Application of Reservoir Physical Property Data in the Classification and Treatment of Under-Injection Wells

X block of an oil field in eastern China, due to various reasons such as reservoir development and injection water quality, some water injection wells experience under-injection, resulting in insufficient formation energy, a decline in the production of connected oil wells, and affecting the water-flooding development effect. In order to carry out targeted treatment of different types of under-injection wells and restore the water injection volume, research on the causes of under-injection was carried out from two aspects: reservoir development and external pollution. Firstly, the differences in data such as the effective thickness of the reservoir, formation coefficient, and the connectivity of oil and water wells between normal injection wells and under-injection wells were studied. Secondly, the relationship between the physical property parameters of the under-injection well reservoir and the proportion of under-injection wells was analyzed. Thirdly, the relationship between the injection water quality over 9 consecutive years and the proportion of under-injection wells was analyzed. The results show that in terms of reservoir development, for injection wells with an effective thickness < 1.1 m, a formation coefficient less than 0.13, the number of connected oil wells < 3, the sum of the formation thickness of connected oil wells < 8.5 m, and an injection-production well spacing > 250 m, the proportion of under-injection is above 60%, which is the main cause of under-injection in water injection wells. In terms of external pollution, the injection water quality directly affects the water injection situation. The worse the water quality, the higher the proportion of under-injection wells. According to the causes of under-injection, targeted treatment measures were formulated, effectively improving the effect of treatment measures for under-injection wells.