Technology and practice of CO2 capture and storage from Yanchang Petroleum

Through the innovative combination of CO2 capture in the coal chemical industry and oil reservoir CO2 storage, Yanchang Petroleum has realized multiple benefits such as clean utilization of coal, carbon emission reduction, and crude oil production increase, and explored a new path for low-carbon development of coal chemical industry. The whole process integration technology and field practice of carbon capture, utilization, and storage (CCUS) from Yanchang Petroleum are systematically presented. For CO2 capture, the low-temperature methanol washing and low-cost CO2 capture technology of the coal chemical industry has been formed. The CO2 capture cost is 105 yuan/t, and the capture demonstration scale is 300000 t/a. For CO2 storage, the storage site selection and potential evaluation methods are established. The evaluation results showed that the theoretical CO2 storage capacity of the oilfield is 8.84×108 t, and the suitable storage area is mainly distributed in the west of the oilfield. In addition, the evolution laws of CO2 storage state across the time scale of storage are revealed. Under the water-gas alternation scenario, the proportions of CO2 storage capacity for structure, residual, solubility and mineral trapping corresponding to 10 years and 100 years is 24.38%, 27.19%, 48.38%, and 0.05%; and 15.09%, 38.65%, 45.77% and 0.49%, respectively. Then the sealing evaluation methods of the caprocks are created. It is specified that the Chang 4+5 cap layer in the Huaziping CO2 sequestration test area mainly belongs to type Ⅰ and type Ⅱ. Finally, a “Trinity” CO2 safety monitoring system is established. The results of safety monitoring show that, there is no CO2 geological leakage in the test area and the safety level of CO2 storage is Ⅰ. The safe and effective storage capacity of CO2 is 10.12×104 t in the field application. The technology of CO2 capture in the coal chemical industry and reservoir CO2 storage has achieved good effects of carbon reduction and crude oil production increase in field practice.