低自由水钻井液体系的研究与应用

Research and application of low free water drilling fluid in Nanpu Oil Field

为了解决南堡油田玄武岩井壁失稳和储层保护问题,研究了低自由水钻井液体系。该钻井液体系通过对自由水的络合,增大了钻井液进入地层的毛管阻力;通过润湿剂降低地层岩石的毛细管自吸水能力;通过封堵地层裂隙、改善泥饼质量,提高井壁的承压能力;该钻井液体系一方面可实现低密度安全钻穿玄武岩,提高油层保护效果,另一方面为简化井身结构打下基础,可进一步提高钻井速度并降低钻井费用。通过在南堡13-斜1064井现场的成功试验,实现了同一裸眼井上部玄武岩井壁稳定和下部储层保护的双重目的,为安全钻进和储层保护提出一个新理念。

The basalt, which is easily to block out and collapse, distributed widely in Nanpu Oilfield with large thickness. In order to resolve borehole wall instability and protect the underneath formation, low free water drilling fluid was studied. Capillary resistance is increased through free water complexation; The capacity of rock for water capillary self-absorbing was reduced by means ofwettabil- ity alteration; The bearing resistance of borehole wall is enhanced by fracture plugging and quality improvement of mud cake. Basalt safe drilling with low density and formation protection drilling fluid is realized. On the other hand, by using the drilling fluid, the hole structure is simplified, the drilling velocity may be increased and drilling cost may be induced. The pilot test in well Nanpu13-X1064 was successful done with notable well stability and formation protection, and a new concept for safe drilling and formation protection by low free water drilling fluid was proposed..