注水开发油田二次孔道最佳封堵时机和最佳封堵位置的室内实验研究

Laboratory Experimental Studies on Optimal Time and Site Selection for Plugging Secondary Channel in Waterflooding Reservoirs

采用平板模型的流动实验方法 ,研究了二次孔道封堵的最佳时机和最佳位置。从最佳封堵时机研究得到油井刚见水时是最佳的封堵时机 ,水道一形成即进行封堵 ,可减少注入水的无效循环 ,也可以减少二次孔道的形成 ;从最佳封堵位置研究得到在靠近注水井的位置是最佳的封堵位置 ,说明封堵越靠近注水井 ,对流线影响越大 ,波及系数越大 ,因此原油采收率越高。

The core flow experiments for optimization of secondary channel i.e. highly permeable zone(HPA) plugging operations are conducted on rectangular platelike artificial cores of 200×200×15 mm with a diagonally directed HPZ and holes( wells) in the corners. HPZ plugging is performed by using a silicic acid gel at different stages of water flooding and the highest oil recovery is obtained when the gel treatment of injection well for HPZ plugging is performed just after the moment of water breakthrough appears at the production well; the later the gel treatment is performed the lower the oil recovery is. In another set of experiments additional holes are made at various distance from the injection well along the HPZ and gel is injected into these holes to plug the HPZ after the water cut of the production well has reached 78% and it is shown that the near to the injection well the gel is emplaced the higher the additional oil recovery can be obtained. The experimental results are discussed.