大庆油田机械分层注聚技术的研究及应用

Study and application of mechanical separate layer polymer injection in Daqing Oilfield

大庆长垣油田主力油层聚合物驱三次采油自1991年开始进入工业性矿场试验以来,应用规模不断扩大,聚驱对象由主力油层转变为二类油层,并开展三类油层聚合物驱的先导性试验,聚合物驱可以扩大波及体积,但不能从根本上解决层间矛盾,必须进行分层注入,以改善聚驱效果,为此,大庆油田最早发展了双泵双管分注工艺管柱。随着聚驱对象的转变,渗透率降低,分注层段数增加,为适应不同时期聚驱开发的需要,聚驱分注技术以提高注聚效果和降低成本为目的,发展应用了双泵双管分注工艺、单泵双管分注工艺、单管同心环形降压槽分注技术、单管桥式偏心分注技术、分质分压注入技术,对聚驱注入剖面调整起到了极为重要的作用。

Commercial field test of tertiary recovery by polymer flooding started from 1991 for principle reservoirs in Changyuan of Daqing Oilfield and had expanded in scale with target layers shifting from principle reservoirs to the reservoirs of the II class, and pilot test of polymer flooding in reservoirs of the III class was also conducted. Polymer flooding can expand swept volume, but can not radically solve interlayer problems. Separate injection is necessary to improve polymer flooding effect. Hence, Daqing Oilfield has developed double-pump double-string separate layer injection process. As the shifting of polymer flooding targets, permeability reduces, and the number of layers for separate injection increases. In order to meet the requirement of polymer flooding in different stages, improve flooding effect and reduce cost, the techniques of polymer flooding by separate injection have evolved as double-pump double-string process, single-pump double-string process, single-string concentric ring groove for blowdown process, single-string eccentric bridge process, and quality- and pressure-dependent injection process, which have played very important roles in polymer injection profile adjustment.