新苏地2井长裸眼段长浸泡地层加深钻井技术

Long open hole and long-immersion formation deepen drilling technology in Well Xinsudi-2

摘要:

新苏地2井是部署在新疆塔里木盆地的一口油气地质调查井，钻进至2468.50 m裸眼完井，裸眼段长2009.24 m，地质评估后设计在原井眼加深钻探至3168 m。以500~600 m井段为例进行井壁稳定性分析。井筒被钻井液长时间浸泡导致井壁含水率增加，泥岩的粘聚力和内摩擦角等强度指标随之下降，导致井筒不具备承压能力，轻微的扰动都会造成井壁失稳。加深工程通过通井划眼阶段采用新型抗污染聚合物防塌钻井液体系、复杂井况下钻具组合搭配随钻震击器解卡、钻遇目的层采用低钻压、低转速、低排量参数组合钻进等技术方法的集成应用，解决了长裸眼段长浸泡地层带来的一系列复杂情况，保障工程顺利完工并实现了地质目的，积累形成了长裸眼段长浸泡地层钻井的宝贵经验和技术。

Abstract:

Well Xinsudi-2 is an oil and gas geological survey well deployed in the Xinjiang Tarim Basin. The well was drilled to 2468.50m with an open hole section of 2009.24m. After geological assessment， it was designed to be deepen drilling to 3168m. This article takes the 500~600m well section as an example to analyze the wellbore stability. The wellbore is soaked in drilling fluid for a long time， which causes the water content of the wellbore to increase. The cohesion and internal friction angle of the mudstone and other strength indicators decrease， resulting in the wellbore not having pressure-bearing capacity， slight disturbance will cause the well wall to become unstable. The project team adopted a new anti-pollution polymer anti-collapse drilling fluid system， a drilling tool assembly with a drill-while-drilling jar to relieve stuck conditions under complex well conditions， and the target layer was drilled using low drilling pressure\low rotational speed\low-displacement parameter combination drilling and other technical methods has solved a series of complex situations caused by long open-hole sections and long time soaked formations， ensured the smooth completion of the project and achieved the geological purpose， and accumulated the experience and technology of drilling long open hole and long-immersion formations.