The Error in Using Superposition to Estimate Pressure During Multisite Subsurface CO2 Storage. Issue 12 (18th June 2019)

• Record Type: Journal Article
• Authors: De Simone, Silvia; Jackson, Samuel J.; Krevor, Samuel
• Is Part Of: Geophysical research letters. Volume 46:Issue 12(2019)
• Page Start: 6525
• Page End: 6533
• Publication Date: 2019-06-18
• Subjects: CO2 storage -- multiple injection -- multiphase flow -- superposition; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2019GL082738
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Analytic pressure estimates for multisite CO2 injection are typically performed through the superposition of single‐site injection models. This is theoretically invalid for multiphase flow because of its nonlinearity. We quantify the error associated with the application of superposition in scenarios with sites located in a rectangular grid geometry. We show that the use of superposition results in overestimates of the pressure buildup, because it neglects the presence of multiple CO2 plumes, which increase the reservoir fluid mobility. The adoption of a dimensionless time scaled to the geometric average between the advective and diffusive characteristic times allows us to define a general model for the maximum error, which may be used to evaluate the validity of using superposition, or to correct the pressure estimates when errors are significant. This procedure can be applied to any analytical solution and advances the extension of single‐well models to scenarios of multiple injection sites. Key Points: Energy systems models should include dynamic reservoir CO2 storage capacity, which implies the need for simplified multiwell models Superposition of single‐well pressure responses returns an error that increases with well number and flow rate Derivation of a dimensionless error provides a correction to the use of superposition in evaluating the maximum overpressure