Guest Editorial: What CO2-EOR Has Already Taught Us About Upscaling Permanent Carbon Sequestration

Abstract

It is not often that one’s career coincides with the initiation and maturation of a technology. So it has been with my career and the use of carbon dioxide (CO2) to increase oil recovery, or CO2‑EOR (enhanced oil recovery). I started in the E&P business in the early 1970s, about the same time as CO2‑EOR became feasible (maybe economic). But in no way do I claim credit for this success; it is the result of hundreds of highly competent technologists working in labs, on computers, in the field, and planning, always planning. But I do claim a sense of perspective as the technology has matured over the years and now is about to morph to a similar one, though one with a very different objective—CO2 storage. I am drawing comparisons between carbon capture and sequestration (CCS) and CO2‑EOR that are largely based on analyzing field data, not numerical models nor laboratory‑scale experiments, though both have played important supporting roles. Many of the oilfield technologies are transferable from CO2-EOR to CCS. Technologies such as petrophysics, numerical simulation, and anything relating to injection wells should apply. This fact should make it easier for petroleum engineers to make the transition to CCS. Experience from fluid production provides valuable insight for fluid movement and displacement in the reservoir, but production is not directly transferable to conventional CCS, which does not envision the operation of extraction wells as of this writing. There have been no detectable caprock breaches and few surface leaks in CO2-EOR. This observation has resulted in the need for minimal monitoring requirements. However, monitoring for CCS will be a major part of a project. Ascertaining the amount of CO2 retained in subsurface during CO2‑EOR is difficult using data routinely available to the public. The importance of accurate measurements of rates and pressures at wellhead and surface facilities will be even more important for CCS and over a longer time.