南海东部油田低成本高效助流注水技术创新与实践

南海东部越来越多的海相沉积砂岩油藏地层能量不足需要注水,但平台无注水工程预留,存在建立注水系统投资大、周期长、效益差的问题,如何实现注水开发是亟待解决的技术挑战。以A油田为例,该油田L层为边水驱动的岩性油藏,地层天然能量不足,水平井投产后地层压力下降迅速,迫切需要通过注水补充地层能量。在注水水源评价的基础上,定量表征相控模式下的压力场,制订针对性的抢救式注水方案;研发助流注水工艺管柱及井下数据监测系统,满足了油藏通过井下注水补充地层能量、提高采收率的要求。结果表明:创新研发的助流注水技术实现了平台无注水预留条件下的注水开发,节省了海上平台空间及工程设施成本,实现了变流量注入、定期酸洗、闭式注入环境下的水质监测、注入水量测调、水源层返排清井及产水能力测试等多种功能,具备成本低、实施周期短、注水效果好的巨大优势。油田采用助流注水后,受效井组的单井采油量增加明显,地层能量得到有效补充,取得了很好的开发效果。

The Innovation and Practice of Low Cost and High Efficiency Borehole Pump Flooding Water Injection Technology in the Southeast China Sea Oilfield

Many marine sedimentary sandstone reservoirs in the east of the South China Sea need energy supplement. In recent years, to realize development of water injection under the condition that the platform has no water injection project reserved has been a technical challenge and is urgently to be solved. In order to solve the problem, the key technologies are tackled to supplement formation energy in time and improve the reservoir development effect. The L layer of A oilfield located is an edge water drive lithologic reservoir, the natural formation energy is insufficient, the formation pressure decreases rapidly and the production decline significantly after the production of horizontal well, some Wells need to produce intermittently or even shut down for insufficient fluid, it is urgent to supply the formation energy. On the basis of water resources evaluation, the pressure field under phase mode are characterized, then the pressure recovery plans are set out. The water injection pipe string and underground data monitoring system are devised to satisfy the reservoir energy supplement and improve the reservoir recovery. Results show that the borehole pump flooding water injection technology realizes the water injection development under the condition that the platform has no water injection project reserved, and the space of offshore platform and equipment investment are saved, and have the features including variable flow injection, regular acid pickling, water quality monitoring under closed water injection condition, injected water volume modification, water layer flowback and cleanup, water production capacity test. After the borehole pump flooding water injection used in the oil field, the single well oil production well group is significantly increased, and the formation energy is effectively supplied, obtained a very good development effect.