鄂尔多斯盆地西缘冲断带页岩气井综合治漏技术

Comprehensive Leakage Control Technology for Shale Gas Wells in Western Margin Thrust Zone of Ordos Basin

  • 摘要: 鄂尔多斯盆地西缘逆冲带区域深层页岩地层交界面存在天然裂缝,长裸眼井段多套承压薄弱层同存,承压能力弱,钻井过程中井漏频发,严重制约着钻井提速增效。研究了随钻承压护壁技术,以提高裸眼井段承压薄弱层的承压能力;采用了长裸眼漏层精准定位技术,以实现漏层的精准定位;研发了酸溶性高滤失堵漏工作液进行裂缝性恶性漏失高效堵漏,以大幅提高钻井时效。由上述技术措施形成了鄂尔多斯盆地西缘冲断带防漏堵漏关键技术。该技术在鄂尔多斯盆地西缘冲断带14口井页岩气井进行了现场应用,专项堵漏时间缩短55.25%,钻井周期缩短15.5 d。鄂尔多斯盆地西缘冲断带综合治漏技术为该盆地非常规油气井的安全高效开发提供了技术支持。

     

    Abstract: The western margin thrust zone of the Ordos Basin are characterized by the presence of natural fractures at the interface of deep shale formations, with multiple sets of weak pressure-bearing layers coexisting in the long open hole wellbore section, resulting in weak pressure-bearing capacity and frequent lost circulation during drilling, which seriously restricts drilling speed and efficiency. To this end, the pressure-bearing wall protection while drilling technology has been studied to enhance the pressure-bearing capacity of weak pressure-bearing layers in the open hole sections. Precision positioning technology for leak layers in long open hole sections has been employed to achieve accurate positioning of the leak layers. Acid-soluble high-filtration plugging fluid has been developed, which was highly effective in plugging severe loss caused by fractures and thus significantly improving drilling efficiency. These technologies have been integrated into key leakage prevention and plugging technologies for the thrust zone at western margin of Ordos Basin. These technologies have been applied in 14 shale gas wells in the thrust zone at the western margin of Ordos Basin, reducing the special plugging time by 55.25% and shortening the drilling period by 15.5 days. The comprehensive leakage control technologies for the thrust zone at the western margin of Ordos Basin provide technical support for the safe and efficient development of unconventional oil and gas wells in Ordos Basin.

     

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