Volume 34: CCUS Technologies for the Carbon Neutrality: Part II

Integrated CO2 Miscible Flooding-Storage Technologies for Complex Fault Block Reservoirs with Low Permeability Yu Sun, Yong Tang, Jiazheng Qin, Youwei He, Yong Wang

Abstract

During the production process of complex fault block reservoirs with low permeability, the systematic research on the combination of oil displacement and storage is fuzzy. This work aims at oil displacement and storage to supplement formation energy and evaluate storage potential. Firstly, the optimal development scheme is designed by layer division and miscible and ability. Secondly, based on large amounts of field data, the novel FAHP evaluation system for CO2 storage site selection is established. Thirdly, since judging adaptability evaluation is suitable, the carbon storage simulation is conducted to contain mineralization, dissolved and structural mechanisms. The results indicate that after 1.2HCPV CO2 injected cumulatively into reservoir, the cumulative oil increase reached 4001.80×104m3 and the final recovery rate was 44.46%, achieving a good effect. At the stage of injection, the CO2 capacity remaining in the reservoir was nearly 1657.53×104t and the gas storage rate reached 43.84%. The novel evaluation system for CO2 storage site selection shows that the target reservoir has more storage space, large injection capacity, high safety factor and low storage cost, which is allowed to storage. At the stage of storage, the effective storage capacity of target reservoir was 2257.48×104t, of which the structural storage capacity was 73.43% and the mineral storage capacity was the least (3.46%). The average annual CO2 storage capacity is about 225.74×104t, which is equivalent to planting 2031.69×104t trees or shutting down 135.69×104 cars for one year, achieving oil displacement/storage synergetic optimization. The findings of this study can offer engineers guidance for ensuring the long-term, stable and safe operation of CO2 storage. For complex fault block reservoirs with low permeability “green, low-carbon, efficient” development has a certain reference.

Keywords miscible flooding, oil displacement/storage synergetic optimization, fuzzy analytic hierarchical process, adaptability evaluation system, storage capacity