Inflow Performance of Cold Co2 Injection in Depleted Gas Fields

Abstract

Injection of CO2 in depleted hydrocarbon fields often leads to differences in temperature between the injected CO2 and the reservoir formation and fluids. A low pressure in the reservoir after depletion leads to decompression and cooling of the CO2. The temperature contrast can become significant, up to tens of degrees centigrade. For safe and efficient injection and storage of cold CO2, simulation of pressure and temperature in the pipelines, wells and reservoir is required. The reservoir is generally represented in a simplified way in pipeline and well models via multidimensional tables. A sensitivity analysis of CO2 injection in a realistic reservoir model shows that for cold CO2 injection below the critical pressure, such tables are too limited. The high variability in CO2 properties (density and viscosity) makes the injectivity highly variable.