复杂断块油藏高含水期化学剂强化CO_2复合驱提高采收率技术

Enhanced oil recovery technology of chemicals & carbon-dioxide combined flooding in high water cut stage of complex fault block reservoir

苏北盆地洲城油田垛一段油藏含油面积小、储层分散、储量丰度低,目前处于注水开发的中后期,剩余油的量化表征及有效挖潜技术优选成为油田深度开发阶段核心工作。以高含水开发阶段复杂断块油藏剩余油挖潜及提高原油最终采收率为目标,开发了化学剂强化CO_2复合驱提高采收率技术体系(Chemicals&Carbon-dioxide,2C复合驱)。室内实验及数值模拟研究表明,水驱后注入洗油剂较大幅度降低流体界面张力,显著提高波及范围内残余油驱油效率,通过段塞式注入的CO_2的超覆作用,携带洗油剂对正韵律含油砂体高部位有效波及,改善垂向剩余油驱替效果。2C复合驱油体系通过耦合化学剂原油降黏及CO_2超覆作用扩大波及双重优势,实现高含水期驱油效率及纵向波及系数的同时提高,显著提高了原油最终采收率。

The Zhoucheng Oilfield Duo I Formation,a oil-bearing reservoir area is small,scattered,low abundance of reserves,is currently in the water development in the late,residual oil quantitative characterization and effective excavation technology optimization has become the core depth stage of oilfield development.A integrated innovation of chemical flooding technology to improve the system of enhanced CO2recovery(Chemicals&Carbon-dioxide,2C).Study on laboratory experiment and numerical simulation show that after water flooding into the washing agent greatly reduce surface tension,improve sweep range of residual oil displacement efficiency,overlap by injection of CO2,carry on the washing agent positive rhythm oil sand body high part of the effective spread,improve the vertical displacement of residual oil for effect.2C technology system coupling chemical oil by viscosity and CO2overlap expand spread the advantages of achieving high water cut period of oil displacement efficiency and the vertical sweep coefficient increase,significantly improve the ultimate oil recovery.