Rigless Re-Abandonment Operations in Wells with Integrity Issues: A Case Study from Colombia of Four Successful Jobs
Authors: Garay Cuesta R. J. , Rodriguez A. E. , Ramirez A. , Mesa N. , Perez C. , Palacios Bayona J. M. , Orozco A. 
Published: March 2024

Abandoning wells is part of the work scope of well construction and intervention and must comply with legal regulations and safety standards. Nevertheless, whenever barriers in an abandoned well fail, a more critical re-abandonment intervention is required to correct the integrity problems. This paper presents four cases where previously abandoned wells with sustained casing pressure issues are intervened with coiled tubing (CT) to correct and permanently re-seal the barriers to carry out a successful abandonment. An overview of the project, including the engineering design process, the planning led by an interdisciplinary team made up of the operator and service companies, the challenges faced during each stage, and the results for each well are presented in this paper as a case study.

Four abandoned wells starting to show integrity issues were presented to the operating company engineering team in Colombia. These issues requiring solutions included environmental concerns, safety, and legal issues.

To perform these rigless operations, 2 in CT was used to mill out the pre-existing 9-5/8 and 7 in cement plugs before cleaning out the casing. electric line (e-Line) was then used for a casing collar cocator (CCL) and cement integrity evaluation. A diagnostic run was then performed to identify internal and external casing wear, erosion, corrosion, and mechanical damage to determine the optimal bridge plug setting depth according to lithological seals. With the bridge plug set, a tubing punch was used to create a flow path between the tubing and annulus before setting cement plugs to isolate the well.

This pioneering re-abandonment operation with CT was delivered flawlessly by a multi-disciplinary team from different product service lines, including CT, cementing and well control fluids, wireline, perforating, testing, and well control specialists. No service quality or health, safety, and environment (HSE) issues occurred during the entire process of successfully isolating and abandoning the wells. For added confidence, several logs were collected and analyzed during the project to confirm the operation was carried out with the confirmation of an adequate operation.

This paper shows that large inner diameter (ID) casing abandonment operations are achievable with 2 in CT. Projects such as these can now be considered economically viable and can be used as a guide as part of a decision-making process for the management of correcting wells with integrity problems with cost savings while preventing any negative HSE issues.

The process developed during these case studies can now be considered a frame of reference for future operations that follow the regulatory requirements. This paper can be considered a guide based on actual data of re-abandonment jobs performed with CT to generate effective barriers for ensuring well integrity and environmental protection. It will assist in identifying, planning, and successfully executing re-abandonment operations to comply with required regulations in wells with integrity failures.