Abstract: Aiming at the source and corrosiveness of carbon dioxide, the in-situ carbon dioxide generation technology to enhance oil recovery was proposed. The mechanism and the capability of this technology were studied. The generation and volume of carbon dioxide in reservoir were determined. The expansion, viscosity reduction, scale and injury of formation and oil-displacement efficiency of this technology were experimentally evaluated. The experimental results indicated that the in-situ carbon dioxide generation technology could be used to produce enough carbon dioxide and get good efficiencies of oil expansion, reduction of viscosity and enhancement of oil displacement. Under the conditions of 12904.1 mPa·s in oil viscosity,70℃ and 6 MPa, the volume of oil could be expanded by 32.5%, and the viscosity of oil can reduced by 52.69%, and the oil recovery could be enhanced by 6.4% to 17.06%. In addition, this technology has no damage to formation. This technology has gotten better result in field application.

Key words: in-situ carbon dioxide generation technology, technical mechanism, laboratory experiment, technical evaluation, oil displacement efficiency, enhancing oil recovery

摘要： 针对CO₂的气源、腐蚀等问题,提出了就地CO₂提高原油采收率技术。利用可视微观模型,对就地CO₂技术的作用机理进行了研究。在油藏条件下,通过实验对CO₂在地层中的产生及气量进行了确定,并研究了对其反应速度进行控制的方法。同时,对就地CO₂技术的性能(原油膨胀能力、原油降粘能力、结垢、地层伤害)及驱油效率进行了评价。实验结果表明,在油藏条件下,利用就地CO₂技术能够生成充足的气体,能膨胀原油体积及降低原油粘度,取得良好的驱油效果。当温度为70℃、压力为6MPa、原油粘度为12 904.1mPa·s时,就地CO₂技术可以使原油体积膨胀32.5%,使原油粘度降低52.69%,能够提高原油采收率6.4%-17.06%。同时,就地CO₂技术对地层不会造成伤害。该技术已经在现场实施并取得较好效益。

关键词: 就地CO₂技术, 技术原理, 室内实验, 技术评价, 驱油效率, 提高原油采收率