间歇蒸汽驱技术及其在河南油田的应用

THE TECHNIQUE OF INTERMISSION STEAM FLOOD AND ITS APPLICATION TO HENAN OIL FIELD

间歇蒸汽驱是注汽井周期性地向油层中注入蒸汽的一种非常规蒸汽驱方式 ,在油层中造成不稳定的脉冲压力状态 ,使之经历地层升压和降压两个过程 ,从而促进毛管渗吸驱油作用 ,扩大注入蒸汽的波及效率 ,达到降低含水、提高油层采收率之目的。同时 ,间歇蒸汽驱可大幅度提高蒸汽驱采注比 ,实现蒸汽驱过程中降压开采机理 :蒸汽比容增大 ,增加了蒸汽波及体积 ,使蒸汽干度、热利用率得以提高。另一方面 ,间歇蒸汽驱还可以减缓和抑制汽窜 。

Intermission steam flood (ISF) is a non conventional steam by which that steam is intermittenty injected in an oil reservoir to produce pays from injection wells. This method induces an unstable pulse pressure state in the oil reservoir, thus the oil reservoir pressure undergoes the courses of ascending and descending, which can further promotes the capillary imbibition drive action and increase injected steam sweep efficiency to result in descending water cut and enhancing oil recovery. ISF can also largely improve production injection ratio of steam flood and achieve the depressurization production mechanism of steam flood so that steam specific volume, steam swept volume, steam quality and heat utilization efficiency are all increased. In addition, ISF can delay and restrain the steam breakthrough and improve the effect of steam flood.