and high permeability fault block reservoirs, have entered the high water-cut development stage. Enhancing oil recovery（EOR） in such reservoirs is crucial for stabilizing production and extending the economic development period of aging fields. The Chun-47 Block in the Dongying Sag of the Jiyang Depression is a medium and high permeability fault block reservoir. Adaptive well pattern design and differential adjustment strategies tailored to the reservoir characteristics during various development stages have enabled efficient exploitation, with a current recovery factor of 78.5% and an ultimate recovery factor of 84%. Analyzing the mechanisms underlying efficient development and identifying the field’s development patterns have academic and practical significance. This study examines the geological characteristics, reservoir macroscopic and microscopic features, fluid properties, and development strategies. Results highlight that favorable reservoir properties form the foundation for high recovery rates, while high waterflood displacement efficiency and comprehensive stage-specific development strategies serve as the key technical aids. The practical experience, strategies, and methods adopted for the efficient development of this block provide valuable insights for similar oilfields.