低渗透油藏水锁损害室内实验研究

Experimental Study on Water Lock Damage in Low Permeability Reservoirs

鄂尔多斯盆地西峰油田储层属于典型低渗透储集层,是细孔微孔型,具有强非均质性强和强水锁性。通过进行该储层岩心水锁伤害实验,并分析影响因素和实验结果,得到以下结论:水锁的伤害程度与渗透率之间的关系呈明显的负相关,渗透率越大水锁伤害就越小;与束缚水饱和度之间的关系呈正相关;而与孔隙度的相关性较差,但总趋势是孔隙度越大伤害越小。水锁伤害对油气田的采收率有严重影响,因此解除水锁伤害对油气田开发有重要意义。利用6块样品所做的室内返排实验表明返排水量与排驱时间、排驱压力和储集层物性有一定的关系,返排压力越大,水锁伤害越小,对低渗透储藏添加表面活性剂有利于实现增产,并且减轻水锁和其他敏感性对储集层的伤害。

The reservoir of Xifeng oilfield is a typical low permeability reservoir, which belongs to fine pore type and has strong heterogeneity and strong water lock. In this paper, The influencing factors of water lock damage were analyzed by water lock damage experiment of the reservoir core. The results showed that the damage degree of water lock was negatively correlated with the permeability. Its correlation with the porosity was poor, but the general trend was that the bigger the porosity, the less the damage. There was a positive correlation with the bound water saturation. Indoor experiments showed that the backflow volume,displacement time, displacement pressure and reservoir physical properties had certain relations, and improving the backflow pressure reduced water locking damage, and using surfactants for low permeable reservoirs can not only increase the oil production, but also help to reduce water lock damage and other sensitivity of reservoir.