华北油田油气井永久性封井挑战及对策

Challenges to the permanent well plugging of oil and gas wells in Huabei Oilfield and their countermeasures

华北油田勘探历史久远且开发历程复杂,包含直井、定向井、大斜度井等多种井型,井筒完整性问题复杂,永久性封井难度大。为从封井设计源头保证废弃井永久性封井的安全,减少环保风险,以Y油田为例,对华北油田面临的永久性封井难点进行了分析。影响废弃井井筒完整性的关键因素是井屏障,结合Y油田实际情况,详细分析了其永久性封井面临的挑战,包括井筒完整性数据不全、固井质量不合格、已封井井屏障设置不合理、地下淡水层保护问题、地层完整性潜在风险、标准规范合理性问题及封井成本控制等。同时,结合国内外永久性封井经验给出相应技术对策和建议。分析结果为华北油田Y油田及类似油田的永久性封井设计、作业等提供参考。

Huabei Oilfield has long exploration history and complicated development history involving many well types,such as vertical well,directional well and high-angle deviated well,so the wellbore integrity is complicated and the permanent well plugging is of high difficulty.In order to ensure the safety of the permanent well plugging of abandoned wells from the very beginning of the well plugging design and reduce environmental protection risks,this paper analyzed the difficulties in the permanent well plugging of Huabei Oilfield by taking Y Oilfield as the example.It is shown that the key factor influencing the wellbore integrity of abandoned well is well barrier.Then,combined with the actual situations of Y Oilfield,the challenges to its permanent well plugging were analyzed in detail,including incomplete wellbore integrity data,unqualified cementing quality,unreasonable setting of well barrier of plugged well,protection of underground fresh water aquifer,potential risk of formation integrity,reasonability of standard and norm,and cost control of well plugging.Finally,the corresponding technological countermeasures and suggestions were proposed based on domestics and foreign experience in permanent well plugging.The analysis results provide the reference for the design and operation of permanent well plugging in Y Oilfield of Huabei Oilfield and similar oilfields.