塔里木盆地超深易漏失井封隔分级固井技术研究

Research and Practice of Sealing and Staged Cementing Technology for Ultra Deep Leaking Wells in Tarim Basin

  • 摘要: 超深井长裸眼固井过程中井漏频发,塔里木盆地二叠系地层漏失问题尤为突出,易造成长段套管封固失效,亟需优化施工工艺以保障井筒完整性。立足塔里木盆地超深裂缝性油气藏地层特性,结合目标井地层承压能力,从封隔分级固井工艺、水泥浆体系、配套关键固井工具等三方面开展了系统研究,通过提升一级固井水泥浆返高,利用封隔器封堵漏失层,确保二级固井水泥浆返至地面,有效缩短空套管长度,实现一级固井少漏失、二级固井不漏失的目标,全面保障井筒完整性。该技术现场应用300余井次,固井质量合格率提升30%~40%,支撑超深井优快完井技术落地,强化了井筒完整性、延长了井筒服役寿命,加快了塔里木盆地勘探开发进程。

     

    Abstract: Leakage occurs frequently during long open-hole cementing in ultra-deep wells, especially in the Permian formation of the Tarim Basin, which tends to result in the failure of long-section casing cementing. Therefore, it is urgent to optimize technical solutions to ensure wellbore integrity. Based on the geological characteristics of ultra-deep fractured reservoirs in the Tarim Basin and the formation pressure-bearing capacity of target wells, this paper systematically conducts research from three aspects: sealing and staged cementing technology, cement slurry system, and supporting key cementing tools. By increasing the cement slurry return height in primary cementing and sealing leakage zones with packers, the cement slurry in secondary cementing is ensured to return to the surface, which effectively shortens the length of empty casing and achieves the goal of low leakage in primary cementing and zero leakage in secondary cementing, thus comprehensively guaranteeing wellbore integrity. This technology has been applied in more than 300 well sites, improving the qualified rate of cementing quality by 30%~40%. It supports the high-efficiency and rapid completion of ultra-deep wells, enhances wellbore integrity, prolongs wellbore service life, accelerates the exploration and development of the Tarim Basin, and provides core technical support for safeguarding national energy security.

     

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