Abstract: Drilling a horizontal well with ultra-long horizontal section in conglomerate reservoir of Mahu Oilfield in Xinjiang is faced with a series of potential problems，including large drilling torque，difficult-to-control well trajectory，low ROP，weak wellbore stability and difficulty in running in completion casing. Systematic drilling and completion technology for horizontal wells with ultra-long horizontal sections in conglomerate reservoir of Mahu oilfield has been developed by means of casing program optimization，trajectory design and control，selection of featured PDC bit，high-performance oil-based drilling fluid，R&D of toughness cement，and safe casing running technique. This technology was applied to the drilling operation of Well Mahu029_H in Mahu15 Well Block，and achieved successful drilling of a horizontal section as long as 3 038 m，smooth running of casing，and satisfactory cementing quality that meets the requirements of large SRV fracturing. A new record has been created for the longest horizontal section in Mahu Oilfield，which accumulated experience for future drilling operations of horizontal wells with ultra-long horizontal sections in Mahu Oilfield，and provided references for the same type of wells in other areas of China.

Key words: tight conglomerate reservoir, ultra-long horizontal section, trajectory control, oil-based drilling fluid, toughness cement;
safe casing running

摘要： 新疆玛湖油田致密砾岩超长水平段水平井钻井存在着钻井摩阻扭矩大、井眼轨迹控制难度大、机械钻速低、井壁易失稳、完井套管下入困难等钻井难题。通过井身结构优化、轨迹设计与控制、个性化PDC钻头优选、高性能油基钻井液、韧性水泥研发、套管安全下入等技术手段，形成了新疆玛湖油田砾岩油藏超长水平段水平井钻完井技术。该技术在玛湖 15井区玛湖 029_H 井进行了钻井实践，完成了 3 038 m 超长水平段水平井钻井，下套管顺利，固井质量满足大型体积压裂要求，创造了玛湖油田最长水平段纪录，为玛湖油田后续超长水平段水平钻井积累了经验，也为国内其他地区超长水平段水平井钻井提供了借鉴。

关键词: 致密砾岩, 超长水平段, 轨迹控制, 油基钻井液, 韧性水泥, 安全下套管