干热岩大幅度提高注水开发采收率研究

THE PRINCIPLE OF INCREASING OIL RECOVERY EFFICIENCY OF WATER FLOODING DEVELOPMENT OF HOT DRY ROCK

制约注水开发的一个重要因素是注入水温度明显低于油层温度,造成油层温度持续下降,增大了原油黏度;长期剧烈的温差导致储层孔喉胶结物及骨架矿物破碎,加剧了大孔道窜流,降低了采收率。物理模拟和驱替实验证实热水驱油能够提高采收率。围绕降低产生热水的费用,提高注入温度,提出了利用干热岩进行热水驱油构想,干热岩中注入的低温水在地下成为高温高压超临界流体(蒸汽或热水),并使岩体产生具有一定方位的裂隙系统,形成热储构造;在适当位置钻穿热储构造,喷出的热水作为注入水进行注水开发。在技术配套方面,无论钻深井,还是注水开发工艺都已成熟。各油田积累的开发实践经验也非常丰富,为利用干热岩进行热水采油提供了便利条件。建议在有利区块率先开展干热岩辅助采油先导试验。

An important constraining factor in water flooding is that the water temperature is significantly lower than the oil temperature,causing the decreasing of oil layer temperature and the increasing of crude oil viscosity.The severe temperature fluctuation leads to the breaking of reservoir pore cement and matrix minerals,intensifying the large channel channeling and reducing oil recovery.Physical simulation and displacement experiments show that hot water flooding can enhance oil recovery.Focusing on decreasing the cost of producing hot water,improving the injecting temperature,the conception of achieving hot water flooding by hot dry rock is proposed.The low temperature water injected into the hot dry rock in the underground will became high temperature and high pressure supercritical fluid(steam or hot water) and it will produce a fracture system with a certain direction,thus form the heat storage structure.Then an appropriate point will be chosen to drill through the heat storage structure,the hot water sprayed out can be used in the hot water flooding process.As for technology,whether deep drilling or water flooding,the technology is very mature.The rich developing experience accumulated by oilfields will provide convenience to use hot dry rock.The hot dry rock auxiliary developing pilot test should be carried out in favorable blocks first.