卫68FP1井泥页岩油藏水平井钻井技术

Drilling Technologies for Horizontal Well Wei 68-FP1in Shale Reservoir

为了解决卫68-FP1井水平段井眼尺寸小、井下摩阻大、井眼轨迹不易控制等问题,在计算不同井眼曲率下摩阻、扭矩的基础上,结合邻井实钻资料,优化了井眼轨道设计,以降低摩阻和扭矩;根据非常规水平井的实钻经验,选用"小角度螺杆+欠尺寸双稳定器"钻具组合,并对螺杆钻具的弯角和稳定器外径进行了优化,以提高井眼轨迹控制精度;选用合理密度的油基钻井液,以保证水平段的井壁稳定性;采用C1+伽马地质导向技术,以提高油层钻遇率;制定了安全钻进技术措施,以确保钻井安全。实钻结果表明:合理的井眼轨道设计能够有效降低钻进摩阻;"小角度螺杆+欠尺寸双稳定器"钻具组合能精确控制井眼轨迹,并能提高旋转钻进比例;C1+伽马地质导向技术能确保水平段始终在油层穿行。卫68-FP1井的顺利完成,可为泥页岩油藏水平井的钻井施工提供借鉴。

In order to overcome technical difficulties in Well Wei 68-FP1, such as slim-hole drilling in horizontal section, high friction and drag, difficult to control well trajectory, etc. , drilling technology for horizontal wells has been studied. The well path was optimized to reduce torque and drag by analyzing the data of torque and drag with different curvatures collected from adjacent wells. Combined with the early practice of horizontal wells for unconventional oil and gas reservoir, small angle PDM and undergauge bi- stabilizer assembly had been used, and optimized PDM angle and the size of stabilizers to improve precision of well traiectory control. Oil-based drilling fluids were applied and reasonable density was determined to maintain hole stabilization at horizontal section. ＂C1 ＋GAMMA＂ geo-steering technique was employed to ensure the horizontal section inside reservoir. The measures of safe drilling were adopted to ensure down- hole safety. The technical application showed that reasonable well path could reduce drag in drilling, small angle PDM and undergauge hi-stabilizer＂ assembly were the key factors in controlling trajectory, and it could also improve the ratio of rotary drilling. ＂C1 ＋GAMMA＂ geo-steering technique could keep the well trajectory inside the reservoir. The success of Well Wei 68-FP1 will provide the reference for horizontal drilling in shale reservoirs.