A Low-Cost Completion Technique for Simultaneous Steam and CO2 Injection in Heavy Oil Reservoirs

Abstract

Steam injection is a known Enhanced Oil Recovery technique with application in heavy oil exploitation. The process is generating a rather high amount of carbon dioxide (CO2) that according to the current climate regulatory initiatives should be reduced. CO2 injection to enhance heavy oil production is a known technique for such reservoirs. The technology of capturing CO2 has evolved today up to a point where it can also be applied to steam generators. This work starts with a comprehensive review of most recent steam generator developments and their possibility of subsequently capturing CO2. Co-generation concepts will also be investigated and their potential to generate steam and CO2 for heavy oil enhanced recovery will be evaluated. The thermal properties of CO2 are well known, and its critical state poses challenges in many injection applications. This low-cost completion is proposing a parallel injection of steam through tubing and CO2 through annular space. While injecting CO2 in a steam-heated well, the elevated temperature keeps the carbon dioxide gas away from its critical state. The gas will cool down the upper part of the well, especially the surface casing, avoiding cement damage and well integrity breaches. This paper describes an economical completion technique that replaces the expensive thermal packer with a new budget-friendly design. This novel setup allows free tubing expansion and protects casing against high temperature through continuous gas circulation in the annulus. It also enables the simultaneously injection of combustion gases from steam generators or other gas supply. In this manner, substantial CO2 credit could be saved by operators while cutting completion expenses and environmental hazards at the same time.