准噶尔盆地石南J_2t_2油藏注水利用趋势及影响因素研究

Study on Flooding Efficiency and Affecting Factor of Shinan J_2t_2 Reservoir

非均质注水开发砂岩油藏的注水利用率是注水开发过程中极其重要的内容之一,注水利用率和主要能量驱替类型是随开发过程变化的,通过阶段性的存水率、耗水比和能量驱替指数等参数计算,确定阶段注水效果,从而进行后期注采方案调整,提高注水开发效果。笔者通过以上参数的计算和评价,认为石南J2t2油藏开发初期以弹性能量驱替为主,随注水的开发,以注水能量驱替为主,边底水能量驱替次之,弹性能量贡献不大;存水率随开发的进行逐渐降低,注水利用率逐渐减小,近期产水有快速增加的趋势。分析认为注水利用率主要受沉积相、储层非均质性、储层介质类型及水力裂缝方位、半长等因素综合影响。

The flooding efficiency of heterogeneous waterflooding sandstone reservoir was one of the essential contents in the exploitation process. Flooding efficiency and chief energy displacing pattern were varied with exploitation process, by calculating the water storage rate,cumulative water-oil ratio and energy displacement index to determine the flooding effect, the later development plan was adjusted, exploitation effect was improved. It is considered that Shinan J2t2 reservoir is displaced by elastic energy early, it is displaced by water energy after that the water storage rate is lower with exploitation, flooding efficiency also, and produced water increase quickly. It is pointed out that precipitation facies, reservoir heterogeneity, type of reservoir medium, hydraulic fracture direction and fracture half length have an impact on the flooding efficiency.