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一直以来,聚合物驱的设计和实施普遍采用“分阶段、统一段塞”的注入方式,即同一阶段内,注聚区的所有注入井注相同浓度的聚合物溶液段塞,不同阶段,聚合物溶液的浓度不同。这种方式没有区别各井(区)不同的地层参数,使有的井因粘度太低而仍存在聚合物窜流,而有的井则因粘度太高注不进去。根据孤东油田六区西北部3-5层的注聚过程中暴露出的问题,提出并实施了“分级注入浓度”聚合物段塞,井与井之间、同一井的不同时段,其注入段塞也不同。为了实现这一点,根据流动系数、单井注入压力、吸水指数、启动压力、大孔道分布等5个条件,设计了5种段塞,在不同井、不同时段注入。2012年12月起在六区西北部3-5层的35口井上实施,26口井见效,到2014年底,比原聚合物驱多增油19190t;在三四区推广实施也取得了明显增油降水效果。
Historically, polymer flooding has generally been designed and implemented using a “staged, unified slug” injection method where all injection wells in the injection zone are injected with the same concentration of polymer solution slugs in the same stage, at different stages , The concentration of the polymer solution is different. This method does not distinguish the different formation parameters of each well (area), so that some wells still have polymer channeling due to the low viscosity, while others can not enter due to the high viscosity. According to the problems exposed in the injection-gathering process of the 3-5 layers in the northwestern part of the six districts of Gudong Oilfield, the authors put forward and implement different stages of polymer plugging, well plugging, The injection slug is also different. In order to achieve this, five kinds of slug plugs were designed according to the five factors of flow coefficient, single well injection pressure, water absorption index, start-up pressure and large pore distribution, and injected in different wells and different time periods. In December 2012, 35 wells were drilled in 3-5 floors in the northwest of 6 districts and 26 wells were in effect. By the end of 2014, more oil was added than the original polymer flooding by 19,190t. Implementation promotion in districts 3 and 4 also made significant increase Oil precipitation effect.