Assessment of CO2 geological storage capacity in the oilfields of the Songliao Basin, northeastern China
Enhanced oil recovery through carbon dioxide injection (CO2-EOR) data has made it possible to estimate the CO2 geological storage in the oilfields of the Songliao Basin, northeastern China. The storage capacity of CO2 in oilfields was determined and the results show that the theoretical storage capacity of CO2 in the oilfields of the Songliao Basin is 2.36 × 109 t, and the effective storage capacity is 0.59 × 109 t with an effective coefficient of 0.25. Among the tectonic units, the central downwarp has the highest storage capacity of 2.17 × 109 t, which accounts for 91.8% of the total storage capacity. On the other hand, the western slope area has a storage capacity of 0.13 × 109 t, which accounts for only 5.6% of the total storage capacity. Thus, the central downwarp and western slope together comprise about 97.4% of the total storage capacity, and these areas could be selected as potential areas for CO2 geological storage in the oilfields of the Songliao Basin. Furthermore, the oilfields can be used as target formations to store CO2 for about 10 years as per the estimated effective storage capacity, and 40 years according to the theoretical storage capacity. Although, the uncertainty analysis of the parameters yielded the cursory estimated results of the CO2 storage capacity, the prospect selection for the CO2 sequestration in the oilfields of the Songliao Basin is feasible based on the assessment scale.