oa Well Control for CO2 Wells, Risk for CO2 Blowout?

CO2 -storage, similar to drilling for petroleum production, represents a risk in terms of accident potential related to “blow-out” during drilling and considerable loss of acceptance in society for the storage of CO2 in the underground.

Gradually, by establishing a multitude of wells for CO2 -storage, in-fill drilling in mature CO2 storage regions will be required. Accordingly, there will be occurrences with drilling of CO2 wells in the vicinity or within existing reservoir volumes containing CO2. Thus, new wells will be established near or penetrating in the CO2 conductive layers.

To address and bridge the knowledge gap between petroleum wells and CO2 wells, Equinor, Shell, Eni, Ebn, CNOOC, Transocean, Baker Hughes, Wild Well Control, Sintef, Gassnova and eDrilling have conducted a project, where drilling fluids mixed with CO2 under relevant pressure/temperature conditions are investigated in laboratory experiments/tests.

The knowledge from the laboratory experiments is synthesized into simulation software from eDrilling for safe and efficient planning of such operations. This software includes solubility of CO2 in oil and water-based drilling fluids, as well as the impact of phase transition from liquid to gas (“boiling”) when the mixture of drilling fluid and CO2 (liquid) is circulated to the surface.