致密砂岩储层水相圈闭损害及防治方法探索

Water Phase Trapping Damage and its Control in Tight Sandstone Reservoirs

刘雪芬 康毅力 罗平亚 游利军

LIU Xuefen KANG Yili LUO Pingya YOU Lijun

致密砂岩气藏孔喉细微、 毛管压力高、 局部超低含水饱和度， 极易发生水相圈闭损害， 降低气井产能。利用相圈闭系数法评价了鄂尔多斯盆地 M气田上石盒子组水相圈闭损害程度， 通过展开毛管自吸、 液相滞留评价实验分析了损害发生的原因， 利用界面润湿性修饰处理剂 FW-134开展了损害预防及解除研究。结果表明， 上石盒子组储层潜在强水相圈闭损害； 物性相对较好的盒 2+3段储层水相自吸能力较盒 1段强， 液相平均返排率 10%数47%， 滤液返排率 22.4%~32.3%， 物性好的储层返排率相对较高； 润湿性修饰为气润湿能有效抑制液相自吸， 液相返排率由 56.3%提高到了 83.4%， 使气测渗透率恢复程度由 66.1%提高至 88.2%。利用界面修饰处理剂使岩石润湿性由水湿变为气润湿， 是有效预防和缓解致密气藏水相圈闭损害发生的重要途径， 对恢复气井产能具有重要意义。图 12表4参 14

Tight sandstone gas reservoirs are prone to aqueous phase trapping damage（APTD），due to narrow pore throat，high capillary pressure，locally ultra-low water saturation，which will reduce the productivity of the gas wells. The extent of the APTD was evaluated with the methods of phase trapping factors in the upper Shihezi formation in M gas field of Ordos basin. Imbibitions tests and liquid retention evaluations were conducted to analyze what cause the APTD，and the prevention and removal of the APTD was explored through using FW-134，a surface-modifying agents for wettability modification. Results showed that there was potentially strong damage of water phase trapping in the upper Shihezi formation. The better the physical properties of the reservoir was，such as He2+3，the easier the water imbibitions and flow back. The average liquid flowback rate in the upper Shihezi formation was 10%—47%，and the average flowback rate of filtrate was 22.4%—32.3%. The use of quaternary ammonium fluoride to change the surface to gas wetting effectively inhibited the liquid imbibition in tight stone. The flow back rate of liquid increased from 56.3% to 83.4%. Gas permeability recovery of the cores was increased from 66.1% to 88.2% after treated by FW-134. Wettability alteration from water wetting to gas wetting is an important way to prevent and alleviate the APTD in tight sandstone gas reservoirs，which is significant to recovery of the gas well productivity.

10.19346/j.cnki.1000-4092.2017.02.005