不稳定注水模拟实验及其在不同类型砂岩油藏中的应用

EXPERIMENTAL STUDY ON THE UNSTEADY WATER INJECTION TECHNIQUES AND OILFIELD APPLICATION IN DIFFERENT KINDS OF SANDSTONE RESERVOIRS

建立了模拟正、反韵律油藏的物理模型以及矿场可能出现的 9种注水模式。利用室内模拟实验和矿场实际应用验证了砂岩油藏不稳定注水提高采收率的机理 ,并量化了平面转网后不同韵律油藏采收率的增加值 ,得出了在不同注入方式下的注入孔隙体积倍数、采出程度、采出程度增加值等参数不同时的累积采油量。实际应用表明 ,不稳定注水缓解了油藏层内非均质的矛盾及层间矛盾 ,且正韵律油藏的注水效果优于反韵律油藏。通过转网缓解了油藏平面的矛盾 ,并且在不同含水阶段转网均可提高采收率。在胜利油区采用不稳定注水取得了明显的降水增油效果。

Physical models are set for experiment on both positive and reverse rhythm sandstone reservoirs. Nine possible water injection models in an oilfield are proposed. The physical model experiments and field application proved oil recovery increment mechanisms of unsteady water injection in sandstone reservoirs. Also the increment of oil recovery factor in different rhythm reservoirs was quantified by changing areal well patterns. The injection pore volume, recovery percentage and its increment under different well patterns as well as the accumulative oil production from different permeable zones are obtained. As a matter of fact, heterogeneous interference and interlayer interference have dropped off by unsteady water injection. In general, the injection effect of positive rhythm reservoirs is better than that of reverse rhythm reservoirs. Well pattern's change can drop off the areal heterogeneity and the increment of recovery factor during different water cut stages. This technique has been successfully applied in such development units of Shengli oilfield. A good effect has been achieved.