吉木萨尔页岩油水平井JHW00421井钻完井关键技术

JHW00421井是吉木萨尔油田第1口超长水平段页岩油水平井,设计水平段长度3 027 m,面临钻进摩阻及扭矩大、井壁易失稳、井眼轨迹控制难度大、井眼清洁难度大、油层套管下入困难等诸多钻井难题。为攻克以上技术难题,开展了以下技术研究和现场实践:优化井身结构并将?244.5 mm技术套管下至A靶点以实现水平段专打;采用旋转导向工具对水平段轨迹进行精准控制并减小井眼曲折度;采用油水比85∶15的油基钻井液,降低长水平段井壁失稳风险、钻井管柱与井壁摩阻系数;基于水平井井筒清洁"传输带"理论,制定详细的井筒清洁技术方案以确保井筒"干净";优选套管柱摩阻计算模型并合理选取摩阻系数,准确预测套管柱下入能力并优选下套管方案;采用多扶正器通井钻具组合、优化套管扶正器类型及安放位置以降低下套管阻力;采用油基冲洗型隔离液并优选注水泥参数来提高水平段固井质量。该井完钻井深5 830 m,实际完成水平段长度达3 100 m,水平段固井质量测井解释为优质,对今后同类超长水平段水平井设计和施工有借鉴和指导作用。

Key technologies for the drilling and completion of shale oil horizontal well JHW00421 in Jimusaer

Well JHW00421 is the first shale oil horizontal well with ultra long horizontal section in Jimusaer Oilfield, and the designed length of its horizontal section is 3 027 m. It faces a series of drilling difficulties, such as large drilling friction and torque, instable borehole, difficult hole trajectory control, difficult hole cleaning and difficult production casing running. In order to solve these technological difficulties, the following technological researches and field practices were carried out. First, the casing program was optimized and the ?244.5 mm technical casing was run to target A for horizontal section only. Second, the rotatory steering tool was adopted to control the trajectory of horizontal section accurately and reduce the borehole curvature. Third, the oil-based drilling fluid with oil/water ratio of 85∶15 was applied to reduce the wellbore instability risks of long horizontal section and the friction coefficient between drill string and wellbore. Fourth, based on the “transmission band” theory of horizontal well cleaning, wellbore cleaning technological scheme was formulated in detail to ensure the wellbore “clean”. Fifth, the model for calculating the friction of casing string was optimized and the friction coefficient was selected reasonably. In addition, the running capacity of casing string was predicted accurately and the casing running scheme was optimized. Sixth, the multi-centralizer drifting bottom hole assembly (BHA) was adopted and the type and setting position of casing centralizer were optimized to reduce the resistance to casing running. Seventh, the oil-based flushing spacer fluid was adopted and the cementing parameters were optimized to improve the cementing quality of horizontal section. The total depth of this well is 5 830 m and the actual length of the horizontal section is 3 100 m. According to the logging interpretation, the cementing quality of the horizontal section is of high quality. The research results provide reference and guidance for the design and construction of similar horizontal wells with ultra long horizontal section in the future.