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

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.