Rigless Permanent Abandonment of a Water Supply Well in a Middle Eastern Oil Field: Overcoming Integrity Failures and Cementing Challenges Through Solvent-Based Cleanout and Adaptive Fluid Management

Abstract This paper presents the successful execution of Company's first Rigless Plug and Abandon (P&A) operation at Well-X (Fig. 2), a vertical Water Supply Well used for water injection cluster within an oil field in the Middle East. The operation was initiated to address severe well integrity issues caused by corrosion-induced barrier failures and extensive scale/sludge accumulation. Due to advanced corrosion at the outer casing, installation of a rig Blowout Preventer was deemed unsafe, and HSE constraints prohibited rig deployment. The objective was to develop and implement a cost-effective, safe, and technically sound rigless solution that could serve as a model for future high-risk well abandonments. A multidisciplinary team of Production & Petroleum Engineers, Well Integrity specialists, and Drilling & Cementing Engineers collaborated to design a novel rigless approach. The wellbore was cleaned using a specialized blend of organic and inorganic solvents, validated through laboratory testing, to remove scale/sludge from 3,788 ft to 5,296 ft. The successful cleanout in total loss conditions was key to enabling the P&A operation. The operation was particularly challenging due to the absence of tubing in the wellbore, requiring the use of 2.0″ coiled tubing inside a 13-3/8″ casing and 8-1/2″ openhole section for both cleanout and cementing. To overcome casing leakage at surface, a specialized suction pump was deployed to manage fluid returns during the cementing operation. Cementing was conducted placing fourteen cement plugs using coiled tubing from 5,296 ft to surface. Each plug was tagged to confirm top-of-cement before proceeding to the next. A customized cement recipe and fluid control strategy were employed to ensure plug integrity while the upper zones remained continuously open, presenting significant challenges to cement placement and fluid containment. The rigless P&A operation was completed successfully, achieving full abandonment in compliance with Company's Corporate Code of Practice. The project resulted in direct cost savings of few million dollar by eliminating rig mobilization and reducing operational time by 21 days. Additional savings per job are projected through optimized execution in future applications. The operation demonstrated that rigless P&A is a viable alternative for wells with compromised integrity, offering enhanced safety, reduced environmental footprint, and significant economic benefits. The cementing strategy effectively isolated all perforated and openhole intervals across the targeted formations. This work introduces a replicable methodology for unconventional wellbore cleanout and optimized cementing under challenging conditions. The integration of chemical cleaning, coiled tubing cementing, adaptive loss control measures, and surface fluid management using suction pumps provides a blueprint for future rigless abandonments. The success of Well-X sets a new benchmark for innovation in well integrity management and reinforces Complany's commitment to operational excellence and sustainability.