YC气层水锁损害及预防

WATER BLOCK DAMAGE IN YC GAS RESERVOIR AND ITS PREVENTION MEASURES

YC气田是江苏油田至今发现的储量最大的气田。通过对YC地区气层的储层特征分析及试验研究 ,表明该气藏属低渗气藏 ,该地区气层水锁严重 ,尤其是入井液水锁严重。进行了气层保护技术的研究 ,提出了使用氧化剂消除钻井液在井壁表面形成的滤饼堵塞 ,使用高抑制性低界面张力型的水基钻井液、完井液及加速储层中入井流体的返排等预防措施。建议采用氧化和酸化复合解堵方法 ,以提高酸化效果。

YC gas field is the largest reserve found to date in Jiangsu Oilfield. Formation characteristics analysis and test study show that YC gas reservoir is a low permeable gas reservoir, and water blocking in this area is very severe, especially the inflowing fluid water blocking. Technologies for gas reservoir protection are investigated, and such methods as using an oxidizer to remove the filtrate cake blockage on borehole surface, using high inhibitative low interface tension water base drilling fluid and completion fluid, and speeding the discharge of inflowing fluid in the formation, etc. are proposed to minimize the water blocking damage. The combined method of oxidizing and acidizing is recommended for plugging removal, so as to improve the acidizing effect.