松辽盆地致密油水平井提速技术研究与应用

Research and Application of Accelerating Technology for Tight Oil Horizontal WellsinSongliao Basin

松辽盆地致密油水平井钻井过程中存在机械钻速低、摩阻扭矩大、施工周期长等难题,为实现致密油水平井优快钻井,针对其地质特点及施工难点,根据靶点偏移距与地层压力系数优化设计井身结构,将三维井眼轨道优化为双二维井眼轨道,降低摩阻和扭矩;针对大段紫红色泥岩等难钻地层,研选高效PDC钻头,同时研发提速工具,提高机械钻速;针对青山口组、泉头组等井壁易失稳地层,研发了具有润滑性好、抑制性强、封堵效果好的低固相KCl聚合物盐水钻井液体系,减少井下复杂情况的发生,形成一套适用于松辽盆地致密油水平井的配套提速技术。该技术在松辽盆地115口致密油水平井进行了应用,试验井平均完钻井深3 120 m,平均水平井段长1 180 m,平均机械钻速提高71.2%,平均钻井周期由46.3 d缩短至34.2 d,创造了松辽盆地致密油水平井215.9 mm井眼一趟钻完钻、单只钻头进尺2 700 m等施工记录,井下复杂率降低15.37%,实现了致密油水平井优快钻井的目标。

In the process of drilling tight oil horizontal Wells in Songliao Basin,there are some problems,such as low penetration rate,high friction torque and long construction period.In order to realize the optimal and fast drilling of horizontal wells in tight oil,according to the geological characteristics and construction difficulties,the well structure was optimized according to the offset distance of the target point and the formation pressure coefficient,and the three-dimensional wellbore trajectory was optimized into a double twodimensional wellbore trajectory to reduce friction and torque.Aiming at the difficult-to-drill formation such as large section of purple mudstone,we developed efficient PDC bit and developed speed raising tools to improve the drilling rate.For the wellwall unstable formations such as Qingshankou formation and Quantou formation,the low solid phase KCl polymer brine drilling fluid system with good lubricability,strong inhibition and good sealing effect was developed to reduce the occurrence of downhole complications and form a set of supporting speed up technology suitable for tight oil horizontal wells in Songliao Basin.This technology has been applied to 115 tight oil horizontal wells in the Songliao Basin.The average drilling depth of the test wells is 3120 m,the average horizontal well length is 1180 m,the average ROP is increased by 71.2%,and the average drilling period is shortened from 46.3d to 34.2d.The completion of 215.9 mm hole drlling in a single trip and the penetration of a single bit of 2700 m were achieved in the Songliao Basin tight oil horizontal well,and the downhole complexity rate was reduced by 15.37%,achieving the goal of optimal and rapid drlling of tight oil horizontal wells.