新疆石油地质

新疆石油地质 ›› 2021, Vol. 42 ›› Issue (zk(English)): 145-150.

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Full-Diameter Physical Simulation of Oxygen-Reduced Air-Assisted Gravity Drainage: A Case Study of Gasikule E13 Reservoir in Qinghai Oilfield

LONG Anlin1, QI Qingshan1, CHEN Xiaolong2, LI Yiqiang2, LU Shanshan1, ZHANG Pei1, LI Xin1   

  1. 1. Research Institute of Exploration, Development, Qinghai Oilfield Company, PetroChina, Dunhuang, Gansu 736200, China;
    2. China University of Petroleum, a. State Key Laboratory of Petroleum Resources, Prospecting; b. School of Petroleum Engineering, Beijing 102249, China
  • 出版日期:2022-01-01 发布日期:2023-07-28

Full-Diameter Physical Simulation of Oxygen-Reduced Air-Assisted Gravity Drainage: A Case Study of Gasikule E13 Reservoir in Qinghai Oilfield

LONG Anlin1, QI Qingshan1, CHEN Xiaolong2, LI Yiqiang2, LU Shanshan1, ZHANG Pei1, LI Xin1   

  1. 1. Research Institute of Exploration, Development, Qinghai Oilfield Company, PetroChina, Dunhuang, Gansu 736200, China;
    2. China University of Petroleum, a. State Key Laboratory of Petroleum Resources, Prospecting; b. School of Petroleum Engineering, Beijing 102249, China
  • Online:2022-01-01 Published:2023-07-28
  • About author:LONG Anlin, E-mail: lalqh@petrochina.com.cn

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摘要： Compared with conventional gas injection methods, the gas-injection assisted gravity drainage has the advantages of restraining gas channeling and expanding swept volume. In this study, a static low-temperature oxidation experiment was conducted to investigate the adaptability of the oxygen-reduced air-assisted gravity drainage in the Gasikule E13 reservoir. Oxygen-reduced air-assisted gravity drainage experiment was carried out with the help of natural full-diameter long core, so as to study the influences of oxygen volume fraction, gas injection rate and core inclination angle on the oxygen-reduced air-assisted gravity drainage. The results show that the oxygen-reduced air with low oxygen volume fraction (5%) plays a significant role in low-temperature oxidation in the Gasikule E13 reservoir, and the oxygen consumption rate can reach 2.19 mol/(h·mL). For the oxygen -reducing air-assisted gravity drainage, under the conditions of the Gasikule E13 reservoir, the ultimate recovery increases with an increased oxygen volume fraction of the injected air. The incremental recovery factor of the core experiment ranges from 1.2% to 6.9%. From the perspective of recovery ratio and safety, oxygen-reduced air with the oxygen volume fraction slightly lower than 10% can be applied as the displacement medium. Viscous fingering may occur when the gas injection rate is more than 1.0 mL/min, while capillary retention may occur when the oxygen injection rate is less than 0.1 mL/min, resulting in relatively low recovery factor. When the gas injection rate is 0.3 mL/min, it is a stable oil and gas flooding with a higher recovery factor. The process of the oxygen-reduced air-assisted gravity drainage is relatively sensitive to gravity. For the reservoirs with small inclination angles, the oxygen-reduced air-assisted gravity drainage is still feasible to some extent. The factors that affect the oxygen-reduced air-assisted gravity drainage in the Gasikule E13 reservoir are gas injection rate, core inclination angle and oxygen volume fraction in sequence according to their sensitivities.

关键词: Qinghai oilfield, Gasikule, oxygen-reduced air-assisted gravity drainage, full-diameter core, physical simulation, low-temperature oxidation, gas injection rate, oxygen volume fraction

Abstract: Compared with conventional gas injection methods, the gas-injection assisted gravity drainage has the advantages of restraining gas channeling and expanding swept volume. In this study, a static low-temperature oxidation experiment was conducted to investigate the adaptability of the oxygen-reduced air-assisted gravity drainage in the Gasikule E13 reservoir. Oxygen-reduced air-assisted gravity drainage experiment was carried out with the help of natural full-diameter long core, so as to study the influences of oxygen volume fraction, gas injection rate and core inclination angle on the oxygen-reduced air-assisted gravity drainage. The results show that the oxygen-reduced air with low oxygen volume fraction (5%) plays a significant role in low-temperature oxidation in the Gasikule E13 reservoir, and the oxygen consumption rate can reach 2.19 mol/(h·mL). For the oxygen -reducing air-assisted gravity drainage, under the conditions of the Gasikule E13 reservoir, the ultimate recovery increases with an increased oxygen volume fraction of the injected air. The incremental recovery factor of the core experiment ranges from 1.2% to 6.9%. From the perspective of recovery ratio and safety, oxygen-reduced air with the oxygen volume fraction slightly lower than 10% can be applied as the displacement medium. Viscous fingering may occur when the gas injection rate is more than 1.0 mL/min, while capillary retention may occur when the oxygen injection rate is less than 0.1 mL/min, resulting in relatively low recovery factor. When the gas injection rate is 0.3 mL/min, it is a stable oil and gas flooding with a higher recovery factor. The process of the oxygen-reduced air-assisted gravity drainage is relatively sensitive to gravity. For the reservoirs with small inclination angles, the oxygen-reduced air-assisted gravity drainage is still feasible to some extent. The factors that affect the oxygen-reduced air-assisted gravity drainage in the Gasikule E13 reservoir are gas injection rate, core inclination angle and oxygen volume fraction in sequence according to their sensitivities.

Key words: Qinghai oilfield, Gasikule, oxygen-reduced air-assisted gravity drainage, full-diameter core, physical simulation, low-temperature oxidation, gas injection rate, oxygen volume fraction