【摘要】 大古2井为大涝坝构造山前构造的一口重点探井,完钻井深为6 702 m。该井二开(φ311.2 mm)裸眼井段长(2 500～5 300 m),钻遇多套高压盐水层和石膏层;三开(φ215.9 mm,5 300～6 552.53 m)存在多套压力体系,地层渗透性强,高密度条件下压差卡钻的风险大。现场采用阳离子乳液聚合物钻井液,并根据不同井下复杂情况加强钻井液性能维护处理,解决了遇阻卡钻和地层出盐水等复杂问题;通过添加超低渗透处理剂和屏蔽暂堵剂,强化对地层的封堵,解决了三开施工中出现的压差卡钻风险,保证了现场安全施工。更多还原

【Abstract】 The well Dagu-2 is a key exploration well of Northwest Oilfield Branch Company of Sinopec located in piedmont structure Dalaoba construction with the total depth of 6,702 m.Some challenges are encountered in the holes of φ311.2 mm(2,500-5,300 m) and φ215.9 mm(5,300-6,552.53 m),which are long open holes,several sets of high-pressure salt water and gypsum layers,multiple sets of pressure systems,high permeability formation and high risk of pipe sticking at high-density condition.A cationic emulsion polymer drilling fluid is used to overcome the problems of tough sticking and salt water flow,and ultra-low filtration rate agents are applied to seal the formations that reduces the risk of differential pressure sticking as low as possible.更多还原