Technical practice of pressure controlled completion with packers in ultra-deep and high-pressure shale gas wells

To address the challenges of CO₂ corrosion in casings and wellbore liquid loading when using casing completion in ultra-deep and high-pressure shale gas reservoirs in Sichuan Basin, as well as issues such as severe reservoir damage, prolonged operation cycles, and high costs associated with traditional packer completion techniques, a new pressure-controlled completion technology with packers under high-pressure wellhead environments based on snubbing operations is proposed. The core of this technology integrates pressure-isolated temporary plugging with packers and pressured tubing string re-insertion. By running an insert packer into the well under pressure using coiled tubing to temporarily isolate the production zone, pressured re-insertion and sealing connection of the production tubing string are achieved under wellhead pressures ≤21 MPa. This method systematically solves six key challenges including reservoir protection, high tubing uplift force, tubing string deformation, blowout preventer leakage, hydrate ice barrier, and packer failure. Successful field applications in three wells demonstrate that production can be smoothly restored by pressurizing the tubing to trigger rupture discs and plugs after operations. The average operational efficiency per well is increased by 45%, while the cost is reduced by RMB 320,000. This technology provides a novel solution to minimize reservoir damage and promote operational efficiency in conventional completions for ultra-deep and high-pressure shale gas wells, significantly enhancing economic benefits and operational efficiency, and offering technical support for the low-cost and efficient development of similar gas reservoirs.