吐哈盆地北部山前带深层致密气藏水平井钻井技术

吐哈盆地北部山前带和斜坡区致密气资源前景广阔，水平井技术是实现致密气有效开发的重要途径。但北部山前带水平井钻井中存在高陡构造地层倾角大，直井段井身质量控制困难；大段煤系地层、薄互层等复杂地层发育，井壁稳定性差，坍塌严重、复杂事故频发；深部地层可钻性差，水平段施工钻头破岩效率低，钻井周期长等一系列技术难题。通过优选适合北部山前带水平井的井身结构、井眼轨迹和钻井液体系，开展个性化钻头、煤系地层安全定向钻井、小井眼长水平段旋转地质导向钻井技术攻关和现场应用，形成一套适合于北部山前带致密气藏水平井优快钻井技术系列，达到提高水平井机械钻速、有效缩短钻井周期的目的，为实现致密砂岩气藏的“安全、高效、优质、经济”勘探开发提供强有力的技术支持。

Horizontal well drilling technique for tight gas reservoirs in Tuha Basin

Tight gas resource is promising in North Tuha Basin, and horizontal well is an key method for effectively develop tight gas reservoirs. However, the angle of bedding is large, leading to difficult control of wellbore quality of lateral sections. Large section of developed coal formation and short lap makes weak wellbore stability and frequent happening of collapse. Deep formation have low drillability and rock breaking efficiency of the bit is low for lateral sections, bring to lengthy drilling period. To solve the difficulties above, through optimizing wellbore scheme of the horizontal well, wellbore trajectory, and drilling fluid, and conducting personal drilling bit, directional drilling for coal formation, and small-hole long lateral-section steering drilling technique, a series of fast horizontal well drilling techniques for tight gas reservoirs are formed. The aim of improving penetration rate and effectively shortening drilling period are achieved, which supplies powerful technical support for the exploration and development of tight sand gas reservoir.