杭锦旗地区致密砂岩气藏水锁伤害评价及防治对策

以鄂尔多斯盆地杭锦旗地区上古生界致密砂岩储层为研究对象,结合工区储层工程地质特征,开展室内岩心水锁伤害以及相渗实验,分析孔隙度、渗透率、束缚水饱和度等因素对水锁伤害影响。实验结果表明:水锁伤害程度与渗透率、束缚水饱和度呈负相关,与储层伊利石含量正相关;太原组、山西组的水锁程度明显大于下石盒子组,伤害率基本都在40%以上,毛管自吸和天然裂缝的作用强化了水锁储层伤害。并提出相应的防治措施:控制压裂规模,减少水相与储层接触时间,添加防水锁剂、液氮等方式降低水锁伤害。

Water locking damage evaluation and prevention countermeasures of tight sandstone gas reservoir in Hangjinqi area

The article makes a study on Palaeozoic sandstone reservoir of Hangjinqi area in Ordos basin.Combined with the reservoir engineering geological characteristics of the work area,indoor core water lock damage analysis and phase permeability experiment have been carried out.The effects of permeability,porosity and irreducible water saturation on water locking damage have been analyzed.The experimental results show that the water locking damage degree is of negative correlation with permeability and irreducible water saturation,and positively related to the reservoir illite content.The water locking degree of Taiyuan,Shanxi formations is obviously stronger than that of Shihezi formation,with the damage rate of over 40%.The spontaneous imbibitions and the effect of natural fractures strengthen the absorption of water lock damage reservoir.Therefore,the corresponding prevention measures have been put forward,namely controlling the scale of fracturing,reducing water facies reservoir contact time,adding waterproof lock agent,liquid nitrogen to reduce the water locking damage.