Abstract This document is an in-depth case study on the application of a snubbing unit for plug and abandonment (P&A) operations. The study highlights the successful execution of two sustained annulus pressure (SAP) remediation procedures within a single run, thereby eliminating the need for a conventional rig. The operation achieved complete rock-to-rock isolation and permanent well abandonment through the implementation of advanced techniques, including strategic perforation, washing, cement circulation, and precise cement plug placement. The operation involved two remediation zones. The shallower zone was perforated to establish circulation to the surface, facilitating effective cement placement. Cement was then circulated to the surface and strategically displaced to form a continuous plug, ensuring full rock-to-rock isolation. This method aligns with the principles of the perforate, wash, and cement (PWC) technique, which has been recognized for its efficiency in establishing annular barriers without the need for section milling. PWC's effectiveness in curing SAP is further supported by its ability to restore annular barriers and improve well integrity, making it a cost-effective solution for P&A operations. Snubbing units, they are very demanded for location with difficult and complex accessibility, in this case additionally to this limitation the well was located extremely near a very sensitive area, holding strategic constructions and equipment, options were analysed and with the location surface limitations, the very extensive location preparations required for a rig to mobilize, it was decided to look for alternatives. The first snubbing unit was mobilized to the country and with the limited capabilities to performing heavy well interventions under pressure, minimum pumping equipment to maintain well control throughout the operation a very robust intervention design and program was created. This approach eliminated the need for a traditional rig, reducing operational time and costs and more important allowing the required and committed intervention. The successful implementation of this rig-less P&A operation demonstrates the viability of using snubbing units for remote, limited access, reduced real state and sensitive areas with complex well abandonment tasks. The approach not only ensures environmental compliance by achieving complete zonal isolation but also offers significant cost and time savings. This case study contributes valuable insights into alternative P&A methodologies and techniques, emphasizing the potential of snubbing units and new technology in modern well abandonment operations. Perforate, Wash, and Cement (PWC) is a proven technique for remediating SAP, also known as Sustained Casing Pressure (SCP), which is a common well-integrity issue in aging oil and gas wells. SAP occurs when pressure builds up in the annular space between casing strings due to compromised cement barriers, leading to potential environmental and safety concerns. In summary, PWC is a reliable and efficient method for addressing SAP issues, offering significant time and cost savings while ensuring environmental compliance and long-term well integrity and it is possible to deploy this technology with a rig or even for rig-less operations.
Hurtado et al. (Mon,) studied this question.