Well Design Differentiators for CO₂ Sequestration in Depleted Reservoirs

Reducing carbon emissions is a global problem which has become firmly established as a common objective. Sequestration of CO₂ into underground oil and gas reservoirs on a large scale has the potential to make significant contribution to solving this problem. The process of carbon dioxide injection has been implemented in many different underground geological formations since the early 1970's as a means of enhancing oil recovery. CO₂ injection purely for emissions reduction is however relatively new. This paper aims to identify key differentiators between conventional well design techniques and CO₂ injection wells in depleted gas reservoirs. Technical focus is placed upon project management, completion well design and integrity assurance. The information is based on industry practices developed from published and unpublished CO₂ sequestration projects and other data sources including input from contracting service companies.

The key objective is to support the concept and to demonstrate that CO₂ sequestration into depleted reservoirs can be achieved effectively and safely from a well design perspective. The information provided in this paper will technically support feasibility studies, demonstrator schemes and contribute to the successful implementation of future CO₂ sequestration projects globally. In summary this paper will review the unique operating environment of a CO₂ injection well, identify critical differentiators and evaluate the impact on the well design.