长庆气区储气库Y37-2H井长水平段钻井技术

Drilling technology for the long horizontal section of well Y37-2H in the Yulin gas storage reservoir,Changqing Gas Field

鄂尔多斯盆地长庆气区Y37-2H井(完钻井深5 044m,水平段长1 819m)是国家储气库项目榆林储气库的第一口注采试验水平井,储气库的建设需要注采井不仅要达到强注强采(50×104～100×104 m3/d)的功能、还要满足长寿命(50年)要求。为此,在分析该区气井生产情况的基础上,采用215.9mm井眼钻长水平段并下139.7mm筛管完井方案来保障注采井强注强采功能;优选长半径水平井剖面,应用先进的随钻地质导向技术跟踪储层并控制水平段井眼全角变化率小于等于4°/30m,满足了固井下套管对井眼轨迹的质量要求;应用水力振荡器在钻井液流过时产生的压力脉冲带动钻具产生温和振动,将钻具与井眼之间的静摩擦转换为动摩擦,有效地降低了摩阻和扭矩,改善了钻压传递,提高了水平段滑动钻井机械钻速和进尺;采用的无土相复合盐低伤害暂堵钻井(完井)液体系既能满足保护山23储层,又能满足长水平段润滑防卡和泥岩防塌的需要。该井的顺利实施,为长庆气区超大库容的储气库建设奠定了基础。

Y37-2H with a total depth of 5044 m and a horizontal section of 1819 m is the first pilot test horizontal well in the Yulin gas storage under the National Gas Storage Reservoir Project.The injection and production well of storage reservoir requires strong working capacity of 50×104-100×104m3/d and a service life of at least 50 years.In view of this,the following technologies are developed to perform the intensified injection and production functions on the basis of a thorough analysis of the production of this pilot gas well.First,a φ215.9 mm borehole is employed in the long horizontal section drilling,and φ139.7 mm screen pipes for well completion.Second,a long-radius horizontal well profile is carefully selected,the advanced technique of geo-steering with drilling is applied in reservoir tracing,and the rate of overall angle change of the horizontal section borehole is controlled not to be more than 4°/30m,therefore meeting the quality requirements of cementing and casing for hole trajectory.Third,the pressure pulse,as a result of drilling fluid flowing through hydro-oscillator,drives the drilling rig to generate mild vibration that transforms the static friction between the drilling rig and the borehole into kinetic friction,thus,effectively reducing friction drag and torque,and improving the weight on bit transfer and the ROP of slide drilling and the footage on horizontal sections.Fourth,a clay-free composite salt and low-damage temporary plugging drilling(well completion) fluid system is applied and proved to be helpful for the Shan23 reservoir protection and to meet the requirements of lubrication and anti-clamp of long horizontal well sections and anti-collapse of mudstones.In general,the drilling of this well serves as a technical basis for the construction of super-large storage reservoir in the Changqing Gas Field.