| After the completion of Well A7 in an offshore oil and gas field, intermittent fluid discharge was conducted, with poor reservoir connectivity and low production. This paper analyzes the causes of its low production. In view of the plugging characteristics, through literature review and extensive field practice, the mechanism and characteristics of multi-hydrogen acid for plugging removal are analyzed. A multi-hydrogen acid-based plugging removal fluid system is selected for acidizing and plugging removal operations. The organic plugging remover is 100% heavy-duty cleaning agent, the preflush fluid is 50% fresh water + 50% multi-hydrogen acid 1, the inorganic treatment fluid is 50% fresh water + 50% multi-hydrogen acid 2, and the displacement fluid is 2.5% clay stabilizer + 1.25% cleanup additive + filtered seawater. Its comprehensive performance is evaluated through laboratory experiments. The results show that all performance indicators of the multi-hydrogen acid acidizing system meet the requirements for reservoir acidizing and plugging removal operations. Further field application results indicate that using the multi-hydrogen acid system for acidizing and plugging removal operations leads to smooth on-site operations, a long effective period, and significant effects. After plugging removal, the well produces 48 m³ of liquid per day with a water cut of 10%, maintaining stable production. |
