Re-Use Potential Of Decommissioned Hydrocarbon Production Wells For Geothermal Energy

Abstract

In the recent past new regulations were placed on onshore oil and gas production as well as on geothermal energy. In addition the number of wells to be abandoned in the near future is increasing due to end of life of several onshore oil and gas fields. Current practice is to abandon these fields and to permanently plug the wells with cement plugs. The developing energy transition may offer new opportunities for existing oil & gas subsurface infrastructure. There is growing interest from multiple stakeholders in life extension for re-use of existing well for geothermal energy. The geothermal energy ambitions require substantial numbers of wells of which a siginificant part may come pre-existing oil and gas infrastructure. This could considerably speed up the construction of the geothermal infrastructure and save capital for the construction of new wells. We are presenting a workflow to estimate the re-use potential of hydrocarbon production wells as geothermal injectors or producers. The workflow builds on previous studies performed at TNO (the Netherlands Organisation for Applied Scientific Research) such as the ThermoGIS Project (e.g., Kramers et al. 2012), for the initial evaluation of the general geothermal potential of the study area, and the estimated schedule of well abandonment onshore the Netherlands. Subsequently, all potential geothermal aquifers at well location are identified and grouped into aquifers that were used for hydrocarbon production, and aquifers situated stratigraphically above and below the reservoir levels. Several different potential workover scenarios are described including open and closed well scenarios, as well as single well and doublet applications that can be applied to the identified aquifers. A geothermal potential calculation based on each scenario using exploration and production data, as well as a detailed analysis of the current state of the well and its casing, is needed for the assessment of the well. The assessment of the geothermal potential is performed based on the previously published specifications for geological research for geothermal projects (Mijnlieff et al. 2017). A detailed description of the assessment of the well integrity as well as the workover scenarios as well as their costs has been compiled in the presented study. The aim of the presented workflow is provide the industry with a guideline to identify and assess the re-use potential of old onshore oil and gas wells for geothermal energy and a document that outlines the necessary aspects that need to be addressed in this context.

AAPG Datapages/Search and Discovery Article #90345 © 2018 AAPG European Region, Geothermal Cross Over Technology Workshop, Part II, Utrecht, The Netherlands, April 17-18, 2018