Utilization of CO_2 Emission to Enhance the Recovery of Low-perm Reservoir

摘要

The low-perm reserves take a large proportion among the proven reserves in China. The recovery factor of such a kind of reserves is quite low by deplete development due to the low nature energy and also improper for water injection. Generally, CO_2 injection is an effective method for enhancing the recovery of the low perm reservoir through compensating the energy and formation of miscible phase with crude oil. The efficiency of development could be improved in the both aspects of economy and technology. The results of "strategy study and potentiality evaluation of EOR for onshore oilfields in China" done recently show that within the total evaluated reserves of 101.36 X 10~8 tons, more than 16.05X 10~8 tons of reserves is suitable for miscible and immiscible CO_2 injection. 2.24 X 10~8 tons of recoverable reserves could be obtained based on the recovery factor of 18.7% for miscible injection and 8.6% for immiscible CO_2 injection. It demonstrates great potential for application. Although the CO_2 injection by using nature resource is hindered due to the less CO_2 resources discovered in the eastern parts of China, it demonstrates great prospect for using the CO_2 resource recovered from flue emission of power plant and petroleum refinery. By making use of the CO_2 from flue emission, both the recovery of oil fields and reduction of air pollution could be improved, and it is an active and effective method. In this paper, the feasibility of CO_2 injection in the low-perm reservoir and recovery processing of CO_2 from flue are discussed, and the problems and solutions existed in the process are also illustrated.