Well Integrity Applied to Geothermal Opportunities for Wells on the Route of Plugging and Abandonment in Colombian Oilfield Assets

As a contribution to the timely energy transition, this document presents the methodology aimed to carry out a well integrity assessment to exploit geothermal resources from inactive wells on the way for Plugging & Abandonment.

This approach requires not only a well-defined sizing of the geothermal potential but also the analysis of the integrity condition of each well with a focus on life extension. The methodological step-by-step provides a workflow to ensure lasting and efficient use of the renewable resource. It promotes the most efficient use of the marginal or inactive hydrocarbon wells for a long-term sustainable project, without losing sight of its profitability.

The protocol evaluates the geothermal resource in the generation of electrical energy which is a workflow to ensure a rigorous technical analysis ensuring the effective use of the geothermal resources and the life extension of inactive wells.

The protocol consists of 5 stages: four of them defining the technical concept and the final bringing the inactive well back to production for the geothermal test.

The analysis of the reservoir plays a very important role since it is this analysis that makes it possible to ensure the sustainability over time of a fluid resource with powerful and reliable temperature. In the same way, extend the life of the assets in their different synergy options with the subsurface resources.

A significant role in the decision to give further use of wells after completing their life cycle is to determine their mechanical barrier condition -well integrity- that would allow for a new well service. The ability for a new service condition is defined by evaluating each mechanical barrier condition, remaining life of materials, and capabilities of the well to withstand new service loads among defined operating envelopes for safe use of inactive wells into geothermal energy producer wells by reuse of infrastructure on the route of abandonment.

A combination of process safety and well integrity would provide basic elements to consider further use of wells that completed their operating life. Wells with significant well integrity anomalies or no chance of repair should be timely excluded and kept on the abandonment path. For its part, the analysis in these early stages allows establishing the baseline of well integrity and consolidating them as assets with a suitable and sufficient remaining useful life to produce hot fluids with the capacity to produce electricity.

As a result of the protocol presented as a methodology in this document, a candidate is obtained that meets all the technical requirements and that allows a profitable business case in the generation of electrical energy since equipment must be energized, while facilities will continue consuming costs in operation and maintenance.

At the global level, the need for an energy transition that allows a reduction of polluting emissions into the atmosphere has been identified. Because of this, most countries, including Colombia, have directed efforts to facilitate this transition initiative from the regulatory standpoint and including the Oil and Gas industry synergies.

The authors of this paper disclose this methodology to generate value among all industry players and lay the foundations for joint, solid, and efficient development among all professionals in Colombia and worldwide.